markwesti

BB in question is a cartridge type 68 110mm . On the drive side the axel sticks out 16.7mm from the shell , on the non drive side it sticks out 22.mm . Why is this ?
Thanks , Mark .

Bill Kapaun

Because it takes a crank that requires those offsets.
The crank determines the BB, not the other way around.

roadcrankr

Good question. It sounds a little odd to me, as well.
I am fond of the old Dura Ace 7410 square taper. Bullet-proof suckers. lol
It measures evenly on both ends for a 68mm shell - probably close to 17mm each. (I just measured a NOS one in my parts bin.)
This should not matter for square-taper spindles of identical length, since the crank arms plunk on there just the same.

markwesti

My story ? OK , I needed a BB and I wasn't sure what size but I knew I needed 68mm . I thought I would start with 110mm , I bought this BB from the bay , it was just advertised as 68x110 no mention of being longer on the NDS . I could see a BB being longer on the DS , I don't understand the other way around . No matter , I'm trying to get my drive line in line and I have determined I need a 103 BB (I think) I need to move in about 5mm to get in line . I see 107 and 103 BBs' but nothing to make the math perfect .

The bike is , was , a Cannondale SR 300 with vertical dropouts . I made horizontal track forks , got that all welded together and then I spaced it to 120mm from 126mm . I did this by making hacksaw cuts to the chain and seat stays , not going through all the way but enough to let it fold into place and then weld it up with a 120mm spacer .

IMG_0881 by mark westi, on Flickr

IMG_0880 by mark westi, on Flickr

2_i 

73mm BB might explain it. Otherwise, asymmetric BBs exist, but in more expensive categories. In my BB system, around TA Axix, I can have asymmetry I want, sticking out more to the left or right.

markwesti

Thank you . The model I'm not sure , it's a Shimano . On the box it's marked BC137 68 mm 110 . Like I said I got it just to see where to start , It was only 20 bucks . I just ordered a 103mm even cheaper at 14 . If that works out I will replace it with some good stuff .
https://www.ebay.com/itm/16252151687...c47e%7Ciid%3A1

2_i 

You can put a cassette spacer on the drive side and get it even.

P.S. Ebay photos suggest that you should be able to take this BB apart and examine in detail what the situation is. Maybe one of the bearings is not seated correctly.