Pacenti Carbon PR50 rim brake wheelset

These Pacenti Carbon PR50 wheels give extra width for rim-braked bikes but without a weight penalty. They're competitively priced, and the customisation options are a welcome benefit of the company's 'made in the UK' wheel-building approach. The braking might make you wish for disc brakes, though.

In case you hadn't noticed, the bike industry is betting pretty heavily on disc brakes, with top-end race bikes increasingly only being available with discs. Certainly the majority of performance road wheelsets we're getting sent to test are disc brake models this year. But there are plenty of cyclists who have rim brake bikes that they're very happy with and who might be in the market for a wheel upgrade, and they’ll welcome the fact that Pacenti is still launching rim brake wheelsets like the PR50.

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If you're still riding with rim brakes you may have heard your friends who've made the leap to discs talk about the enhanced comfort they get with bigger tyres and wider rims. No rim brakes means that disc brake frames can be made to accommodate much wider tyres, which you can run at lower pressures for a bunch more cush.

These Pacentis are the widest rim brake road wheels we've come across, offering some of those benefits to riders on rim-braked bikes. How wide is wide, in 2021? The key dimension is the internal width between the rim flanges, as that's where your tyres push up against. These measure 21mm here, where not that many years ago 15mm would have been more typical. This means the set of 25mm Schwalbe Pro-One TLE tyres fitted to our test set come up almost 28mm wide, and – being tubeless – they can be run at lower pressures too, further improving comfort.

Pacenti says these wheels are suitable for tyres from 23mm to 30mm, if your frame, fork and brake callipers can accommodate them. (Clue – you likely won't fit 30mm tyres.) The limit in my Rose frame is 25mm, and the rims themselves only just fit – with new brake pads I had to set my Shimano Ultegra callipers as wide as they’d go.

The external profile is a bulging U-shape, which reaches a whopping 29mm at its widest point. It is so wide, in fact, that the brake surfaces taper back in – the first rim brake wheelset I can recall where these are not parallel surfaces. They are 1mm wider externally and 2mm wider internally than the 50mm rims Hunt uses in its 'Wide' rim brake wheelsets.

Given the width (and the 50mm depth), the weight of these Pacenti wheels is impressive at 1,440g. That is lighter than Hunt's 50mm Wide wheelset and a whole raft of other 50mm wheels at prices higher and lower than this, and pretty much the same as a couple of narrower competitors – the Lightweight version of Prime's BlackEdition 50 Carbon wheelset and Scribe's Aero Wide 50 wheelset.

Of course, weight might not be the main objective for everyone, and if you want a stronger wheelset then you can have Pacenti build you a set with some extra spokes. Its line on rider weight is: 'With all Pacenti hand built wheels there is no upper weight limit ... If you are a larger rider, then just drop us a line and we can then advise on the best wheel build for you.' As standard, the PR50s are built with 20 spokes laced radially in the front wheel, and 24 laced two-cross in the rear, and you can opt to have four more spokes in either or both.

And the choices don't stop there – you can also pimp your hubs, with options including Hope, DT Swiss and Chris King, and add tyres, which you can have set up tubed or tubeless. Smaller custom wheelbuilders often offer these options, whereas bigger brands buy their wheels built in batches and so this isn't an option. I really like this level of 'we'll build it how you want it', so props to Pacenti for that.

With a novel 'Revive and Ride' offer, Pacenti will even let you send in your old hubs and build wheels around them for £100 less than if new hubs were included, provided they have a compatible number of spoke holes.

Talking of hubs, the default hubs that Pacenti uses are easily recognised Bitex models – most smaller wheel brands use hubs from the likes of Bitex or Novatec – and they're fine, although there is more drag from the bearing seals than I'd expect. I spun both wheels by hand at the start and the end of the test period and they came to a stop in about half the time of some other wheels. You wouldn't feel this when riding, but it must offset some part of the watt-saving you expect from adding aero to your wheels.

If you want fancier hubs, no problem, just choose that option. While I've been writing these up, Pacenti has started to offer the very bling Oil Slick Hub option as a £50 upgrade on these and its other wheels. I like.

Pacenti doesn't provide any data on aerodynamics, but in general you'd expect there to be a benefit from a deeper rim profile like this compared with something shallower. Without a whole bunch more science than we have at our disposal, we can't really quantify this, but I would say they feel subjectively comparable to other 50mm wheelsets I've tested.

A bulging U-shaped rim is generally held to be better in crosswinds than a narrower or V-shaped rim, and these are reasonably good here. Again, objective comparisons are really hard here, but if you ride for long enough you form an impression of a wheelset and get used to how they respond to sudden gusts. I would say that the best 50mm-ish wheels I've ridden in the wind are from Swiss Side and I think these Pacentis are discernibly more affected by crosswinds, needing just a bit more of a steady hand on the bars to keep you going in the right direction when passing gaps in hedges and the like. But certainly not enough to put me off buying them.

I used them for a bunch of local riding, both fast and slow, and also took them on a trip to the Pyrenees including a tilt at the Col D’Aubisque. Initially I used the Swiss Stop Black Prince pads I had on my bike – these are carbon rim-specific and a pad I really rate. In the dry, I found braking to be quite good – not the very best among the wheels I've tested, but entirely acceptable against other (rim-braked) competition.

However, a ride on a cool, drizzly day in the Mendips provided an unwelcome surprise – wet braking was really poor. After a second or two of very limited braking as the water clears from the brake track and some heat builds up, braking then requires noticeably more effort on the levers than I've got used to with other modern carbon wheels. I never felt that I couldn't actually stop the bike, but I found myself allowing markedly more space and tending to brake earlier. Plus, pulling the brake levers harder all ride adds fatigue in your hands, wrists and forearms.

We talked to Pacenti and the company supplied us with a set of its preferred (unbranded) brake pads – these are always included with these wheels to customers. I found that wet braking performance with Pacenti’s pads was indeed improved, but at the expense of dry braking, which became worse than with the Swiss Stop pads.

To be specific about this criticism, there were two main issues. First, you have to pull the brakes harder to achieve a given amount of braking deceleration. As noted, this becomes tiring on long rides or long descents. There was also a spongy feel which I think results from two things – the Pacenti pads are a bit softer, and that the braking surfaces are not parallel with each other on the rims.

I made it down from Col D’Aubisque in one piece, but my first thought at the bottom was “this makes disc brakes seem like really a good idea”, which isn’t exactly a ringing endorsement.

Was it enough of an issue that I would avoid these wheels? Well, that really depends on your use case. I’d certainly argue that if racing or even fast club rides are on the agenda, then you should look elsewhere as good braking is essential with such fine margins to play with.

Of course, early carbon wheels famously had really poor braking and that didn’t stop the pros from using them in races because of the combination of weight and aerodynamics that was unattainable with aluminium rims. But things have moved on, and if it was my money in 2021 then I would be unsatisfied with the compromised braking on offer here.

> Buyer’s Guide: 33 of the best disc brake road wheelsets

Aside from the braking, I liked the Pacenti PR50s, as they are strong, light, wide and tubeless compatible. The rear wheel went out of true during testing, and this is harder to live with than on a narrower rim, as my brake calliper was already set as wide as it would go. Conventional external nipples mean that a quick true-up is easily done, though.

Verdict

Light, aero and wide, but compromised braking makes them hard to recommend