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Swiss Side launches “benchmark” Hadron² Ultimate aero wheels

New wheels, available in three depths from 50mm to 80mm, are designed to reduce drag and improve stability

Swiss Side has launched new Hadron² Ultimate 500, 625 and 800 disc brake aero wheelsets which, it says, offer a large reduction in drag over their predecessors and set new benchmarks in terms of crosswind stability.

The brand says that the new Hadron² Ultimate wheels offer a 10-20% reduction in aero drag with an increased sailing effect ('capturing' sidewinds to produce thrust – or negative drag – and push the bike forwards) and maximum aero stability, meaning that they're significantly less affected by crosswinds than the original Hadron wheels (there's to a 26% reduction in steering moment, if you speak that language).

2021 Swiss Side Hadron Ultimate rim.jpg

The Swiss Side Hadron² wheels are very similar to the DT Swiss ARC 1100 Dicut Wheels that we told you about earlier in the week

"We have developed them in collaboration," says Swiss Side. "The only small difference is the internal ratchet system in the rear hub, where we choose to keep the more cost efficient, performance neutral, star-ratchet system over the new EXP-ratchet system. And, of course, we think our graphics and colour options are a lot cooler!"

Swiss Side’s price points are also lower.

2021 Swiss Side Hadron Ultimate aero comparison - 1.jpg

The new tubeless ready Hadron² Ultimate wheels come in 50mm, 62.5mm and 80mm rim depths. Those rims now have a 20mm inner width, compared with 17mm previously. Swiss Side says that this allows the wheels to accommodate wider tyres and improve rolling resistance without a weight penalty. The wheels are optimised for use with 25mm and 28mm tyres, and Swiss Side recommends not going wider than 32mm (although 64mm is technically possible).

2021 Swiss Side Hadron Ultimate  wind tunnel 1.jpg

Swiss Side has gone with a hooked rim. Why?

"The hookless rim construction is not compatible with higher tyre pressures (over 6bar)," says Swiss Side. "The new Hadron² Ultimate wheels are designed to be compatible for all tyre sizes, including 25mm tyres which are run at up to 8bar pressure."

The Hadron² Ultimate wheels use DT Aerolite II spokes that are just 0.7mm thick with a longer chord blade (they're deeper) than previously. The spoke profile is designed to reduce the rotational drag component and the wheels' overall aero drag.


The hubs are DT Swiss 180s with SINC ceramic bearings.

“The biggest achievement, from my perspective, is the massive 26% reduction in steering moment," says Jean-Paul Ballard, CEO and co-founder of Swiss Side. 

"The new Hadron² wheels feel one size smaller in comparison to their predecessor Hadron wheel models, and they were already the benchmark for crosswind stability!"

The new wheels come with a lifetime warranty for the original owner on material and workmanship defects, and what's called a Fair-Share Policy that offers "cost-conscious repairs" on riding damage for 10 years.

Swiss Side Wind Tunnel Rake.jpg

Swiss Side says that 95% of the development work on the Hadron² Ultimate wheels was done using CFD (computational fluid dynamics) software, in particular the rim shapes, before the wheels were taken to the wind tunnel to confirm the CFD-predicted performance and for fine tuning. Swiss Side tested in the wind tunnel using the front wheel alone, with wheels fitted to bikes, and with an athlete on board a bike.

"In our final confirmation step, we make on-road measurements with our numerous unique tools to confirm the performance of a new wheel is measurable and felt out on the road, the only place it matters," says Swiss Side.

Swiss Side hasn't published data comparing the Hadron Ultimates with aero wheels from other brands. For what it's worth, though, here are the claims it makes for its wheels compared with a "standard road wheel set".

2021 Swiss Side Hadron Ultimate aero comparison 2 - 1

Hadron² Ultimate 500 €2,198 (approx £1,986)

2021 Swiss Side Hadron Ultimate set.jpg

Swiss Side says... Top level aero performance on any course, in any conditions, the Hadron² Ultimate 500 aero wheels are at home speeding down twisty mountain passes, as well as on time trial and triathlon courses. Their shallow rim profiles are designed to maximise handling and aero stability in high wind conditions by minimising the sensitivity to gusty crosswinds.

Weight 674g (f), 804g (r), 1,478g (total)
Aero profile height 50.0mm
Maximum rim width 27mm
Inner rim width 20mm
Hubs DT Swiss 180 DICUT (Shimano, SRAM, Campagnolo & XDR compatible: 10,11,12 speed), SINC ceramic bearings
Spokes DT Swiss Aerolite II and Aero Comp II Straightpull / DT Swiss pro lock hidden aluminium nipples, 24 spokes front and rear (2-cross pattern)

Hadron² Ultimate 625 €2,198 (approx £1,986)

2021 Swiss Side Hadron Ultimate 625 set.jpg

Swiss Side says... Maximum aerodynamic performance with the widest operational range, the Hadron² Ultimate 625 aero wheels are designed for absolute maximum overall performance for road racing on any course profile, as well as for unmatched all-wind condition performance in time trial and triathlon. Our performance simulations and testing show that this is the fastest road-setup for any course up to 7.5 % gradient!

Weight 776g (f), 906g (r), 1,682g (total)
Aero profile height 62.5mm
Maximum rim width 30mm
Inner rim width 20mm
Hub DT Swiss 180 DICUT (Shimano, SRAM, Campagnolo & XDR compatible: 10,11,12 speed), SINC ceramic bearings
Spokes DT Swiss Aerolite II and Aero Comp II Straightpull DT Swiss pro lock hidden aluminium nipples. 24 spokes front and rear (2-cross pattern)

Hadron² Ultimate 800 €2,198 (approx £1,986)

2021 Swiss Side Hadron Ultimate 800 set.jpg

Swiss Side says... Specific for time trial and triathlon racing, the 80mm deep profile is engineered to deliver maximum speed and thrust in medium to low wind conditions whilst maintaining predictable, stable handling in the gusty conditions, comparable with competitor wheels 20mm shallower... The world’s lowest drag, maximum sailing effect aero wheel, setting the new benchmark for aerodynamic performance.

Weight 811g (f) 939g (r), 1,750g (total)
Aero profile height 80.0mm
Maximum rim width 32mm
Inner rim ridth 20mm
Hubs DT Swiss 180 DICUT (Shimano, SRAM, Campagnolo & XDR compatible: 10,11,12 speed), SINC ceramic bearings
Spokes DT Swiss Aerolite II and Aero Comp II Straightpull DT Swiss pro lock hidden aluminium nipples, 24 spokes front and rear (2-cross pattern)

The maximum system (bike plus rider) weight for each of these wheelsets is 110kg.

The Hadron² Ultimate aero wheels are available to order now on We'll have a review of the Hadron² Ultimate 625 wheelset here on soon.

Mat has been in cycling media since 1996, on titles including BikeRadar, Total Bike, Total Mountain Bike, What Mountain Bike and Mountain Biking UK, and he has been editor of 220 Triathlon and Cycling Plus. Mat has been technical editor for over a decade, testing bikes, fettling the latest kit, and trying out the most up-to-the-minute clothing. We send him off around the world to get all the news from launches and shows too. He has won his category in Ironman UK 70.3 and finished on the podium in both marathons he has run. Mat is a Cambridge graduate who did a post-grad in magazine journalism, and he is a winner of the Cycling Media Award for Specialist Online Writer. Now over 50, he's riding road and gravel bikes most days for fun and fitness rather than training for competitions.

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Sriracha | 3 years ago

Hadron? I dunno, word association kicks in.

OnYerBike replied to Sriracha | 3 years ago
1 like

Supercollider? I 'ardly know her!

hawkinspeter replied to OnYerBike | 3 years ago
1 like

I was going to launch into some criticism of the Large Hadron Collider, but it's hard to discern.

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