BBSHD slightly too wide for 68 mm bottom bracket

[sysrq]

When tightening M6 bolts there is a 0.5-1 mm gap left between the steel bottom bracket and fixed holder. This will prevent the fixed holder to sit in parallel with the bottom bracket when tightening down the M33 locknut rendering some of the serrations unable to bite in to the bottom bracket.
Surprisingly wasn't able to find discussions about this issue.
Actual size is 68.08 mm.
On a nearby aluminium frame it's 68.43mm.
Probably the only solution is to file down the M6 tabs on the motor.

 

[tomjasz]

Google is your friend, a number of resellers have 1mm, 2mm and 3mm spacers.

search string "BBSHD 1mm spacer"

Where are you located? If USA I likely have a few in my unused bits pile. They can go in a first class envelope for cheap.

 

[sysrq]

Google is your friend, a number of resellers have 1mm, 2mm and 3mm spacers.

search string "BBSHD 1mm spacer"

Where are you located? If USA I likely have a few in my unused bits pile. They can go in a first class envelope for cheap.

Putting the 1 mm spacer on the nondrive side would render the serrations useless. On drive side it wouldn't make any difference.
BBSHD is made for 68.98 mm according to measurements.
Another option is to file down the 4.20 mm fixed holder since it doesn't transmit any torque anyway.

Might try 1 mm aluminium spacer to see how it holds up.

Actually 1 mm spacer on the drive side will also work but will reduce the Lekkie chainring offset from 20.8 mm to 19.8 mm.

 

[tomjasz]

the serrations ime we’re not effective i unless we used bafang torque specs. but even then. it’s why my old shop designed the stabilizer and made it open source. Doug at california ebike did more for BBSxx users than any other reseller.

 

[sysrq]

Incorrect non-drive side motor gasket thickness could be the main reason why is it wider than specified. Still seems wierd that this is the only example having this kind of a problem. Probably just a bad batch.

 

[Mongo]

IIRC, on the BBSHD / 68mm BB bike I have, I curved the holder tab ears out a touch, using a bench vice and a large crescent wrench. I've curved the ears in on some 73mm builds. Whatever's needed, as opposed to washer stacking. Tightened with a socket and a breaker bar, and the motors haven't moved.

 

[mcfizzlestag]

When i had my BBSHD on an aluminum frame, it did loosen off from time to time, and i needed to keep tightening it with my very accurate beater screw driver and hammer This may be due to cold flow from aluminum (not sure if it affects 6061 alloy tbh). However on a steel frame it doesn't budge. I do recommend a bit of rubber between the motor and the downtube though. As for the spacers, i have a 73mm bottom bracket and boost frame, so i have to get creative. Think im using a pair of larger brass nuts atm, but i've used random washers/lock wasters with no problem. Whenever i order lekkie parts, i always forget about trying their spacers :/