SRAM GX 1×11 Drivetrain

Construction Differences Between GX and X1

SRAM made the GX kit cheaper in two primary ways:

(1) They changed the rear derailleur from forged aluminum to cast aluminum.

(2) They used a riveted cassette similar to X1, but unlike X1, the three smallest cogs are riveted together instead of machined from a single block. Both of these changes increase weight, but reduce cost.

Riveted cassette construction is fairly standard. It isn’t as light or cool as the one-piece construction that SRAM uses on their more expensive cassettes, but I’d be surprised if it presents any issues. Maybe it will collect more mud, but that has never been a significant problem for me on any number of riveted 9- or 10-speed cassettes I’ve run over the years.

Cast aluminum, however, is something I’m a bit leery of. Casting is a much less expensive technique than aluminum casting, so it likely helped SRAM hit their desired price point. But I worry that it might make the derailleur less durable and less precise.

(Aluminum forging molds aluminum pieces into a formed shape with heat and a great deal of pressure. This yields a very stiff and strong part. In aluminum casting, molten aluminum is poured into a mold, then allowed to cure. This is a great way to make a part with little material waste. However, air bubbles or other defects can occur with this technique, and the strength of the resulting part often isn’t particularly high, relative to forging.)

The Ride

Getting the GX drivetrain dialed in took a little while, longer than I’m used to with Shimano or SRAM systems. I suspect that this is at the root of the tuning challenge. It could also be the result of imprecision in the shifter, but the shifter seems to be much more similar to the X1 version than the derailleur.

Once I got out on the trail, my first impression was how positive the shifting was. It has a strong “clunk” when shifting both up and down. It is much more distinct than X1, and more positive than Shimano 10-speed options.

Coming off a Shimano 1×10 setup most recently, I quickly remembered that I really like the SRAM shifter ergonomics, and prefer pushing the shift release lever upward instead of forward or back. I think it is easier to stab at the SRAM levers blindly and get the necessary result (when compared to the Shimano levers that are closer together).

I did, however, miss the double downshifts that Shimano’s XT and XTR allow. I find a double shift to be perfect for undulating terrain. This isn’t at all critical, but it is worth noting.

The GX shifting is quick, but not quite as quick as on the more expensive SRAM lines or Shimano XT or XTR.

As I mention above, tuning is a bit harder / more particular than on the more expensive options, and as such, it is hard to get quite the same performance out of GX that one might get out of X1.

So one of my biggest, initial questions has been answered: GX isn’t bad, but it does represent the first real step down in shifting performance in the SRAM 11 speed lineup.

I’ll say it again: GX isn’t bad, it just doesn’t follow SRAM’s remarkable run of getting almost exactly the same shifting performance out of less expensive components.

The bottom bracket and cranks have both been great. The GX 1400 cranks are identical to the X1 1400 cranks as far as I can tell. Both are hollow, forged aluminum.

SRAM identifies the X1 1400 crank as being made of 6000 series aluminum, while they describe the GX 1400 crank as being Open Core Technology (OCT™) Aluminum. I’m guessing they are two names for the same material. The cranks are stiff, smooth looking and offer a direct mount chainring option.

The bottom bracket has held up so far, but I would have been very disappointed if it hadn’t. It has seen a bit of mud and a lot of dust, but not enough miles to start creaking. I’ll keep riding it and update if and when anything changes.

The GX chain is the same as the X1, and has held up fine. But I’ll need to check back in once it has more miles on it to report on durability.

The steel cogs on the cassette don’t yet show any signs of wear, and there are only very small wear marks on the 42t aluminum cog.

The cassette has worked beautifully so far for me. It could be that it is holding back shifting performance relative to a more expensive cassette, but I don’t believe so, as the shift ramps appear to be identical to the X1 cassette. See the images below. These show the X1 cassette and the less expensive 1150 cassette. Ignoring the 42t cog on the 1150 cassette since the 1175 cassette has a ramped, aluminum 42t cog, you’ll note that all the other cogs have very similar if not identical shift ramps to the X1 cassette.

 

 

 

 

 

 

 

 

 

 

 

 

NEXT: Comparisons, Bottom Line