With a price tag of nearly a grand for a derailleur and shifter, SRAM X01 AXS upgrade pack takes the humble drivetrain into previously uncharted waters.

Product Overview

Overall rating:

Score 9

SRAM X01 AXS Upgrade Kit


SRAM X01 AXS Upgrade Kit review


Price as reviewed:


With a price tag of nearly a grand for a derailleur and shifter, SRAM X01 AXS upgrade pack takes the humble drivetrain into previously uncharted waters.

Read more: Mountain bike groupsets – buyer’s guide

“How much?” That’s become the immediate response to so many new mountain bike products and with this SRAM AXS kit the depth of your pocket must be measured in fathoms.

To put this into some context, a cable-operated SRAM XX1 derailleur and shifter costs around £430, which is strong money considering Shimano XTR is around £300. But the X01 AXS upgrade kit more than doubles that price, even if you do get a battery and charger thrown in. Enough about the price though, because if you’re seriously in the market for an AXS upgrade you’ll be well aware of how much it costs, and will have reconciled yourself with that fact. What you really want to know is, is it any good? And my unwavering answer to that question is, yes, it is very, very good indeed.

sram x01 axs

Seamless transitions using a single paddle

The upgrade kit is suitable for anyone with a current 12-speed SRAM Eagle drivetrain, be that 10-50t or the newer, wider-range 10-52t. It replaces your rear derailleur, shifter and inner/outer cable, with the mech simply screwing into your mech hanger and the shifter attaching to the bars with either the included band-on clamp or a Matchmaker mount. You’ll need to split the chain, or remove the lower pulley wheel, to install the mech, but fitting the system is ridiculously quick and simple. Honestly, it took me longer to remove the old parts than install the new ones. And once you’ve adjusted the limit screws and B-gap (using the supplied guide tool) pairing the two units takes seconds, at which point you immediately have perfect shifting. For someone raised on ensuring smooth cable runs and the perfect cable tension, it’s pure witchcraft. Then you can sit on your bike and marvel at your new, remarkably clean, minimalist cockpit.

Geared for geeks

Once set up, you can just get on with riding, or you can geek out playing with settings on the SRAM AXS smartphone app. As well as letting you update firmware and giving you the current shifter and battery charge status, the app also lets you select between single shifting (recommended for e-bikes) and multi-shifting – where the derailleur will sweep anything between two gears and the whole block when you hold the paddle down. You can also reverse the action of the shifter too, so nudging the top of the paddle gets you an easier gear, or vice versa.

And you need very little force to change gear compared to a cable shifter. The SRAM X01 AXS switch/shifter is actually a single paddle on a rocker; where you press either the top or the bottom to shift. There’s even an extension of the rocker at the front that makes it more ergonomic to select a harder gear when you’re out of the saddle. Because the action is light and the throw minimal, shifts are faster and require less effort, so I found myself changing gear more frequently than I would with a cable set-up.

Downshifts, to an easier gear, are exceptionally rapid and precise, while upshifts can be slightly more protracted in the biggest sprockets, but speed up considerably in the middle of the cassette. Every shift is accompanied by a pleasingly soft ‘pzzztt’ from the derailleur’s servo motors.

So it shifts great, but what about rocks and stumps ruining your day and putting a £700 hole in your wallet? It’s a fair question, particularly as SRAM mechs don’t have the best reputation for durability. Personally, I’ve directly experienced two broken SRAM mechs in the last couple of years and I never damage anything, or really ride anywhere that tries to shred your bike to ribbons. So imagine my horror the first time out with this kit when a 2cm diameter branch got thrown up and wedged between the mech and the underside of the chainstay? Once the stick was removed, the gears functioned but didn’t stay enagaged and no amount of adjustment could get them to work properly again. I’d genuinely thought the mech was going to end up in some giant robotic scrap heap, like the one C3PO finds himself in during Star Wars. But luckily, the mech was completely undamaged and a change of hanger was all that was needed to enjoy perfect gears again. To this end SRAM has cleverly integrated a breakaway function, where the motor disengages inside the mech in the event of an impact, allowing it to swing out of the way. So while it’s a big investment to bolt onto your frame in arguably the most vulnerable position on the bike, in my experience it has proven more robust than I expected.

At the start of my AXS experience I was also concerned about battery life, both in terms of running out of juice on a ride, and having yet another device that needed regular charging. I needn’t have worried, because the SRAM X01 AXS drivetrain is incredibly frugal when it comes to power consumption. During lockdown I rode my AXS-equipped bike every day (at which point the parts were already a few months old) and I only had to recharge the battery once. Obviously how long your battery lasts will depend, to a large extent, on how many times you shift, but even if you have the itchiest trigger finger in the west and ride everyday, you’ll only need to charge it every couple of weeks. And if you’re really worried about running out, a spare battery costs around £50 and weighs only 25g, so it’s no sweat to carry in your pack. As for the C2032 watch battery in the shifter, mine is still at almost full capacity after 11 months.

You most definitely don’t need SRAM X01 AXS shifting. It doesn’t transform your ride in the same way as a new suspension fork or new wheels can. Nor will it make you whoop and holler for joy like a riding holiday in the Alps. But once you’ve tried it, you’ll be smitten with the precise, effortless shifting, reduced maintenance and decluttered cockpit of your bike. It’s an excellent product for those fortunate enough to be looking for that last little advantage.


Rear derailleur:363g