The DT Swiss RC 38 Spline wheels are a very well made pair of wheels, that impress perform well out on the road and tick nearly all of the boxes when it comes to future-proofing too. Lose the internal nipples and make a slightly wider rim and these wheels would be faultless.
Stiff under braking and acceleration
Cover all bases when it comes to axles
Rim could be wider
Internal nipples make maintenance tricky
By Symon Lewis
The DT Swiss RC 38 Spline wheels have been around for three or four years years now, with these disc brake clincher versions (which were first released at the tail end of 2014) sitting pretty much slap bang in the middle of the Swiss company's extensive range of wheels.
>>> Buyer's guide to road bike wheels (video)
The obvious starting point with the DT Swiss RC 38 Spline wheels is the weight. At just 1,470g for the pair (670g front and 800g rear), these wheels manage to scrape under the magical 1,500g mark, which is something that cannot often be said of disc brake wheels with this depth of rim. And as for the rims themselves, they are also a very respectable weight for their depth, with DT Swiss claiming a rim weight of just 453g.
However the rims on the DT Swiss RC 38 Spline wheels are certainly not the widest on the market, with 15mm internal and 21mm external widths. According to the manufacturer, the maximum width of tyre that you could safely run on these wheels is 35mm, which seems fine, but having a narrower rim will decrease the volume of air within the tyre at any given pressure, meaning a less comfortable ride. This means that there are better disc brake wheels out there if you're looking to take in anything other than silky-smooth tarmac.
Thankfully the DT Swiss RC 38 Spline wheels are right on trend with their tubeless-ready construction, making them a good option if you're looking to make the transition across to tubeless tyres in order having to waste your time standing at the side of the road fixing punctures rather than enjoying a bike ride. However, they're not quite as tubeless-ready as other wheels, as you'll need to use the supplied rim tape to cover the spoke holes.
Watch: Buyer's guide to road bike wheels
The DT Swiss RC 38 Spline wheels take centrelock (rather than six-bolt) rotors, so watch out if you're taking rotors from your existing bike or another wheelset as you can't convert six-bolt rotors into centrelock. Fitting the front rotor is a little complicated due to the diameter of the axle, requiring a DT Swiss locking ring and a Hollowtech 2 bottom bracket tool, but nothing any moderately adept home mechanic shouldn't be able to handle.
The reason for this is that the front wheel is designed to with a 15x100mm thru-axle, while the rear wheel works best with a 12x142mm thru-axle. However there are also adaptor supplied for quick release, and 12x100mm front and 12x135mm or 10x135mm rear thru-axles, so DT Swiss has certainly covered off every standard when it comes to axles.
The whole point of the Spline range of wheels is that they come with straight-pull spokes, so the DT Swiss RC 38 Spline wheels come with 24 of them, with alloy nipples used trim a bit of weight. The only problem is that the nipples are internal, making maintenance and adjustment tricky especially if they're covered with the tubeless rim tape.
The spokes are attached to a hub that features DT Swiss' Ratchet Freewheel Technology, which has a 20º engagement angle - not the smallest on the market but I certainly wouldn't describe the engagement as in any way sluggish. My test wheel came with a Shimano/SRAM freehub, but there are also Campagnolo and even XD options available, so DT Swiss certainly have all bases covered.
Watch: road bike wheels - jargon busting
But after all that discussion of technical specs, how do the DT Swiss RC 38 Spline wheels perform out on the road?
These wheels are genuine all-rounders, performing well whatever you ask them to do. The light rim weight means acceleration is good when climbing, and I didn't have any problems with flex whether on steep ascents or sprinting out of corners.
>>> Are wider tyres really faster?
I was also impressed with the DT Swiss RC 38 Spline wheels' performance under braking. Quite often when disc brake wheels are designed around their rim-braked relatives, the wheels can flex when subjected to hard braking, but thankfully DT Swiss has changed the lacing on the spokes on the front wheel, so I didn't have any such problems.
Despite having a V-shaped rim rather than a more on-trend U-shaped option, I didn't notice any problems in crosswinds with the 38mm rim, and I also felt a slight aero advantage over standard wheels. But perhaps this could have been greater if DT Swiss had decided to follow most of the rest of the industry with a wider U-shaped rim.
Finally, what was perhaps most impressive was the quality of construction of the DT Swiss RC 38 Spline wheels. After a few months of banging them into potholes they're still running straight and true, so these are certainly wheels that are built to last.
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