Review: Can SRAM GX Transmission live up to the hype?

When SRAM released its new direct-mount design, it hailed the wireless group as a revolution. A massive change in how riders shift gears. We got ahold of a GX level transmission from SRAM to review to see for ourselves. Is doing away with the derailleur hangar worth the hype?

This newest GX version of Transmission launched in July. It followed quickly on the heels of the more expensive versions (XO, XX and XXSL) which came out this past March.

I built up our GX Transmission on a Revel Ranger V2 test bike. In the months since I’ve used GX for several months of riding in Ontario and over an intense eight days of racing at BC Bike Race.

How is Transmission different?

Unlike past drive trains the Transmission mounts directly to the frame with no derailer hanger.  This is at first disconcerting after all hangers are designed to break when a big impact occurs, instead of the frame or derailleur breaking.  To alleviate our fears, SRAM had videos of staff jumping up and down on the derailer to show it is so tough it won’t break. That goes some distance to also ensuring your bike runs smoothly. I struck the derailer at least once hard and the shifting was not affected. There is also an overdrive or crash mode, which allows GX to move inboard when impacted without damaging the internals. Still, I am still left wondering what will break on big impacts. Only time will tell, however the derailer is highly fixable with a number of replaceable parts.

GX vs XO: What’s the difference?

Out of the box, GX looks similar to the XO except for a few clear differences.  Firstly the aluminum chain ring and crank arms look different in shape and colour than the higher-end groups, without any of the cut-outs and much less shaping.   GX comes with a bash guard already installed.  Secondly, the derailleur battery has been moved from the back of the derailleur hanger to sit more inside the derailleur and under the axle, hopefully putting it out of harm’s way.

Those are the two most visible changes, but there’s also an increased weight. You can see where SRAM’s added weight in several locations.  The cranks are heavier, the derailleur is heavier, the chain is heavier and the cassette is heavier. The shifting pods I received were the same as the XO model, so not much I can comment on there, but weight-wise wise they will be the same. Overall the GX group is 112.9 grams…