x1124x

I've settled on the Eighthinch Crankset for my Bridgestone Single Speed conversion.
On the Eighthinch site they suggest the 68 x 107 JIS style BB. The Bridgestone has a 73mm BB shell. I wrote Eighthinch and asked if the Shimano UN54 73 x 107 would work and their response was they've never seen one of their cranks used with a 73mm bottom bracket and if I can find a 73x107mm it should work. Which I did.

They said it would still fit the 73 x 110 fine but the cranks would be farther out from
the frame which may start messing with the chainline. They suggested I try to browse
some forums and see if anyone else was trying to do the same compatibility.

Should I go with the 73 x 110 and just adjust the rear chainline?
Thanks for any and all help!

rithem

110 is all I see ... for a SS the 1.5mm of difference won't matter much unless you run your chain super tight, which you shouldn't anyway, the 1/8th drive train should tolerate the slight deflection, I wouldn't suggest this on fixed, some might and it might work fine. I hate noisy drivetrains and dropping chains is for numbnuts

cocchiarell

73 is the width of the bb shell and doesnt have anything to do with the length of the spindle. if you can get the 73x107, do that. or get the 73x110 and mount the chain ring on the other side of the spider. also, there are all kinds of little tricks you can do to adjust the chain line (spacers, redishing).

x1124x

Cool, Thanks for the info.
Found this one on Ebay for $15 shipped.
https://cgi.ebay.com/Shimano-BB-UN54-...01853083825326

Scrodzilla

Perfect.

Steev

I had typed a reply saying something like that, but I did a quick check around the garage before posting and noted that the clearance between the BB flange and the inside of the crank is sometimes barely 2.5mm.
The best thing the OP could ask is if somebody who is running this crankset on a 107mm spindle could measure the gap between the crank inside face to the BB flange to see if there's 2.5mm to spare to go to a wider shell.

Scrodzilla

My wife had an EighthInch crankset for a while and found that with the chainring on the outside of the spider, she actually needed a 103mm spindle for a straight chainline. A 107 may put your chainline off by a few mm (which is no big deal) but solve any clearance issues.

x1124x

Awesome. Thanks for the input. Just got my frame back from the powder coater and looking to get started on the build!

Xgecko

This........... I have a 103mm spindle on my Dawes SST and I'm running an Eightinch Crankset...... it works