[Closed] Fat bike build help

Having just upgraded a 1x10 I found 1x12 with a sunrace cassette to be cheaper than 1x11 (for a 50t rear).

If you're going fully rigid you'll appreciate 4" tyres.

Worth checking to see if the frame clearance is enough for a 29+ tyre - not all 170mm frames can take them - they work far better on natural terrain e.g. water bars. A 197mm frame will also allow you to fit bigger tyres which can be the difference between pushing and riding in snow seeing as you're in the Cairngorms. Fatbike parts are relatively specialist and if on a budget check out the various Facebook Groups as used parts are often listed. Tyres may seem prohibitely expensive but you can easily get 3 years out of a tyre so worth investing money in better tyres rather than cheap junk like Vee Missions.

£450 would get you all this (plus I’ll throw in a hub for the fork too...)

https://singletrackworld.com/forum/topic/fs-fat-frame-and-bits-job-lot-bluto/

I’ve run that, and my current one, as a 29er and it works pretty well. As for groupsets, anything will work, cranks can be bought specific to fatbikes. I use 1x11 same as my Normal bikes without any issue.

I'd suggest a 150 front and either 177 or 197 will give you more choice in second hand wheels. Possibly 197 is slightly more common than 177 these days, but not sure about that.

Cranks are fatbike specific (with lots of variability in the width of the bb shell). A 100mm shell is probably most common. Everything else is just standard mountain bike kit though, so it depends what you've got in your parts bin and what you can pick up cheap.

So what is your budget? And what size are you?

That will make a difference to the advice I can give you.

Ther are lots of complete bikes as well as frames to choose from. Second hand is often a good way to go.

Cheers

Sanny - Singletrack's fat bike nut

I'd just get a complete bike and avoid the faff of having to find all the parts.  Calibre do one at Go Outdoors (good frame/forks with the more common 150/190 spacing) or an On One Fatty off eBay (135/170 spacing but unless you want a bluto and need 4.8" tyres its probably a better off the shelf spec and available in more sizes).

I bought a second hand rolling chassis Singular Puffin about 18 months ago.

If you are starting from scratch I'd suggest getting a frame that can take 5" tyres, you might not want them now but if you do so in the future then you're covered. The Puffin will take up to 4.6" tyres at the rear. While looking at tyres it's worth going for high TPI as they are considerably lighter than low TPI tyres, my wheels/tyres are about 1kg lighter than my wife's even though I've heavier rims, the only difference is I've got 120tpi tyres and hers are 27tpi.

Tyre width also has an effect on chainline and with a 2x setup you might struggle to clear the tyre when in the small ring and looking to move to the big cogs. I went 1x10 (my other bikes were 10spd so made sense to stick with that for spares) and with a 4" tyre didn't have a problem. I went with a RaceFace AEffect direct mount crank as I wanted a 28T oval chainring and direct mount's the only way to get that.

As @roverpig says, everything else is just standard MTB kit

Here's mine:

There is a wealth of info on forums and Fb for this but my 2€ worth..

135 and 170 will be QR, and likely limited to a 4" tyre. 150/197 use through axles which imho are  better/stiffer
Cranks are fatbike specific. 100mm sets are easy to find, bb's usually threaded and work with HTII cups
Hydro / cable brakes. both standard, personal preference here and all the usual names work fine
Single / twin chainrings.. preference again. Singles are great on 11/2psd but get a 190/197 rear frame for this
Cassettes and derailleurs off a 9/10 spd donor bike will fit and work with an existing shifter
Shifters, bars, stems, flats, clips all standard stuff.
Internal cable routing may make frame bags a little easier. Look perhaps for rack mounts on the frame too
Seatposts / dropper posts again, standard fare
Wheels/tyres is where the weight is. Tubeless is well worth it.. tubelessing a wheel full of holes can be a faff
Don't get too hung up on the common brands. Some very good stuff coming direct from China.

Complete bike vs a self build...
Complete bike works straight away, but the price/weight connundrum applies. Some bikes are cheap but have their own gravitational field....
If you are going to build yourself, just work through things steadily. There are a lot of different standards but its not too much of a problem, just read twice, buy once.
The only thing that really may trip you up is the fork / hub combo for mounting the caliper. Front disc spacing and rear disc spacing may lead to the front caliper being in the wrong place, laterally for the front disc. Its all solvable and part of the fun.

HTH...

Merlin are selling off Salsa fat bike complete builds at 40% off retail at the moment.

Alternatively, try Ghyllside Cycles or Bothy Bikes for great fat bike advice.

Ah, forgot to mention tubeless. Definitely worth it on a fat bike.

Just checked my notes: the Puffin built up to a trail ready weight of 14.3kg so that's including pedals (Hope F20 at the time). There's nothing weight weenie in the build, if I wanted to go much lighter then a carbon rather than steel frame would save a bit.

Oh, get mudguards unless you want to bring most of your ride home with you!

Just spotted "Aviemore"
Scotroutes of this parish is an (well, I was going to say Aviemoron, but its very unkind..), Aviemorist.... and has been a Fatbikist in that area for a long time..... maybe he will be along to help out.

32 hole 170mm QR hubs are getting hard to find - cheaply - so I'd be tempted to go 197mm.

Thanks very much for all the info.  I think I'll go to Bothy Bikes and chat to them about the frame and a build.

Smokestone henderson 177 rear, takes 4.3 edna, 100mm BB, fits 29+ £450

Without being a Standards Nazi, whatever frame it is you're looking at has 2 pretty much obsolete hub standards, and is limited by its tyres as well. I wouldn't touch it, not when 150/197 has become so dominant and 4.8 tyres are such a useful option.

I think TINAS is spot on tbh, the Calibre Dune's build is very low spec but it gets you out the door with a working bike for £500, all current standards etc, and a frame that if it said Salsa on the side would sell for that much so even if you replace most parts like I did, you still don't really lose out from buying a full bike. And it lets you dabble and figure out what you actually want and like rather than pretty much having to jump into the unknown. You can whack brakes and better tyres on it and instantly have a bike that'll do everything you could want from a fatbike

Yes, that's helpful.  I suspected things had moved on, which is why the frame is selling at a massive discount.  I once had a recumbent with a proprietary hub, and trying to get that fixed/replaced when it broke was a nightmare.  It would be okay if the 135mm/170mm setup is likely to be around for years, but with the way things have moved on in the MTB world in recent years, that might be unlikely, especially if they were niche/unpopular standards. I'm not even sure a fat bike is for me.

I wouldn't say 135/170 is obsolete, the front is (usually) a SS rear hub and 170mm hubs are available from all the usual places (Hope, Novatec, bitex) its only DT that never made one.

Surlys latest two bikes are 170qr/150 and 135qr/135qr so there's legs in both yet.  I<span style="font-size: 0.8rem;">'d probably say 190mm fatbikes (or even fat bikes in general) are about as 'obsolete' they've been dropped from the big brands ranges!</span>

The advantage of 150mm front hubs is an easier upgrade to suspension. 190mm rears do have more clearance for 5" tyres, but also require larger q-factor cranks and longer chainstays so it's not all benefits.

Whatever you get there will be compromises and comparability issues which is why I'd just get a Dune or Fatty, gets you rolling for the minimum outlay and you can tweek from there or sell it and get something bigger/smaller if it doesn't suit.

I'd be aurprised if you got it under £400 unless you went sh

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"190mm rears do have more clearance for 5″ tyres, but also require larger q-factor cranks"

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Nah. Well, if you want a double then yes but I have a 4.8 minion in the back of mine with a Raceface crank designed for 170mm rear and a flipped ring.