Question on Shimano 7800 Bottom Brackets Help

Satellite · #1 03-08-2009, 05:03 PM

I have just tore down two of my bikes to tune them up for the return of Spring.

All my bikes are dressed in D/A 7800 and I have just noticed that two of my bottom brackets are different. The one on the left has a larger bearing surface. Did Shimano change the designs is one better than the other? Do I have to match the cranks to the proper bottom bracket because I am NOT sure which is which now.

Any help is appreciated,

Satellite

LegendRider · #2 03-09-2009, 08:58 AM

Anyone?

Spicoli · #3 03-09-2009, 09:20 AM

I had the same thing, My original 7800 group had a different BB than another 7800/01 group I got a little less than a year later. I believe the one on the right is just the newer version? Cranks however did not change so it should not matter which crank goes where. The inner spec and width are the same on both BB's to the best of my knowledge.

Ken Robb · #4 03-09-2009, 10:02 AM

I guess the first one was the Beta version. I hope it doesn't make your computer

lock up.

LegendRider · #5 03-09-2009, 10:04 AM

Speaking of 7800 bottom brackets, mine are stuck. Should I use a rubber mallet to give my ratchet a tap OR should I find some sort of cheater bar for add'l leverage?

Ken Robb · #6 03-09-2009, 10:24 AM

I would try gentle taps first because they may undo any corrosion and allow you to get the bb out without using as much torque as you would need to apply with a cheater bar to achieve the same end.