On-One Fatty Build Question

I recently moved to Munich where there is (thick) snow on the ground for 5 months of the year and snow in the Alps, which are only 40miles away, for most of the year.

I therefore find myself “needing” both
1) A fat bike
2) A fat bike with a granny ring

This is even necessary not just for playing in the woods, where many of the trails become covered in inches of permanent ice under the snow all winter, but even for my ride to work, where the best route became unrideable most days, even in March and April. The On-One Fatty looks like a great option, but it “only” comes in 1×10 with a Truvativ SS crankset.

Questions:

1) Can I fit a granny ring to these cranks? Despite there being a custom build option, I can not change them in the “bike builder” and I would need a granny to get up many of the mountains here in summer, let alone in the deep winter snow

2) If I can’t, what are my options for a replacement 100mm BB shell crank, that will take a granny ring (for snow and hills) and a middle ring (for the fast bits, so I am not late for work)?

Thanks in advance 🙂 I’m sure there has to be more than a few fat bike officionados on STW

Rob

The orignal cranks cannot be added to.

Replacements are available from Surly, RaceFace, SRAM and others.

I find the current set up fine, I push some pretty hideous hills round Snowdonia.

Many thanks scotroutes

I don’t suppose you know the names of any of the replacement cranks, and what might be an affordable solution, before I start hitting google?

Rob,I happen to use RaceFace cranks on my 9:zero:7 but you’ll get lots of Fatty-related answers, examples and details over on the UK Fatbike Forum

thanks for the “advice” twoniner, but you didn’t really answer my question, although you’re clearly much harder then me.

I’m pretty fit (see HERE[/url]) and I can assure you that the hills mountains round here need a granny ring, some of them even in summer. I used to live in the Peaks and pop over to your neck of the woods and even rode SS for several years, and this was all “fine” too. However, given the climbs here are much larger than anything in the UK (and I’m not sure you can compare the hills in Snowdonia to the Alps?!), and the snow is deeper and everywhere here all winter, permanently, I want a granny ring. Last year I was riding in the mountains nearby with Josh Ibbett and we both were forced to use our granny ring (which we both near killed ourselves to avoid) and even walk up some of the steeper sections, and Josh is a lighter and more talented rider than I will ever be (on both counts)

So, given you own a Fatty, are you able to answer either question? Can you confirm I can definitely not fit a granny? And where/how can I buy 100mm BB cranks?

I found this link, but they’re all looking pretty pricey, the only sub $100 option is an ISIS BB 🙁 CLICKY

fab – thanks scotroutes, I guess this thread is done then, cheers STW!

Have you considered just buying a Fatty Rolling Frameset option? It’s hardly worth buying the standard cranks and then bin them. You’ll also need a front mech, shifters, possible a brake upgrade (lots of owners not happy with the stock items) and new skewers (if recent chat is anything to go by).

I’m with twoniner.

I even told Brant when it was launched that it needs a granny ring, but as he said it was for a “trail” bike set up.

Since I picked it up in February I’ve never felt the need for a granny ring on mine.

So I’d say buy the £999 full bike and ride it for a while, then if you feel the need for an upgrade then you can do it as and when parts wear out.

double post, sorry

I would go for the rolling frame or just the frame sadly wasn’t an option when i bought mine.

I added these TRUVATIV Pédalier HUSSEFELT 3.1 44/32/22 – 175m paid about 50 quid fit on the standard BB chucked on an E type you can fine for 20 quid. I beefed up the brakes and added a suspension fork(temopararely removed for an overhaul); Granny works a treat and is definitely needed to haul me up the GR’s here in France

I’m with twoniner.

I even told Brant when it was launched that it needs a granny ring, but as he said it was for a “trail” bike set up.

Since I picked it up in February I’ve never felt the need for a granny ring on mine.

So I’d say buy the £999 full bike and ride it for a while, then if you feel the need for an upgrade then you can do it as and when parts wear out.

I have a 20lb carbon “race” bike, and feel the need for a granny ring, when climbing up the side of the mountains in the Alps near me, let alone in the rain and, more importantly, snow that I will have to deal with in winter. As in the original post, I want to use this in the snow, in fact it is being bought specifically for using in the snow, not as a trail bike, for which I am sure a single ring will be just fine for the UK.

The conclusion is then, buy the full bike, swap out the cranks. Any recommendations on what cranks and where to buy them greatly appreciated. I just moved to Germany, so online retailers preferred, 3 months of German doesn’t extend to bike shop natter, let alone the german for “fat bike crank arms for an external bottom bracket fitted to a fat bike 100mm bottom bracket shell” and the ensuing conversation!

I dunno if I should ask this, but why a Fatty? Have you looked at the Mukluk or Pugsley?

I went for the “fatty” purely for cost reasons, at £500 for rolling chassis or £1000 for a full bike. This is a tool to get me through winter in and around Munich and in the Alps when a normal bike will be toally overfaced by snow, rather than a bling summer trail bike or a beach bike.

Unless there’s a killer deal on a Salsa or Surly somewhere?

Just wondering. Replacement cranks, brakes, mech and shifter will add a bit to the cost. On One have been careful to say that the Fatty was designed primarily as a trail bike. Mukluks have always been designed to handle snow. Not that I believe there is anything on either that makes them unusable in the “other” environment 🙂

thanks for the “advice” twoniner, but you didn’t really answer my question, although you’re clearly much harder then me.

I’m pretty fit (see HERE) and I can assure you that the hills mountains round here need a granny ring, some of them even in summer. I used to live in the Peaks and pop over to your neck of the woods and even rode SS for several years, and this was all “fine” too. However, given the climbs here are much larger than anything in the UK (and I’m not sure you can compare the hills in Snowdonia to the Alps?!), and the snow is deeper and everywhere here all winter, permanently, I want a granny ring. Last year I was riding in the mountains nearby with Josh Ibbett and we both were forced to use our granny ring (which we both near killed ourselves to avoid) and even walk up some of the steeper sections, and Josh is a lighter and more talented rider than I will ever be (on both counts)

So, given you own a Fatty, are you able to answer either question? Can you confirm I can definitely not fit a granny? And where/how can I buy 100mm BB cranks?

I found this link, but they’re all looking pretty pricey, the only sub $100 option is an ISIS BB CLICKY

You have got it hard eh? I nearly had a little cry for you then. Maybe you should swap your granny for a jokey wheel.

You have got it hard eh? I nearly had a little cry for you then. Maybe you should swap your granny for a jokey wheel.

Quite the opposite, with the Alps on my doorstep I’m a very lucky boy indeed.

On One have been careful to say that the Fatty was designed primarily as a trail bike

Many thanks for the tip. I shall go and do some careful sums on the real/final cost of a Mukluk vs. an adapted Fatty.

I might have the crank off you with BB if you are selling soon?!

Hi Rob

Welcome to the world of the non granny ring jihadist!

It makes me laugh how 1 x 10 polarises opinion. 😀

Re cranks, there are a number of options – Surly, Middleburn, e13 and Race Face all do cranks that are suitable for what you are looking for.

Personally, I really like my Salsa and would happily recommend their bikes. The new 2014 bikes will be out soon. For my money, Rolling Daryl rims with Husker Du tyres work really well for me. They are light for a fat bike which I happily ride as a normal mountain bike and I reckon make a real difference to the ride feel as they just roll really nicely and I’m happy to do multi hour rides on the Fatty up some reasonably big hills here in Scotland. That combo with a double gets my vote.

Hope this helps?

Cheers

Sanny

Rob, granny ring won’t fit the stock cranks, unless they have changed recently. Granny/middle will work fine with a normal front mech and shifter, but currently cranks are expensive. There were some bargain Truvs that would fit but cant spot any now- it’s a SRAM DH style BB pattern BB so a PITA to get anything to fit. Drop me a mail if you want more info.

lots of the older style truvativ (hussfelt-holzfeller) cranks should fit the bb no prob, got a brand new 32-22 set off ebay for £60. £20 for an e-type mech and used an old shifter. job done in less than an hour.

my fatty has coped well with all conditions but the granny ring has helped me get to even more places.

a 1*10 fat bike is like having a bmw x5 (other soft roaders are available) , it will get you more places than a normal car but is not the same as a proper 4*4 with low ratio gearbox and locking diffs. more for posing really 😉

fatbikes.com/ in the US has the biggest selection that I have seen.

I went 2×10 on mine immediately, though in hindsight the original setup would have probably been fine for trail riding in hilly Pennsylvania. The granny helps a lot in the snow, though.

I got a RaceFace Evolve 24-36-bash. Gearing is perfect IMO, but the 36 just barely clears the chainstay by about 1 mm! 😯 Mine is getting some wear on the chainstay. Sounds like you’d be better w/ 22-32 anyway.

shaggy, Sanny, doh & JoeG, many thanks, some good and really useful advice there.

Time to price up a mech, shifter & 22:32 chainset (and possibly a new BB) plus some pedals and see what the full bike will cost me…..

I am interested in a granny for my Fatty and would like to get it done before Septembers trip to the Pyrenees
so if any one can post up the model nos of cranks and front mechs that will do the jobyhat would be most helpful

Mine are RF Evolve cranks[/url] though the other RF fat cranks should be interchangeable, just at different price points.

I used this PS direct mount adapter

And an M786 direct mount front derailleur, 2x version. It has a cable stop, so you won’t use the one on the Fatty’s seatube.

JoeG – Front mech to crank alignment, what a great top tip, I had completely failed to think about that possible issue with wider cranks!

JoeG- Where did you get the RF cranks in 100mm flavour? Cant find any 2 piece in 100mm.

ska-49, try eds bikes, Barker Lane, Snainton, Scarborough, YO13 9BG
01723 850598

rob – some folks have successfully used a regular Shimano front derailleur without the adapter, but they have had to modify them (longer limit screws?) to get them to work. The adapter isn’t cheap, but no improvising is needed.

Edit – got my cranks from fatbikes.com, but I’m in the US.

Rob,
Dunno if you’re still looking but we’ve 2 Fattys in the family & recently converted them to 2 x 10. I used Truvativ Holzfeller 2.2 RG Chainset & BB MY10 – 170mm – 22/32 Rings – White from Merlin Cycles. I used a standard front mech off another bike just at a slightly strange angle, but it all works just fine.
Re the Fatty in general, it’s great value for money & fantastic fun in all conditions, snow, sand, mud, rough rooty stuff or just popping down the pub. We got fed up with the Avid brakes, they needed bleeding a lot so changed them. The wifes bike is running very well but I’m a bit harder on mine & have done a set of rear wheel brgs & my BB is now horrid! but most of that has been caused by the sandy conditions in the Surrey Hills last winter, had them since last December.
Hope that helps a bit 🙂

beerbiker, are they on one fatty’s you’ve fitted the truvativ cranks to?
I’ve just spent about three hours trying to fit a race face chester 100mm crank to my fatty, fiddling with shims etc, it doesn’t appear to be compatable

In what way??

I’ve fitted xt chainrings 40 + 28t
the bb comes with 1x 3mm cup spacer and 5x 1mm axle spacers, got it set up so the chainrings don’t touch the chainstay but are still very close, but with all the supplied spacers fitted when you tighten the axle bolt the bearings are too tight, if you drop out one of the 1mm spacers and tighten the bolt they are too lose and the crank moves very slighty side to side

Can you replace the 3mm spacer with a 2.5mm and then use all the axle spacers?

I take it all the spacers are on the drive side?

Thanks for that, i’ll see if I can get hold of one and give it a try

Standard Shimano BB spacers are 2.5mm

mtbdog – are you running your chainrings on the granny and middle position? If so, I don’t see how you will fit the 40 as a 36 just barely cleared the chainstay on my Fatty.

Anyhow, RaceFace has some good info that might help you:

Fat Crank Chainlines

Fat Crank Clearances

The above links are from here.[/url]

Yeap fitted to both our On-One Fattys, one small & one medium. Out in the rain and mud again today & working brilliantly. Original BB and what I fitted looked just like I took off except it has a 36 & 22 instead of just a 32 ring.

got one of these Truvativ Holzfeller 2.2 RG Chainset from merlin, but still comes with a 68\73mm bb,