Problem with SRAM PF30 Bottom Bracket

[carbonazza]

Back in June, when ordering my 256 frame, I thought PF30 is the new standard, and took this format.
Then I installed the stock SRAM PF30 that comes with the XX1 groupset.

So far so, good. No creeks or any noise, and without the need of loctite.
Spinning the pedals by hand - without the chain on - was far from smooth, but ok.

Things started to get wrong after the first real ride in the mud.
The bearings were immediately contaminated.
Spinning was sticky, and the bearings made a noise like there was sand in them.

I took the bearings out, cleaned them. And packed them with grease.
If you wonder. They were pre-loaded correctly and I don't pressure wash the bike.

Unfortunately SRAM's BB looks to be designed either for dry conditions only. Or as disposable gear you discard after a race.
A the next wet ride, the bearing were making again the scraping noise and the spin seriously degraded.
It may be a little mental-thing(like many on a bike), but having a resistance when pedalling was depressing.

So I started to look at alternative options.
And found bbinfinite.com

I liked the design immediately, and ordered one.
Mounting it was easy, and wow... what a difference!
The spin was so smooth that I made this comparison video:


Now, after a few weeks of very wet/muddy rides(see the attached picture of a soft one).
The BBinfinite is now making a light noise too(non-drive bearing).
But it keeps spinning like in the video.
Nothing compared to SRAM's noise and friction.

I returned the BB to SRAM(through bike24.com), explaining the design issue for wet rides.
They were very kind, and returned me a new BB.
Unfortunately without any word or explanation, so I guess nothing will change on SRAM's side.

[Sussed.]

Great write up Carbz ! 

I agree that SRAMs bearings don't seem to last.  My drive side bearing has become a bit gritty, I have cleaned it up as best as I can but there is still a crunchiness to it.

I have a replacement ready to go and will swap it out when it gets to the point of really annoying me !

[blueducati]

awesome pic of the bike, by the way! 

[Carbon_Dude]

I've stuck with the BSA (w/SRAM GXP External BB) and have had very good luck with my bottom bracket bearings.  No creaks, no scraping, smooth crank rotation, no early wear out.  If anyone asks me, I continue to recommend BSA/External BB.  I don't see the benefits of BB30 being lighter, stiffer, and lower Q-factor.  My hard tail is less than 20lbs, the carbon is plenty stiff, and the 168Q is good for stability, for someone who may have knee problems, I suppose a more narrow Q-factor would be desirable.  Although, XX1 is also available in 156Q so again, BB30 loses that advantage with XX1 cranks.

BSA also does not require pressing the bearings into place and fits the largest variety of cranksets.  The only BB tool needed for BSA is a simple wrench or socket tool.  Servicing my BB is very easy.  I tend to think BB30 or PF92 are new standards that may offer some small improvements but bring in new problems.

As an aside, I did jump to thru axles for both wheels, that just made sense to me, even though it is slightly heavier.  I always hated having to fiddle with aligning my QR wheels.  I don't notice any difference in stiffness, thru axles are just more convenient, easier to remove and install the wheels.

[cmh]

As an aside, I did jump to thru axles for both wheels, that just made sense to me, even though it is slightly heavier.  I always hated having to fiddle with aligning my QR wheels.  I don't notice any difference in stiffness, thru axles are just more convenient, easier to remove and install the wheels.

Yeah, dunno how much the stiffness is actually improved, (or if most folks could really feel the difference) but I like the concept, but I _really_ like the ease of reinstalling the wheels.  With QR wheels I usually pop the bike out of the stand and set the QRs with the bike on the ground and weight on it.  With thru-axles, you put the wheel in, put in the axle, _done_.

[brmeyer135]

Heck, the thru-axles aren't necesarily a weight penalty if you spend some cash....Extralite
But, much like many like the ease of XT brakes....their weight penalty is overlooked also.

Surely, stiffness is improved just from more material 12mm vs 9 or 10mm...same with bb30
Now, is it any of us can register....seriously doubt it.

[cmh]

Surely, stiffness is improved just from more material 12mm vs 9 or 10mm...same with bb30
Now, is it any of us can register....seriously doubt it.

Exactly.  The engineer in me says "it's demonstrably stiffer! It's math!" and the rider in me says "yeah, but does it really make a difference?" Maybe to my wife who knows when her tire pressure is off by a PSI or so.   

[JohnnyNT]

When it comes to BB, some companies make BSA bottom brackets that allow BB30 wider spindle (Rotor being one example). It is a solution gathering advantages from both systems nicely.