Long time lurker first time poster.
Is this installation correct? Do i need a wave washer? Why this frame has a 95mm wide bb shell?
Please enlighten me.
Strange bb-frame setup, help needed
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kaptanpedal
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- Joined: Sat Mar 03, 2018 6:10 pm
Last edited by kaptanpedal on Fri Apr 01, 2022 9:18 pm, edited 2 times in total.
What is the frame?
The bottom bracket shouldn't be sticking out like that. Can it be reseated so the lip of the bb sits against the frame?
There should be a wavy washer (+/- 0.5mm plastic spacers) on the driveside to take up the gap between the driveside bottom bracket shell and the crankarm/spider. This is too eliminate the 'dead space' on the axle that allows migration of the bottom bracket cup out of the shell.
The bottom bracket shouldn't be sticking out like that. Can it be reseated so the lip of the bb sits against the frame?
There should be a wavy washer (+/- 0.5mm plastic spacers) on the driveside to take up the gap between the driveside bottom bracket shell and the crankarm/spider. This is too eliminate the 'dead space' on the axle that allows migration of the bottom bracket cup out of the shell.
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kaptanpedal
- Posts: 37
- Joined: Sat Mar 03, 2018 6:10 pm
Some more measurements: length of the crank spindle: 117mm
Distance between two extremes of bb: 105mm.
Which leaves 12mm of spindle to install left crank arm.
Distance between two extremes of bb: 105mm.
Which leaves 12mm of spindle to install left crank arm.
Last edited by kaptanpedal on Fri Apr 01, 2022 9:19 pm, edited 1 time in total.
When you slide a GXP crank into a GXP bottom bracket it stops when the step on the axle contacts the non-driveside bearing. The driveside crankarm doesn't actually touch the driveside bearing shield. Therefore if the driveside bottom bracket shell comes out a little, as yours has, the chainline doesn't change.
By design GXP leaves a gap between the driveside bearing shield and the driveside crankarm. With a pressfit cup it can migrate out of the shell until it stops against the crankarm. That is why pressfit GXP bottom brackets ship with a wavy washer and microshims to fill that gap.
Either you bottom bracket wasn't pressed all the way in, or it has migrated out of the shell with use. Have it pressed in again and install the wavy washer.
By design GXP leaves a gap between the driveside bearing shield and the driveside crankarm. With a pressfit cup it can migrate out of the shell until it stops against the crankarm. That is why pressfit GXP bottom brackets ship with a wavy washer and microshims to fill that gap.
Either you bottom bracket wasn't pressed all the way in, or it has migrated out of the shell with use. Have it pressed in again and install the wavy washer.
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kaptanpedal
- Posts: 37
- Joined: Sat Mar 03, 2018 6:10 pm
Yes, it looks like washer got brittle and broke off. It was installed by a pro and i never had a problem at the begining. I checked the road bike and washer there was in two pieces and fallen off. Damn washers are hard to find too.
Better to renew my dental insurance while at it.
Better to renew my dental insurance while at it.
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robbosmans
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Any bike shop should have the wavy washers in stock
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