which size rear derailleur do I need please?

daffyavfc
daffyavfc Posts: 237
edited October 2010 in Workshop
Hi

I've got a 2009 GT GTR series 4 road bike and the rear mech got damaged in the car!!
I'm going to get a 105 mech as the one on it at present is a Sora shimano.

It's 16 speed and has a 50/39 chainset and an 8 speed rear cassette 12-25.

What size cage rear mech do I need for this set up please ?

thanks

http://www.evanscycles.com/products/gt/gtr-series-4-2009-road-bike-ec016380

Comments