NDG

The sram red 10-speed rear derailleur on my 2012 Trek Madone just broke and seem not repairable.
What is the best option out there to replace it with a new one?
I see that some of the original derailleurs still seem to be available, but are quite costlty. Not sure I want to invest that much on an older bike,
Any suggestions?
A Sram force perhaps, such as this?
https://www.tradeinn.com/bikeinn/en/...E&gclsrc=aw.ds

Thanks!

Kontact

You can use SRAM 11 speed road derailleurs.

tFUnK

Anything that is "Exact Actuation" will work. I went with GX (make sure they are Exact Actuation) on most of my SRAM 10 speed bikes - allows for clearing a larger cassette, too.

Kontact

GX is a decent choice for really large cassettes, but a less than ideal choice for standard road gearing due to the distance between the pulleys and cogs.

NDG

My present cassette is a 11-28. So, do I understand correctly that using a GX would not be ideal?

tFUnK

True; I agree with this both in theory and in personal experience. The shifts are slower particularly when going down the cassette too smaller cogs (higher gears).

But over the years I have made the gradual jumps from 28t to 32, then 34, and now 36 on one of my gravel bikes, so in a way that GX has future-proofed against my gradual loss of fitness (and gains in body weight).

tFUnK

I was tempted to say "you won't notice a difference" but the Red RD is so crisp and precise so anything other than another Red or Force may be a perceived downgrade. For me, I don't race or do group rides where I need my shifts to be instant, I haven't had any issues with a GX RD.

Kontact

I would choose a Rival or something road oriented for that gearing.

hayden52

Since you are used to Red, I would spend the $$$ and go with new old stock Red. I had to do this after my Red derailleur over shifted and wrapped the chain between the sprocket and hub. This stressed the DR and after I fixed the chain, the DR exploded. I had to spend $300 on a new old stock Red 10 speed, but it shifts perfectly.

datlas 

There are used ones on EBay in decent condition at reasonable prices.

NDG

My LBS has just ordered for me a SRAM force 10 speed. NOS Sram red 10 speed were really too expensive (double the price of the SRAM force). Lets see,

NDG

Yes, but mostly likely with worn down galleys etc... I prefer a new force than a used red. I hope this is the best choice.

6thElement

I was going to suggest just looking for a 10 speed Force version. I'm still running my 10 speed Force groupo from 2007 on one of my bikes.