We first spotted prototypes of these wheels being tested by IAM Cycling at the Giro d’Italia. They are used by the pros, but how good are they? We put the DT Swiss RRC 65 DiCuts to the test.
Having been developed with the IAM Cycling professional team and refined in the wind tunnel, the updated DT Swiss RRC 65 DiCut wheels feature wider rims, to accommodate bigger tyres and now feature a U-shape profile, which aims to provide a significant improvement in cross wind stability over the previous version.
Another improvement over the previous version is the braking surface. DT Swiss were concerned about preventing delamination of carbon rims, something which can be caused by dragging the brakes, resulting in a significant build up of heat. This can cause the resin to melt, resulting in wheel failure.
To counter this the Swiss manufacturer told us that it “sets its own internal standard to a level far above the existing regulations, which include braking tests according to DIN EN 14781.” In comparison to the previous RRC DiCut rims we improved the overall braking pressure by nearly 20%.”
Included with the wheels are bags and Swiss Stop Black Prince brake pads, which DT Swiss recommends as the only pad you use, to ensure maximum breaking performance.
The result? The braking on these wheels is easily among the best we have experienced on carbon rims. They really bite. The brake track on lesser quality carbon rims often gives pulsing, inconsistent braking when under prolonged use, such as on a long descent. This can be caused by imperfections and inadequate heat dissipation. It is much harder to manufacture a perfectly flat braking surface from carbon than it is from aluminium.
No pulsing was experienced here and it took a lot more braking stress too cook these rims than I have experienced on other carbon wheels. But, although these rank among the best carbon rims for braking, they are still carbon, meaning that as soon as the heavens open, you will be wishing for either an aluminium braking surface or disc brakes.
Having raced on these tubs, the reduced drag over a shallow rim is noticeable and the pickup when accelerating is excellent. This is in part down to the sublime hubs, ceramic bearings and relatively low weight, for such a deep wheel. Enve 6.7s are slightly lighter, but they are also more expensive and the braking is no where near as good.
The 240 hubs roll beautifully, but there is also an option to choose the more expensive 180 hubs –I would argue you don’t need to. Cross wind stability is much better than the previous version of the RRC 65, which would often catch a gust, something which was especially noticeable every time a lorry blasted past you on an A-road TT course.
The different parts of a road bike wheel explained
The RRC 65s are super stiff and ideal for criteriums. This is in part down to the Pro Lock aluminium nipples, which are claimed to allow for a higher spoke tension. The skewers are worthy of mention too. DT Swiss skewers are the best quick release on the market, with a ratchet design that allows you to pull out and turn the lever to the desired position after you have tightened it.
I tested the wheels with Schwalbe One 26mm tubs, which offer excellent grip but sit little wide on the 24.8mm rim. I chose this combination because IAM Cycling were using these tubs in the 2015 season. It is likely that a 24mm or 25mm tyre would be better for aerodynamics as this would sit flush against the rim.
Purely subjective, but I think DT Swiss has played it safe with the decals. They are pretty understated, which will appeal to some riders, whilst others like flashy bling logos. I think the best thing would be to offer a choice, but at present the wheels are only available with the decals you see here.
While the tubular version will appeal mainly to racers, the clincher version comes tubeless ready and is slightly heavier (1550g). Although primarily designed for racing, time trials and triathlon, the wheels are still light enough to be used on hilly and even mountainous terrain. We took them into the mountains found they performed admirably. The only really downside to these wheels, is that they don’t come cheap, but pro-quality often doesn’t.
Best suited to racing and triathlon, the front is a good all round TT wheel too. Braking is very good and they roll beautifully. Although expensive they are a pro-level wheelset offering superb performance.