Kindergarten geometry playground

[Alpinum]

Enough thread hijacking.
Here's our own kindergarten playground.

[...]but without context[...]

You may want to re-read and find that perhaps you have taken my words out of their context:

[...]
I have a Surly Krampus and a Pipedream Moxie. Both will take a 27.5 x 3" tyre.

My Moxie will just about take Maxxis 27.5 x 3" tyres on i35 mm and the newer Version have 10 mm longer chainstays, so have a tad more space. I can highly recommend this bike. A real 3" on a 40 mm rim may not fit though.

Most will be fooled by the numbers of the Moxie, but they just don't know it better and haven't tried how it actually rides.
10 x more fun to ride on any terrain than the Krampus. Frame finish is a different class too.
Surly is just cheap made stuff sold expensive thanks to good marketing and courage.

I know a few who ride Nordest Sardinha and say good things about it. Same for Kona Unit and Honzo.
A mate rides a Stanton Sherpa, likes it too.
Another got a Tumbleweed Prospector, but isn't too happy with it, huge amount of clearance with 27.5 x 3". He might sell it.

I rode some of the above and Kona Honzo amd Stanton Sherpa where by far the best feeling bikes. Fun inducing, simple and pure fun and comfy geo for long rides. Especially with Kona you get loads of bike for the money. The Tumbly Prospector rides awful and is expensive for what you get.
[...]

The steeper STA aspect of LLS bikes for longer, more seated MTB/off-road touring riding can be tricky, or at least by the time a STA is steep enough to aid climbing it's putting me out of balance on flatter open trails that make up enough of my riding for it to be influential in comfort

Indeed. After some riding (3 years) with bikes with both, more laid back (72 something °) and a steeper (I have three bikes with ≥ 76.5 and 77 °) seat tube angle I find the steeper STA a prime example for how touring bike's geo can benefit from mountain bike's geo;
for my trip across the Puna de Atacama I rode the above mentioned fatbike. The front is long enough, the seat tube angle steep enough to put quite some load onto the wrists.
I agree with

out of balance on flatter open trails

Unless...
Unless, I use a higher riser bar. It's that easy and exactly what I did and have mentioned before too.

Rode this for most of the time during a 6 week holiday. Fully loaded, high handlebar position. I've never ridden in so much comfort. Lovely.
Rode it later lightly loaded, lower handlebar position. Still lovely.
Thanks to the short ht I can adjust bar height freely (opposed to most touring bikes) and fit any type of fork to the bike.

For the first two years on the Moxie (size Longer, 510 mm reach, 76.6 ° seat tube angle) I rode with a 32 mm stem and 20 mm riser bar at 770 mm width. Not too long ago, I changed to a 20 mm stem and a 25 mm riser bar at 800 mm (which might get cut down, but currently too comfy with it...). Besides the not so subtle changes in handling, the bike has become absolutely long distance capable. Riding it before stumpy stem had required a lot of core, shoulder and upper arm strength. With only backing reach + stem length off by 12 mm I get both, an agile feel and stable ride at high paces.
Infact, I've dropped the additional 5 mm rise back to where it was before with removing spacers from below the stem so the bar height is were it was before.
The way the bar input translates into bike behaviour is fantastic.
I remember riding a mate's Bombtrack (Beyond+ IIRC) with Jones' H bar - the first time I felt comfy holding an H bar (as his bar ends pointed downwards) and found the steering sensation quite different, special, even exciting and suddenly saw the appeal.
The pivot was about level with my hand position.

This translates lovely across other bikes, also one with a 7.6 cm(!) longer reach since a stumpy 20 mm stem, a 9 ° backsweep has a much related feeling, yet is super easy to control when things get rowdy.

Then there's the often fashioned (on mtbs) short seat tube topic.
I'd be happy with a 480 mm seat tube on a bike I don't use for steep stuff, but more the kind of offroad riding of everyday use or some irregular (except perhaps for 2019) offroad travelling. Yet, why bother with a long seat tube, when I can go short on it and get it out of the way for the steep bits and but use a long seat post instead with will also add to comfort which may have gotten lost with a steep seat tube angle (especially in the era of dropper posts with > 180 mm stroke).
31.6 mm seat tube diameter (which will allow almost all available seat posts, dropper or not) and use a 27.2 mm thin one (eg Waltly, they make some lovely ti posts which are reliable) with a plastic reducer sleeve for touring comfort.

I think what makes it all difficult is that a geo change that may be great needs a long time to get used to and adjust around so there's a lot of riding time on a bike that feels wrong at first - and may stay that way, may not.

I feel many don't get this. Feels odd – is rubbish.
I'm at a point where I feel like this about my Krampus (2017, same geo as today's)
Thankfully things can be tweaked and when I ride only this bike for a week or two, it begins to feel mostly okay again.
The power of habit.

I've seen a few to just roll across the car park and come back to describe how the suspension behaves.
The bike I can ride fastest doesn't feel good in a car park, it feels harsh. Once on single tracks at a certain pace it comes to life, builds grip, holds lines.

my Troll is OK and the Longitude not bad at all but the Pug is best. If I could find an ECR frame I recon I would build one up with the Rohloff from my Troll.

Interesting, lets pick the conservative numbers of a Pugsley and compare old vs. new.
So I had a look at the numbers of the old Pugsley and the newest version.

2011, 20" 2018, 18.8"
Seat tube [mm] 508 478
Top tube actual [mm] 582 591
Top tube effective [mm] 610 620
Head tube angle [°] 70.5 69.5
Seat tube angle [°] 72 72
Bottom bracket drop [mm] 55 65
Chainstay [mm] 448 460
Wheelbase 1097 1127
Head tube [mm] 130 145

- 3 cm for the seat tube.
+ 1 cm for the top tube
- 1 ° for the head angle
no change in seat angle
- 1 cm for the bb
longer chainstay, but that's to accommodate larger tyres.
+ 3 cm for the wheelbase
+ 1.5 cm for the head tube

That's a conservative change over something like 7 years or so. Yet we see the frame got longer and a little slacker.

Then, for more extreme changes, look what Salsa has done to their trail bikes (which seem to be loved by bikepackers unisono).
This also applies to oh so many other brands. Be ready to embrace the changes and ride bikes which will become longer, lower and slacker.
I'm warning you, you might even like it



From another thread:

Perhaps the trail geo of the other two aren't a barrier to traipsing into the wilderness?

I understand this as a rhetorical question and like the statement behind it.

[jameso]

: )

Will read and digest. RE context, it was really the comments like 'nervous' related to the Tumbleweed and how that can be read literally. But I don't want to dwell on that aspect of it, people have to read anything said for brevity with a filter.

Steeper STA offset with a higher bar - I think you'd like how Geoff Apps' bikes ride. Feels quite steep STA, very high front so no wrist weight/stress. Super-agile. Undoes/against all the good of a LLS as it's quite extreme but has some really nice traits at low speeds.

This also applies to oh so many other brands. Be ready to embrace the changes and ride bikes which will become longer, lower and slacker.
I'm warning you, you might even like it

I already do, but I wouldn't want to see it as the only answer. I'm not coming at this as anti-LLS, fighting for the old-school - I don't care what numbers a bike uses a long as it feels great. Thinking a set of numbers is 'it' is a trap.

I've spent time on LLS 29er HTs. They're great. The last round of Ramins were LLS and the sample bike that came before it went a step further than that. I don't ride LLS FS or on Alpine stuff that justifies it well these days though. I've got 4 long, new-geo gravel-ish frames here that I've been playing around with since 2013. Varying ways to increase FC and get down to 35-50mm stems. Some were slacker or had lots of fork offset, some with a longer chainstay to re-balance there. 2 have slack STAs, were ridden with posts reversed. A couple work with up to 76 deg or so STA. The TNR was based on a ride I did to try one out on more Alpine roads and tracks and day 1 of the 2nd TNR I lost skin and a jacket pushing an experiment geo round hairpins too far. I'm looking for change and I've come back from some of it having discounted it for what I want the bike to do.

[jameso]

Interesting what you say about the Bombtrack and the H-Bar. Your Moxie has a sus fork, right? Would you use an H-Bar on that? FWIW I love the Jones geometry with an H-bar but the same bar felt like a disadvantage on a hardtail for me, and I expect the H-bar on a more LLS bike (rigid or not) wouldn't be as good as a wider riser. But I'm not sure where that point is headed. Something about bikes as a system that is too detailed to do on a forum in writing I think.

31.6 mm seat tube diameter (which will allow almost all available seat posts, dropper or not) and use a 27.2 mm thin one (eg Waltly, they make some lovely ti posts which are reliable) with a plastic reducer sleeve for touring comfort.

Agree, was std spec on the Pinnacle Ramins and an old Genesis Ti 26" HT.

[fatbikephil]

You ever ridden a Jones Alpinium?
In some ways it flys in the face of modern geo thinking but appears to work very well, albeit with a some foibles.

[Hamish]

Interesting discussion.

Some thoughts...

I guess part of the story is that there is more than one way to be comfortable on a bike, and geometry is not the only thing that makes you comfy.

The touring orthodoxy is that you need a slack seat angle to stick your backside out behind you as a counterweight to your arms and hands with your feet as the fulcrum. I kind of get that and slack seat angles do work for me on my Pugsley.

The other theory I have heard is that as your handlebars get higher, your other contact points rotate backwards in response, with your saddle moving backwards relative to your feet.

If I have understood, Alpinum's suggestion is that with a steep seat angle you can still raise the bars and bring them closer and stay comfy. I guess that puts you in a more upright position with your body more inline? It makes sense when I think about it. I am also thinking that it may mean you sit more lightly on the seat and transfer weight and effort onto your feet.

Anyway. Probably better not to over think and theorise but to go and try it...

[jameso]

^ It does work, it's what the Apps bike does positioning-wise but the rest of his bike is the opposite of LLS. Designed for agility at low speed, trials-XC.
The shorter saddle to bar shouldn't be a problem for most riders, the Jones is really short by current standards but Jeff Jones' take on it is that you stand up to climb when that short reach becomes a problem, the rest of the time the shortness is a positive. It works for me though there are times when it does get cramped for seated climbing but I don't really want to be out of the saddle. Part of why I like it as a SS so much, don't have much choice..

My gravel bike at the moment has a steep STA and the bars are closer than I'd normally ride a drop bar but after a long time of not being able to make the shorter fit work for long periods on the drops, it does. The steeper STA was what worked with the bar position. But I'd not really thought about it in the way it's explained above (body more inline), I thought it was about my body-hip-leg angle or maybe a simple c of g thing. It puts more weight on my hands but is still 'normal', it was coming from a position that had almost no weight there in the pedalling position (fitting ideas that came from hand damage I got in a few years back).

Thinking of bikes as 2 linked diagrams helps for me - 1 diagram is the side view of the 3 contact points as a triangle, the other is where the wheels are in relation to that triangle. eg

The other theory I have heard is that as your handlebars get higher, your other contact points rotate backwards in response, with your saddle moving backwards relative to your feet.

in that case the whole rider contact triangle is rotating back around the BB so your c of g will act through your feet more than the hands. I spoke to a good bike fitter once and his take was that once your saddle put you in a balanced position (which depends on your body shape, how hard you push on the pedals, etc) then your bars can be in a wide range of positions. It's true, but if you think about being in balance on the flat vs on a climb it gets more difficult to figure out.
Always thought it was interesting how many of my bikes felt a bit comfier on a shallow 3-4% climb by my house - because my weight is shifting back a bit.

Maybe there was some merit in this idea after all


Would love one of these for experimenting with. I have a bike fitter's adjustable stem which is quite useful, with the seatpost too I could really confuse myself : )

[stevenshand]

Thinking of bikes as 2 linked diagrams helps for me - 1 diagram is the side view of the 3 contact points as a triangle, the other is where the wheels are in relation to that triangle. eg

^^^ this times 1 billion ^^^

Fit and riding geometry are 2 things that constantly get mixed up all the time. I understand the chat around seatangle but without knowing where your saddle is on the rails, if you have an inline post or layback or how high your saddle is, seatangle doesn't really tell you much. What is useful is knowing what your setback is (how far behind the BB is the tip of your saddle). Get that right and you're half way there.

I often use the illustrations below to show an extreme example of mixing up fit and geometry. The fit points on both of the bikes are almost identical, saddle height, reach to bars, bar drop and saddle setback. Wheelbase is the same, front centre is the same and trail is the same. Where you sit in relation to the wheels is the same and your cog is (almost) the same. The only thing that might make one bike ride differently over the other is the stem length (15mm diff).

Bike 1

• HA:70.5

• SA:71

• Stack:595

• Reach:363

Bike 2

• HA:69.5

• SA:74

• Stack:572

• Reach:355

You can see that the 'geometry' is very different (especially seatangle) but the fit is almost identical. I don't think I'd be able to tell the difference between either bikes if I was to ride them in a blind test.

There is another category of dimensions that do effect ride characteristics but don't effect fit, BB drop, CS length etc. But that's another conversation.

[Hamish]

Thinking of bikes as 2 linked diagrams helps for me - 1 diagram is the side view of the 3 contact points as a triangle, the other is where the wheels are in relation to that triangle. eg

^^^ this times 1 billion ^^^

Fit and riding geometry are 2 things that constantly get mixed up all the time. I understand the chat around seatangle but without knowing where your saddle is on the rails, if you have an inline post or layback or how high your saddle is, seatangle doesn't really tell you much. What is useful is knowing what your setback is (how far behind the BB is the tip of your saddle). Get that right and you're half way there.

I often use the illustrations below to show an extreme example of mixing up fit and geometry. The fit points on both of the bikes are almost identical, saddle height, reach to bars, bar drop and saddle setback. Wheelbase is the same, front centre is the same and trail is the same. Where you sit in relation to the wheels is the same and your cog is (almost) the same. The only thing that might make one bike ride differently over the other is the stem length (15mm diff).

Bike 1

• HA:70.5

• SA:71

• Stack:595

• Reach:363

Bike 2

• HA:69.5

• SA:74

• Stack:572

• Reach:355

You can see that the 'geometry' is very different (especially seatangle) but the fit is almost identical. I don't think I'd be able to tell the difference between either bikes if I was to ride them in a blind test.

There is another category of dimensions that do effect ride characteristics but don't effect fit, BB drop, CS length etc. But that's another conversation.

I get that 100% and the frame geometry is just the starting point. You then overlay the fit- but the limits of the fit are constrained to some extent by geometry. For example, if you can't get as much setback as you (think you) need. I ride a Pug with 72 degree SA and a layback post. If I went to 74 or steeper frame I would struggle to get the same amount of setback - but I agree that I may not actually need it.

Similarly with reach. Get a long and low frame with a steep SA and then use a layback post and the bike gets longer. It is then hard to shorten it as it's designed to use a short stem already. I guess a slack head angle helps if you can use a longer steerer to bring it back a bit.

I take the point about trying it all out and giving time to settle into a new position. Indeed I am open minded about it all. I was just attracted to the discussion because I recon my very old school geo Pug is stupidly comfortable the way it is set up... And most new designs seem to be so different.

[jameso]

but I agree that I may not actually need it.

On that note, Steven's points abut where your saddle actually is, and on the prompt/nudge this thread and the preceding chat has given me, I had a good day today on my gravel experiment bike. Long ride thinking a fair bit about seat angles.. the inside of my head can be a dull place to be on winter road rides..
I'd realised the STA was too slack some time ago, that sitting back a bit more solved one problem and created others. It's now got an inline post with the saddle well fwd, about as far as it'll go. I've not ridden the bike more than twice in the last 6 months, been on the Jones and my audax bike or my Equilibrium, both conventional road saddle positions with layback posts. A comfy set up apart from my lower back tension after 5-6hrs or a lot of climbing, that I think comes from tight hamstrings (an older road bike ended up on an inline post which solved the back discomfort). It's been bugging me the last few months as I've been doing more long rides but not stretching enough.

Anyway, today I was out for 7hrs on the experiment bike and I made an effort to sit further fwd on the saddle most of the time. Yes it pitched me forward and put a bit more weigh on my hands. No, it wasn't uncomfortable and yes I can support my weight OK on this bike - it has much less bar drop than my other drop bar bikes (front of the saddle isn't a good place to sit for too long though!). The interesting bit - that my back tension didn't appear, at all. The more open hip angle seems to help, as it did on that old road bike. Maybe because I don't get the back tension I'm not having any problem supporting myself with that steeper STA. If I was off-road on fast bumpy stuff that weight on my hands might seem like a problem but then I'd also not be as glued to the saddle either.

It's not that steep an effective STA (saddle position), equivalent to about 76 degrees if used with a layback or 74.5-75 with an inline. That's unusual but not unique for a gravel/all-road bike, I think. And I can ride it all day, day after day.
I also realised why I like the flat Fabric saddle on this bike - so I can sit right on the back on road sections if I want to. I can move fore-aft 50mm or more easily, that's 4 or 5 degrees of STA.
Not sure where I'm going with this apart from yes, I've let my own biases (or assumptions that didn't apply here) hinder me in how I'm trying to solve this bike geo puzzle and yes, Alpinum's point about steeper angles not undermining comfort is right. In setting my bike up on feel and trying to avoid measuring it too often I hadn't realised quite how far from the original fitting intent I'd gone, but it's better for it.

The other thing I was thinking about was Keith Bontrager's KOPS - Debunking The Myth essay where he uses the example of a skier's crouch to show how as you reach forward (eg for the drops) you have to stick your backside out to stay balanced on your feet. And that works in reverse.
And, how a 4-5 degree change in effective STA that comes from sitting in different parts of a flat saddle matches how 4-5 degrees of road gradient affects how your balance feels on the bike but not uncomfortably so, it's only at 8-10 degrees or more you start to make more obvious shifts to correct your balance.

(I did say it's a dull place to be!)

[Alpinum]

I think you'd like how Geoff Apps' bikes ride

I already have a penny farthing for upright riding.

Your Moxie has a sus fork, right?

Yes, 150 mm DVO Diamond.

Would you use an H-Bar on that?

No.
Perhaps if I intended to use the Moxie for road and easy offroad riding, which is very far from what I currently do with it.

Two main reasons, leverage/power/control and an old injury.

Two different types of riding.
One, for which I can well imagine a current H bar, is:

(google found it, not mine)

And


That kind of stuff.


The other situation more like:

(google found it, not mine)

And


Etc.

I ride the Moxie in ways where loss of visibility is a real issue due to the speed it can carry on rough stuff. The geo allows to go really fast, but still it's a hardtail, the 27.5 x 2.8 Magic Mary with insert can only do so much... The bone shaking rear hits travel through the whole bike, especially my ankles get a hammering, but also my hands are more tired and it's ssp. I feel I need all possible leverage and control I can get and don't feel I'd get what I ask for with much more back sweep or less than about 760 mm width. I never tried an H bar in the rough though. I also have a bit of a wrist issue that makes it difficult in rough terrain when the back sweep is large.
With large angles in back sweep with a fairly fixed hand position all seemed good.

Before going back to Iceland last year, my girlfriend asked if I was planning on riding the Moxie. Seems wrong to ask, but in fact she wasn't so wrong at all and the choice was made more 'cause of the bosses rather than geo/fit.
In the end we both rode our Krampusses and it was a good choice, but the Moxie would've been a good choice too, with just a higher bar, I'm sure. But then, I know from own experience, that the Krampus (also with a well tuned 130 mm fork) is nowhere near as capable as the Moxie in the high mountains.

[Alpinum]

I think there are two equal ways to gain lovely handling for touring. Both share a long wheelbase, both are short at one area, either before or behind the bb/saddle.
Does one shine more on a steep mountainside?
I think so.

I'll provide a closer look into this later.


Whilst I was out visiting the mountains on foot for 3 days …


…

I thought about how I could explain exactly why (in my books) a long front centre/short rear is much more preferable than … well, the other options, but after a few mountain days, I need to work and eat.

Soon.

[Alpinum]

If I have understood, Alpinum's suggestion is that with a steep seat angle you can still raise the bars and bring them closer and stay comfy. I guess that puts you in a more upright position with your body more inline? It makes sense when I think about it. I am also thinking that it may mean you sit more lightly on the seat and transfer weight and effort onto your feet.

Anyway. Probably better not to over think and theorise but to go and try it...

nailed it

[Alpinum]

Coming back to see where this thread has gone, I'm really happy to find one of the main thoughts 'pivoting' in my head:

Thinking of bikes as 2 linked diagrams helps for me - 1 diagram is the side view of the 3 contact points as a triangle, the other is where the wheels are in relation to that triangle. eg

^^^ this times 1 billion ^^^

Also, I imagined how I could explain myself better and think the Jones (LWB) is a prime example for a comparison. So thanks for coming up with that James and Phil.

The LWB is also a bike that helps me understand, why I have certain preferences, which started to become tangible in 2010 with my 2011 size L Mondraker Summum (slackest hta I ever rode at 62.2 ° and a wheelbase > 1220 mm).

It always took a moment to get back into it, since my other bikes back then were more regular (eg 66.3 ° hta, 1180 mm wheelbase), but gosh, once I hit the switch it was pure precision, poise and beauty.
I can't say this for the bunch of DH bikes I had ridden before (or after).

I'd love to ride a LWB, not just because it's fun and interesting to feed one's own database and experiences, but also simply to prove/disprove my thoughts about geometry.

Over the last few years, especially when ordering my own custom made frame, I came back to this page and read it at least half a dozen times (as many other geo chat from var. manufacturers) and did so again today:
https://jonesbikes.com/jones-steel-plus ... slsfv6o4i0

Have you read it? Don't you think there's a lot of thoughts Jones shares with mine, coming from the long, low slack fad (I'll go with you James, LLS is so much easier)? (Rhetoric question)

Long(ish) wheelbase, centred body position, slack(ish) hta, lots of fork offset, low bb – if I was to believe in those numbers, I'd much agree with Jones.

I'll take it apart and we will find a few interesting vertices:
"I realized that I do not need or want a bike that has the absolute shortest wheel base possible for every ride, and I knew that you don’t need to have a steep head or seat angle to have a responsive bike that is fast, efficient and comfortable."

"Länge läuft" (length runs). I know this from kayaking and sailing, from snowboarding and skiing and feel the very same on bikes. Testing a bunch of long travel 29ers in 2017 I found I was faster and more at ease in tight, techy stuff with a wheelbase round about 1220 mm, and felt just as comfy speeding on rough straights if compared to longer bikes.
Since then, I must have adapted my riding, since 1250 mm or more feel just as good.

His further words
"This is really even more of a ‘rigid specific geometry’ for a ride that is much more comfortable and stable yet still with very quick handling. It is balanced in a way you wouldn’t expect."
May be also adopted for full susser of any travel. The balance is where I see the crux. Short front and long rear or long front and short rear. Yet, between the spread out wheels one must stand/(sit) – so it seems.

Further he states
"It’s big but feels right. You ride very much in this bike. There’s no roughness, no “I’m gonna crash” sensation or fears. It’s just smooth! And it climbs. If you stand there’s no wheelie."
Exactly how I feel about long reach/front ends and short rear.

More
"I’m talking about the big space for the rider to move around (in the bike) and still have their position, the grip and the power transfer working for them)."
Again, exactly how I feel about long reaches. I get room to shift my weight without unsettling the bike.
This, a bike like the Prospector struggles to achieve. It's an in between thing.
It's neither nor. It felt cramped and nervous. Cramped doesn't only mean your position when sitting, like knees to close to the bars, sitting position like a croissant, but also freedom to move about when climbing/descending out of the saddle. When I rode it, I was with my fatbike (66 ° hta, 51 mm offset, 77 ° sta, 491 mm reach, 1242 mm wheelbase). A hard comparison I could think, but this just approves of how I want a bike to feel and how to achieve it.

Jones goes very low with his bb, likely to give great cornering feel and easy balance in the steep. I could find any figures but it looks like a 75 mm drop or more, surely a huge bb drop. The low bb becomes a real issue in mountainous terrain, especially traversing steep mountain sides.

[url=https://fotos.mtb-news.de/p/2424804][/url?mc_phishing_protection_id=77755-bv2v7n29lhslsfv6o4i0]
Kill zone

My Moxie's (easiest to take into comparison, since my other trailbikes are full sussers) bb drop is a little more than 64 mm (geo stated by Pipedream, unsaggeed, but since I run it mullet and with an angle set, it must be a bit lower) and the rock guard and pedals get a beating. It's borderline low for alpine mountain paths. Due to not adjusting my riding enough I've been hitting the pedals and rock guard and not only damaged material but also my body, some bad bruises have left so much scarred muscle tissue (thigh and shoulder), it's still visible after 2 years.

Of course you can cut that corner (as so many) by argumenting for the use of shorter crank arms, flatter pedals, yet, the bb stays low and the stuff I often ride does regularly cause the rock guards (or chainring on the bike I don't have a rock guard) to hit the deck. I can't always hop the wheels in a way to protect the bb area. Perhaps Danny Madskills could.

On the other side; with a longer front, the bb position can be higher whilst controlling stability by your only contact points when riding out of the saddle. Pedal, bar, body centre. The magic triangle? I think it is indeed very important (James used it for a seated position, but it too works when stood.

^^^ this times 1 billion ^^^

and I'm not alone.

Flat sta and a short front gives some room between saddle and bar (when seated), but the bottom bracket is still forward, closer to the front wheel axle. Our bodies pivot around the bb when climbing or descending. With Jones' geo you gain some leg room when seated, thanks to a slack sta, but that's gone once you're standing.

I might be alone with this, but after a youth with loads of crashes (clearly only because bikes where too short) I have sensitive knees and am absolutely uncomfy when pedaling "from behind". I used to slam the saddle all the way forward, which now with steeper sta, thankfully is a thing from the past and I can have the saddle in the middle of the rails where – I'm sure – it does its job best. My current everyday/offroad touring bike has a 73 ° sta. Okay, but more comfy for me with the saddle slammed forwards. Doesn't help it's ssp. So I have the saddle slammed all the way forward, but then there's not loads of reach to have some space and a longer stem would impact the steering in a way I don't like… the solution for me is easy; steep sta, long reach, short stem and depending on what I want to ride, high(ish) or low(ish) bar position.

Let's reconstruct, or long story short(er):

Jones' LWB seems to centre you nicely between the wheels. He seems go give his bikes a playful touch by going with a short front center, whilst adding the benefits of a long(ish) wheelbase.
LLS does the same, thankfully many manufacturers give the bikes a playful touch by going with a short rear.

Same achievement, different approach.

In my experience the long front works for both, touring and hammering down steep mountainsides.
A short front will have you leaning more backwards once things get really steep, making it harder to keep balance, leverage and thus control.
With a long front you can comfortably stay well centred and have more leverage to find the right balance, since the space between bottom bracket and bar is static - our only points of contact when riding stood up.

I ask myself if it's so much of a difference if I go short front/long rear or long front/short rear?

In offroad touring I struggle to see how it could be much off a difference.

Unless you like to stand when climbing and descending, but given that most off road tourers mostly ride on stuff used by some sort of motorized 4 or more wheeled vehicules, you're not going to come down any grades you easily find on mountain paths (of the mountain hiking quality).

One may suggest that a steeper sta is better since it opens your hips a bit more but it seems it needs to come with a long reach. A long reach doesn't work with a slack sta. Vice versa? I guess so.

In mountainbiking environment things are different as (standing) body position on a long reach places you more behind the front wheel than a short reach, less otb feeling, more range with arms, more control, balance etc. (I know, I'm repeating myself).

Something about bikes as a system that is too detailed to do on a forum in writing I think.

My posts kind of prove your statement.

[fatbikephil]

The LWB Jones BB drop varies from 88 to 76 I think (I read that somewhere....) Its definitely an issue over big rocky stuff although you do get used to it (or you get used to maching the bottom of your cranks into a rock). Switching the BB to the high position seems to make a disproportionate difference to the ground clearance. Jeff also recommends short cranks - 170 or 165. I switched to 170's as I was getting the beginnings of knee issues and even that made a difference to ground clearance.

The stuff about being balanced in the middle is hard to describe but you very much are. There are times when both front and rear wheels are getting quite lively over the rough stuff but you seem almost disconnected from it in the middle and in control (ish). The steering is very neutral (although one of the foibles of the big offset is a tendency for the front wheel to catch the edge of a rut and rip the bars out of your hands - I think this is a mix of the grip of a plus tyre and the the leverage back to your hands from the 76mm offset) and seems able to maneouver the plot through nadgery stuff whilst still being fine at high speed. The grip is also phenomenal. Plus tyres again but the amount you can lean it over in dodgy grip conditions is well beyond my bottle.

I too have often wondered what a bike with the jones geo and riding layout with 6" of bounce would be like....

[jameso]

Got some reading to digest there, and some thoughts on this weight back / weight fwd thing that I need to try to get down, but on the Jones,

'Centred' is very much it. It doesn't ask you to weight either end much unless on a steep climb, you're just in the right place to ride or react or can move as needed without being caught too far off-centre if that makes sense. So easy to get weight back that the short FC of the old Jones layout doesn't feel risky. It's got a stiff fork and a low BB so it's really hard to endo - I'd go as far as saying there's nothing else I've ridden that is as capable on steep, rocky ground - at low speed that is. Would be interesting to simply lengthen the front 50-100mm and see what it was like.

The LWB is a very agile bike for it's size, a lot of fun, easy to hop/unweight once you get used to a bit more input. The old Jones is like a bat through the woods or a 4X bike in comparison, gets out of shape more easily as you'd expect on anything fast and rough but rides out of situations where I've already spotted my probably crash landing or gone past thinking I could recover it. The front end stiffness and weight-back combo, maybe.
What I like about the older Jones layout for touring/BP that includes MTB terrain is that it's always involving and responsive, makes easy or road sections feel natural. I've never known a rigid bike cover XC distance as well as playful feel or technical line ability like it (though I'm sure there are others). I've been into MTBs for a lot longer than drop bar bikes but I am swayed by a bike that covers road and off-road well, accepting that a loaded off-road ride / tour means I'm not pushing it technically in the same way as I might on a Welsh/Alpine day ride. Having said that.. think back to what I have ridden it down on BP trips and it's probably not much different, my ability or willing to risk is the limit rather than the bike.

I wonder if it's possible to have more range at each end of the spectrum in the one bike - not many bikes seem to cover a range as wide as the Jones to begin with but that may be more about designed specialism being easier to sell. I had a long wheelbase, 'Jones-y' drop bar frameset made to try to cover a more road-tour to almost Jones-y XC ability, it was great in places off-road compared to an Arkose or similar but terrible on a hairpinned road descent. A longer wheelbase can still be agile off-road where tyres can slide but that's not how road corners work. Though a dropper and more MTB cornering attitude would have got it round tighter, that's a fail as you may as well be on something more MTB-like.

This is getting really multi-facetted and I'm not sure if I'm following a thread ... But back to FC-RC balance and weighting, the cornering balance on road and off-road does come into all this, maybe that's where I'm looking generally. Weight distribution. It doesn't solve the sliding or sticking tyre thing or the drop bar influences though. It's a different mix of priority than your bikes Alpinum, I think? Or, yes I want the technical ability too but I'm prepared to draw a line at suspension for this line of ideas/development and want to know what rigid bikes can do (hence being drawn to the Jones originally).

(Thinking back to the Genesis Fortitude, 2011, that had a longer front, not by current standards but was about 700mm FC in the L size for a rigid-specific bike. Originally on a 425mm CS, plus a longer trail front end from a 69.5 HTA -that was slack-ish for a rigid 29er then- and a short fork offset. Handled well with a middling STA and inline post. Not as agile or wide-ranging as the Jones though, I realised - I got the Jones about a year or so later. I'd like to go back to that bike now out of interest.)

[Alpinum]

The LWB Jones BB drop varies from 88 to 76 I think (I read that somewhere....) Its definitely an issue over big rocky stuff although you do get used to it (or you get used to maching the bottom of your cranks into a rock). Switching the BB to the high position seems to make a disproportionate difference to the ground clearance. Jeff also recommends short cranks - 170 or 165. I switched to 170's as I was getting the beginnings of knee issues and even that made a difference to ground clearance.

The stuff about being balanced in the middle is hard to describe but you very much are. There are times when both front and rear wheels are getting quite lively over the rough stuff but you seem almost disconnected from it in the middle and in control (ish). The steering is very neutral (although one of the foibles of the big offset is a tendency for the front wheel to catch the edge of a rut and rip the bars out of your hands - I think this is a mix of the grip of a plus tyre and the the leverage back to your hands from the 76mm offset) and seems able to maneouver the plot through nadgery stuff whilst still being fine at high speed. The grip is also phenomenal. Plus tyres again but the amount you can lean it over in dodgy grip conditions is well beyond my bottle.

Much appreciated

76 - 88 mm
Wow... I can imagine this to make up a large part of its character. I can only imagine how much fun it must be, once you get the hang of the low bb. It must carve turns incredibly and surely adds a poor show loads of stability.

In theory it doesn't astonish me how much related your descriptions even in detail (as the effect of ripping on the bar) are to riding LLS. Still, reading how this translates into practise amazes me.

Makes me think that perhaps less offset, like 44 rather than 51 mm when round about 64 ° or less hta, would lead to a general improvement in my case(s).

I too have often wondered what a bike with the jones geo and riding layout with 6" of bounce would be like....

Would be interesting.
Surely wouldn't have the great aesthetics of the LWB and 'its' fork.

[Alpinum]

So easy to get weight back that the short FC of the old Jones layout doesn't feel risky.

That's one of the larger differences I see. On LLS you don't put your weight back. There's no need in it.
I can ride in a perfectly centred position down a flight of stairs. Slow, fast. I can stop and get off the bike as if it was in its natural habitat.
Yeah... stairs. I know. But this is exactly where I first realised how I can feel the balance and position with a constant baseline on bikes.

It's a different mix of priority than your bikes Alpinum, I think? Or, yes I want the technical ability too but I'm prepared to draw a line at suspension for this line of ideas/development and want to know what rigid bikes can do (hence being drawn to the Jones originally).

Yeah, you can leave the paved road away for me, but otherwise... no I don't think so. Maybe a little yes, but my next custom bike would probably be a replacement for the Krampus and 'till then a few things may change, but if I was to do it now, the geo would be very similar to that of my fatbike. Which is a rigid bike too...
Of course full susser and hardtails have a dynamic geo with which we can play, preload and unweight, but the geo that works there, also works for me in other areas.

Designing my fatbike I was tempted to drop the bb more, but then I do ride stuff where I want to be able to pedal through without pedal kicks to clear stuff.
And snow.


This was telling. I saw a fascinating rock formation in a geologically interesting area in the Puna de Atacama. After visiting 'el Fraile' - the rock formation - I needed to regain a double track along a salar. I took a risky short cut. First smooth, then rough and rogher. The bike still loaded with food and fuel for about 2.5 week and mountaineering gear, I rode over lumps and hole the size of body parts with little effort. Until the holes and lumps would swallow my wheel...
You can't reall see from the photo, but I was later able to follow dunes, like islands, to get me across easier. All terrain which would challenge any geometry.
A long wheelbase and centred position surely is key.
Here a very low bb would've seen me off the bike pushing earlier.
A short bike like a 'Range-Rider'... well, I don't share many view points with G. Abbs, since I still occasionally get to ride old trail bikes (first gen Nukeproof Mega, first or second gen Trel Remedy) in 26". They're short, cramped, nervous (to me) and my friends riding them get along better with newer LLS, despite 'lack' of muscle memory and feeling to be in an unused position.

[jameso]

Amazing pics, the sky, is that altitude giving it the colour?

That's one of the larger differences I see. On LLS you don't put your weight back. There's no need in it.

Yes - the LLS bikes I've ridden (but not spent as much time on as the Jones) and the Jones LWB have the centred feeling all the time. Can make it a bit less hop/pop feeling (-at least the LWB with the long rear end is - a shorter rear offsets that though then we're into the fore-aft balancing) and doesn't corner on road in the way a shorted bike can but I'm kidding myself if I think that 2-4" of wheelbase makes the difference in how tight I can corner off-road.

On the lumpy terrain and long vs short wheelbases - you can get away with a lower BB with a shorter wheelbase, less of that grounded-lorry-on-a-bridge situation? But that's a weak pro vs stronger cons overall. Htrider's point about the Jones low BB - it annoyed me at first but I adjusted to it and now only see the advantages, though if I rode really rocky places all the time I might go to 165s.

It's worth getting a ride on a Jones LWB if you can. It has a lot of what's being discussed here going on, with some key differences also and with a standard STA. Not sure exactly what it is, around 72 degrees I think for a 6' rider. They're odd bikes in some ways, I needed to spend some time adjusting to both LWB and SWB but they're worth it. They make me wonder if there's other ways to manage unusually wide ranges of handling - and what you're saying about the 'LLS' off-road tourer and your fat bike makes sense. If I could just get a similar balance working on this drop bar bike.

The Range Rider, that's it. I can't see it working well for really long distances, certainly not a design for higher speeds. Seems like a very well evolved no-trail bushwhacker for a certain riding style / taste. Not 'range' as in use range anyway.

[Alpinum]

Thinking of bikes as 2 linked diagrams helps for me - 1 diagram is the side view of the 3 contact points as a triangle, the other is where the wheels are in relation to that triangle. eg

^^^ this times 1 billion ^^^

Fit and riding geometry are 2 things that constantly get mixed up all the time. I understand the chat around seatangle but without knowing where your saddle is on the rails, if you have an inline post or layback or how high your saddle is, seatangle doesn't really tell you much. What is useful is knowing what your setback is (how far behind the BB is the tip of your saddle). Get that right and you're half way there.

I often use the illustrations below to show an extreme example of mixing up fit and geometry. The fit points on both of the bikes are almost identical, saddle height, reach to bars, bar drop and saddle setback. Wheelbase is the same, front centre is the same and trail is the same. Where you sit in relation to the wheels is the same and your cog is (almost) the same. The only thing that might make one bike ride differently over the other is the stem length (15mm diff).

Bike 1

• HA:70.5

• SA:71

• Stack:595

• Reach:363

Bike 2

• HA:69.5

• SA:74

• Stack:572

• Reach:355

You can see that the 'geometry' is very different (especially seatangle) but the fit is almost identical. I don't think I'd be able to tell the difference between either bikes if I was to ride them in a blind test.

There is another category of dimensions that do effect ride characteristics but don't effect fit, BB drop, CS length etc. But that's another conversation.

This is a great example of what I mean by going with a LLS geometry and then setting the very frame up to get not only a capable touring bike, but also a capable mountain bike. Fun and efficient in both.
Touring bike
- higher rise bar, perhaps more sweep.
- possibly swap spacers under stem.
- swap stem if need be (likely not).
- change position of brake levers, triggers.
- thin, comfy titanium seat post with a reducer sleeve.
Mountain bike
- less rise, less sweep.
- dropper seat post.
- different position of brake levers, trigger.

Obviously one would swap tyres, rotors, perhaps a different chainring size etc.

Many bikes out there can do both.

But how many are near "perfect" for both (highly varied) touring and mountainbiking?

No matter how "off" the Prospector felt to me, the idea to make a bike for varied offroad touring (whilst not new) was taken very far. It seems a bit too far, wanting to have all those options brought restrictions.
There is a frame inside which one has to move, like a certain limit of tyre width.

[Alpinum]

I was wrong, I completely forgot about a few things, like Rocky Mountain Suzi Q, Voytek Otso, mates Waltworks and a few other custom creations.

I thought the creators of the Tumbleweed Prospector went with such long chainstays to accommodate various wheel sizes and tyre widths whilst sticking with a 73 mm wide bb and 135 mm wide rear hub (apparently Rohloff only when going up to 26 x 4.0").
I must have believed in the reviews and marketing talk and forgot about what I actually do know.

A bike with the option to run 26 x 4.0" can come with short(ish) chainstays < 440 mm given the same specs as the Prospector.

With the same setup as mentioned above, 26 x 4.0" or 27.5 x 3.8", 73 mm bb, 135 mm hub, Rohloff, you can indeed go with 435 mm chainstays as shown here:
https://www.mtb-news.de/news/bike-der-w ... eedskater/
The numbers:

Zur Geometrie
seat tube 460 mm
top tube 610 mm
head tube 110 mm
chain stay 435 mm
seat tube angle 73°
head tube angle 65°

from here:
https://www.mtb-news.de/forum/t/projekt ... 638/page-3

A friend who lives in Colorado and knows Walt (?) the frame builder, has put my attention on to short cs, narrow Q-factor and wide tyres. I'm sure Google would show some results.

There are more tricks out there, got to love flipping the chainring.
I used a 100 mm bb (the "old" narrower fatbike width, which was meant to be used with 177 mm rear hubs) on my 197 mm hub frame and flipped the direct mount chain ring to achieve a correct chain line, space for 5" tyres yet not need a 120 mm bb shell.
Not a genuine idea at all, but it makes you feel smart when it all comes together.

Same goes for narrower fatbikes, for example with Raceface Turbine cranks;

83 mm bb (DH standard), a Raceface RF143 spindle (Q-factor 187 mm), flipped chainring and a 177 mm hub will allow for even 430 mm chainstays yet still go up to 27.5 x 4.0". Use a RF149 mm spindle, same hub and bump it up to even the widest 27.5" tyres with still not so wide q-factor of 193 mm.

Drop the Q-factor further by using different cranks, say a Next. This will drop another 10 mm.

That said, I never had issues with the Q-factor on my fatbike (Raceface Turbine with RF169 spindle: 213 mm).
Stand on the floor as neutral as possible. How far apart are your feet? I do question the potential of knee issues and hip problems. I don't know one single person how has knee problems when riding his/her fatbike.
Has the aero gain of road/indoor cycling discoloured any factual biomechanic talk when it comes to Q-factor?

Having visited the Tumbleweed site I found that they changed from QR only fork options to thru axle or QR options.
One large improvement in my books.

[jameso]

Walt (?) the frame builder

- an OG of short chainstay 29ers.

Stand on the floor as neutral as possible. How far apart are your feet? I do question the potential of knee issues and hip problems. I don't know one single person how has knee problems when riding his/her fatbike.
Has the aero gain of road/indoor cycling discoloured any factual biomechanic talk when it comes to Q-factor?

Been wondering about this re E-bikes, just not in any detail. There's probably a lot of assumed facts around Q-factor coming from the same place a lot of old stuff in bike design does, early road race bikes.
Many mid motor E-bikes have 190mm or more Q-factor, though new EP8 is fairly normal compared to old triples ~175-180mm. I've not heard of knee problems from riders who've suddenly started pedalling more due to getting an E-bike and statistically they're older riders on average.
Shorter riders are more likely to feel out of line on wider Q-factors so perhaps a wide crank is something a taller rider gets away with more easily?

[marcinski]

I ask myself if it's so much of a difference if I go short front/long rear or long front/short rear?

Interesting discussion for sure. I can't help thinking that a reasonably long FC with relatively longish RC wouldn't be a bad compromise? Long enough front so that stand-up space is not restricted, but short enough so that not very steep STA works and longish RC to balance the rider properly between the wheels.

I sort of did that in Rondo with Bogan (longish FC and longish RC for a gravel bike). I also experimented with significantly longer FC and short rear and while capable off road, it definitely is less comfortable than long-chainstay Bogan (all else being equal)

Marcin

[jameso]

Looked up the Bogan, got distracted by the Mutt.. some interesting things going on there, good stuff Marcin

[marcinski]

Thanks, James! Glad you like it.
Marcin

[Alpinum]

Amazing pics, the sky, is that altitude giving it the colour? 

Cheers.
Aye, the closer to the sky, the thinner the atmosphere, the less gas and particles which scatter light and thus the darker the sky seems.
Then I also often use a polarization filter.

From the high point of the trip:


I tend to reduce saturation in the blue of the sky since I want my photos to be more of a documentary style, rather than garish. Sensia vs. Velvia kind of thing I guess.

I'm kidding myself if I think that 2-4" of wheelbase makes the difference in how tight I can corner off-road. 

True. Yet, often when I changed gearing or tyres (2.4 to 2.6) on my ssp (used to have one for many different duties) and went from as short (cs) as possible to rather long(ish), I noticed how it follows differently. Tame, but also lame in a way. The feeling stuck (of course also in my head). The difference would have been about 20 mm or so.

No, surely not a difference in how tight I could turn, but to a sensitive (corner cutting) chicken enough to feel a difference. I don't think it's just placebo since some bikes by which I didn't know the chainstay length, I felt I could tell which was longer.  

On the lumpy terrain and long vs short wheelbases - you can get away with a lower BB with a shorter wheelbase, less of that grounded-lorry-on-a-bridge situation? But that's a weak pro vs stronger cons overall. Htrider's point about the Jones low BB - it annoyed me at first but I adjusted to it and now only see the advantages, though if I rode really rocky places all the time I might go to 165s

True, hadn't considered that.

But yeah, that low bb makes me thinking…

Riding ssp, what changes when going with shorter cranks, say 10 mm shorter? Cadence goes up since muscle memory give the pedal more speed but the circumference is shorter I guess. Do you feel the change in leverage much? Something I also wanted to ask htrider...

It's worth getting a ride on a Jones LWB if you can. It has a lot of what's being discussed here going on, with some key differences also and with a standard STA

I bet it is. I should seriously try to get a spin on one... stupid Swiss and their bloody normal trail bikes, those that win tests in magazines kind of bikes.

They're odd bikes in some ways, I needed to spend some time adjusting to both LWB and SWB but they're worth it. 

That's the tricky part. How much riding is needed to feel a bike properly. Short tests are always a bit tricky. The odder, the longer it may take, but the more important the time scale would be.

I too think the Range Rider is a very specific piece


Sorry for not stinking to any chronological order with my posts and responses and questions.