Need advice on upgrading my rear derailleur on my Fuji
I have an 09 Fuji Crosstown 4.0 and want to look into upgrading my rear derailleur. Currently it is a Sunrace RD-M4S 7 speed. It is made out of plastic and I dont think it is very durable. I could be wrong though.
Can anyone please help me with an aftermarket replacement that would be more durable?
Also I am using my stock shift lever SRAM MRX Twist. I can replace that too if you think I would be better off.
IMO the factor that has the biggest influence on a RD's performance is state of wear and contamination rather than which quality bracket it belonged to when sold.
In other words, if it's reasonably clean and hasn't seen many miles yet it's unlikely that you'll notice any huge differences from replacing it. Wear it out first, then replace it.
Besides, a 09 bike that comes with a 7-spd drivtrain is unlikely to be a financially sensible candidate for upgrades, which is another reason to go for maintenance only.
But AFAIK the SRAM MRX is compatible with Shimano RDs, so if you manage to wear it out before tiring of the bike pretty much any Shimano RD would do. Acera would be a reasonable replacement in a 7-spd drivetrain.