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DT Swiss overhauls its ARC line of aero wheels

Sam Challis
12 Aug 2020

The DT Swiss ARC range uses new rims, hubs and spokes in an attempt to make racers faster

In its new ARC wheelset line-up DT Swiss has taken advantage of an opportunity opened up by aero bikes’ widespread move to disc brakes. By removing the restrictions of the rim-brake caliper and brake track, DT Swiss says it has been able to completely re-engineer its aero wheelset range.

Although DT Swiss has always been pretty progressive in its attitude towards tubeless technology and road disc brakes, and has had ARC disc brake wheels for several years, the brand admits that previous iterations of similar designs had to be largely derived from their rim brake counterparts.

Now all that has changed. The latest DT Swiss ARC wheels are disc-only, so the rim could be totally updated. It is now wider – the internal rim dimensions increase from 17mm to 20mm – and DT Swiss says it balances conflicting attributes (like weight and width or stability and aero efficiency) better.

As a result DT Swiss says the wheels are the complete package for all-round race performance.

 

New rims

‘The rim shape of the new wheels is the result of extensive computational fluid dynamic analysis,’ says Jean-Paul Ballard of SwissSide, the aerodynamic expert with whom DT Swiss has a long-standing working relationship.

‘We tested hundreds of iterations. Then came the rapid prototyping – aluminium box-section rims with 3D printed fairings over the top to validate the CFD in the wind tunnel. Even when DT Swiss committed to moulds and full carbon fibre construction, the rim shape continued to be refined in the wind tunnel.’

Many of DT Swiss’s competitors have touted the benefits of even wider internal dimensions – up to 25mm in some cases – for their aero wheelsets, so it is interesting to see that DT Swiss has kept to 20mm and recommends a tyre pairing of 25mm front, 28mm rear.

‘Primarily this was driven by rolling resistance and aerodynamics,’ says Ballard. ‘You don’t get lower rolling resistance with a 25mm tyre by going wider than 20mm internal. For competitive cycling, and these wheels are very much aimed at competitive cycling, 25mm tyres are the norm.

‘They haven’t got to 28mm tyres on the front yet. 28mm on the rear? For sure, as it doesn’t affect aerodynamics. You get better rolling resistance numbers with a 28mm but on the front wheel this would bring with it a disproportionate increase in drag.’

The new ARC rims will come in 50mm, 62mm and 80mm depths and use a ‘hooked’ rim design. Again, this differs from several competitors who are moving towards ‘hookless’ bead walls.

‘As a 25mm tyre is the prime tyre for overall performance with these new ARC rims, hooked rims are the safest way to go as the tyre pressure will be comparatively high,’ says Ballard.

’It also allows for broader end usage – while the new wheels are tubeless ready as standard, with hooked rims consumers have the option to run regular clinchers and tubes as well as tubeless tyres.’

 

New spokes

Unique among its competition, DT Swiss talks about the effect ‘rotational drag’ has on performance, as well as the type of drag more commonly considered, which it labels as ‘translational drag’.

Rotational drag can be described as the additional friction that occurs between the wheel and the air as it rotates while moving forward.

‘Rotational drag accounts for up to 25% of total drag compared with 75% for translational drag,’ says DT Swiss. ‘Since the spokes are the link to the rim and hub, they take on significant importance that must not be underestimated in the fight against the wind.’

Taking that effect into account, DT Swiss has designed to new types of aero spoke, the Aerolite II and Aero Comp II.

The brand says the Aerolite II is 35% wider and 23% thinner than the first Aerolite, while the Aero Comp II is also more aero and stiffer laterally than Aero Comp I.

DT Swiss says it compresses the spokes more during the forging process for increased tensile strength, as well as designing them with a ‘T’ shaped head, to make sure there are no alignment issues in the hubshell.

 

New hubs

Not long since being released, it hasn’t taken DT Swiss long to further refine its Ratchet EXP hub design specifically for its new ARC wheels.

By embedding one of the ratchet drive rings inside the hubshell, Ratchet EXP reduces the moving parts in DT Swiss’s venerable drive system, which bodes well for ease of servicing and long term durability. DT Swiss also says it makes the hub stiffer.

In a similar way to the new rim shape, the hubshell shape has been refined to apparently make it more aero – it is slimmer than previous with smaller flanges – as well as lighter. Cut outs on the centre lock mount reduce the weight of the hub by 11g.

 

Wheelset weights in general are reduced compared to previous ARC designs – the latest ARC 1100 Dicut 50 weighs a claimed 1472g, with the 62mm and 80mm versions weighing 1676g and 1762g respectively.

Those figures undoubtedly put the wheels among the very best in the market for their respective depths, so there is a similarly impressive price tag to match: UK pricing for the new wheels is set at £2199.98.

There is a second tier for the new ARC wheels at DT Swiss’s 1400 level (1100 is top-tier), which retain many of the same features but cede a little weight and retail for £1799.98.

DT Swiss has sent Cyclist a set of the ARC 1100 Dicut 50 wheels so check back in a few months for our thoughts on the new design’s real-world performance.

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