BB30/PF30 bottom bracket advice

mickisup

Are all BB30/PF30 brackets compatible with any BB30 frame?

Or does the BB need be of the same manufacture as the Crankset?

Looking for advice as there are mixed reviews of the SRAM PF30 and I can't quite stretch to a Chris King!

Many thanks

tgotb

BB30 and PF30 are completely different, from the frame perspective. In other words, a PF30 frame needs a PF30 BB, and a B30 frame needs a BB30 BB. However the cranksets are identical, so a BB30 crankset fits a PF30 BB/frame (this was my CX setup for last season).

There are also a bunch of adaptor BBs. So, for instance, you can get adaptors that fit a PF30 frame and allow you to use a standard Hollowtech crankset. One of my bikes has a BSA (standard threaded) BB, and I'm using a BB386EVO adaptor to allow me to run a BB386 crankset. Not all combinations are possible, but there's a surprising number of combinations.

One thing to be wary of (since you posted this in the CX forum): Standard BB30 and PF30 bottom brackets are pretty poorly sealed, and struggle to cope with serious amounts of mud, or pressure washing. Last season, once it got muddy I was having to strip down my PF30 bearings after every ride, and replaced the bearings completely at least twice during the season. The only good thing is that both PF30 and BB30 enable you to replace just the bearings, and I seem to remember you can get them for a shade over £10 a pair if you shop around. You will need a bearing press though...

Monty Dog

If you haven't got yourself sorted with cranks, then look at fitting a 24mm spindle crank (Hollowtech 2 / MegaExo / GXP etc) with the appropriate adaptor (e.g. Praxis, KCNC) and save yourself a whole deal of grief. BB30/PF30 use the same bearing/spindle interface just that PF30 sits the bearings in a plastic housing in the vain hope that it might stop the bearings from creaking.

tgotb

Monty Dog wrote:

PF30 sits the bearings in a plastic housing in the vain hope that it might stop the bearings from creaking.

If you seat your PF30 with the recommended type of Loctite you should be able to stop the creaking.

NB: The above isn't so much an endorsement of PF30, as a tip for PF30 owners. Unless you have a strong preference for a 30mm spindle, the recommendation to adapt your way down to 24mm is a good one...

ugo.santalucia

Loctite is the 21st century evolution of gaffer tape, which was the late 20th century evolution of steel wire... when you need Loctite to keep things together, you know the engineering is censored

plodder73

ugo.santalucia wrote:

Loctite is the 21st century evolution of gaffer tape, which was the late 20th century evolution of steel wire... when you need Loctite to keep things together, you know the engineering is censored

Absolutely right and it doesn't work. My LBS has used two different types of Loctite, result still creaks. Given up with it going to order a Praxis adaptor and new chainset. That's £150 I shouldn't have to spend.

tgotb

ugo.santalucia wrote:

Loctite is the 21st century evolution of gaffer tape, which was the late 20th century evolution of steel wire... when you need Loctite to keep things together, you know the engineering is censored

Which is why I said it was a tip for existing PF30 owners rather than an endorsement of PF30 :roll:

Anyone with a PF30 frame who is opposed to the use of Loctite on religious grounds is more than welcome to reassemble their bike without it, and enjoy the creaking. They might also want to check the rest of their bikes, in case Loctite has been used elsewhere and needs to be removed; the bolts attaching disc brake calipers to frames, and rotors to hubs, seem to be common culprits. come to think of it, stem bolts seem to come pre-loctited too :shock:

ugo.santalucia

TGOTB wrote:

They might also want to check the rest of their bikes, in case Loctite has been used elsewhere and needs to be removed; the bolts attaching disc brake calipers to frames, and rotors to hubs, seem to be common culprits. come to think of it, stem bolts seem to come pre-loctited too :shock:

The difference is that loctite is used on threads as a preventative measure, or in other words it does what it's meant to do... but it's not essential... the screw will work fine without it. My point is that if you need loctite to stop something from creaking, then you know you bought a pile of censored ... and you agree on this... anyway, off topic... :shock:

tgotb

ugo.santalucia wrote:

The difference is that loctite is used on threads as a preventative measure, or in other words it does what it's meant to do... but it's not essential... the screw will work fine without it. My point is that if you need loctite to stop something from creaking, then you know you bought a pile of censored ... and you agree on this... anyway, off topic... :shock:

Since we're getting technical...

Loctite is a brand name rather than a specific material, though the name's often used loosely to describe threadlock (in the same way as Hoover is used generically for vacuum cleaners).

The Loctite recommended for use with PF30 BBs is Loctite 641, which is described in the data sheet as "designed for the bonding of cylindrical fitting parts". This is a pretty accurate description of what's required for a PF BB.

Plodder - do you know which types of Loctite your LBS tried? If they just used the threadlock they had on the shelf, they might aswell have used PVA glue or even cheese. My experience of LBSs is that, whilst they're probably great at replacing chains and gear cables, if you want a less-mainstream job done properly you're often better off doing it yourself.

For what it's worth, I don't reckon the PF part of the PF30 is actually that bad. Even if you assemble it without any form of bonding agent, all that happens is that it creaks a bit; it's not going to start moving around significantly, damage any other components, or fall apart. The plastic part of the BB is softer than the aluminium or carbon/epoxy frame material, so any permanent deformation should be limited to that component, which is easily replaceable. It's a compromise, but so is an aluminium BB shell threaded into a steel or carbon frame; seized aluminium bottom brackets have resulted in the demise of more than a few frames. For me, the real issue with PF30s and BB30s (and, by the look of it, the BB386Evo adaptor I installed on my new CX bike) is the rubbish seals.

In terms of serviceability, robustness and longevity, I've yet to see an improvement on the steel BB cups screwed into a steel frame with loose steel ball bearings and a square taper crank, that I had when I was a teenager. It was probably heavier and flexible than modern bottom brackets, but there wasn't much to go wrong. Mind you, the cottered crankset that preceeded it was an absolute disaster!

ugo.santalucia

TGOTB wrote:

In terms of serviceability, robustness and longevity, I've yet to see an improvement on the steel BB cups screwed into a steel frame with loose steel ball bearings and a square taper crank, that I had when I was a teenager. It was probably heavier and flexible than modern bottom brackets, but there wasn't much to go wrong. Mind you, the cottered crankset that preceeded it was an absolute disaster!

Exactly... everything was enclosed in a mechanism produced by one manufacturer, the fitting was idiot proof, nothing could go wrong. While now you have the frame and BB shell made by X, that has to fit the bearings made by Y, which have to go with the crankset made by Z. In addition the fitting is more critical, as it doesn't rely on a foolproof thread. There isn't a protocol for tolerances and it's a game of guessing... will it work? Will it not? To make up for the various degrees of tolerance, the manufacturers suggest to stick some bonding compound essentially to fill the gaps, freeze it and make everything tight... it is a censored solution, the real solution would be for Shimano to make BB shells that go into the frames and the bearings, at least the tolerance problems would be avoided.
There is a reason threads have been so popular for centuries and the reason is they are very reproducible and the fitting is not subject to how good the fitter is.
If you fit some bearings in a hub with a press, then I do the same and John does the same, you can be sure the mileage will be different

mickisup

Thanks all for your answers thus far. However I am still rather confused the Ridley frameset (X-Fire) mentions that it's a BB30 model but also lists PF30 in the technical spec.

Am I looking for something like this?

http://www.chainreactioncycles.com/sram ... -prod40333

Or do I need this?

http://www.chainreactioncycles.com/sram ... lsrc=aw.ds

Crankset will be SRAM Force.

tgotb

Looks like PF30 according to this:
http://www.ridley-bikes.com/gb/en/bikes ... e-20-1502b
Which would be the second of your links. Might be safe to check with Ridley though.

The bearings are identical; the PF30 includes a plastic housing, whereas the BB30 BB is just the bearings themselves plus some circlips to locate them in the correct place within the frame; all the other bits in the BB30 pic are seals, wiggly washers etc, which will come with both. I have knocked the bearings out of a PF30 housing and replaced with standard BB30 bearings on several occasions.

The BB30 SRAM Force chainset will fit either.

If you're going to be racing this bike you need to keep a very careful eye on these bearings once it gets muddy, especially if you use a pressure washer. Part of my post-race routine involves taking the cranks out, removing the bearing seals and cleaning/regreasing the bearings. Only takes 10 mins but if mud and water get in and you don't do this, your bearings won't last very long at all.

If you don't want the BB to creak, fit with Loctite 641 :-)

Ridley make nice CX frames :-)

mickisup

Many thanks TGOTB, I think I will buy both and then just return the one that isn't correct. I have emailed Ridley but they havent yet replied.

Interestingly the retailer who supplied the frameset weren't sure either!

In the future would a Chris King BB be a better solution?

In terms of Loctite, does that present an issue later if the BB ever needs to be removed?

tgotb

The sealing issue isn't so much with the particular model of BB, as the BB30 design in general; the bearings are relatively exposed, and the seals not particularly effective. Something like a Chris King PF30 to Hollowtech adaptor BB might be better sealed, but that won't work with your BB30 crankset, so you'd need to replace the crankset too. To be honest, they all have their pros and cons, and the flip side is that the BB30 is way easier to service than any other BB I've come across. Something like a Shimano Hollowtech BB may be better sealed but if you do get mud in it you're expected to throw it away, whereas cleaning out a BB30 is a 5 minute job. I've just finished building a new CX bike with a BB386EVO BB (which is basically a wider version of the BB30, but with all its disadvantages). I specifically chose that because, for me, the upsides (lighter, stiffer) still outweigh the downsides.

When your frame arrives it'll be pretty obvious whether it's PF30 or BB30, especially if you have the BBs to hand.

Loctite 641 is specifically designed for components you might want to remove later; I accidentally removed mine (user incompetence, wrong size bearing extractor) and it came out easily enough.

Edit: Just noticed you're in Hertfordshire. Are you going to be racing in the Central league? If so, I'll see you around...