Atherton’s interest in a belt-driven downhill bike started six years ago in co-founder Dan Atherton’s caravan, but it wasn’t until August 2024 that the brand began pursuing the project seriously.
Five intensive months of development and testing later, the A.200.G was released to the world – and boy did it make a splash.
The Atherton A.200.G eschews derailleurs in place of a gearbox and belt drive – tech that many commentators believe is the future of mountain biking.
Built specifically for Charlie Hatton – the 2023 downhill mountain biking world champion – to race at Hardline Australia and through this year’s world cups, the bike is currently a one-off.
Atherton invited BikeRadar and MBUK to its factory in Machynlleth, Wales, for an in-depth, behind-the-scenes look at 2025’s most talked about downhill bike, and to learn why the brand is investing in gearboxes and belt drives.
The future of MTB tech?
Although the Atherton A.200.G is an evolution of the brand’s previous downhill bike, Rob Gow, Atherton’s lead engineer, explains this shift is a bold one: “We’ve taken the bike Charlie won the World Championships on and said ‘No! We’re gonna get rid of that and we’re going to do something completely different. You’ve got to trust us'.”
But why risk messing with what is clearly a winning formula?
Gearboxes are claimed to offer many benefits, especially on downhill bikes.
While a gearbox generally weighs more than a derailleur drivetrain, this isn’t a concern on a downhill bike.
In fact, Hatton was strapping 500g of lead around the bottom bracket of his previous race bike to improve performance (a practice some brands, including Orange, have dabbled with in the past).
A gearbox sits where a typical bottom bracket shell would, so the additional weight is ideally placed.
Adding unsprung weight (ie, adding weight to the rear triangle and anything mounted to it, including the wheel) impacts suspension performance.
Reducing unsprung weight results in a more sensitive suspension system.
With no derailleur or cassette at the rear of the bike, all else being equal, using a gearbox can improve the sprung-to-unsprung weight ratio of a bike.
A gearbox is also, potentially, more reliable than a derailleur system.
In a gearbox, the gear mechanism is protected inside a metal housing, where lubrication is also taken care of, away from dirt and grime. There is also no derailleur hanging off the back wheel, where it’s at risk of race-run-ruining damage.
Gearboxes can also enable you to shift gears without pedalling.
That may sound like a gimmick, but Hatton says it offers genuine advantages on the track: “There’s limited time for gear shifts in a straight and I need to be in the right gear. [With the gearbox], I can shift mid-air if I need to.”
While mid-air shifts may be useful to an elite rider such as Hatton, mere mortals had more prosaic concerns about the gearboxes of old, which struggled to shift under load and generally used GripShift-style shifters.
Pinion has largely eliminated these concerns with its electronic SmartShift tech, which offers near-instantaneous shifts with a conventionally shaped trigger shifter.
What about efficiency? A gearbox and – in the case of the A.200.G – the belt drive that powers it, is generally less efficient than a chain and derailleur.
Reporting seen by BikeRadar suggests a 4 to 5 per cent efficiency loss with the Pinion system, although this was measured at lower power, rather than full sprints – where the loss is said to be less.
Either way, Gow explains this isn’t a concern for downhill racing.
Even at a 5 per cent loss in efficiency, this shouldn’t make a marked difference in a sprint, compared to a trail bike or XC bike, with the benefits outweighing any drawbacks.
In fact, Gow claims “you get efficiency gains at that peak point of a finish line sprint”.
Is Atherton chasing the Belted Purse?
Gates made headlines when it announced its Gates Belted Purse prize fund.
To grow interest in its system and add a little jeopardy to the race calendar, Gates announced that the first elite-level rider to win a UCI downhill race on a Gates-equipped bike would win €100,000.
Gow says that, of course, this is tempting – it would generate headlines and any rider would love to win the biggest prize fund in cycling.
But that’s not why Atherton opted for a belt drive.
In our review of the Atherton AM 130.1, tester Luke Marshall described the DW6 linkage used on the bike as “the new benchmark” for suspension performance.
This Dave Weagle-designed 6-bar linkage was used on the previous A200, but has seen a slight revision for the A200G.
The design is now a mid-high pivot, with the main lower linkage sitting higher in the chassis than previously.
Weagle, an integral part of Atherton’s design team, had a concept for a mid-pivot version of the DW 6 linkage that makes the rear wheel’s axle path near vertical in the most active portion of the bike’s suspension travel.
Rob Gow explains; “The benefit of that being your wheelbase isn’t changing, as you’re pumping through a corner so the grip therefore is maintained evenly between your two tyre contact points.
"This takes the existing race bike to a new level.”
It may have been possible to utilise this design with a conventional drivetrain.
However, Gow says the packaging requirements of the pivot placement and drivetrain would have required a more complex drivetrain, potentially including a dual-chain or dual-idler setup, as seen on the Pivot Phoenix.
The Pinion box is over-geared, enabling Atherton to use smaller Gates sprockets, ensuring the mid-pivot architecture can be used.
Add in the shifting and weight-distribution benefits of the Pinion gearbox, and the reliability and durability of the Gates, and the decision was made.
