Swiss Side Hadron Ultimate 625 wheelset

The Hadron Ultimate range from deep-section upstart Swiss Side takes a lot that we loved from the Hadron wheels (we've previously tested the 485 and the 625) and pimps it up with full-carbon rim construction and spanky ceramic bearings, as well as adding disc brake versions to the range. They remain a superb-handling deep-section wheel, now with a lower weight and a higher price. The move away from an aluminium braking surface has some of the downsides you might expect, though.

As with the previous Hadron range, the new Ultimate wheels are available in a choice of depths. These 625 wheels at 62.5mm rim depth are in the middle of the range, with the 485 below and the 800+ above (which has 80mm front and 85mm rear). All depths are now also available with disc-compatible hubs, which is good news. The rim is the same whether supplied for rim brake or disc brake.

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Where the original Hadron range had an aluminium structure and a thin carbon fairing, here the whole rim is built from carbon, but still in a similar fashion. The fairing appears similar or identical to that used before, with the spokes still passing through the inner edge to hidden nipples on the outer structural part of the rim.

Another significant change is that the Hadron Ultimate range are tubeless-compatible, a first for Swiss Side. They are supplied taped, meaning that even if you're running them with inner tubes, truing is going to be a bit awkward. Happily our test wheels were true when unboxed and remained so throughout the testing. Swiss Side uses quality Sapim CX Ray spokes, with 16 laced radially at the front and 21 at the rear (7 radial spokes on the non-drive side and 14 in a 2-cross pattern on the drive side). Bonus point duly awarded for the use of brass nipples.

The hubs are the same as those used in the Hadron range but with an upgrade to Enduro ceramic hybrid bearings. Ceramic hybrid means that the races are conventional hardened steel while the balls themselves are made from ceramic silicon nitride. Check this link if you're wondering about whether ceramic bearings are worthwhile. We conducted a simple spin down test between the front wheel on test here and the Hadron 625 with its standard ball bearings. The Hadron Ultimate has a lower inertia thanks to the full-carbon rim but was still spinning after the Hadron had stopped (which – truth be told – took a really long time anyway), suggesting that there is indeed lower friction here.

The hubs are forged and machined to a good finish. My only criticism regards the freehub, which suffered badly from being bitten into by the cassette. It appears the same as the one used in the standard Hadron, but my first 500km on these wheels were spent in the Pyrenees after which it was quite tricky removing the cassette. A couple of steel 'anti-bite' strips would be a really worthwhile addition.

I've ridden these wheels for the thick end of three months, in the mountains and in the rolling terrain around Bath, and they compared largely as expected to their alu/carbon brethren, which is to say exceptionally well behaved in the wind and with (per Swiss Side's well documented testing) a significant aerodynamic benefit. Braking suffers – again, as might be expected – especially with the Equinox pads that are supplied as standard. 

Aerodynamics

Let's take the aerodynamic benefits first. Swiss Side claims that these are marginally more aerodynamic than the equivalent-depth Hadron, saving 10.5W at 45kph compared to a reference shallow-section rim (compared to 10.0W for the alu/carbon Hadron). Swiss Side reckons that over 40km this would give a saving of 97 seconds.

As far as I know, no wheel manufacturer has been as open about its test and development programme as Swiss Side, inviting journos (including us) to spend time with them in the wind tunnel and doing comparative tests with the Big Names in the wheel market, which it reckons show that the Hadrons display similar drag to some of the leading rivals (which cost quite a bit more) while also offering better crosswind stability than many of them.

We talked to Jean-Paul Ballard, the technical director and co-founder of Swiss Side, who explained that "aerodynamic stability is a big focus of ours at Swiss Side as we've identified that this is where big performance gains can be made by effectively reducing rider drag by keeping them in a lower, stable, confident position more of the time". In other words, if you're more confident in the wind, you'll stay in an aero position more of the time, which itself contributes more to your speed than any wheel will.

Indeed, just as we found with the previous Hadrons we've tested, the Ultimate 625 gives you a real sense of confidence on windy days. Even riding across the M48 bridge to Wales on a blowy day to see the Tour of Britain was a much less alarming experience than you might imagine. The wide, U-shaped rim profile is very similar to that used in the Hadron 625, and the key dimensions are identical (27mm max width, 23mm across brake surfaces). The slight improvement in aerodynamics is apparently due to a minor modification in the shape of the rim and the resulting change in how the reference tyre sits against the rim. Obviously it would depend on your choice of tyre anyway.

Braking

What of braking then, the habitual bugbear of a carbon rim? With the supplied pads, Equinox BR006, they do a respectable job of slowing you down, but at ambient temperatures any higher than mid-teens made an appalling noise while doing so. Setting them up toed-in didn't help, and the screeching was such that I found myself trying not to brake unless I really needed to, which wasn't ideal. On long Pyrenean descents there were times where the power seemed to drop off as the pads and rims heated up. Also not ideal.

Pad wear was a problem too – 500km in the mountains and they were toast. Chatting to Swiss Side about this, I was told that the choice of pad was imposed upon Swiss Side by its rim manufacturing partner, but said partner sent a set of SwissStop Black Prince pads over for comparison and they were a massive improvement (and are also approved for use with these wheels). Thankfully, the screeching noise vanished and the wear rates became rather more acceptable. It appears on its website that Swiss Side still supplies the Equinox pads as standard, so I would strongly recommend replacing them immediately if you buy these wheels.

Swiss Side made a video talking about the design of the wheels, in which it discusses the unusual approach of using two-part construction for a full carbon rim. This, it is claimed, allows it to "decouple the lateral stiffness from the vertical stiffness". In my experience, it's extremely hard to detect any noticeable variation in vertical stiffness from one wheel to another. There's an argument that deeper rims and shorter spokes makes for a harsher ride, but it's not one I'm really convinced by. Here, I would suggest that the relatively wide rim profile and consequent effect on the tyre shape and volume has a greater effect than the fact that the spokes pass through the fairing.

> How to get more aero without spending a fortune 

Lateral stiffness, on the other hand, is certainly an area where there is variation between wheels, and one where I was a bit disappointed with the Hadron Ultimates. At the rear, particularly, it wasn't overly difficult to provoke brake rub, and I had to set my brake pads wider than I would have liked to eliminate it. I hadn't noticed this being a problem with either of the alu/carbon Hadron wheelsets I'd tested previously. Curiously, Swiss Side told me that lab tests show the Hadron Ultimate to be laterally stiffer than the equivalent Hadron, leading me to wonder whether it was simply the fact that brake rub on carbon makes a more audible noise that made me more aware of it here.

The Hadron Ultimate wheelset is supplied with branded QR skewers and spare spokes. Wheelbags aren't included but are available for an extra cost. Maximum rider weight is 105kg and maximum tyre pressure is 120psi.

Conclusion

We scored both previous Hadron wheelsets highly on road.cc and I had big expectations for the Hadron Ultimate. In most respects it is a really impressive wheelset, giving the same blend of straight-line speed and superb stability as the Hadrons, and saving a useful chunk of weight too (nearly 200g lighter than the same depth Hadron wheelset). Braking with the supplied pads is very disappointing, though, and not for lack of outright stopping power – the noise that accompanies it and the pad wear are the worst I've experienced. Happily, that's a problem that is easy to fix by swapping pads – these should really be included.

> Read our buyer's guide to road bike wheels

Measuring these up against competitor wheels I would say they do pretty well – they are fast, a good weight for the depth and their stability makes them among the most reassuring of deep-section wheels on a gusty day. The price represents a chunk of cash, sure, but against wheelsets from the likes of Zipp and Enve it looks like good value.

For me, the bigger question – if it was my money – is: are they worth the extra money over the alu/carbon version? Right now you can get 10% off the Hadron Ultimates and 20% off the Hadrons, making the Ultimate 625s more than 60 per cent pricier than the Hadron 625 wheelset. The extra money gets you a lighter and decidedly better-looking wheelset, but if I'm honest I'd probably buy the standard Hadrons, which are currently something of a bargain.

Verdict

Fast and stable, a great perfomer once braking issues were sorted, but is it worth the extra over the standard Hadron?