Record Pista Left Crank Warning

I feel I have a duty to bring people's attention to a thread that I posted a little while ago:

http://www.lfgss.com/thread40318.html

I won't bore you any more.

Matt

We know. Tell Campagfailo!

did you grease the spindle? did you mix'n'match jis bb spindle and iso crank?

I have. They got back to me asking for details, pics, etc.

Sorry if this is patronising, but 3 days after the crash I can't walk properly, sit down easily or earn money.

So send them the details.. and continue to keep us informed.

did you grease the spindle? did you mix'n'match jis bb spindle and iso crank?

Copper grease, correct BB.

removed and reinstalled or repeatedly tightened?

removed and reinstalled or repeatedly tightened?

Re-fitted on new BB.

So send them the details.. and continue to keep us informed.

You don't say.

Funny, I know of 3 failing and all 3 people greased the spindle.

Some kind of pattern?

User error blamed as faulty goods?

"I broke my hand cause I hit it with a hammer"

i guess they must be a bit crap then, you couldn't do that by overtightening the crank bolts, only tightening them, then noticing they become loose (because the crank scooches up the spindle), so tighten again, and then the crank scooches up again, etc until it cracks.

I have. They got back to me asking for details, pics, etc.

Sorry if this is patronising, but 3 days after the crash I can't walk properly, sit down easily or earn money.

You earn your living walking and sitting down?

Funny, I know of 3 failing and all 3 people greased the spindle.
Some kind of pattern?
User error blamed as faulty goods?
"I broke my hand cause I hit it with a hammer"

Yeah, the pattern is shit cranks.

Yeah, the pattern is shit cranks.

Close.

The pattern is incorrect installation.

The pattern is incorrect installation.

How? The OP clearly stated he used grease on installation, albeit copper grease, which may not be ideal but should be fine. It shouldn't cause the crank to snap, basically.

The issue is clearly a manufacturing/design fault with these cranks. Most cranks installed "incorrectly" wont even break...

Close.
The pattern is incorrect installation.

I still find it very hard to believe they snap this easily.. think about the number of bodged installs that people have done with other cranks that don't just snap. Old pieces of shit too.. these breakages are all newer cranks. I would always lightly grease my tapers (ooh err) and nowadays install with torque wrench. If the torque is correct (or even close) grease shouldn't matter. There has to be tolerance for this kind of thing, like max psi ratings on tyres.

Summary: These cranks are dangerously shit.

I still find it very hard to believe that someone posts a thread, to inform us of another thread that they started, ... and you haven't merged them yet.

I dislike Record cranks that much..

but you have a point..

jobst brandt who probably knows more than any of us:

Install and properly tighten new cranks on the spindle after greasing the tapered square ends of the spindle. Proper tightness should be achieved with a torque wrench or by a skilled hand.

...

However, cranks cannot be split by overtightening them. This can be proven by attemting to do so. An M8x1 bolt is not strong enough to split a major brand crank.

Failure from "over-tightening" is caused by repeated re-tightening of properly installed cranks. In use, an aluminum crank squirms on its taper and, because the retaining bolt prevents it from moving off the taper, it elbows itself away from the bolt and up the taper ever so slightly. The resulting loss of preload, after hard riding, can be detected by how easily the bolt can be turned.

...

The claim that a greased spindle will enlarge the bore of a crank and ultimately reduce chainwheel clearance is also specious, because the crank cannot operate in a plastic stress level that would soon split the crank in use.

source

as this did not happen in this case, the cranks must be of poor quality.

It could be anything, from overheating of the alloy to simply being a bad piece of engineering.

How? The OP clearly stated he used grease on installation, albeit copper grease, which may not be ideal but should be fine. It shouldn't cause the crank to snap, basically.

Because correct installation of Campag pista cranks to campag ISO BB is dry.

Anything else is incorrect installation.

Crank failure isn't exclusively the domain of Campy...see 105 that snapped and had me over my bars a few weeks ago

I realise crank failures happen with any brand but Record Pista cranks seem to give up just by looking at them which makes me question their design.

How old were those? They look like they'd been split on the outside face for a while and then let go.

If they're meant to be installed dry then so be it. I stand corrected.