In June 2025, the bike wheel specialist Swiss Side found to its dismay that a surprise UCI equipment ruling excluded its 68mm deep HADRON³ Ultimate 680 wheelset from sanctioned races. It had only been brought to market two weeks earlier! So a UCI-compliant wheelset was a challenge that the Swiss Side team and partners rose to.
Four months later, the HADRON³ Ultimate 650 wheelset is released. With a 65mm deep rim it pushes the limit of the latest rulebook, yet remains UCI compliant. As the ruling comes into effect on the first of January 2026, the 680 wheels were still allowed to be used by the Decathlon AG2R La Mondiale team this summer.

Although only 3mm less deep than the 680, the HADRON³ Ultimate 650 are 33 grams lighter for a pair, yet they keep the 22mm inner rim width in common with the 550, 680 and 850 models. This is also true with the use of DT Aerolite II T-head spokes, Swiss Side / DT Swiss 180 – AERO hubs and SINC ceramic bearings.
The front wheel comes in at 706 grams, the rear 820g, with the pair weighing in at 1526g. This is 135g less than the previous HADRON2 650 version.
The RRP of the wheelset is £1,988, or if you buy direct online from Swiss Side then the price drops to £1,591. You also have the option to pair different (rim) depth wheels if you prefer, along with being able choose which freehub you’d like. The four options are Shimano/SRAM, SRAM XDR, Campagnolo 12-speed, or Campagnolo 13-speed.

The HADRON³ Ultimate 650 wheels are optimised for use with a 28/29mm tyre, but are able to perform with tyres between a 25mm to 32mm width. The front wheel now has a 20 spoke count, which reduces weight, but also provides less rotational drag. A hooked bead is used in the rim construction too.
Swiss Side took this oportunity to develop and enhance riding stability over the 680 model. Swiss Side claims an impressive 12% reduction in steering moment so that cross-wind sensitivity is improved. This was measured at 45km/h, and carries a 0.5W aero drag penalty. A reasonable trade-off, all things considered.
Alongside its involvement with the Decathlon AG2R La Mondiale Pro team, Swiss Side has two pro triathletes in its race team: 2024 women’s Ironman world champion Laura Philipp, and 2023 men’s Ironman world champion Sam Laidlow. Their wheels have been used to set world record bike splits, too.
It should be noted that the HADRON³ Ultimate 680 still remain legal for any non-UCI events such as triathlons or to anyone just wanting to go “full-gas”, says Swiss Side!






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18 thoughts on “Swiss Side launches new HADRON³ Ultimate 650 wheelset to work around UCI’s new rim depth regulations”
Too narrow. Any wheels with
Too narrow. Any wheels with less the 25mm internal width is lready obsolete.
You’d have thought given they
You’d have thought given they were redesigning them anyway, they could’ve made them a bit wider.
please post your aerodynamic
please post your aerodynamic qualifications and which F1 teams you have worked with, thanks.
No need, but we’ve seen the
No need, but we’ve seen the data on rolling resistance and aerodynamics of the top wheels with Zipp and HED leading the way. Their 680s(designed by those experts you’re referencing) are very good but not the best.
Best is subective
Best is subective qualification, not an objective one. As for leading the way, well, let’s see the indepdendent test data, the test procedures, etc.
Psi Squared wrote:
Indeed. I read that Swiss Side are one of the few companies that do ‘proper’ testing with yaw angles and changing crosswinds that characterise actual road riding rather than static tests. Such is the incompatibility of different test protocols and data presentation you’d need a degree in aeronautics to make sense of it, to the point its useless for the layman.
Has to be said in this day and age £1600 for a decent wheelset seems good value. I thought it was for one wheel!
GravelIsNothingNew wrote:
Wider rims are only marginally more aerodynamic for wider tyres, because of the tyre wheel interface. Wider tyres are in vogue because frames are all too stiff. At least in part frames and forks need to be stiffer to cope with disc brakes. It is a perpetual cycle of improving something and making something else worse as a result.
Narrower things are
Narrower things are inherently more aerodynamic, it’s incredible how many people have been gaslit into believing otherwise
Absolutely… CdA… all
Absolutely… CdA… all other things being equal drag is proportional to width, a 28mm tyre and matched rim will have 10% more drag than a 25mm equivalent.
Rider frontal area dominates drag of course.
These wheels look nice and aren’t too heavy. That matters too
All things being equal, you
All things being equal, you are correct when looking at a wheel in isolation. But it doesn’t necessarily follow that the system as a whole will be more aerodynamic.
Also a lot of older aero wheels were narrower but flatter, which wasn’t optimal. A wider object can have a lower CdA than a narrower one depending on its shape. And that’s before we get into lift effects at different yaw angles.
That’s still marketing
That’s still marketing bollocks though. The only “system” they mostly look at is rim+tyre. They don’t bother to check the bike or the less than aero meatbag on top.
The only fact you need to armed with is that 9 times out of 10 deeper is faster. The rest is marginal sales bollocks.
Buy the deepest wheels you can for your budget and cross wind tolerance. And poo before your ride.
I’m not talking about the
I’m not talking about the marketing.
Cobblers. It makes zero
Cobblers. It makes zero real world difference to 99% of riders.
Rim width is for pointless stats nerds and marketing droids or those that have drunk the kool aid.
Which one are you?
They have “worked around” the
They have “worked around” the UCI rim depth regulations by complying with them. A bit like working around the speed limit by slowing down to the speed limit. Cunning.
The difference is that speed
The difference is that speed limits have been in place for a very long time. They weren’t arbitrarily imposed at a few months’ notice. And they didn’t need product redesign/ retesting/ new moulds etc.
The speed limit in front of
The speed limit in front of my house changed a couple months ago with similar notice.
I envision someone at
I envision someone at corporate daydreaming for hours about contending with this rule change.
Make them crash-proof and
Make them crash-proof and call them Hadron Colliders.