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New 2018 SRAM GX Eagle 12-Speed Mountain Bike Drivetrain - Ten Things to Know

June 09, 2017
New 2018 SRAM GX Eagle 12-Speed Mountain Bike Drivetrain - Ten Things to Know

SRAM has followed up the launch of the XX1 and XO1 Eagle drivetrains in 2016 with yet another nail in the 2x transmission coffin in the form of the GX Eagle. The new drivetrain features the same 1x transmission, 12-speed cassette, and 500% gear range of the other Eagle options, with similar performance but a significantly reduced price tag.

Here are the top ten things to know about the new groupset.

1. More cost effective version of X01 Eagle and XX1 Eagle.

Last year SRAM launched two 1x, 12-speed drivetrains to effectively kill off the front derailleur on its premium mountain bike groupsets, however, for many the cost was prohibitive. Now comes GX Eagle, another 1x, 12-speed drivetrain that mirrors many features of its Eagle brethren but with more cost-effective materials and manufacturing processes. The cost of the new groupset is virtually half of the X01 Eagle option which should have plenty of XC, Trail and Enduro riders excited.

2. Front derailleur killer

SRAM has fast moved toward solely utilizing 1x-specific drivetrains on nearly all of its intermediate to premium groupset options and the introduction of the GX Eagle continues that movement. The success of the GX Eagles predecessors is largely due to the 500 percent gear range that sacrifices little compared to 2x or 3x drivetrains set-ups. Thanks to the massive 12-speed 10-50T rear cassette, the Eagle series can offer even more gear coverage than a typical 2x 36/24T, 11-36T set-up. The simplified shifting, less moving parts, and weight saving are all other advantages along with the expansive gear range.

3. Impressive weight

It would be reasonable to assume a hefty weight addition for the GX Eagle compared to the X01 Eagle given the disparity in price and lack of carbon fiber components, but that doesn't appear to be the case. A 14% increase in overall weight (1,847g total) of the GX Eagle compared to the XO1 Eagle would be considered a relatively small penalty by many.

4. Crankset specifics

fullpage sram 2018 gx eagle mountain bike groupset ten things to know crankset 1

The GX Eagle crankset features 7000 series forged aluminum arms with aluminium chainrings, which saves significant costs compared to the carbon composite construction of the XX1 and XO1 Eagle cranksets. There are three crank arm lengths available – 165mm, 170mm and 175mm. And three chainring options of – 30, 32 and 34. The crankset is compatible with all other levels of the Eagle drivetrain system so you can mix and match components as you wish.

The cranks are available with either 24mm (GXP) or 30mm bottom bracket axles, with SRAM offering bottom brackets to suit Pressfit 30, BB386, BB30, Pressfit86 and English Threaded frames.

5. New XG-1275 cassette

fullpage sram 2018 gx eagle mountain bike groupset ten things to know cassette 1

On the more expensive XO1 and XX1 Eagle cassettes, the first 11 cogs are machined from a single piece of steel requiring more specialized manufacturing and higher consequent costs. The cost savings are apparent with the 10-50T GX cassette that uses stamped steel cogs held together with stainless steel pins and at 450g, is approximately 90g heavier than the XO1 version. The steps between the cogs are; 10t, 12t, 14t, 16t, 18t, 21t, 24t, 28t, 32t, 36t, 42t and 50t.

Like all SRAM cassettes that feature a 10T small cog, this cassette requires the use of an 'XD' freehub body, something that's available for just about any quality mountain bike wheelset with exception of Shimano products.

6. Trickle down continues to the rear derailleur

fullpage sram 2018 gx eagle mountain bike groupset ten things to know rear derailleur 1

The similarities between the XX1, XO1 and GX continue to the rear derailleur that features the 1x-specific X-HORIZON design and the larger, 14-tooth X-SYN lower pulley. The Type-3 roller bearing clutch also features which SRAM says provides a "smoother torque curve for a quieter, more consistent operation and feel". The GX rear derailleur is made of steel and aluminium with lower grade bearings, once again, enabling the overall price to stay low while offering similar performance to the XO1 and XX1. Total weight is 290g.

7. New chain to pull it all together

fullpage sram 2018 gx eagle mountain bike groupset ten things to know chain 1

Linking it all together (see what we did there), is the GX Eagle chain that weighs 258g (20g heavier than XO1 and XX1). It features solid pin construction and a hard chrome coating. This chain is missing the polish of the XO1 and XX1 equivalent, lacking the hollow pins and ti-nitrate treatment of more expensive options, but coming back to price, it's highly competitive.

8. The shift control

fullpage sram 2018 gx eagle mountain bike groupset ten things to know trigger shift 1

The right-hand GX Eagle trigger shifter is the final impressive component of this new groupset made of a plastic body and forged aluminum trigger, weighing in at 122g. SRAM technologies, Zero loss and X-Actuation feature, which should keep shifting sharp, consistent and precise much like XX1 and XO1.

For those still in love with where SRAM originally came from, there's a gripshift option too. SRAM claim this option remains superior for ultra-endurance and cold weather users.

9. Pricing

We've itemized the components below but it is possible to buy complete boxed groupsets with either 170mm or 175mm GXP crank (bottom bracket not included) for just $545

  • Trigger: $40

  • Gripshift: $40

  • Rear derailleur: $110

  • Chain: $30

  • Crankset $120 - $170

  • Cassette: $195

10. Availability

Groupsets arriving early August 2017, visit your local bike shop to get on the back order list if you're keen.


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