Drop bars and dropper posts. Do the two belong together? RockShox clearly seems to think so after launching the new Reverb AXS XPLR gravel dropper alongside the RockShox Rudy Ultimate XPLR gravel fork and SRAM XPLR drivetrain.
This new gravel post comes in a 27.2mm diameter, is offered with either a 50 or 75mm drop and uses the brand’s wireless technology to actuate it.
While the subject of adding a dropper post to a gravel bike is potentially divisive, fitting one will have clear benefits when it comes to off-road handling, especially when tackling particularly technical terrain.
Getting the saddle down and out of the way enables you to lower your centre of mass and stay more central on the bike when descending.
Don’t believe me? Well, you only need to look at the final descent of the 2022 Milan-San Remo, when Matej Mohorič made the most of the 60mm of drop on the Fox Transfer post fitted to his Merida Scultura. He compressed the post then set off down the Poggio at breakneck speed, using every millimetre of tarmac (and even some of the gutter) to pull away from the race’s favourites, and eventually took the win.
Droppers won’t suit all riders or types of riding, though. While they’re now universally accepted in the world of mountain biking, not all gravel riders will feel the need to use one. And that’s fine.
But if you do think your riding will benefit from having one – especially if you like to dabble in more technical trails – the RockShox Reverb AXS XPLR post has a lot to offer. It’s by no means cheap, though, and isn’t quite perfect.
RockShox Reverb AXS XPLR dropper post details
RockShox offers the Reverb AXS XPLR with either 50 or 75mm of drop and in a 27.2mm diameter only. The 50mm-drop post comes in a 350mm length. You can, however, get a 400mm post with a 50mm drop, or the longer 75mm drop that I have on test.
Pricing for the post doesn’t include the shifters/controllers, so it’s worth remembering that if you do decide this is the post for you, you’ll need to dig a bit deeper into your savings to buy it and get it working.
Inside, the Reverb AXS XPLR relies on an adjustable air spring only, with no hydraulic oil. While this helps to reduce weight, it also enabled the brand to introduce some squish into the post – something RockShox worked hard to avoid with the mountain bike equivalent of this dropper post.
This means that, while the post is rock-solid when fully extended, once you drop it ever so slightly into its travel, you’ll experience what RockShox refers to as ActiveRide.
This essentially means you can turn your dropper post into a suspension seatpost, which should help reduce vibration and up comfort when seated and hammering along rough trails.
To actuate the post, it needs to be weighted and both shifter paddles need to be pressed simultaneously, just as they would be when shifting between front chainrings using SRAM’s electronic groupset.
If you want to customise the setup, you can add one of SRAM’s Blip buttons to enable you to actuate the post from anywhere on your bar. SRAM’s latest wireless Blips aren’t currently compatible with the Reverb (so you’ll need the wired version), but SRAM assures us that a firmware update is on the way, so they soon will be.
Like other AXS components, the Reverb AXS XPLR post relies on the brand’s universal AXS battery, which clips onto the rear of the seat clamp.
The batteries weigh just 25g, are easy to install and take about an hour to charge fully.
You can get about 40 hours of ride time out of one of these batteries on a mountain bike. However, I use the dropper far less on my gravel bike in comparison and have gone much longer between charges during testing.
Unfortunately, the position of the battery means you’ll struggle to fit a saddle pack (though we’re aware that some brands are launching new, compatible packs soon, so keep an eye out).
For now, you’ll need to consider a different way to stash your essentials on your bike if you’re planning on buying a Reverb.
Finally, the seat clamp itself is pretty neat. This uses just one T25 Torx bolt to tighten up to clamp your saddle in place, and when this is loosened off, there’s another T25 bolt at the front of the clamp that enables you to accurately adjust the saddle angle. It’s easy to use and works really well in practice.
RockShox Reverb AXS XPLR dropper post performance
Easy to live with
With no cables to worry about, fitting and setting up the Reverb AXS XPLR dropper is easy and you can sync the post and controller using the AXS app.
It also means that (assuming you have other SRAM AXS-equipped bikes) you can swap the post quite easily between bikes (as long as they’re compatible).
At full extension, the post feels rock-solid with no unwanted squish up or down when riding.
Over the last six months, my post has developed a small amount of torsional play, which can, on occasion, be felt when I’m really digging in and pushing my bum back into the saddle on steep climbs.
The movement is minimal, but in these instances can at times be felt, although not constantly.
As a mountain bike tester, I’ve used a lot of droppers. There’s a little more play here compared to the mountain-bike version of a Reverb AXS post, and a little less than I’ve experienced on a Fox Transfer post.
It’s certainly not off-putting and I’ve found it easy to live with, mainly because it does what it’s designed to do so well.
Used in anger
Dropping the post is really quick and easy. Not only is it rapid to compress, but it’ll fire back up to full extension in the blink of an eye.
The minimal effort and lack of resistance means dropping the post, especially when hovering over the saddle making micro-adjustments to the height, takes no real effort at all. Few droppers can better the Reverb AXS XPLR in this regard.
I also had no issues with pushing both controllers simultaneously.
That said, when riding a trail blind, or if the terrain is particularly bumpy, making those split-second movements to drop the post isn’t as straightforward, though it’s still doable with a bit of practice.
It’s nice to have the option of adding a Blip to make life (and actuation) that bit easier.
The ActiveRide feature is a bit of an odd one and something I haven’t used a whole lot. Why? Although the squish beneath you can be felt as soon as you dip the post into its travel, by dropping the post to access this feature, your saddle height will be incorrect.
That means the ride might, in theory, be a little more comfortable, but I found my legs tiring more easily because I couldn’t pedal as efficiently.
In terms of feel when the post is slightly dropped and you’re using the ActiveRide feature, it can be compared to a more refined suspension seatpost of old.
That said, Warren Rossiter, our senior technical editor here at BikeRadar, says, with regards to its performance as a suspension seatpost, that it’s no match for the Redshift Shockstop post.
Of course, you can set the post higher than you’d normally have it, dropping the post and your saddle down to your preferred height and enabling the ActiveRide feature. But it’s a bit of a fiddle to ensure you get it to that place each time.
The big question, just as you’d expect, is “do I really need a dropper on my gravel bike?” My answer to that is it really does all depend on the type of terrain you’re looking to ride.
I may do some rides where I’ll not touch it, with all the off-road sections being relatively mellow and requiring more in terms of pedal power than technical prowess. But then there are rides that’ll take in a good chunk of woodland singletrack.
Here, you can find yourself swooping between the trails, coasting over steep drops and navigating tricky rock and root-riddled sections. In these instances, a dropper post makes the world of difference and really adds to the overall fluidity of the experience.
Once you’ve acquainted yourself with how to actuate the post, getting the Reverb slammed and the saddle out of your way helps to boost control and handling on the bike.
I’ve confidently navigated tracks that I’d have previously only ever touched on a mountain bike (albeit at a far slower speed) without feeling I’m on the edge of control.
And when those sections are behind you, a quick push of the controllers and the post rapidly pops back up ready for you to carry on.
Yes, adding a dropper comes with a weight (and cost) penalty, but if off-road control is what you’re after, or you’re simply looking to up your aero gains and win big races with death-defying descending skills, then the Reverb AXS XPLR is well worth considering.
RockShox Reverb AXS XPLR dropper post bottom line
While the Reverb AXS XPLR dropper post is pricey, it does what it’s designed to do really very well. There’s a touch of play (but no more than most droppers) and it’ll add a bit of extra weight to your bike, but if you’re looking to boost off-road control and confidence, it’s definitely worth considering.
The lack of cables is a real plus when it comes to setup, and also gives scope for switching it between multiple bikes, which is handy and helps when it comes to considering overall value.
Again, though, because it’s a hefty investment, it’s worth considering how and what you ride before taking the plunge. Don’t forget, there’s no space for a saddle bag, which may irritate some.