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SRAM doubles down on gravity 1x with affordable GX DH Group

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AM_Whistler-GXDH-160527-217
All images c. SRAM

SRAM is on a roll when it comes to 1x groups. Not only have they introduced a 1x group for almost every discipline, but now they’re making sure there are plenty affordable options as well. What started as a pricey debut with XX1 now flows all the way down to the recently introduced NX group. While the rest of their 1x options were moving to 11 (or even 12!) speed, SRAM went the opposite way with their first 1x group specifically for DH riding. Deciding it was more important to have fewer shifts between the first and last gear, less chain slap, and more room between the derailleur and the spokes, SRAM’s X01 DH went to just 7 gears.

Now, SRAM is following that same winning formula but with something a little more, ok a lot more affordable. Yes, DH 1x is getting the GX treatment. That equals much of the performance of X01 DH without the price tag – and without an XD freehub body…

SM_GX_DH_RD_7spd_Black_Side_M SM_GX_DH_Cassette_7spd_Black_Front_M

SM_GX_DH_SL_7spd_Black_Side_M

Other than the cassette, the parts look very similar to their X01 DH cousins, but in a muted grey on black finish. The GX DH X-horizon derailleur uses the same X-actuation as X01 DH which means they are cross compatible, as is the entire system. That longer X-Actuation cable pull claims to deliver more consistent shifts in tough conditions. Its geometry uses the same X-Horizon layout of X01 DH, that SRAM says better maintains consistent chain gap across all gears and limits the up-and-down movement of the derailleur body (instead rotating the cage and moving it in and out on the cassette) to virtually eliminate ghost shifts resulting from stutter bumps and big impacts. The derailleur includes a medium aluminum cage with a max tooth count of 28 (which could conceivably be assembled from individual cogs.) The best part? It’s only $104/119€ (compared to $272 for X01 DH) which should be a little less painful when you rip it off on the first lap at the park.

The same 7 speed X-actuation is used in the GX DH shifter. A dedicated 7 speed shifter, the body is compatible with SRAM’s Matchmaker levers and will sell for $43/48€. It also is compatible with X01 DH making it a low cost crash replacement if you break one of the more expensive shifters.

Maybe the most important component for a budget drivetrain is a new PG-720 cassette which makes use of a standard splined freehub body rather than SRAM’s XD driver. Equipped with 7 gears in 11, 13, 15, 17, 19, 22, and 25t steps, the remainder of the cassette spacing is occupied by a spacer that helps prevent the chain from going into the spokes. While we’ve seen e*thirteen make use of this extra space to make a stronger wheel with their 7 speed cassette, theoretically, this space allows the derailleur to sit farther out from the spokes which should give you some leeway in case the hanger gets bent. Again, the cassette is a total steal at just $30/36€. An added benefit is that it is fully compatible with the X01 DH group, so if you want to build up X01 DH group with a wheel that has a splined freehub you can use this cassette, or if you build a GX DH group with a wheel that has a XD-driver you can use the X01 cassette.

AM_Whistler-GXDH-160529-736

AM_Whistler-GXDH-160527-055

Those are the only GX DH specific parts, but SRAM recommends pairing them with a PC-1130 chain and a Truvativ Descendant DH crank with an X-Sync chainring. SRAM’s photoshoots of the new GX DH group had bikes built up with Avid Code brakes, but we expect to see more riders on the newest update of the Guide brakes with revised S4 calipers. Everything above should be available this month.

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sxm235
sxm235
6 years ago

11, 13, 15, 17, 19, 22, and 25t

Sounds beautiful for a beater cross bike!

TheFunkyMonkey
TheFunkyMonkey
6 years ago

That was quick trickle down. Hopefully we’ll see the same with 12 speed.

Veganpotter
Veganpotter
6 years ago

Been a while since I’ve seen chainrings bigger than the cassette…

yard dog
yard dog
6 years ago

i’d like to run this on a road bike. so sick of more cogs back there.

Technician
Technician
6 years ago

Now bring back my 7-speed road cassette and make all retrogrouches happy.

JBikes
JBikes
6 years ago

DH seems a great place for internally gear rear hubs.

Dominic
Dominic
6 years ago
Reply to  JBikes

There’s a few good reasons they aren’t more of a thing in DH. The first being the fact that you have to maintain chain tension as you would a singlespeed setup. The problem there is that for long travel applications the relative distance of the axle from the BB changes. It could be worked around, but it wouldn’t be worth a lot when you consider how the extra weight at the wheel has a pretty negative impact on the way the suspension follows the ground, which also means a lot more hard hits on the rim.

All that being said, they have been used more centrally to the frame as in, for example the old Lahar high pivot designs

JBikes
JBikes
6 years ago
Reply to  Dominic

Well, I’d say the only downside is unsprung weight, the solution to that is a crank pinion gearbox.
Chain tension is not an issue. A simple chain tensioner or even RD would maintain tension as CS changes, same as a full derailleur set-up but obviously no shifting needed.

JBikes
JBikes
6 years ago
Reply to  JBikes

But no free lunches right – crank gearboxes mess up pivot locations…

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