Creaky BB in Ti frame - Should I grease the cups?

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Calnago
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by Calnago

PF30 came about as a result of the difficulty manufacturers were, and still are, having in creating shells within spec. PF30 does not ease the manufacturing tolerances, it just uses a plastic (delrin) cup to be able to better compensate for the poor tolerances that manufacturers are producing.
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bikerjulio
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by bikerjulio

Calnago wrote:PF30 came about as a result of the difficulty manufacturers were, and still are, having in creating shells within spec. PF30 does not ease the manufacturing tolerances, it just uses a plastic (delrin) cup to be able to better compensate for the poor tolerances that manufacturers are producing.


Perhaps a more diplomatic way of saying the same thing.

The tolerance for PF30 is 46.0 +0 / -0.05 mm

The tolerance for BB30 is 41.985 +0 / -0.025 mm. Which would be 1/2 the allowed tolerance for PF30.

PF30 does have a looser tolerance because as you say manufacturers were having a harder time with BB30 which pretty much requires a bonded in machined alloy shell to achieve, whereas PF30 does not.
There's sometimes a buggy.
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One.

So let's just say I'm drivin' this buggy...
and if you fix your attitude you can ride along with me.

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Calnago
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by Calnago

Interesting. Is that the original Cannondale BB30 spec or some interation of it like BBRight or something? I always throught the nominal spec for the BB shell was 42.00 +0.0/-.05. Ha, I just refused to even deal with the whole thing until PF30 became so prevalent that I had no choice. But even PF30 has not alleviated the issues. The delrin cups are a poor attempt at dealing with tolerance issues and bearings. But it's what we have. I've installed Praxis, Chris King PF30 (alloy) and regular PF30 (delrin) cups and so far have 100% long term success in solving creaks etc. so a lot of it is all about proper installation, which is kind of rare it seems. Still, I vastly prefer a threaded BB shell but with manufacturing the way it is and the costs to produce such shells in carbon frames I doubt we'll see them back anytime soon. Too bad.
Colnago C64 - The Naked Build; Colnago C60 - PR99; Trek Koppenberg - Where Emonda and Domane Meet;
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bikerjulio
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by bikerjulio

Image

I reversed the tolerance to make them both work in the same direction, but yes BB30 is a max of 0.025 mm.

I could not find a SRAM drawing for PF30 but this looked plausible

Image

It's easy to forget how old the BB30 standard is. I think the first BB30 frame out of Cannondale was MY 2000 or 2001. Not too many carbon frames back then, and about 10 years before Cannondale had one, and it had an alloy insert.

I found it a little ironic that the originators of the BB30 standard, have now abandoned it on their high end frames in favor of PF30.
There's sometimes a buggy.
How many drivers does a buggy have?

One.

So let's just say I'm drivin' this buggy...
and if you fix your attitude you can ride along with me.

http://www.youtube.com/watch?v=GekiIMh4ZkM

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Calnago
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by Calnago

Thanks for the charts. I think that first BB30 chart is saying exactly the same as 42.00 +0.0/-.05 isn't it?
Isn't it reading 41.95 (minimum diameter) + 2 x 0.025 / -0.0
I may be wrong, and at his point it's just for my own understanding of that chart, but I "think" it's saying that the gap at any point can be no more than 0.025mm but that gap could be the same on both sides for a total of 0.05mm. Hence the "2x" in front of that spec.
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bikerjulio
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by bikerjulio

Calnago wrote:Thanks for the charts. I think that first BB30 chart is saying exactly the same as 42.00 +0.0/-.05 isn't it?
Isn't it reading 41.95 (minimum diameter) + 2 x 0.025 / -0.0
I may be wrong, and at his point it's just for my own understanding of that chart, but I "think" it's saying that the gap at any point can be no more than 0.025mm but that gap could be the same on both sides for a total of 0.05mm. Hence the "2x" in front of that spec.


No you are misreading it. The 2X just means repeat for the other side.

The bore tolerance is 41.96 +0.025/-0.0.

Backed up by the equivalent below in inch measurement.

In ancient history I used to draw stuff like this.
There's sometimes a buggy.
How many drivers does a buggy have?

One.

So let's just say I'm drivin' this buggy...
and if you fix your attitude you can ride along with me.

http://www.youtube.com/watch?v=GekiIMh4ZkM

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pdlpsher1
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by pdlpsher1

Lots of good info here.

Is Pinarello is only large manufacturer to only use threaded BBs?

I have read that with outboard bearing placement a 30mm spindle is overkill and not necessary.

What's the diameter of the UltraTorque spindle?


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bikerjulio
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by bikerjulio

pdlpsher1 wrote:Lots of good info here.

Is Pinarello is only large manufacturer to only use threaded BBs?

I have read that with outboard bearing placement a 30mm spindle is overkill and not necessary.

What's the diameter of the UltraTorque spindle?


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Pinarello may indeed be the only major with threaded BB.

I think it speaks to something that Shimano and Campy (except for the Overtorque mistake) never adopted BB30 or 30 mm spindles.

Shimano spindles are 24 mm and Campy (except OT) are 25 mm
There's sometimes a buggy.
How many drivers does a buggy have?

One.

So let's just say I'm drivin' this buggy...
and if you fix your attitude you can ride along with me.

http://www.youtube.com/watch?v=GekiIMh4ZkM

lannes
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by lannes

In addition to the Praxis threaded, I'd also look that the WheelMFG models

http://wheelsmfg.com/bottom-brackets/pf ... ckets.html

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Calnago
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by Calnago

@Bikerjulio: Thanks for the clarification on the BB standard specifications.

As to manufacturers who still use threaded BB shells, aside from individual builders etc., and Pinarello (although why they use right hand Italian threads still is beyond me), there is the Colnago Threadfit system, which is kind of a hybrid. Recognizing the need to provide for Pressfit Crank solutions, but also recognizing the pitfalls of having those cups pressed directly into the frame shell, Colnago now has an integrated alloy threaded sleeve in the bottom bracket. The alloy Threadfit cups then thread into this sleeve. From there you can press in the cups appropriate to the crank you're using. Basically adds another layer to the whole thing, but if the threadfit cups get damaged in any way, they are easily replaceable, with no damage occurring to the frame itself. Also being alloy, the machining tolerances are much tighter and better than I've seen in strictly carbon shells. I feel it's the best solution to date from a frame manufacturer in response to the mess that BB pressfit systems have imposed on us.
Colnago C64 - The Naked Build; Colnago C60 - PR99; Trek Koppenberg - Where Emonda and Domane Meet;
Unlinked Builds (searchable): Colnago C59 - 5 Years Later; Trek Emonda SL Campagnolo SR; Special Colnago EPQ

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