Hi everyone

hope you’re all well

have recently purchased and received an on one fatty trail with the oversized chai stay problem (whoops)

given current situation I’d rather not go through returning if there’s a workaround so

problem is this

frame is 100mm bb

chainstays do not clear a 100mm crankset

apparently they were designed to clear 120mm bb crankset.

i have limited budget to amend the issue

what cranksets might be able to be successfully ’spaced’ out to 120mm using a 100mm bb

im already planning on using widest bb cups I can plus extra 2.5mm bb cup either side (poss more if I can use the saint Bb I’ve got)

over to you hive mind

Boost crank or chainring might give you some more breathing room.

There were a number of on-one fatty frames that had manufacturing issues. Sounds like you may have bought one.
As above boost chainset is the best option. If not you may have to return the frame.
If you go on the UK Fatbike Facebook page you may find more answers there.

On One reject frames.

These might work, but you would need to check whether the bearings rest on the machined part of the axle, and get some 24mm spacers for each side. With the Saint BB you could probably get away with maybe 5mm extra spacers on each side and 5mm on the axle each side?

Race Face Ride Fat Bike Crank Armset – 190mm – Black

I don’t think “boost” would work, isn’t the issue that some cranks hit the chain stay, not just the chainring? Is boost even a thing for fat bikes?

You need to run a 120mm BB crankset like an Aeffect (if you can find one) or Turbine with a 100mm BB and simply fit a 10mm spacer to either side. This is how I run my cranks on my fat bike – I designed it that way, rather than a manufacturing cock-up.

Fantastic, glad to hear there are workarounds.

Im transplanting parts from my fatty v2 and did know about the clearance with a 100mm crankset. Trying to minimise extra spends as thought this was a bargain.

Dovebiker excuse my ignorance were you part of the original design team? If so I have a headset question too. Good to know a 120 aether will work.

Just spoken with the eBay seller, he doesn’t seem to believe me that there is an issue. Have supplied plenty of examples of the problem and he’s going to research it.

Other frames he’s got look like the same problem/ issue batch.

shame cos the frame looks really nice, just not prepared to drop several hundreds to bodge a solution.

edit

sellers a prat, suggests the fault is all down to pre load and actually shows evidence from the mtbr thread of the cranks working if you don’t actually tighten them up properly (it doesn’t)

avoid stormwholesale on the bay of e

There seems to be quite a few mint looking On-One Fatty Trail frames going on eBay from multiple sellers…

As far as I recall there are only two real “fixes”:

1) “You need to run a 120mm BB crankset like an Aeffect (if you can find one) or Turbine with a 100mm BB and simply fit a 10mm spacer to either side. This is how I run my cranks on my fat bike – I designed it that way, rather than a manufacturing cock-up.”

2) Go for one of these:

With the longest axle you can get then run a square taper BB. Photo shows a 120mm width. You would want a 100mm BB with a 159mm axle. Something like this:

Neco Fat Bike Sealed Bottom Bracket Square Taper

I run a set up like this on my Commando. The Commando doesn’t suffer the same issue per se as these On One frames but does have very wide stays. Works a dream and bearings look simple enough to replace:

Raceface have stopped doing the Aeffect for fat bikes, the Ride is the only 24mm spindle one they do.

I had this problem. It was cheaper and easier to buy another frame for £80.

On one should have destroyed them all. Now that they are out in the wild they should feel obligated to buy them and crush them.