Prime RP-38 carbon clincher road disc wheelset review

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Prime is a new wheel brand brought to life by Chain Reaction Cycles, the online retailer based in the UK. It is no small undertaking, though, since the in-house collection comprises over two dozen different wheelsets with a choice of alloy and carbon rims and prices that will catch the eye of any thrifty online shopper.

In this review, Australian tech editor Matt Wikstrom takes a close look at the RP-38 carbon clincher designed for road disc bikes.


The rise of online retailers has had an indelible effect on the bicycle industry. Where once local bike shops dictated the retail landscape for most shoppers, online retailers have re-defined it, expanding the horizons in every direction. That includes pricing and the opportunity to experience new brands and/or products.

Some online retailers, like Chain Reaction Cycles and Wiggle, have enjoyed extraordinary growth over the last ten years. Not content with simply retailing products for other companies, they have gone on to develop their own product lines, such as Wiggle’s dhb brand of cycling apparel, Ribble Cycle’s extraordinary range of self-branded bikes, and the resurrection of Vitus Bikes by Chain Reaction Cycles.

Such an undertaking is no doubt helped by the amount of retail intelligence that online retailers have at their disposal. Not only do these companies have intimate understanding of the buying habits of their customers, they are well placed to identify trends well before manufacturers that rely on a traditional supply-chain for distributing and selling their products.

In this regard, I found it very interesting that both Wiggle and Chain Reaction Cycles have established their own range of wheels in the last year or so. It’s a part of the market that’s already stacked with a multitude of products and brands, big and small. Yet, in both instances, Wiggle and Chain Reaction Cycles unveiled bargain-priced carbon wheels and even lower-priced alloy wheels.

Chain Reaction Cycles’ Prime wheels are a relatively new product, with the company launching the in-house brand in August 2016. Prime wheelsets, rims and hubs can be found in the company’s road wheel catalogue however there is also a dedicated website with shopping links that direct buyers to the relevant page at Chain Reaction Cycles.

There are over two-dozen wheelsets in Prime’s catalogue, comprising alloy clinchers, carbon clinchers, and carbon tubular wheelsets. Furthermore, there is a rim- and a disc-brake version for every model of rim with prices starting at AUD$272/US$200/£155 for alloy clinchers and AUD$1,166/US$858/£665 for carbon wheelsets.

Looking more closely at the range of carbon wheelsets, there is a choice of three clincher rim profiles (28mm/38mm/50mm) and another two tubular rim profiles (35mm/50mm). There are also two kinds of build on offer: the RR build makes use of hubs with conventional flanges and j-bend spokes (DT double-butted), while the RP build features hubs with straight-pull flanges and spokes (Sapim CX-Ray). As a result, RP wheels save some weight and provide a little extra stiffness over RR wheels, however it comes with a bump in price (~AUD$200/US$150/£115).

For this review, I spent a few weeks riding Prime’s RP-38 carbon clincher road disc wheels, courtesy of Chain Reaction Cycles, and I discovered that while these wheels might be bargain-priced, they come stacked with a lot of nice features.

Before the ride

Prime’s RP-38 carbon clinchers road disc wheelset features all-carbon tubeless-compatible clincher rims married to road disc hubs with straight-pull flanges. The wheels are laced with 24 Sapim CX-ray spokes, front and rear, with external Sapim alloy nipples.

All of the carbon clincher rims in Prime’s catalogue are tubeless-compatible and the wheels are tubeless ready straight out of the box thanks to pre-installed rim tape and tubeless valves. As mentioned above, buyers have a choice of 28mm, 38mm and 50mm rim profiles, but they all share the same U-shaped semi-toroidal profile that is 25mm wide with 16.5mm rim bed (measured hook-hook).

All of Prime’s carbon rims are open-mould products. The wide U-shaped rim profile was an important pre-requisite; so too was tubeless compatibility. The company may not have been responsible for manufacturing the rims, but I’m told that it conducted its own lab tests followed by an extensive period of on-road assessment before the specifications for each wheelset were finalised.

Prime’s RP-38 carbon clincher wheels are not only tubeless-compatible, they are supplied as tubeless-ready with pre-installed tape and tubeless valves.

This last point may be an easy thing to claim but there’s plenty of evidence that Prime carefully considered every detail. This is most obvious in the range of adaptors that are provided with each wheelset and the inclusion of spare spokes and nipples. In short, Prime wheels might be priced to catch the attention of bargain-shoppers, but that doesn’t mean the company has taken any shortcuts in developing the final product.

Novatec provides the hubs for all of Prime’s wheelsets. As mentioned above, there is a choice between a conventional hub design and j-bend spokes, or a lighter hubset with straight-pull flanges and spokes, which is what is used for the RP-38 wheelset.

Straight-pull spokes add a very contemporary feel to the look of the wheelset. While it might have been tempting to use a cheaper spokes, the RP-38 features semi-bladed CX-Rays that have an excellent reputation for strength and durability as well as a significantly higher asking price.

For some smaller brands, it might have been enough to opt for high-end spokes, but Prime go a step further by supplying axle adaptors for the front and rear hubs. Thus, buyers will be able to fit this road disc wheelset to bikes that use quick-release axles as well as those making use of thru-axles.

For the front hub, changing between a quick-release axle and 12mm or 15mm thru-axles is simply a matter of swapping end-caps for the hub axle. Setting up the rear hub for a thru-axle is a little more involved, since the standard 135mm quick-release axle must be swapped out for a 142mm axle, but everything that is needed (excluding tools) is supplied in the box.

For those that are unfamiliar with disc brake fittings, there are two options for mounting the rotors to the wheel, 6-bolt or Center Lock. The RP-38 road disc wheelset (and all of Prime’s other road disc wheelsets) opts for the former, the traditional standard for disc brakes, however it will create problems for buyers replacing Center Lock-equipped wheels (new 6-bolt rotors will be required).

I would have preferred to see Center Lock hubs used for this wheelset, since an inexpensive adaptor can be used to fit any 6-bolt rotor. I’ve seen road disc owners struggle with this issue before, so Prime could tackle it as effectively as the issue of axle compatibility by switching to Center Lock hubs and supplying 6-bolt adaptors with the wheelset.

Novatec’s “Anti-bite guard” limits the amount of gouging a cassette can inflict upon the aluminium freehub body.

All of Prime’s wheelsets are supplied with an 11-speed Shimano/SRAM-compatible freehub body. For those using Campagnolo, a suitable freehub body is available, however only as an after-sales option.

Chain Reaction Cycles supplied a pair of 700x23c Schwalbe’s Pro One tubeless tyres with the RP-38 road disc wheelset, a tyre that I’m very familiar with. Mounting and inflating the tyres proved to be a simple affair, though I had the benefit of a home air compressor to ease the process. Once inflated, the tyres measured 25mm wide, which is typical for a 23c tyre on a wide rim.

For those wondering about conventional clinchers, they can be easily fitted to any of Prime’s carbon clinchers. Just remove the tubeless valves that are supplied with the wheelset and install your preferred tyre and tube combination.

The RP-38 road disc wheelset supplied for review weighed 1,503g (front, 685g; rear, 818g) with rim tape and tubeless valves. That might not seem impressive, but to put it into context, Enve’s SES 3.4 road disc wheelset retails for almost three-times the price but only manages to best the RP-38 by ~60g (claimed weight with DT 240s hubs, 1,439g).

As for the asking price, Chain Reaction Cycles lists the recommended retail price as AUD$1,482/US$1,090/£845, but at the time of this writing, was discounted to AUD$1,277/US$1,005/£760.

There is a choice of two finishes for the RP-38, gloss white or grey logos on the raw unidirectional carbon rim. I found the white logos a little too bold for my liking, however there is no easy way to remove them since the water transfers are protected by coat of hard lacquer. For those that appreciate the logos, at least there is the promise that they will be long-lasting.

All of Prime’s wheelsets are backed by a two-year warranty, though it’s important to note that there is a weight limit of 114kg/252lb for these wheels. In addition, they are rated for a maximum tyre pressure of 110psi/7.5bar.

The RP-38 road disc wheelset is supplied with rim tape and tubeless valves, a pair of quick-release skewers, axles/adaptors to suit both quick-release and 12/15mm thru-axles, and spare spokes (one for each spoke length for a total of three spokes) and nipples. For more information visit Prime and Chain Reaction Cycles.

After the ride

I was impressed with Prime’s RP-38 road disc wheelset well before I started riding the wheels. As discussed above, the wheels are supplied with all the fittings to suit the range of axle types found on road disc bikes, so buyers shouldn’t have any trouble fitting the wheels. With that said, one obvious exception is any Specialized bike using the SCS system.

The front hub is easy to convert from one axle type to another, since it is just a matter of swapping the end-caps for the axle. The rear hub is a little more complicated since the axle has to be removed, so home mechanics should be familiar with servicing hubs in order to take on this job for themselves.

I spent the entire review period riding the wheelset with 23c Schwalbe Pro One tubeless tyres inflated to 60-80psi. I’ve been using this tyre on my own wheels for well over 12 months. Not only is it one of the best tubeless road tyres on the market today, it also matches the performance of many high-end clincher tyres.

My bike is fitted with rim brakes so a pair of Cannondale road disc bikes was seconded for review. Those bikes were each fitted with a Mavic Aksium wheelset that weighed over 2kg, so the RP-38s had an immediate and significant impact on the performance of each bike. The bikes were easier to accelerate and felt more nimble, and while I can’t say they were any faster, the extra responsiveness was a welcome upgrade.

The RP-38 road disc wheelset was sure and sturdy under load, and there wasn’t any obvious flex when I was out of the saddle tipping the bike side-to-side. Most riders would normally use brake rub to judge the lateral stiffness of any wheelset, but that’s not relevant for road disc wheels. With that said, I’ve only experienced brake rub on a few occasions over many years of riding, so I don’t have the weight or power output to challenge the lateral stiffness of a wheelset.

The radial stiffness and ride quality of the wheelset was unremarkable, which is to say, they weren’t unnecessarily rigid or harsh. I expect most riders will enjoy the RP-38 wheelset, but since I weigh around 75kg, I can’t comment on how the wheels will behave for riders that weigh over 90kg. In this regard, it’s worth noting that the RP-38s have a low spoke-count (24 spokes, front and rear) that I wouldn’t recommend for riders that weigh 90kg or more.

As for the aerodynamic performance of the wheels, they seemed to be no better or worse than other wheels with the same rim depth. According to Prime, the aerodynamic performance of its rims has been optimised for 25c tyres, so prospective buyers may want to pay attention to this if they want to maximise their marginal gains.

While the aerodynamic performance of the wheels may have been difficult to judge, it was clear that crosswinds affected the 38mm rims. Strong gusts would push the front wheel around, but I never had to wrestle with it to keep the bike on line. For those buyers that are considering 35-40mm rims for their goldilocks appeal, I should point out that while these rims are much less susceptible to crosswinds than taller rims, they are not exempt.

I had no difficulties with the hubs over the course of the review period, and the wheels were still round and true when I was finished with them. The external cam skewers were satisfactory but extra effort was required to secure the wheel. A good internal cam skewer will always offer a smoother, lighter closing action, greater security, and withstand the long-term effects of wet weather. I’m almost inclined to forgive Prime for this decision, but there’s no good argument for the ongoing use of external cam skewers by any wheel brand, big or small.

Summary and final thoughts

Prime’s RP-38 should be a crowd-pleaser. First, there is the low asking price; second, they are widely available via a proven and reliable online retailer; third, the rim and hub design keeps pace with current trends; fourth, the wheels are supplied with all the parts for maximum axle compatibility; and fifth, there are no shortcomings in the on-road performance of the wheels.

On the basis of price alone, this wheelset trumps almost everything on the market while providing the backing of a major retailer. There is a two-year warranty for the RP-38 wheelset, however buyers should keep in mind that shipping costs can be expensive if the wheels have to be returned to Chain Reaction Cycles in the UK as part of a claim.

Be that as it may, I still see the RP-38 as a very tempting upgrade for a road disc bike. In fact, I don’t see any barriers to purchase unless buyers are intent on the marginal gains associated with cutting-edge aerodynamics and a handful of grams.

 

What do each of the individual ratings criteria mean? And how did we arrive at the final score? Click here to find out.

Disclosure statement: Chain Reaction Cycles has advertised with CyclingTips in the past.

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