Q's for Fatbike users

[FLV]

So, following on from Voodoo_Simons Rov150 thread I was thinking about fatbikes again. I dont really know why I fancy one, but I do but I have some questions.

If you're using it in proper snowy conditions, like the Rov150 or Iditerod, or indeed just proper snow elsewhere, are the 3.8 tyred bikes enough?

If they are, they're not that much bigger than a 29+ at 3.0 so has anyone tried a 29+ in real world snowy conditions?
If the 3.8 dosnt quite cut the mustard, what size is generally accepted at big enough?

I know rim width also affects things too, so lets throw that in there!

Bikes like the mukluk get 82mm rims and 3.8 tyres, pug gets 65mm rims and 3.8.
Some fit the monstrous 100mm clown shoe with 4.8's

Its all pie in the sky for now anyway but any opinions anyone?

[mountainbaker]

I had a mukluk a couple of years back. Then I sold it. I just didn't 'get it'. Sure I took it to the beach a few times, which was great, especially riding with the dog running alongside. But on local trails the 3.8s seemed to just attract thorns. So many punctures it was silly.

They don't roll as badly as you'd think by looking at them. I'm interested in 29+, seems like a good compromise of fat/diameter. 3.8a and 4.8 tyres just gave my too much undamped bounce. Used to fire me up on the air of roots and stuff.

That's my two pence.

[summittoppler]

Well I've had my 2014 Mukluk since last October and I must admit I haven't even looked at the other bikes (FS & HT). Unfortunately as last winter was a bit on the mild side I haven't had a decent spell on the snow. Having said that they are just so much fun. Unlike the previous post I haven't had any punctures (yet), it goes beyond where you think a bike should go and is just such a buzz.
But to partly answer your question if you ever watch any youtube videos on the Iditerod race then I'm pretty sure all the riders are on fat bikes, as for what tyre width though is down to someone who's done it.
The key is to run them at low psi in order to get the best floatation.......

[firedfromthecircus]

Just as with every other aspect of bicycles you get nothing for nothing.

The wider the tyre, the better the float, and the more the drag.

Snow conditions vary massively. The deeper and drier the snow, the more extra float will help you out.

The best compromise for fatbikes seems to be 4" tyres on 85mm rims, which sit between the 'skinny' fatbikes and the 'fat' fatbikes.

I run 100mm rims and the knobbiest 5" tyres available. I love the float, and the grip and don't care about the drag. A lot of other people seem to dislike the drag. When I had BFLs (less knobby tyres) I found the grip lacking in certain circumstances. That is not a problem now, but it does come at a cost.

So you really need to think about the kind of riding you do (or want to do) and buy according to that. If you are just riding UK trails then 29+ is probably the better compromise, or at least it will be once there is more tyre choice.

[mountainbaker]

Punctures I experienced may well have been down to using the early Surly fatbike tyres, which I beleive, they don't even make anymore anyway.

[firedfromthecircus]

Endomorphs are indeed no more.

I often find thorns sticking out of my tyres, but the stans juice inside the tubes does a grand job of keeping the tyres up.

[JohnClimber]

As a Mukluk rider and a 29er+ rider I wouldn't take the 29er+ on snow when I had the Fat Bike.

On sand the 29er+ is only just a little better than a normal mtb, where as the Mukluk floats over the sand., I've not had the 29er+ in snow but I would guess it would be just the same as it is on the sand.

Fat Bikes on snow are fantastic as long as it's the right snow and not much deeper than this


Anything deeper the wheels fill with snow and your pedals keep stamping on the snow slowing you down so much it's quicker to walk.

[fatbikephil]

A fatbike offers less ground pressure but it aint magic so their ability to ride snow varies hugely on the conditions. On rough chopped up snow compacted by walkers they will cruise effortlessly whereas a normal bike will get kicked around everywhere. On the fluff they will cope better than a normal bike but only too a certain depth and some people argue a narrow tyre is better for fluff as it cuts though it. Firm windslab or freeze / thaw slab is where you get the biggest benefits as you will be much less likely to break through the crust. they are also excellent on hard ice as you can drop the tyres to 5 psi and find grip where you thought there would be none. My biggest snow fail was on 3-4" of very wet fresh snow - absolute nightmare as the tyres just floated over the gripless surface - something like a panaracer spike (or whatever) would have cut through to the firmer dirt underneath. The thing is they will keep going long after normal bikes fail, but that does make you try to go places you'd never even consider on a normal bike! 4.8 tyres don't weigh much more than 4's and the difference in rolling resistance between the two sizes is trivial - its all dependent on tread. My theory is always 'big is good, bigger is better' and you can always run 4" tyres on a bike design or 5,s' but not the other way round which is why my muk may well turn into an ICT next year. 29+ does give some float but nothing like what you get on a fat bike - they are totally different animals (I have both!) and offer little benefit over a 26er or 29er with 2.5's

And remember that snow is just one area that fatbikes work. As well as sand they are the business for boggy ground and pathless moor plus they excel at rock riding.

[Alpinum]

That's a good write up by htrider.
Most fun I get out of trails compacted by snow shoes hikers and back country skiing tracks/winter hiking tracks (compacted by groomers). That's on bottomless snow. Even a fresh track on deep snow can suffice.
But you also gain efficiency with 10 cm of snow on frozen dirt. Although cornering will be better with regular tires.
There's an overlap of conditions where a deep tread on regular 29ers tires will be just as fun as fat bikes, but as grounds go less soft, say you head back for the valley floor and leave behind deeper snow, fatbikes bounce around like ... it's just poor show.

On my trips in the Jura and Engadin at least 90 % would have been unridable with anything less than 4". I run 83 mm rims, test wise with borrowed On-One Floaters now with Bud and Lou. Big difference. Not just the floatation but also steering and propulsion in the soft stuff. To me fatbikes only make fun and sense on the soft stuff, so why bother with more drag on the hard surfaces...

If you go fat, go full fat. Some frames, like Muru's Witjira, just about take 4.8" tires on a 80 mm rim with a single ring up front and a 170 mm rear. Running higher pressure (>0.8 bar) will cause rub on the chainstays as the tires grow like baloons. Mostly I run 0.2 - 0.5 bar

The training effect is bonkers. I was able to step up the gearing on my other bikes. In March.

For some thing like the Rovaniemi150 or a long trip abroad I'd take a Specialized Ground Control 4.8 rear and Big Fat Larry up front.


Hard snow with a thin layer of softer snow on top. 29er would have been faster, albeit less comfy (cushioning).




Groomed track with tracks of hikers, all covered with 10-20 cm fresh powder. Hard work, absolutely no change sub 4". Pressure in conditions like this will be around .2 bar.


Fresh groomed track on tons of fresh powder (90 cm in less than 2 days). This is fatbike heaven.




Slush. Completely sodden cold mess. Walking it would've drenched my boots ankle deep in iced water. I was able to ride.


1.5 months later, in the middle of daily freeze - thaw cycles. This was a semi thawed crust.








Yes, it does take you where I used to go ice climbing and touring...


Fatbike heaven on snow shoe trails.


Fatbike heaven off track. Only the steepness made riding possible.


Groomed track with drift. Semi soft snow under a layer of loose drift. Tough going.

Too tough for me. You can see just how deep the snow I'm standing in is

Hope that gives you a better image. FLV, would be fun to repeat some suffering with you mi casa es su casa

[johnnystorm]

I'm rather jealous. :(

[Alpinum]

I'm rather jealous.

Sorry for that, only wanted to make FLV jealous.

[Zoglug]

I too am rather jealous! Excellent pics!

[FLV]

All excellent info thank all.

I had almost decided to go for a muk but this makes me think that i should look at bigger perhaps. If I manage to convince myself I need one (I almost have)
Stuff like the ICT has a very wide BB, that put me off a little

Cheers Gian, Hopefully meet up for trip before too long.

[johnnystorm]

Blackborow Dinglespeed.

[FLV]

Blackborow Dinglespeed.

Looks good dosnt it

*not sure about the aesthetics of the TT brace

[johnnystorm]

Yeah, it doesn't look great in profile. Stick a frame bag on or hop off the saddle and have your feet sink in the snow and I reckon you'd see past it.

[Ian]

Looks good dosnt it

D'ya think? Looks awful to me. Maybe it's the angle of photo, or the perspective that the bars are around your ears while saddle is low down. I'm prepared to overlook the anything cages, but don't get me started on the rack

This is a one-sided recommendation, as the only fat bike I've ever ridden is a Puffin, but with an eye of everyday rideability and good handling, I'd recommend having a go on one to see how it differs from a Salsa /whatever/. You're welcome to try mine.

Off snow, the benefits of traction and cushioning from 4" tyres on regular trails shouldn't be under estimated. I'm faster up some hills on the Puffin than I am on a normal 29er

[FLV]

Lots of things about the back barrow I like, not necessarily the aesthetics, though I think the angle of the picture makes it look wierd. As I mentioned, I think the brace spoils the look a little too.

I did look at the puffin, quite like that too.I rode around the field on it at the BB200 last year.
Do you ride it singlespeed Ian? Hows it compare?

[johnnystorm]

Or with gears. Looks extra steamrollery here:

[Ian]

I ride the Puffin geared now. Singlespeeding a fat bike round here is quite an undertaking...

[FLV]

I ride the Puffin geared now. Singlespeeding a fat bike round here is quite an undertaking...

good to know...

[Alpinum]

Singlespeeding a fat bike round here is quite an undertaking...

can imagine

The alu freewheel body of my Hope FatSno has deep marks and is pretty much chewed up, even by the smallest cog (30t x 11t). I usually don't get that from small cogs - not after only 500 km. You surely can torque the sub standard out of the material with those baloons.

Should you run gears, make sure your cassette has alu spider (on the larger sprokets) or sram XX etc. or else run steel freewheel.

Oh and at snow DH races friends and self made the experience that mineral oil based brake systems will start to fail below -15 °C, DOT systems will hold up much longer. Never had problems (got down to -25 °C). Yet most seem to run Avid BB7 in Alaska.

[fatbikephil]

Good photos Alpinum, you know yer sub standard!
'15 Kona wo looks good - £1500 for a 190 back end with v tyre 4.8's
Quite like the backborrow (assuming someone will import one!) but the numbers on the Surly ICT really look good - A Krampus with 5" tyres, oh yeah!

[johnnystorm]

Good photos Alpinum, you know yer sub standard!
'15 Kona wo looks good - £1500 for a 190 back end with v tyre 4.8's

They haven't carried much over from 2014 have they?!

[composite]

All you need to know about fat bikes is right here Dave.
http://www.ebay.com/itm/THE-GOLD-BIKE-T ... 2518.l4276