I’m no bearing design expert but I recently ran into some issues with Truvative’s GXP bottom bracket that I thought I should share. 

First of all my setup is an SRAM crankset with a GXP spindle.  What this means is that the crank spindle is tapered from the drive side being 24m OD to the non drive side being 22mm.
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My problem was rapid wearing of the bottom bracket. I started getting creaks then soon there was simply play in the arms that rendered the crankset non operational.  I tried greasing, cleaning, shimming, and tightening the spindle bolt but nothing worked.  The BB was worn beyond repair in less than 1k miles.

I found that one issue with the BB lead to its early demise

The drive side of the BB uses a 23.95 ID bearing that fits snugly to the crank spindles with steel on steel contact.  This works gear and is still fitting tightly.
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The Non drive side, however,  uses the same bearing with a 23.95 ID bearing.  In order to make it fit the spindle they used a 21.98 ID Aluminum Sleeve that fits between the bearing and the spindle.  This works fine at first but the aluminum gets Crushed quite quickly and in turn the system develops play.  Had a been a 21.95 ID bearing on the non drive side the system would last much longer.
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That was some time ago and I recently decided to put the crankset back in use and bought a new Sram bottom bracket.  Problem is SRAM bb’s are made by Truvative!

The first problem, and this is not really Truvative’s fault, I bought it off a cycle store on eBay, The BB came with a missing sleeve/bearing cover on the non drive side!

Now I have to figure out how to make a sleeve and being aluminum it’ll likely wear out quickly again unless I can find some stainless to work with.
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The other problem…  the new bottom brackets now use a 25mm ID bearing on the Drive side with a plastic cover/sleeve!  The one bearing that they got right on the earlier version is now wrong too! If an aluminum sleeve was wearing out too fast, why would they replace it with a plastic piece??  AHHHhhhhhhhhhhhhhh
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Just to be fair though, these BBs are the cheaper alternatives.  I cant speak on how the higher end ones are designed.  I’m just curious what the price difference is between a 25mm ID bearing and a 23.98mm ID bearing or a 22.1 ID bearing vs a 21.95 ID bearing.