Prime RP-38 Carbon Clincher Wheelset

Looking for a set of full-carbon, tubeless-compatible race wheels on a budget? If so, then you should take a look at these Prime RP-38 clinchers from Chain Reaction Cycles. They're nicely built, with a low weight and decent braking performance, even in the wet.

The 38 in the name refers to the depth of the rim; 38mm is a fairly common depth for all-purpose wheels. It's deep enough to give you a bit of a nudge on the aero side, without being so deep that you have a white-knuckle ride when it gets windy. I've taken these RP-38s out in some fairly hectic conditions and found them to be very predictable – they do catch the wind a bit more than a standard box section rim but they're never scary.

As regards their aero properties, Prime isn't making any particular claims for them other than describing the rim profile as aero. It's a fairly wide and blunt shape as aero wheels go, not as bulbous as something like a Zipp 303 but still fairly chunky. You might go a bit quicker on your evening 10 over your shallow alloys, you might not. Given the depth, I'd expect the gains to be fairly marginal. It's more of an all-round wheelset than something you'd buy for shaving seconds.

> Check out our buyer's guide to road bike wheels

You're more likely to be fitting them because carbon wheels look cool. I mean, because they're lightweight and tubeless-ready. How light? Well, Prime claims a wheelset weight of 1,360g and when we stripped ours down to the bare wheels – no rim tape, skewers or tyres – that's exactly what they were: 620g for the front wheel and 740g for the rear. Sub-1,400g is proper lightweight territory but these wheels don't feel flimsy, anything but. Spoke count – 24 at the rear and 20 at the front – isn't high, but they're good quality spokes – Sapim CX-Ray – and evenly tensioned. You get spare spokes and nipples included.

The hubs are decent straight-pull alloy units with sealed cartridge bearings (four in the front and two in the back). The freehub is alloy, but it has a steel anti-bite guard plate to stop the sprockets digging into the metal. It works too: pulling the cassette off after a few hundred miles revealed minimal notching, and the cassette didn't need to be persuaded off with hitting tools. There are four pawls in the rear hub with 26 engagement points, and they're nice and clicky without being too loud.

The rims are T700 unidirectional carbon fibre, with a 3k weave used for the brake track. The surface of the brake track is textured 'for enhanced all-weather performance', we're told. Does it work? Well, they're not a match for a good alloy rim in terms of grab from the supplied Braco pads, but braking in the dry is good, and predictable. There's no change in brake feel as the wheel turns, so they've been built to a tight tolerance. In the wet there was some judder from the pads at first, but as they wore in it subsided; the braking performance in the wet is decent rather than stellar, but they're predictable and I never had any issues stopping the bike.

Prime uses a staggered brake track, moving the braking surface down and away from the bead to increase heat dissipation between the brake surface and the bead, which is the most vulnerable part of the rim. I spent a few mornings dragging the front brake all the way down the descent from my house into town and managed to get a considerable amount of heat into the rim but it was never so hot that you couldn't touch it, and there are no signs of any deformation or delamination. Prime says it has tested the rims up to 350°C – you do get some deformation at those temperatures but the integrity of the bead wasn't compromised. And it's not a temperature you're likely to be able to achieve outside of a lab, anyway.

The staggered brake track presents an issue, though, and it's that my brakes, especially the front, are right at their bottom limit in terms of pad adjustment. In fact, if I could I'd set them about a millimetre lower, but without taking a Dremel to the callipers that's not possible. With a certain combination of frame/fork and short-drop calliper you may not be able to set the brakes on the brake track properly, so watch out for that.

If you buy these wheels they'll come set up with tubeless valves and rim tape, ready for tubeless tyres. With a 16.5mm internal width you can fit anything up to a cyclo-cross tyre; ours came set up with 25mm Schwalbe Pro Ones. The valve setup is excellent: it's a quality valve and there's a flat section at the valve hole to make sure the rubber O-ring gets a decent seal. The rim tape isn't as great, it's a bit flimsy and it's easy to knock off the rim when you're seating a tyre, so be careful.

> Read our guide to the best tubeless tyres

Out on the road these wheels are everything you want them to be, really. The light weight is mostly noticeable when you're putting the power down to get up to speed, and there's very little flex in them – they're really well built. They don't noticeably wind up when you sprint and they don't pitch over when you lean them into a corner. Even when sprinting or putting in an effort up a hill, I didn't get any issues with rubbing on the pads. Mostly they do what they need to do with a minimum of fuss. They arrived true, and they've stayed that way.

I've reseated the tyres a couple of times and each time they've gone back up with the Bontrager Flash TLR pump, and stayed up. The Pro Ones are a favourite of mine (once you've got past the first couple of rides where they're a bit sketchy in corners) and the 25mm width suits the rims really well, giving a decent level of comfort without being over-heavy. I've mostly been running them at around 90-95psi, a bit less than I would with a standard clincher and tube, because there's no risk of pinching them on an unexpected pothole.

> Should you go tubeless? The pros and cons… 

The quick releases are okay; they're an external cam design and they feel a bit flimsy but I haven't had any issues with them working loose. In the end I swapped them out for a pair of internal-cam Shimano ones. Attaching wheels to my bike is not an area where I really want to save weight.

Overall these wheels are excellent for the money. Eight hundred quid isn't exactly small change but it's not exactly expensive for a set of carbon, tubeless-ready wheels either. The positioning of the brake track might give you some headaches, and the skewers are okay rather than good, and the braking in the wet is a bit less powerful than I'd like, but there are no deal-breakers there. If you want to go tubeless then they're definitely a worthy upgrade: light, stiff and well-built. And if you don't want to go tubeless they're still a great value pair of carbon race wheels.

Verdict

Really good tubeless-ready carbon clinchers for racers on a budget