After almost two years, my SRAM PF30 BB has finally died – not bad considering that it sounded cement mixer rough as I rode it out of the shop back in September 2014.

I’m running XT cranks with adaptors, is this the replacement BB I need?

That Praxis BB is the right one, and they’re good quality, but I’d go for a Wheels mfg one personally. I had the Praxis for a little while and it worked fine, but because of the collet system it can sort of tighten down on itself before it’s actually tight in the BB shell (if your BB shell is a on the narrow side of the tolerances). The Wheels one is pretty much the same but without the collet bit, and it’s easier to change the bearings.

Wheels MFG PF30 to 24mm

I’d recommend the Praxis Works conversion BB

I’ve had 4 Stumpjumper frames (1 aluminium, 3 carbon) and each of the 3 PF30 frames had a different tolerance (loose fit) on the inside diameter of the BB shell, which caused ongoing BB problems

Only the BB30 frame was within normal tolerance.

The Wheels BB would not stay tight and creaked. I tried grease as recommended, then fibre grip, did not work.

The Praxis BB would only stop creaking under power with a liberal application of Finish Line Fibre Grip (for carbon) on the BB shell interior before insertion – I used grease as normal on the metal/metal interface between the Praxis cups.

Perhaps an issue with the Praxis design is they use a PF30 nylon sleeve around the BB30 bottom bracket. I am sure with a “pure” PF30 design with the collet having a greater range of expansion they could accommodate a wider tolerance range.

You won’t know until you try to fit it, or have access to vernier calipers and can measure the shell ID, and check against the recommended tolerance (46mm +0/-0.05)

Thank you guys, much appreciated.

I’ll give the Praxis one a try. So far, my SRAM BB has lasted well over eighteen months (that’s got to be some sort of a record, surely?) so I reckon my BB shell is in good shape. Plus, it’s in stock at the Evans at the end of the street.

@PJM

follow the Praxis fitting instructions to the letter

here’s the Wheels one I tried without success

Praxis that worked with fibre grip

great vid from Praxis Works on youtube:

https://www.youtube.com/watch?v=5eeT7c7Xcqc

its very easy to miss a critical step during the installation, which can cause a looseness once tightened down

Thanks for the tip – again, much obliged.

🙂

PJM1974….

Was that the original bb then ?

Interested to hear what adapter set you are using and how it feels etc ? Any creaking at all ?

Would it be cheaper to buy a decent bb30 bottom bracket and carry on using the adapters ?

Got this to contend with on my own stumpy.

My Stumpjumper now has a brand new Praxis BB with XT cranks installed. I’m just waiting for a day off so that I can take it for a test ride. Fitting the BB was an absolute doddle, I simply twatted out the old bearings and nylon cup and pressed in the Praxis assembly and tightened with two standard Shimano BB tools.

@Renton:

Yes, somehow the original BB had lasted nineteen months of Kentish filth and neglect. The NDS bearing flew apart upon being tapped out, the race, balls and retaining cage were officially ronnied, given the amount of ferrous dust that fell out. The DS bearing was in better condition, but was clearly on its last legs.

For the last eighteen months, I’ve used the Wheels Manufacturing adaptors, which did the job without fanfare. I wasn’t aware of any creaks, but the fit of the adaptors into the bearings themselves was a bit ropey – I couldn’t cinch my cranks up enough to engage the locking tab.

TBH, you’re better off with a Hope or Praxis bottom bracket, if only for the superior bearing seals.

We have had one of ours fail so far and had it replaced with a Hope one, my new frame was specked up with a Hope one. If and when the rest need replacing will use the Hope ones again.
My big concern at the moment is that the new headset bearings on the later models aren’t lasting long at all and I cant find the equivalent replacements. Think Hope do a bottom one but not sure on the top.

Or even better; fit a FSA PF30 adaptor sleeve and never have to worry about crappy press fit bottom brackets again… Did it on my 2012 Stumpjumper evo & it’s worked perfectly (standard shimano HT2 type external bearings just screw in to the alloy sleeve which is press fit & loctited into your BB shell)
It amazes me that FSA haven’t made a bigger deal of this item, as it’s a f***ing awesome bit of kit! 😉