UK downhiller Harriet ‘Hattie’ Harnden just won her first Elite DH World Cup this weekend in Les Gets. And in doing so, on this gearbox, belt-drive Gamux Sego DH bike, she also managed to win an extra 100,000€ at the same time.
We’ve been talking about the Gates 100K Belted Purse for three seasons now. Curious to see how long it would take until a gearbox bike without a chain would win a top-level downhill race, ever since the UCI finally gave belt-drives the OK back at the start of 2023?
Now we know.
Mission accomplished.
So then, let’s take a closer look at her bike. There are plenty of cool details and customizations to nerd out on.
I bet Crankbrothers will even give you your own ‘World Cup Winner‘ Mallet pedals. That is, if you win an Elite DH World Cup on them, too.
Hattie Harnden is coming for all the wins!
Harnden’s done it. She won a DH World Cup. And on the same belt-drive bike she was racing last season, a bike that officially entered Gamux’s line-up just before Gates announced the original 100k Belted Purse back in 2024.
Up against the fastest women in downhill racing, her decisive win shows both her own potential and versatility.
If you didn’t know, this 25-year-old rider two years ago won the UCI Enduro World Cup overall & an Elite EWS race back in 2021. And before that, she was twice the Elite British Cyclo-cross champion, in both 2020 & 2022.
Now, she’s only been dedicated to racing Elite DH for two full seasons.
Gamux Sego Pinion gearbox, Gates belt-drive DH race bike
The bike Harnden won the Les Gets DH World Cup and Gates 100k Belted Purse on is a Gamux Sego, custom tuned for her. It’s a CNC-machined aluminum frame that uses box section carbon tubes bonded into the front triangle for stiffness control. It’s a 200mm travel DH bike we’ve been following for years, first spotted as a belt-drive prototype three years ago.
It is not Gamux’s latest bike.
That would be the wild U-shaped spar AON Racing prototype we spotted back in May. We asked AON why Harnden is still racing the old frame design – although clearly it’s not holding her back. And they confirmed that they tested the new platform for her and “decided to stick with what we know for her“.
Gamux CEO & frame designer, Pascal Tinner confirmed that there was no technological reason for Hattie not to race the new evolution. It was just a simple matter that “she felt better on this one“, a bike that she knew well and has been racing for two seasons now.
Pinion gearbox + Gates belt-drive FTW
Let’s call this one the money shot. Skill is what won Harnden her first World Cup. But this Pinion gearbox and Gates centerline belt drivetrain is what won her an extra €100,000 in Les Gets.
The Sego features a relatively simple mid-high single-pivot suspension design with a 2-piece linkage to drive the rear shock. But with the belt setup, it still gets an idler pulley to decouple the belt from suspension movement, and a tensioner behind the gearbox to keep everything taut.
A Smart.Shift electronic setup delivers quick, consistent gear changes to the magnesium housing of the lightweight Pinion C-line gearbox.
All the weight in this bike is really low, which is also why it gets some super short 140mm North Shore Billet machined alloy Talon cranks to drive that gearbox.
Manitou shock tweak
Just like we spotted last season, Harnden gets a custom-modified Manitou Mara Pro air shock. Originally developed for enduro, she doesn’t need the two-position remote for “Work & Party” modes that’s standard on this shock, instead sticking with its unrestricted & externally adjustable hi- & low-speed compression circuits.
Her race bike also got a fresh coat of black duct tape on the sides of its downtube in Les Gets, covering up the carbon bonded into the machined alloy frame. I asked AON Racing if there was anything special going on under the tape. But apparently, it’s just there to keep the finish of the carbon tubes from getting scratched up by the gritty mud this past weekend.
But beyond some duct tape, we were more curious about what was zip-tied to the downtube…
Race day add-ons & other custom kit
I asked AON if that was simply adding weight to her frame to tune the bike’s handling? If so, how heavy it was? And expressed surprise that just two plastic ties were secure enough to survive the brutality of a World Cup DH race.
AON Racing’s response was a simple, “No Comment.”
But it seems pretty clear that this is some kind of universal-fit added weight setup, right? It looks like a folded & welded alloy box with a V-shape to fit against round frame tubes, with an external bolt that presumably lets the team secure weights inside to vary how much added weight is desired.
As for those pedals…
When I first spoke AON’s team manager about getting photos of Harnden’s Belted Purse-winning Gamux Sego, he said the bike was still exactly as Hattie raced it, except the pedals. He explained that some Crankbrothers guys came over right after the race and swapped them.
I initially suspected that maybe Harnden was racing with some prototype pedals or had broken one in the race, but the reality is much cooler.
Instead, immediately after confirming her win, Crankbrothers race support gave her a fresh set of Mallet DH pedals that say, “I Won A World Cup Today”.
More customized Manitou suspension
Rounding out Harnden’s Gamux Sego suspension setup is a hybrid Manitou Dorado Expert & Pro fork. Note the EXP decal on the machined alloy uppers next to her race number, not carbon tubes like the lighter, higher-spec Pro model. But it still gets the top-tier internals, and the more extensively machined shiny silver crowns from the Pro level? Curious.
Also, not the piggy-back prototype we saw her teammates on earlier this season, or one of the all-silver prototypes they were racing this weekend – similar-looking to the Nicolai-only Dorado Pro Silver we learned about last week.
But the front end also gives an interesting view of her upright cockpit!
Unconventional short Reach, high Stack cockpit setup
Like her teammates, Harnden’s Gamux Sego is set up with an extra-high bar position, and a reversed stem to shorten reach. Even though she runs the adjustable headset in its more-forward, longer frame Reach position.
Her cockpit combines a 50mm hi-rise Ergotec handlebar and a Burgtec direct mount stem, mounted backwards. The team describes the stem position as: +70mm Stack and -10mm Offset.
Harnden explains that the more upright, rearward position on the bike means less weight on her hands and improved ability to shift her weight over the front OR rear wheel, depending on what the situation calls for.
“Coincidently, this reduces weight on my arms, meaning less fatigue on them. The more upright position also gives you much more space to move and manoeuvre the bike with your legs and arms being more straight, rather than squatted and stretched out from a normal setup. I’ve also noticed less leg fatigue, as my legs aren’t constantly very squatted.
This has other, smaller knock on effects, like being able to look up and [ahead] more easily and able to drop your ankles/[heels] more easily. All in all, it puts you in a much more upright position through the middle of the bike. It really took me by surprise but also made more sense the more I thought about it.”
The last interesting bit of her cockpit beyond those classy purple Hayes Dominion brakes… A set of prototype shock-absorbing RevGrips with integrated bar ends. Just like we saw on her teammates’ bikes, these promise to keep her hands from slipping off the bars on the roughest DH track, without having to hold on for dear life. They look pretty well-finished, so we only wonder how long until RevGrips offers them to the public.
Lastly, a quick look at her rolling stock.
Carbon Reynolds Blacklabel 309/307 DH Expert carbon wheels laced to 6-pawl 8° engaging Ringlé Bubba hubs, curiously with no logos on the rear carbon rim. Wrapped with Schwalbe Dirty Dan Gravity Pro tires, and kept sealed with OKO Magic Milk.
I asked about what tire casing (for ex.: bias-ply or radial) Harnden was racing. And was told that AON is part of Schwalbe’s “continuous development with race teams” so they couldn’t share any details on tires.
Gates 100K Belted Purse has been claimed
So, is that the face of a pro downhiller that just realized she not only won her first UCI DH World Cup, but also an extra €100,000 bonus from Gates’ 100K Belted Purse?
Yeah, Hattie Harnden was pretty thrilled to have won her first World Cup.
But the Gates race support team seemed pretty excited, too. Even if it was a pretty expensive day at the office for them. It is nice to see that they were ready to hand over the prize. And hopefully there isn’t really €100,000 in cash in that box, and some more secure electronic transfers have since been made.
That said, Gates have gotten a lot of publicity out of the 100K Belted Purse over these three seasons, without having had to pay out yet. Yet now, they have the evidence in a top-level race win. Gates can set aside any remaining doubt. Belt-drives clearly are now a viable solution for gravity racing at the highest level. So, it seems like they probably got their money’s worth.
What next?
I’d guess we probably need to get used to Hattie winning. And probably more belt-drive bikes, too!
There have been several in the top 5 this season, for both men & women, and both in quallies and race day finals. In a time when significant numbers of top-level DH racers are adding weight to fine-tune suspension, handling & grip, the benefits of gearbox gravity race bike design is becoming more obvious.
Four top teams are currently racing DH on gearbox bikes. That’s not going to change now that the 100,000€ bonus has been claimed. In fact, we wouldn’t be surprised to see even more gearbox bikes by next season!
For now though, it seems AON Racing is leading the charge.