Can't lower my front derailleur enough to accommodate my new compact crank...?

Triathlon Forum
1

I have run across trouble trying to install a compact crank on my Tri bike (older bike from 2003). It has a braze on front derailleur and there is not enough adjustment room on the bottom to accommodate my new compact crank. Are there any options I have to lower my front derailleur?

2

I have run across trouble trying to install a compact crank on my Tri bike (older bike from 2003). It has a braze on front derailleur and there is not enough adjustment room on the bottom to accommodate my new compact crank. Are there any options I have to lower my front derailleur?

Round file, you could use a dremel but there is a chance that it might skip and scratch your frame.

Maurice

3

I need to lower it close to 1 cm. My bike is at the shop now so I’ll take a look tomorrow, but what if there is not enough room to safely file down 1 cm? It’s a titanium bike if that helps. Pretty tough to remove the old tab and add a new one lower?

Or do they make adapters I could add? I’d like to hear all the possible options. I would really like to get a compact crank on my bike without spending a fortune.

4

When you get your bike back, post some pictures. If grinding isn’t an option, it might be possible to machine an adapter.

.

5

could you fit a band on derailleur ?

6

It’s an aero seat tube, so I don’t think so. Here is a picture of my bike:

http://img.photobucket.com/albums/v236/Neopian_Knights/bike1.jpg

7

What type of front derailluer? The SRAM Force and maybe the rival have two different mounting options to account for adjustment options.

8

An olderish Shimano Ultegra, I believe 6600. I’m definitely willing to upgrade my front derailleur if that will fix the problem.

9

If it’s at the shop have them test a force front. That’s what I had to use to run a compact crank on my 07 P2.

10

I tried to run a compact on my wife’s Cervelo Dual and it would not work. I removed it and went back to a standard crank and all is well. Lesson learned. Older bikes were not made for a compact crank.

11

What derailleur did you try?

12

I have run across trouble trying to install a compact crank on my Tri bike (older bike from 2003). It has a braze on front derailleur and there is not enough adjustment room on the bottom to accommodate my new compact crank. Are there any options I have to lower my front derailleur?

I’m thinking the cage will work on the 50 tooth ring but not the 34T?
How about replacing the small ring with a 36T?

13

I’m going to stop into my LBS tomorrow and chat about trying a Sram force FD, also trying to dremmel down the braze on slot. Besides though options, any options? Why did bikes mount the braze on FD hanger so high? I am in my lowest setting right now for a standard crank. What was the extra vertical movement created for? Really a poor design if you ask me. I would hate to send back the compact crank that I was so excited to install…

14

Compact cranks were just starting back in 2003, and most all bikes had std cranks.

Suggest as people mentioned above:

  1. Try another derailleur. Note it doesn’t “need” to get a low as the shimano specs to work. perhaps a newer MTB derailleur would work.
  2. File the braze on down 3 mm
  3. Cut off the braze on and put clamp
15

Another option is swap the rings to 52x36
.

16

+1

I have this ´semi-compact´ option on my Canyon, it´s a very good choice.

17

I have run across trouble trying to install a compact crank on my Tri bike (older bike from 2003). It has a braze on front derailleur and there is not enough adjustment room on the bottom to accommodate my new compact crank. Are there any options I have to lower my front derailleur?

I’m thinking the cage will work on the 50 tooth ring but not the 34T?
How about replacing the small ring with a 36T?

This!!!

Try 50x36. When I switched to compact cranks on my ancient steel Salsa, I couldn’t move the front derailleur, so I just swapped the 34 for a 36 and it works very well! Caveat - I have Campy 10s chorus but vertical spacing between big ring and little ring should be the same no matter what group you use.

18

+1 on SRAM Force, it is a common issue for many older frames and I have used the force derailleur on over 10 builds including a QR.

Cheers!

19

Cassette size? - Looks like you could keep crank and make the gear/ratio change there.

20

I got mine to work on the same ultegra derailleur on a cervelo dual with fsa compact. It does not have the 1cm recommendation between cage and ring but I still got it to work.
Not sure what kind of rings you have, but fsa make a compact derailleur you might want to try (and return if it doesn’t work). It will get the cage closer to the rings.