new fr der necessary with use of compact crankset

[wgp]

Greetings all -

A quick question: I plan to buy a Campy Chorus Compact UT BB (50-34) to complement my Chorus UT 53-39, and know that this year's (2008) Campy lines of FD work with both compact and regular cranksets. But ..

I have a Record FD purchased fall 07 and wondering whether I can get away with using it for both cranksets? Or do I have to pony up for the newer model (I'd buy Chorus) in order to run both cranksets?

[Ray]

Originally Posted by wgp

Greetings all -

A quick question: I plan to buy a Campy Chorus Compact UT BB (50-34) to complement my Chorus UT 53-39, and know that this year's (2008) Campy lines of FD work with both compact and regular cranksets. But ..

I have a Record FD purchased fall 07 and wondering whether I can get away with using it for both cranksets? Or do I have to pony up for the newer model (I'd buy Chorus) in order to run both cranksets?

It'll almost certainly work fine. The only caveat is if the frame takes a braze-on front derailure. Some of the little braze on tabs are located too high for the derailure to work well with a compact. In which case you may need a derailure designed to accommodate the smaller chainring. But if its a clamp on, just slide the clamp down a couple of mm.

I use normal derailures with compacts all the time and I usually have a 48 or even 46 tooth big ring. No problem with a clamp-on, but I had a real issue with a braze on frame I had several years back, before compact was popular. I'd hope that newer frames would be designed with a tab that could deal with that. And if you keep the 50 tooth big ring, probably a non-issue regardless.

-Ray

[palincss]

The main issues you have to deal with are:

- getting the derailleur down low enough to maintain the correct distance above a smaller chain ring -- and Ray has discussed that in detail and with great accuracy.

- curve of the front derailleur cage may not match the curve of the smaller chainring, causing the back end of the FD cage to be too far from the chainring

- back end of the FD cage is so long that when you lower it down to be the proper height above the smaller chainring it comes too close to, or even comes in contact with, the chainstay.

I have experience with only one modern Campagnolo front derailleur, a Racing T. I'm using it on a 46T chainring, as shown in the illustration. The curve of the cage is a pretty good match to the chainring, and (unlike the various Shimano FDs the LBS tried) the back end of the FD cage has plenty of clearance. I'm told the current production Campagnolo triple FDs differ from this one only in cosmetics and model name.

In any event, I think your chances are good, and your best approach would be to go ahead and try it; if it works, you're home free. If it doesn't, try Plan B.

[Ray]

Originally Posted by palincss

The main issues you have to deal with are:

- back end of the FD cage is so long that when you lower it down to be the proper height above the smaller chainring it comes too close to, or even comes in contact with, the chainstay.

I have experience with only one modern Campagnolo front derailleur, a Racing T. I'm using it on a 46T chainring, as shown in the illustration. The curve of the cage is a pretty good match to the chainring, and (unlike the various Shimano FDs the LBS tried) the back end of the FD cage has plenty of clearance. I'm told the current production Campagnolo triple FDs differ from this one only in cosmetics and model name.

I've only run into these issues with triples and 110-74 bcd triples with very small granny rings. And on frames with very shallow seat tubes, at that. For small chainring triples, Campy front derailures are definitely better than Shimano. I've never bothered to think about why, but I've sure found it to be the case.

But I've never had any of those particular problems setting up a compact double.

-Ray

[wgp]

Ray and Palincss -

Thanks so much for the input, guys!

I'm going to try my current FD once the new crankset arrives and see. My frame is a Parlee, and so uses a clamp and not a braze-on, which will likely allow for the downward adjustment to fit the 35 ring.

The standard chainring works fine for my climbs in the metro DC area, but having just got back from CO and wanting to return there with my bike next time, I'm clear that a compact will make the riding there far more comfortable. I'm also considering doing a Charmichael climbing camp in the NC mountains in the fall, and would likely find that helpful there too.

Again, thanks for the input!

[palincss]

Originally Posted by Ray

I've only run into these issues with triples and 110-74 bcd triples with very small granny rings. And on frames with very shallow seat tubes, at that. For small chainring triples, Campy front derailures are definitely better than Shimano. I've never bothered to think about why, but I've sure found it to be the case.

Check, check and check: 110/74 cranks; 24 or 26T grannies, otherwise, why bother; and 72 degree seat tubes go very well with long legs and Brooks saddles. I guess I win the trifecta.

It surprised me very much how well that Campagnolo Racing T works with my sort of cranks -- after all, they are very, very far from the sort of thing Campagnolo is usually known for. I'm sure I'm not the only one with that huge blind spot.

[Orin]

Originally Posted by wgp

Greetings all -

A quick question: I plan to buy a Campy Chorus Compact UT BB (50-34) to complement my Chorus UT 53-39, and know that this year's (2008) Campy lines of FD work with both compact and regular cranksets. But ..

I have a Record FD purchased fall 07 and wondering whether I can get away with using it for both cranksets? Or do I have to pony up for the newer model (I'd buy Chorus) in order to run both cranksets?

I've used a Campy Daytona (Centaur) regular FD with compact cranks without any problem. In fact, a Centaur CT FD was fussier than the regular FD. As pointed out elsewhere, the Racing-T FD works well for many front chainring combinations and I've used it with a compact crank too.

I would install a chain catcher whatever FD you use... cheap insurance against losing the chain on the inside and scratching/gouging the BB.

Orin.

[torquer]

Originally Posted by Orin

I would install a chain catcher whatever FD you use... cheap insurance against losing the chain on the inside and scratching/gouging the BB.

Orin.

+1

Definitely try this first, before you invest in a new FD.

[sg8357]

Originally Posted by palincss

It surprised me very much how well that Campagnolo Racing T works with my sort of cranks -- after all, they are very, very far from the sort of thing Campagnolo is usually known for. I'm sure I'm not the only one with that huge blind spot.

Campy does make the best brifter for triples with non-standard rings.
Now if someone would make a 7 speed index gear for Campy,
every iBob, Rivendellista etc would be a for sure Campy rider.

Scott G.

[dnades]

I run a 10 speed dura ace fd with the campy chorus compact ut crank(36-50) with no problems(dura ace drivetrain and shifters). I would give the record front derailleur a shot before ponying up the cash to get a compact fd.

[wgp]

Again thanks to the new responders since my first acknowledgement - much obliged!

Bummer was the guy selling me the CT sold it to someone else two hours before I responded back that I wanted the crankset - oh well, I'll keep my eyes out for another used Campy CT Ultra-Torque Crankset!

[Ahneida Ride]

for what's it worth ...

I run a 2002 Record Triple FD with a 22-36-48 TA Zephyr ...

Shifts rather well indeed. No complaints.

The height of the FD needs to be correct and I had to "cold set" the
FD just a bit.

Bottom line, a small amount of tweaking had a huge payoff.

[rustychisel]

... and my partner uses a standard FD with 50~34 compact cranks, all carbon Record. It works fine.

I use Shimano Ultegra 9 speed FD with FSA SLK Compact 50~34, also no troubles.

Both installed etc by me, need a little tweaking to get best performance, but sweet as...