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Discussion Starter · #1 ·
Just wondering if there is a consensus on outboard/external bottom brackets in going with Sram gxp vs. Shimano (Hollowtech?). I'm looking at ease of set-up and servicing with wet weather riding. I understand the recommendations for higher end/aftermarket versions of these bb. I'm just wondering if there tends to be a preference among those who work on a number of different bbs.

Also, and this is the weird but important question, do certain external bottom brackets have wider thread areas on the cups. Simply put, will one bottom bracket have more threads on a cup than another? I mean any brand/style here, aftermarket gxp or Shimano.
 

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I've thrown a wrench around numerous examples of each.

I've had a GXP BB and crankset that's moved from 5 different bikes.

I've seen Shimano external cups do the same.

I honestly think they are both very strong and easy to work with. If I HAD to chose, Shimano has a better QC department than Sram. So I'd base my choice from manufacturing statistics.

Are you trying to decide between the two?
 

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Discussion Starter · #4 ·
Thaks for the replies. I currently have the Sram set-up, but I haven't had the best luck. I started reading about the web, and there is a lot of grumbling about the gxp bb system being a bit fussy where torque tolerances are concerned, plus the non-driveside cup tends to back out...which happened to me twice now, one OE gxp bb and one aftermarket gxp bb, and it also ruined my eccentric bottom bracket.

In another thread regarding the eccentric, Thomllama provided some great advice, and made the suggestion to stick with gxp, but upgrade to a high-end bottom bracket. I could do that, but for the same price I could also buy an SLX crank, sell my Sram set-up, and come out about even. Costs would be essentially the same.

However, now that I'm replacing the eccentric and the external, I'm going to learn how to do the maintenace on the bb area. I was just wondering if one set-up is more reliable and less fussy. I'm a bit gun-shy of the Sram after my issues, but I also recognize that there's more to the equation than system type. I'm kind of a set it and forget for as long as possible type, which you really can't do with my bb area set-up. If enough mechanics came on and said one style causes fewer headaches, I would go that route. If I'm just over-thinking things and making much ado about nothing, I'll stick with gxp.
 

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I have used a Sram Hammerschmidt BB (Half External half ISIS) as well as a Shimano Saint BB. Both have been pretty solid. The Hammerschmidt has 5 years of riding and many miles on it and still runs smooth. Although the Hammerschmidt inherently has drag so that my hide something in the way of the BB bearings. There is no slop or play though.
I just replaced the Hammerschmidt with a Saint M820 crankset about 4 months ago and it has been solid so far. I do like the way Shimano crankarms are held on with pinch bolts and the preload can be adjusted over the Sram single bolt threading into the crank spindle. And I do like how inexpensive the Shimano BBs are. Bearing go bad, replace the whole BB. The dust seals on the Shimano BBs also look more substantial.
Just to add, Saint BB have longer threaded areas than Shimano's other BBs. Gives you more thread engagement when running a chain guide.
 
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