Minimal rear rack like this

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survivor
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Minimal rear rack like this

Post by survivor » Thu Oct 03, 2019 11:01 pm

Just seen this minimal rear rack and it got me thinking of ditching the seat pack for a more dropper friendly setup... Is anything else like this available as this is a bit spendy.

http://www.tumbleweed.cc/store/t-rack

https://bikepacking.com/news/ratking-t-rack/

chris n
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Re: Minimal rear rack like this

Post by chris n » Fri Oct 04, 2019 6:33 am


lune ranger
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Re: Minimal rear rack like this

Post by lune ranger » Fri Oct 04, 2019 6:52 am

chris n wrote:
Fri Oct 04, 2019 6:33 am
100g lighter and £100 cheaper. :-bd
https://www.sjscycles.co.uk/carriers-ra ... ls-silver/

I could be wrong but i’d think that the Tortec rack won’t clear a 29+ tyre.
The one in the op is expensive alright but the kind of money looks like the going rate for well made tubular steel racks, anything by Surly, Salsa, Tubus etc is about that.

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Bearbonesnorm
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Re: Minimal rear rack like this

Post by Bearbonesnorm » Fri Oct 04, 2019 9:57 am

Trouble is, no matter how strong the rack, it's still completly reliant on 4 M5 bolts in sheer :roll:
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Alpinum
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Re: Minimal rear rack like this

Post by Alpinum » Fri Oct 04, 2019 10:17 am

lune ranger wrote:
Fri Oct 04, 2019 6:52 am
going rate for well made tubular steel racks, anything by Surly, Salsa, Tubus etc is about that.
Well made by Surly? I mounted two 8 pack rack on our bikes and in both instances had to grind down the fittings of the rack as they were so rough and cr@ppy produced that it wouldn't assemble. Other parts for mounting were really rough, but went together with some elbow grease.
Once installed they do a great job though.

Salsa as well as Surly being part of the QBP corporation, I wonder if the Salsa racks come with Tubus build quality or the Surly rubbish.

If I were you I'd simply put less gear in the back, cinch the seat bag down more to get more clearance on the dropper - perhaps use a Valais collar. Or get a seat pack specifically made for dropper posts.

A rack will not solve clearance issues you may have. It just invites you to take more gear :wink:

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Alpinum
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Re: Minimal rear rack like this

Post by Alpinum » Fri Oct 04, 2019 10:29 am

Bearbonesnorm wrote:
Fri Oct 04, 2019 9:57 am
Trouble is, no matter how strong the rack, it's still completly reliant on 4 M5 bolts in sheer :roll:
I think racks mostly brake close to the mounts but not on the bolts. There were vibrations get passed on and the material thickness changes. Lets not forget the bolts are tightened and holding multiple parts together, so there's a bit more going on than pure shear stress on an M4.

I happily to use M4 ti bolts, load the racks with 25 - 30 kg (gardening/shopping booze/bbq etc.) and ride along the river over roots and rocks or take it across a desert. Two years in, all all still going strong. And on biggish trips I have a couple of spare bolts with me anyways, but the reason for this is more that I'm afraid to loose bolts when reassembling the bike after its transport.
Last edited by Alpinum on Fri Oct 04, 2019 1:05 pm, edited 1 time in total.

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Bearbonesnorm
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Re: Minimal rear rack like this

Post by Bearbonesnorm » Fri Oct 04, 2019 10:38 am

Lets not forget the bolts are tightened and holding multiple parts together,
Obviously, but the load on the bolts is still sheer. The fact the bolt is tightened and under tension, doesn't make the potential problem better. :wink:
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ScotRoutes
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Re: Minimal rear rack like this

Post by ScotRoutes » Fri Oct 04, 2019 10:40 am

While we're racking, any suggestions for a rack to fit over 4.4 - 4.8" tyres? No mounts on the frame either and it's a 12mm axle so looks like P-clips and one of those seatclamp mounts might be required.

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whitestone
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Re: Minimal rear rack like this

Post by whitestone » Fri Oct 04, 2019 10:54 am

Colin, there's a list on bikepacking.com - https://bikepacking.com/gear/rear-racks-for-fat-bikes/ and I seem to remember that Halfords did stock one of those listed but can't see anything now.
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ScotRoutes
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Re: Minimal rear rack like this

Post by ScotRoutes » Fri Oct 04, 2019 11:01 am

Thanks Bob. Bookmarked.

Landslide
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Re: Minimal rear rack like this

Post by Landslide » Fri Oct 04, 2019 11:55 am

Might summat like this help?

viewtopic.php?f=7&t=14792&p=182810

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Alpinum
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Re: Minimal rear rack like this

Post by Alpinum » Fri Oct 04, 2019 1:04 pm

Bearbonesnorm wrote:
Fri Oct 04, 2019 10:38 am
Obviously, but the load on the bolts is still sheer. The fact the bolt is tightened and under tension, doesn't make the potential problem better. :wink:
It would be if you don't tighten the bolt. But I guess we all tighten them.

Shear strength is lower by a factor of about 0.5 to 0.6 (depending on model) compared to tensile strength. But, tightening/loading the bolt will lead to more and more tensile stress and less and less shear. Then also friction comes more into play and the shear potential takes a back seat.

The potential problem you see isn't there if the bold is correctly tightened.
I never had a bolt break by shear.

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Alpinum
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Re: Minimal rear rack like this

Post by Alpinum » Fri Oct 04, 2019 1:18 pm

ScotRoutes wrote:
Fri Oct 04, 2019 10:40 am
While we're racking, any suggestions for a rack to fit over 4.4 - 4.8" tyres? No mounts on the frame either and it's a 12mm axle so looks like P-clips and one of those seatclamp mounts might be required.
I got this one and like how I can get it to sit low.
https://www.topeak.com/global/de/produc ... ourist-fat

I like the simplicity of this one
https://www.tredz.co.uk/.M-Part-Ridge-R ... _45246.htm
But have no experience with it. Probably as minimal as fatbike rack go...

techno
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Re: Minimal rear rack like this

Post by techno » Fri Oct 04, 2019 1:34 pm

Alpinum wrote:
Fri Oct 04, 2019 1:18 pm
I like the simplicity of this one
https://www.tredz.co.uk/.M-Part-Ridge-R ... _45246.htm
But have no experience with it. Probably as minimal as fatbike rack go...
I have this one, and the lower struts bent when subjected to a weeks riding in the highlands.
a similar design with solid lower legs would be better.
Image

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Re: Minimal rear rack like this

Post by jameso » Fri Oct 04, 2019 3:39 pm

Bearbonesnorm wrote:
Fri Oct 04, 2019 9:57 am
Trouble is, no matter how strong the rack, it's still completly reliant on 4 M5 bolts in sheer :roll:
Daft isn't it. I remember talking to Chris Juden about it and he was in favour of M6s for at least the rack foot mounts, makes a lot of sense. I've seen a few M5s broken by racks. There's the point about friction (6 disc rotor bolts don't need much torque for all that to stay in place) but there's not a lot of area being pulled together by that small bolt - I know, pressure is force over area, but throw in a layer of paint on one side and/or 2 surfaces that probably aren't that flat anyway and the 25kg rating on many racks seems high compared to the mounting. Also a Q of what bolt spec gets used, I expect the M5s I've seen broken were basic bottle boss spec rather than something higher grade/class.

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stevenshand
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Re: Minimal rear rack like this

Post by stevenshand » Fri Oct 04, 2019 3:48 pm

anything by Surly, Salsa, Tubus etc is about that
Not sure I would lump Tubus in the same category as Salsa/Surly.

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PaulB2
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Re: Minimal rear rack like this

Post by PaulB2 » Fri Oct 04, 2019 4:19 pm

Hasn't surly just issued a recall on all their 8-pack and 24-pack racks?

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Bearbonesnorm
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Re: Minimal rear rack like this

Post by Bearbonesnorm » Fri Oct 04, 2019 4:58 pm

Daft isn't it. I remember talking to Chris Juden about it and he was in favour of M6s for at least the rack foot mounts, makes a lot of sense.
M6 would certainly be a step in the right direction. Shame we can't have some kind of mechanical couple ... wouldn't take much, maybe if the foot-end of the rack slotted onto / into some sort of cup or maybe over the braze-on* and the bolt was then simply used to secure it.

*I'm imagining something like a cowled drop-out.
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Alpinum
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Re: Minimal rear rack like this

Post by Alpinum » Fri Oct 04, 2019 6:28 pm

jameso wrote:
Fri Oct 04, 2019 3:39 pm
Bearbonesnorm wrote:
Fri Oct 04, 2019 9:57 am
Trouble is, no matter how strong the rack, it's still completly reliant on 4 M5 bolts in sheer :roll:
Daft isn't it. I remember talking to Chris Juden about it and he was in favour of M6s for at least the rack foot mounts, makes a lot of sense. I've seen a few M5s broken by racks. There's the point about friction (6 disc rotor bolts don't need much torque for all that to stay in place) but there's not a lot of area being pulled together by that small bolt - I know, pressure is force over area, but throw in a layer of paint on one side and/or 2 surfaces that probably aren't that flat anyway and the 25kg rating on many racks seems high compared to the mounting. Also a Q of what bolt spec gets used, I expect the M5s I've seen broken were basic bottle boss spec rather than something higher grade/class.
M4 is not daft, the problem isn't the bolt size, it's the right torque with which it gets tightened and the contact area. Get that right and they will hold.
As you say yourself.
Putting oversized bolts in such a place is just fighting symptoms.
techno mail wrote:
Fri Oct 04, 2019 1:34 pm
I have this one, and the lower struts bent when subjected to a weeks riding in the highlands.
a similar design with solid lower legs would be better.
Oh... shame. Yeah, does look a bit thin down there.
Bent my Tubus Vega. Actually I have to bend it back about 2 x a year. It's down to regular 10 or more kg of food/drink getting transported on not so smooth cycle paths. One sided with an Ortlieb pannier. As always there's a limit to everything and loading even a well built Vega one sided, riding it on easy offroad terrain will lead to issues.
I may add that none of the M4 screws ever failed, despite being titanium.

survivor
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Re: Minimal rear rack like this

Post by survivor » Fri Oct 04, 2019 6:42 pm

A rack will not solve clearance issues you may have. It just invites you to take more gear :wink:
Clearance isn't the problem for me. I'm a bigun so when the saddles dropped it doesn't hit anything It's the swaying and momentum behind the swaying that doesn't seem dropper friendly... i.e. wearing of the guide pin slots and top bushing.

I'm not really that fussed about it if I'm honest. It's a cheap dropper that doesn't owe me anything now but I like the idea of the rack with a dry bag strapped on it which will almost certainly
invites you to take more gear :wink:

So maybe not the best idea going. :lol:

Shane no one makes a cheaper one to try out but I do like the inventive effort in this thread https://bikepacking.com/gear/rear-racks-for-fat-bikes/ extra points for the clips and duct tape as far as I'm concerned.

Probably like everyone here I've got the dream bike idea in my head that will tick every box for me but no one seems to make it surprisingly :???: A decent drop dropper post is one requirement instead of the 100mm I've got now. This rack just got me thinking

survivor
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Re: Minimal rear rack like this

Post by survivor » Fri Oct 04, 2019 6:44 pm

I'll also add M6 m mounting points to dream bike now :-bd

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ScotRoutes
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Re: Minimal rear rack like this

Post by ScotRoutes » Fri Oct 04, 2019 7:49 pm

Alpinum wrote:
Fri Oct 04, 2019 10:17 am


A rack will not solve clearance issues you may have. It just invites you to take more gear :wink:
It will if you strap stuff on the sides and not the top.

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stevenshand
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Re: Minimal rear rack like this

Post by stevenshand » Fri Oct 04, 2019 8:11 pm

One issue with M4 (isn't most M5 anyway?) hardware is that when the fasteners inevitably get seized, there's a much better chance of snapping them during removal potentially leaving a real problem in the frame.

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Alpinum
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Re: Minimal rear rack like this

Post by Alpinum » Fri Oct 04, 2019 8:47 pm

ScotRoutes wrote:
Fri Oct 04, 2019 7:49 pm
Alpinum wrote:
Fri Oct 04, 2019 10:17 am


A rack will not solve clearance issues you may have. It just invites you to take more gear :wink:
It will if you strap stuff on the sides and not the top.
Obviously it will.

With the underlying parameters of this discussion I evaluated the issued topic to be about replacing the seat bag with one dry bag on the rack, which should come in a minimalist way, likely not facilitating a strap stuff on the side fashion.
survivor wrote:
Fri Oct 04, 2019 6:42 pm
I'm not really that fussed about it if I'm honest. It's a cheap dropper that doesn't owe me anything now but I like the idea of the rack with a dry bag strapped on it which will almost certainly
See

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Alpinum
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Re: Minimal rear rack like this

Post by Alpinum » Fri Oct 04, 2019 8:57 pm

stevenshand wrote:
Fri Oct 04, 2019 8:11 pm
fasteners inevitably get seized,
Inevitably? I've damaged about two bolts (rotor) in 25 years.

C'mon folks, be nice to your M4's and they'll do what you ask from them :wink:

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