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Not encountered this issue before - Shimano HT2 BB on a 68mm BB shell (Mason Bokeh)
2x2.5mm spacers on the driveside, 1 on the non driveside as instructed. Can't get the NDS crank fitted, doesn't seem to be enough of it sticking out and can't engage the thread on the preload cap.
Am I OK ditching one of the spacers, there seems to be enough clearance?
Are you sure the crank is fully pressed home? I know its only meant to need hand pressure but mine has needed a little persuasion with a mallet before now....
Is it definitely a 68mm shell? Is it definitely an MTB BB, and not a road version (they're wider) ?
Mason claims it's 68mm...
Definitely a MTB BB, and it did have a little persuasion on both sides with the rubber mallet.
Taken one DS spacer out now, and it fits fine, with roughly the same clearance both sides.
Bit confusing though, I'll have a proper measure of the BB Shell in a bit.
EDIT: Caliper says 68, and the spacers are the right thickness too.
Same issue! I thought it was cos it was a budget build - cheap ebay cranks and cheapo BB, but after a mishap (crank arm fell off), tried one spacer, only to find the oval ring rubbed on the chainstay… hmm, checked shell - 68mm, checked instructions, spacers- 2 drive side, 1 non… nope crank cap won’t reach threads.
I’m gonna just fit whatever spacers work when I get round to it
Might stick a 1mm spacer in there instead to see what difference that makes.
Still, the missus has just tested positive for Covid, so the build is back on the backburner for the next few days, and probably til after Christmas knowing my luck.
Had this with eBay bbs before, but not Shimano units. Had an eBay bb on 73mm shell with no spacers and a Shimano crank fit fine. Odd.
I have a Bokeh and it’s defo 68mm. I’ve had both road and mtb chain sets on it. The only thing I found was that the bb had to match road to road or mtb to mtb as the cups are a different size. Mind you I’ve only used Shimano ones though ! 2 spacers drive side, 1 non drive.
You could also talk to Mason about it - they’re pretty good at getting back to you.
Isn't the Bokeh a gravel bike and hence designed to use road cranks? Shimano road cranks / bbs don't use spacers. They're designed to run on 68mm shells only and don't require spacers.
I assume you've not fitted a BB mount front mech?
How much paint is on the ends of the BB shell?
You don't have any sort of spacer stuck on the driveside crank? (I've had that problem with Raceface cranks)
The only thing I found was that the bb had to match road to road or mtb to mtb as the cups are a different size.
I've seen this stated on here before, but I've mixed and matched BB cups. When I've measured the only difference is the length of the thread, (to account for a different number of spacers) and the mud shield tube in the middle which can be reused from the old one.
Road cups are definitely deeper.
Assembled MTB BB set ups are 5mm wider than Road as MTB axles are 5mm longer than Road ones, in spite of having 7.5mm more spacers (or 5mm extra shell + 2.5mm spacer when a 73mm shell), so Road cups are 1.25mm wider each than MTB ones.
An MTB BB set up will be 5mm too wide for a Road/Gravel chainset, (and an otherwise MTB set up with Road cups substituted for MTB cups will be 2.5mm too wide for an MTB chainset).
You could remove 5mm of spacers on your existing set up and a Road/Gravel chainset will fit, but your chainline will be out by 1.25mm either way depending on which side your single spacer is fitted, and pedals wil be offset a little.
I’d just buy Road cups and do it right - esp if using a double as you’d need to deviate from the set up guide line on the front mech due to the altered chainline.