Bafang ultra ISIS bottom bracket? or something else?...

General Discussion about electric bicycles.
Post Reply
Jimmydoerty   100 µW

100 µW
Posts: 7
Joined: Sep 13 2019 4:15am

Bafang ultra ISIS bottom bracket? or something else?...

Post by Jimmydoerty » Dec 11 2019 6:16am

Hi all, second post today; trying to push some thoughts out while they're still fresh..

Long story short I have stripped the threads on my left crank arm (non-drive side) on my Bafang ultra Alu cranks. I can't seem to find ANYTHING on these exact model of cranks for a replacement, so I am left to do some digging. Picture below showing Bafang Ultra / Samox collaboration cranks.

After looking around, bafang (and almost every post I've seen) says these are ISIS 10-spline universal standard style for the bottom bracket and cranks.

From this, I've bought a set of Truvativ Hussefelt ISIS drive cranks, but to no avail as they don't tighten / fit properly. When fitting the cranks, they will fully slide onto the bottom bracket splines but even when tighetened they do not sit fully secure and have a wobble. One would assume this is a problem with the locking nut being too long for the bafang bottom bracket, but I beg to differ as the crank has side to side, AND slight forward and back movement,
as if its not tightly engaging with the splines on the bb. Also looking at the two different bottom brackets shows slight slight differences in width of spline.

Don't really want to buy another set of cranks to find out if I'm wrong or an ebay seller was wrong, but these seem like ISIS drive cranks from all the googling I have done. If anyone has any insight into the spec on the bottom bracket the bafang ultra uses I'd be super grateful as I'm eventally going to have to do some hacking x-(

Thanks all.
Attachments
6BDDB7DD-0CC2-4486-990F-93ADB472AD71.jpeg
6BDDB7DD-0CC2-4486-990F-93ADB472AD71.jpeg (62.26 KiB) Viewed 611 times
97A35D3A-0EBB-4FDD-8060-B92326254127.jpeg
97A35D3A-0EBB-4FDD-8060-B92326254127.jpeg (446.84 KiB) Viewed 611 times
DEC184AD-9FFB-4AC7-B702-A03CD4ED1436.jpeg
DEC184AD-9FFB-4AC7-B702-A03CD4ED1436.jpeg (219.18 KiB) Viewed 611 times
298C43CE-3593-40DA-AC74-62B9CBDAB03F.jpeg
298C43CE-3593-40DA-AC74-62B9CBDAB03F.jpeg (320.39 KiB) Viewed 611 times

Post Reply