compact drivetrain on your cv frame
 

Anyone running 50/34 crank with their 11t cassette on their 80s 90s cv frame? If so, when the chain is on the 11t, is the chain rubbing the frame? Anyway to avoid this? Put more spacers to increase the OLD?

I would think it has less to do with your tooth count and more to do with spacing. How many speeds you running and what's the frame spaced to?

I'm running a 50/34 with an 11.34 on my Ciocc, but it is a 10 speed and I've had the frame spread. It works flawlessly.

My wife's Panasonic is set up this way, 130mm rear wheel with 7speed cassette and suntour indexed down tube shifters. Works like it was designed to be that way. I used Sugino cranks (the ones Velo Orange sells) a 50/34 chainring set.

There's too many variables to predict the outcome of such a setup. Minute differences in chainstay angles, brazing of drop-outs to chainstays, drop-out type, hub spacers, cassette lock rings, original spacing and whether it has been set, etc.

That said, I have a 1985 Look 753 frame that, without cold setting, seems made for Campy 10 speed with an 11T small cog. A Merckx frame of the same vintage is maxed out by Campy 8 speed with a 12T cog.

Running 9 speed Ultegra with a compact crankset on my 1987 Prologue.

I run a 50/34 with 12/25 9 speed on my Centurion DS without a problem.

Be ready for a lot of FD action and cross chaining if you live on the flats.
I got rid of my compact after 100km because of that.

Yes, compact cranks are not for flat rides. And in the mountains, without an 11T cog, you will be dropped on the descents.

Thanks for the replies guys.. Im running an ultegra compact with a 9 speed cassette. It has not been cold set and is 126. Not sure if this is worth mentioning...the cassette is on a set of mavics. IIRC I needed to put a spacer on before i mounted the cassette to take up the play.
Related question. If a 10 spped cassette has a shorter stack, it seems that it could be moved closer to spokes to avoid chain rub??? will i need a spacer as well?

you can install an 8 spd cassette with a spacer on the outside.

My max speed on 50/12 is 45 mph, and it's not too tough at all to reach speeds in the upper 30's on descents. Depends who you ride with I guess, and of course how serious your group is.

Since I get dropped long before any descents, it doesn't matter. All hills and mountains around here.

+1 Agree, be prepared to do a lot more shifting on the front derailleur.

Lets see, in the keeper fleet right now, I have three compact crank road bikes (84 Lotus, 87 Schwinn Prologue, 95 Fuji), one standard double road bike (03 Colnago), one triple crankset touring bike (00 Trek), and one triple MTB (92 Trek).

I have a compact on one of my AZ bikes, running a 12-25 on the rear. I'm too scared to go over 45 on a descent.

At 45mph, or long before, I'm not pedaling anymore but merely taking advantage of gravity on the real steep, straight stuff. Gearing becomes inconsequential, for me at least.

What I mean about getting dropped is in the ~30mph range where spinning out is a real factor in keeping up. 5-10 miles of, say 6% grade will make you curse that compact crank pared with a 12T cog if the rest of the group ride in 53-11.

But these musings of mine are esoteric circumstances of little real life value, and only hurts the ego should they arise, so all's good.

I'm running a 10 speed 11-25 cassette on a modern 130mm Dura Ace hub on a 1987 Trek 400 Elance. No issues.

http://i289.photobucket.com/albums/l...ictures017.jpg

Mines not really a "compact", but I'm running 47-41 with 13-23 on my early 1980s Ciocc. Living as I do in south Louisiana where the steepest climbs are freeway overpasses, I've no need for any lower or higher gearing.

If it works for you, then just do it. :thumb:

Running 43-30 with 13-24 in the rear works fine here:
http://www.os2.dhs.org/~john/bumby/build6.jpg