Changing from 53 to 50 chainring...what do I do??
 

Hi,
I am putting a compact 50/34 cranks and swapping out the 53/39. Rear cogs are 12-25 9 speed.

What changes do I need to do?

I read that it may not be necessary to shorten the chain? Or should I take out 2 links?

I am guessing I also need to lower the FD? By how much?

Thanks for any info you can give. I would like to try and do this myself instead of bringing it to the LBS.

anne

I would think a few links would have to come out to take up the slack from loosing the 3 teeth. The FD will have to come down, Sheldon says:

"Height of the front derailer is a principal factor in how well it will shift. Manufacturers commonly recommend 2mm clearance between the bottom of the outer cage plate and the teeth of the large chainwheel. This is a bit of an oversimplification. Best performance will result from the very lowest position that still just barely keeps the cage from hitting the outer chainwheel teeth.
The lower you can get it, the better it will shift."

Yes, installing a FD is easy. Remember to have a powerlink in your chain, makes maintenance much easier.
This is something you can do yourself.

IRD and Campagnolo both make front derailleurs designed to run with compact cranks.

http://www.glorycycles.com/irdcdfrdefor.html

Many riders have reported good results from using a standard road derailleur. I'd try the old derailleur first.

Al

thanks....when my new cranks come in i will try this meself!
anne

This one is easy, you can do it!