Schaltwerk ESP X4 (8/9-Gang | Langer Käfig | 1:1)

Works as a replacement of SRAM X3 1:1, albeit with X4 I was able to get only 6 out of 7 rear gears. The huge advantage of SRAM X4 is that it can be installed on a bike without breaking the chain!!! You can remove the two little guide wheels on X4, install it, then put back the guide wheels back. I give it 4.5 stars for non-perfect fit as a replacement of X3, upgrading to 5 stars because of a reasonable price.

The sram x4 is a great rear derailleur. Easy, precise shifting. I have one for the front, just haven't had the time nor need to replace the current one.

Straight swap from an old/damaged derailleur. Works well. Does the job. New parts always work well from reputable manufacturers. I would recommend as an entry level component. Shifts well. Easy installation. Fine tunable

Great derailleur! I bought a used Schwinn hightimber from my local shop and had awful shifting for weeks before I decided to swap it out. Combined with an sram index shifter (a 1:1 ratio shifter is required for this derailleur which I didn't know at first) I'm more than happy on my rides to work now! I have to take a small hill to get there and I couldn't hold a gear let alone shift while pedaling hard but now it's so crisp and fast I don't even think I just shift. And for the money (about $60 all together for the swap) it's a great deal considering it made my used bike feel brand new again! Can't say how long it will hold up with abuse but I don't do much trail riding anyway. Will be getting a gaurd for it just to be safe

I received this product more than a month before I installed it. I found that when I was going to install the derailler, it was missing the B-bolt. I could not return the product because It was beyond the return grace period. I contacted SRAM tech support, which is excellent BTW. They suggested that I contact the seller to see if they could help me. I sent a picture of the derailler with the missing B-bolt, and they sent me a replacement! This vendor is top notch. They responded quickly and resolved my issue by sending me a replacement derailler, despite my not being able to return the product through Amazon. I have a few SRAM products and highly recommend them. I also highly recommend this seller, as they take good care of their customers.

This thing is junk. Not even a year old and, as I was riding through a smooth, grassy field (after having it on my bike less than 1 year), it folded in half, broken--the cheap pot metal just gave out. Save money and time and buy higher quality parts. This is junk.

This SRAM X-4 rear derailleur replaced my damaged 1991 SunTour derailleur. 4 months ago I fixed the worn Sun Tour upper pulley - jockey wheel with a hard to find pulley and it work with some modifications. (Note SunTour been out of business decades, and forget about NOS -new old stock .) It was still very difficult to down shift the rear 7 cog gear set. And I essentially had only 4-5 gears that the SunTour would drive. So after damaging the Sun Tour and purchased the SRAM X-4 last week. I received it yesterday and installed it. First impression are- well made metal construction and heavier than the Sun Tour. I had to loosen the both jockey wheels in order to get the chain routed through. I adjusted the H, L and B screws to smoothly shift through all 7 cog set 12-28. I made the first ride today, what a difference. So much easier to up & down shift and much more precise. No more death grip to shift down to lower gear (bigger gear) The only issue was sometimes it would not stay in specific gear and shift into a higher cog-gear. Maybe do some more fine tuning of the H,L, B and cable tension. But I may just leave alone, if its not really broken, don't fix it. Usually I make things worse by screwing around too much trying to make it perfect. . I also using the Sram Grip shifter. But overall really please with the Sram X-4. Gave my 1991 Cannondale SM-1000 new life.

Bought this 'cause I destroyed a Shimano acera by picking up a stick while trail riding. I own 3 bikes all of which have Shimano drive trains---until now. This derailleur shifts really smooth and quick and because it keeps more "tension" on the chain it stops most of the chain slap on rough terrain. Just be fore warned as Sram states in their description of this derailleur--YOU WILL NEED TO PAIR WITH SRAM SHIFTERS--this derailleur has a 1 to 1 actuation ratio most Shimano rear derailleur ratios are 2 to 1 and the shifters are not compatible. But in the end it's well worth the investment.