Can I mix a DA 7900 bottom bracket with my Ultegra SL group?

[jojoma]

For the past couple months I have noticed a tiny bit of "play" on the drive side when pedaling. It's very slight, but it has messed up my right knee quite bad. I thought it was my pedals, so I bought brand new Speedplays and Ultegra SL pedals. But I still feel it when using either of those pedals. Next I thought it was my shoes/cleats, so I bought the highest end Shimano's (R300). But I still feel this "shiftiness" in my foot when I pedal.

So know I'm thinking maybe it's the bottom bracket. The cost difference of a BB is not huge, so I might as well get the best one. Will a DA BB work?

Thanks

 

[alienator]

For the past couple months I have noticed a tiny bit of "play" on the drive side when pedaling. It's very slight, but it has messed up my right knee quite bad. I thought it was my pedals, so I bought brand new Speedplays and Ultegra SL pedals. But I still feel it when using either of those pedals. Next I thought it was my shoes/cleats, so I bought the highest end Shimano's (R300). But I still feel this "shiftiness" in my foot when I pedal.

So know I'm thinking maybe it's the bottom bracket. The cost difference of a BB is not huge, so I might as well get the best one. Will a DA BB work?

Thanks

Yup.

 

[Peter@vecchios]

For the past couple months I have noticed a tiny bit of "play" on the drive side when pedaling. It's very slight, but it has messed up my right knee quite bad. I thought it was my pedals, so I bought brand new Speedplays and Ultegra SL pedals. But I still feel it when using either of those pedals. Next I thought it was my shoes/cleats, so I bought the highest end Shimano's (R300). But I still feel this "shiftiness" in my foot when I pedal.

So know I'm thinking maybe it's the bottom bracket. The cost difference of a BB is not huge, so I might as well get the best one. Will a DA BB work?

Thanks

Yep, the 7800 or 7900 one.

 

[alfeng]

FYI. You can simply replace the bearings used in most-if-not-all external BB cups.

 

[Camilo]

I think you should figure out what the problem is before you continue to throw parts at it. It seems to me it wouldn't have been that difficult to actually pinpoint the problem before you started your solution quest.

 

[stevebaby]

It may just have loosened off a bit, which can also cause BB lay. Check the cups.

 

[jojoma]

I think you should figure out what the problem is before you continue to throw parts at it. It seems to me it wouldn't have been that difficult to actually pinpoint the problem before you started your solution quest.

I took my bike to a couple of the best shops in the San Fran Bay Area, but they could not identify any problem. But I still knew there was something wrong, so I kept buying stuff in the hope that it would go away. I even considered buying a brand new bike, but I took a few deep breaths and came to my senses.

But I happened to take my bike to a young 20-something mechanic a few days ago and he identified the issue in about 5 seconds. It was a worn cassette. I guess the grooves widen and it doesn't mesh well with the chain. So I bought a new CS-6600 and the problem is gone.

 

[Tech72]

On the bright side, you now have a nice and new shoe/pedal combo......

 

[jojoma]

On the bright side, you now have a nice and new shoe/pedal combo......

And a DA-7900 BB. Someone please tell me this bottom bracket is far superior to Ultegra so I don't feel as bad.

But it looked like pretty much the same thing when I was installing it. Good thing I didn't go with the Chris King ($150?) that the LBS had.

 

[Albert 50]

I took my bike to a couple of the best shops in the San Fran Bay Area, but they could not identify any problem.

& they were the best

 

[Peter@vecchios]

FYI. You can simply replace the bearings used in most-if-not-all external BB cups.

You can replace the bearings in these and other cups but I wouldn't call it 'simple'. I have a tool kit from Phil Wood and if you don't have some sort of 'kit' you really can't hammer these things out and in w/o killing the new ones.

 

[swampy1970]

For the past couple months I have noticed a tiny bit of "play" on the drive side when pedaling. It's very slight, but it has messed up my right knee quite bad. I thought it was my pedals, so I bought brand new Speedplays and Ultegra SL pedals. But I still feel it when using either of those pedals. Next I thought it was my shoes/cleats, so I bought the highest end Shimano's (R300). But I still feel this "shiftiness" in my foot when I pedal.

So know I'm thinking maybe it's the bottom bracket. The cost difference of a BB is not huge, so I might as well get the best one. Will a DA BB work?

Thanks

*** edited for political correctness ***

 

[swampy1970]

You can replace the bearings in these and other cups but I wouldn't call it 'simple'. I have a tool kit from Phil Wood and if you don't have some sort of 'kit' you really can't hammer these things out and in w/o killing the new ones.

Big vice and a few pieces of good ol' 2x6 wood.