SRAM Eagle Expansion review

It was no accident that Shimano’s 12-speed options introduced a 51-tooth largest sprocket to throw some shade on SRAM so it’s no surprise that the latest ‘expansion’ of Eagle returns the ratio roast. But what are the details and what does it ride like on the trail?

Image 1 of 2

Be 52

The big news is that SRAM’s Eagle cassette is now expanded from 10-50 to 10-52 teeth on the XX1, X01 and GX families. XX1 also gets a new copper colourway on the XG1299 cassette as well as the existing black, gold and rainbow finishes. There's still the same split between one-piece machined architecture on the XG 1299 and XG 1295 cassettes and separate pinned cogs on XG1275. Even on the cheaper cassette the larger outer cog only adds 5g (447 v 452G) compared to the 10-50 block so it’s still lighter than Shimano XT (470g) but £51 more expensive.

GX takes the spotlight

GX is definitely the focus of the push from SRAM too as that includes all the increased 520% gear range advantages as the upper-tier groupsets but it’s had the most obvious makeover. That’s most obvious on the new silky looking crank finish that’s used on both the 631g alloy DUB crank and the 555g Carbon GX crankset. The outer lip and teeth of the chainrings are now raw anodised so they don’t look untidy over time as the black finish wears off. They still use the same three-bolt splined fixing onto the cranks, too.

The rear mech architecture is slightly altered (longer parallelogram and repositioned upper jockey wheel) to give more chain wrap and handle the bigger bloc. There’s a new, much easier to use clearance checker for setting up the ‘B-gap’. All the ‘expanded’ derailleurs get a new extended ‘foot’ for better chain management and protection around the lower jockey wheel. This adds 9g to the mech but we doubt many folks will notice that on the trail. The shifter pod doesn’t change apart from the new colourway but the whole group definitely looks a lot sharper and more aspirational than it used to. As long as you match the bigger block with the new mech, all elements are back-compatible and you’ll still be able to get a 10-50T version if you don’t think you’ll use the 52T.

There’s no change in pricing either which is quite refreshing given that most hop-ups are an excuse for a hike in cost too, so the whole group with alloy crank is still £495, sliding it just under XT on the Shimano ladder.

Performance 

We’ve only had limited time on Expanded Eagle, but we’ve managed to get trail time in on both X01 and GX setups. Most of the time there’s no difference in practical performance with the usual positive and solidly communicated shifts right across the block. If anything the new derailleur cage set up seems to make things crisper. Unlike some super-wide cassettes we’ve used, there’s no obvious lurch or lag as you surrender into the 52 either. Compared to the 4 tooth ratio changes between gears 7 to 11, the 10 tooth gap to the new largest sprocket is hardly seamless in terms of cadence though. The final gap is much bigger than Shimano 10-51 too although the preceding ones are smaller. Having talked to other riders we know we’re not alone in wanting a smaller spread of gears (similar to Shimano 10-45) but we guess that’s a harder sell outside of the hardcore. 

• RockShox Reverb AXS dropper post review
• Best MTB groupsets

Verdict 

Whether you need an even lower gear obviously depends on where you ride and how strong you are, but as the ‘Expansion’ is an option rather than a replacement it doesn’t really matter. What matters is that - aside from the big jump from painful grind to the sudden spin of the massive cog gap - GX and X01 still work as well as they've always done. In fact, they might even work fractionally better. Weight increases are negligible and there’s no change in price either.

The other big bonus is that GX no longer looks like the hard-working Cinderella of the Eagle upper echelons, she’s now the talk of the 12-speed ball.

Tech spec: SRAM GX Eagle

• GX shifter: 122g, £36
• GX mech: 299g, £110
• GX alloy 32T 170mm crank: 631g, £134
• GX carbon crank: 555g, £260
• XG 1275 10-52T cassette: 452g, £196g
• Overall price: £495 (GX with alloy 32T 170mm crank)
• Overall weight: 1504g (GX with alloy 32T 170mm crank)