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Discussion Starter · #1 ·
Hi, I have a '03 campy record (10 speed) drivetrain with 53/39 chainrings. I'd like to go to the compact cranks (50/36 front chain rings). I have a campy record bottom bracket with a square tapered spindle.

Can I purchase a new right crankarm to accommodate a smaller BCD and 50/36 chainrings? I know I'd have to match the length of the left crankarm.

Thanks,

Michael
 

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thoughts...

The only way you're going to get a new right side only at a reasonable cost is to buy a whole crank, either used or NOS. Sell off your old crank and it will cost even less.

Think about why you want a 50/36. A bike setup with a 53/39 and a cassette starting with a 13T could have the same range as a 50/36 and a cassette starting with a 12T.

In most cases, a 50/34 makes more sense and it's about all you'll find from sellers of new cranks. I run a 50/34 with an 11-25 for the Colorado mountains. It works nicely with a little more top gear than a 53/12 and low that's not quite as low as a 39/29.

Personally, I'd move on to the new UT crank.
 

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Discussion Starter · #3 ·
C-40, thanks for the comments.

The principle reason for the change is to gain more uphill mechanical advantage. (Though I don't have Colorado elevation, I do have lots of mountains to climb).

Presently I have a 12-25 rear cassette and gaining three teeth adds about an 8% advantage. I didn't think the front Record derailleur could handle a 16 tooth differential (34->50). If it can, 34/25 would be even better.

I do understand your view point, however. After 7yrs and > 25k miles, my bike components are nearing the end of their useful life. I'm undecided about reinvesting in components or going for a new full-on bike. I'm trying to squeeze in one more season on the current bike and then figuring out next steps later in the year.

In the meanwhile, I thought switching out a right crankarm would be a low cost way to help on the mountain rides.

Thanks,

Michael
 

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another option...

You might consider getting a 13-29 cassette. With a short cage RD, it works on some bikes, but not all, since it's really beyond the limit of the RD's wrap capacity. Some bikes have a more perfect chainstay length and gain up to 2T of wrap, making it more workable.

As long as you never shift into the 53/29, you won't have any problem, but if that's a risk, then a 1-inch longer chain is needed. It might then hang loose in the 39/13. You want the chain as long as possible without hanging loose or rubbing on the upper chaing guide tab on the RD cage.

A standard Campy FD will usually shift a compact adequately. The '08-'09 models work with either one.
 

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Discussion Starter · #5 ·
Thanks C-40. All good points. Appreciate the feedback. I'll keep you posted.

Tailwinds,

Michael
 
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