Bicycle Mechanics - Need Shimano Front Derailleur Help

Bikeforums.net is a forum about nothing but bikes. Our community can help you find information about hard-to-find and localized information like bicycle tours, specialties like where in your area to have your recumbent bike serviced, or what are the best bicycle tires and seats for the activities you use your bike for.




canam73
08-05-08, 11:03 AM
I am building up a road bike for my wife and plan using a R600 compact crankset (50/34) with a SRAM 9-speed cassette. I recently ordered Tiagra derailleurs from Nashbar to complete the drivetrain. This is the front that I ordered:

http://www.nashbar.com/profile.cfm?category=600083&subcategory=60001037&brand=&sku=22608&storetype=&estoreid=&pagename=Shop%20by%20Subcat%3A%20Front%20Derailleur

mainly because it said it was compact crank compatiple and had a multi-clamp that should work with the 31.8mm seat tube. But when I received it and opened it up it looked completely different than the picture, the clamp was for a 34.9mm tube and there were no shims or other provision to make it properly fit a smaller tube. Also, the instruction specifically list the maximum chainring difference as 15 or less, not the 16 that my (and most other?) compacts have.

I called Nashbar and talked to a tech who told me that 1)The picture on their website for that product is wrong and that the double which I need is longer slender like the one that I received. 2) They forgot to send the shims and he would send a set right out. And 3) that the one they send would in fact work fine with a 16t chainring spread.

So can anyone confirm or deny what I have been told? I don't have the rest of the parts yet to actually test it out.

Thanks, Steven.


Al1943
08-05-08, 01:11 PM
If she has shifting problems a good alternative may be to replace the 50t big ring with a 48 or 49 (110 BCD).

maddmaxx
08-05-08, 01:51 PM
It will work fine with the 16 tooth spread.

1. Shimano is very conservative with their max ratings which can almost always be beated by a tooth or 2

2. Shimano came late to the compact crankset party and took the time to make a crankset that was spec'd to work with the existing Shimano derailliurs without problem. Some of the other early compact cranks worked best with a special derailleur for the 16 tooth spread.

I believe that once you have the shims that you will be good to go.