sean000

I recently installed some C-Record cranks that I think are late-80s to early 90s on a square spindle BB (Shimano UN72...a combo that has worked for years on this bike). Park's website recommends 312-324 in-lb for Campagnolo crank bolts for square spindle BB's, so that's what I used.

These cranks had already been on this bike (which I purchased from the previous owner), and the front derailleur appears to be where it needs to be. When I first screwed the cranks on, before torquing them tight, everything was spinning fine. After torquing them down the large outside chainring rubs the outside of the front derailleur cage when it is positioned over the smaller inner chainring. It only rubs when the right crankarm is between one o'clock and six o'clock. That made me wonder if the chainring was warped, or if I torqued things too tight and now the rings are not perfectly parallel to the bottom bracket?

Should I back off the torque or just adjust the derailleur so it's out of the way? Could I have trashed the cranks? I'm thinking about installing a triple anyway, but figured I'd get a little more out of these old cranks for awhile.

Thanks,

Sean

canopus 

To late to back off the torque or anything like that. You will just have to raise the FD on the seat tube/braze on bracket so that it clears the chainrings by about 1.5/2mm and readjust.

fietsbob

The crank arm fit on the BB spindle is not the best, Shimano's taper
and what Campag uses, are different.

You may have kludged up the taper in the crank-arm.

sean000

Thanks...that's what I figured I would probably need to do.

sean000

That's what I am afraid of. Since the crank is softer than the BB spindle, maybe the damage is just to the crank. I guess there is no danger in riding it as long as I can adjust things to make it run and shift well? Any idea what torque I should have used, and what's the worst that can happen from not torquing them enough? I guess you can damage the crank taper if they loosen up while you're pedaling hard. I actually had a crank arm come loose on me many years ago, but I noticed the problem as soon as it was a little loose... long before it was anywhere near falling off. Just tightened it up after the ride and no problems.

I actually have another C-Record crankset left over from an old racing bike that I could put on there, but I could end up damaging that one too, and I think I'd rathe run a triple on this bike anyway. It's a sport-touring bike, so while the C-Record crank sure is pretty... it's not exactly the gearing my 40-year-old body wants for riding around the steep hills and mountain roads of Western Washington.

Sean

Zef

The point you are missing is that it is not a matter of torque. In this case it is a matter of dimensions. The dimensions of the square hole in a Campagnolo crank arm is of a different dimension than the square taper on a shimano bottom bracket spindle.

If you were to install your second C-record crank onto your shimano bottom bracket you stand a very good chance that you will F-up that crankarm as well.

-j

sean000

I bought the bike used, and it came with the C-Record crank and a UN72 BB. I planned on switching the crank out anyway and was more interested in the frame (A Kogswell Model P). The crazy thing is that the calipers measure the BB as 115mm. The chainline seems fine though and it shifts okay. I figured for awhile I would just right it with the cranks it came with though.

My other C-Record cranks are on my '88 Pinarello that is using a Campy BB. Of They are a much better match on a bike like that. Why the previous owner put a C-Record double on a Kogswell sport-touring frame is a bit of a head-scratcher. Then again I used to have a 1986 Reynolds 531 Trek 640 that had a Campy Nuovo Record or Gran Sport double, so maybe it's not that odd. Not sure why he went with this BB though.

sean000

You're right and I'm not going to take that chance, but I have read elsewhere that others have run the same combo for whatever reason without any issues, and I'm not sure why the previous owner of the bike chose this combo. I figured if it worked for him why not go with it?

BCRider

Since the tapers are different you will have deformed the crank arm socket to some extent already. But if yoiu RIDE it like this you will totally ruin it beyound any hope of being useful. And likely it's flare out the taper socket to where the cranks will wobble and ruin themselves even more.

As it sits now the arms are likely salaveable if you remove them and swap the BB for a Camy taper. But if you ride it for more than a gentle flat spin around the block all bets are off.

Someone that didn't know any better apparently replaced the BB either a while back or just to sell the bike. Hopefully it was just to sell the bike otherwise the arms are very likely ruined already. A careful inspection and testing with the crank just loose on a proper Campi spindle would be needed to determind if the crank arms are toast or not.

canopus 

All this is taper talk is BS. Yes, the tapers are different, No you shouldn't mix them. However if you do, it isn't the end of the world and NO, they won't fall off the bike killing you. Once it is done you just can go back, So you will always have to use a Shimano BB on your arms now. Just make sure that the bolt doesn't bottom out on the spindle when you tighten the arms.

I used Shimano Arms on a Campy Bottom bracket, It had been on the bike for 20 years when I finally upgraded. Older square taper was little closer than what it is today.

So the point is, leave everything alone, readjust the FD and ride. Ignore everyone telling you how you are going to die for making this mistake. If the arms no longer tighten or do fail at some point, replace them then.

sean000

I haven't ridden them more than up and down the flat street at an easy pace while I tested out the shifting. I'll take them off and try them out on my Pinarello's Campy BB. My Pinarello also has C-Record cranks, but the crankarms are in better shape cosmetically. The previous owner's shoes rubbed big dull spots on the sides of the cranks that came on the Kogswell, so maybe he included them because he thought they weren't worth much because of the cosmetic wear? The chainrings are in nice shape though.

sean000

Thanks for the counter-point. I have read elsewhere that others have used this exact combination successfully for whatever reason, but since I would prefer a triple anyway I might as just go ahead and replace the crankset. This is going to be a fair-weather road bike that probably won't get ridden much until the Spring, so I planned to do some other work on it over the Winter. I've got a touring bike with fenders for Winter riding and commuting. If I do remove the cranks and try them out on my campy BB and find they are toast, then I guess I've got some spare chainrings I can sell or save for my other C-Record crankset.