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review

Pacenti Carbon PR50 rim brake wheelset

5
£1,050.00

VERDICT:

5
10
Light, aero and wide, but compromised braking makes them hard to recommend
Light
Wide
Tubeless compatible
Braking is weak
Width may give issues depending on your frame/brake callipers
Weight: 
1,440g

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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.

> Buy these online here

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.

2021 Pacenti Carbon PR50 rim brake wheel set 700c - braking surface.jpg

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.

2021 Pacenti Carbon PR50 rim brake wheel set 700c - spoke nipple.jpg

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.

2021 Pacenti Carbon PR50 rim brake wheel set 700c - front hub.jpg

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.

2021 Pacenti Carbon PR50 rim brake wheel set 700c - rear hub.jpg

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.

2021 Pacenti Carbon PR50 rim brake wheel set 700c - rim.jpg

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.

2021 Pacenti Carbon PR50 rim brake wheel set 700c - valve.jpg

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

road.cc test report

Make and model: Pacenti Carbon PR50 rim brake wheelset

Size tested: 700C

Tell us what the wheel is for and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?

Pacenti says, 'For the rouleur in you, the 50mm wheelset offers a great performance choice. Designed and handbuilt in the UK. With a 21mm internal rim width, this all-new wheelset maximises the tyre profile with the widest clincher profile rim brakes can take.'

Tell us some more about the technical aspects of the wheel?

Pacenti lists:

Tyre type Hooked Clincher

Tire Size 700c

Tubeless ready Yes

Rim Construction Molded carbon

Material Carbon Fiber

Weight 1440g +/- 15g

Internal rim width. 21mm

External rim width 27mm - 29mm tapered brake surface

Rim Height 50mm

Max tire pressure As tyre recommends

Freehub body Shimano HG, Sram XD/R or Campag

Hub bearings TPI Taiwan

Spokes front Sapim CX-Ray

Spokes rear Sapim D-Light

Spoke drilling front 20h

Spoke drilling rear 24h

Lacing pattern front Radial

Lacing pattern rear 2 cross

Rate the wheel for quality of construction:
 
7/10

Handbuilt in the UK. Tight and true as received.

Rate the wheel for performance:
 
4/10

Extreme width helps maximise comfort from whatever tyre size you use. Not the best I've used in windy conditions. Hubs aren't the most free-spinning. Braking is the biggest flaw, though – compromised either in the wet or dry depending on your pad choice.

Rate the wheel for durability:
 
7/10

Only issue during testing was the rear wheel going out of true.

Rate the wheel for weight
 
10/10

Very, very light for a wheelset of this depth and width.

Rate the wheel for value:
 
5/10

Certainly competitive with other decent mid-range carbon wheels from the likes of Hunt, Prime and Scribe.

Did the wheels stay true? Any issues with spoke tension?

The rear wheel didn't stay true – after a few hundred miles of testing it was quite a bit out of true and with uneven spoke tension.

How easy did you find it to fit tyres?

Pretty straightforward – tubeless tyres sealed with just a track pump.

How did the wheel extras (eg skewers and rim tape) perform?

The wheels were supplied for test taped and with tubeless tyres already mounted. No QRs were provided.

Tell us how the wheel performed overall when used for its designed purpose

Good for climbing or going quickly – less good for slowing down.

Tell us what you particularly liked about the wheel

Light for the depth, easy tubeless compatibility.

Tell us what you particularly disliked about the wheel

Braking in the wet is poor with market-leading pads, and braking in the dry is also below par when using Pacenti’s pads.

How does the price compare to that of similar products in the market, including ones recently tested on road.cc?

There's a plethora of options for 50mm carbon wheels around the £1k mark from UK brands such as Scribe, Hunt, Prime and Parcours. None are as wide as this, mind.

Did you enjoy using the wheel? Less than some other comparable wheelsets – braking is an area where weakness is hard to overlook.

Would you consider buying the wheel? No

Would you recommend the wheel to a friend? Unlikely

Use this box to explain your overall score

This could be a good wheelset, offering very competitive weight for the depth and width. However, in 2021 you don’t need to accept poor braking in the search for aero or weight advantages, and this lets down these wheels.

Overall rating: 4/10

About the tester

Age: 42  Height: 188cm  Weight: 83kg

I usually ride: On-one Bish Bash Bosh  My best bike is: Rose X-Lite CRS

I've been riding for: Over 20 years  I ride: Most days  I would class myself as: Expert

I regularly do the following types of riding: road racing, time trialling, cyclo cross, commuting, touring, club rides, sportives, general fitness riding, fixed/singlespeed, mtb,

Jez spends his days making robots that drive cars but is happiest when on two wheels.  His roots are in mountain biking but he spends more time nowadays on the road, occasionally racing but more often just riding. 

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16 comments

Avatar
PRSboy | 3 years ago
0 likes

I wonder if the taper of the braking surface has affected the braking efficiency.  Unless one achieves the same angle of contact from the pads then it stands to reason that there will be a sub-optimal contact from the pads on the rim surface, so proper set-up would be important.

Personally I don't get too hung up on wet braking on rim brakes; my riding on my 'best' wheels will be in the dry unless caught in a shower. 

Avatar
wycombewheeler replied to PRSboy | 3 years ago
0 likes
PRSboy wrote:

I wonder if the taper of the braking surface has affected the braking efficiency.  Unless one achieves the same angle of contact from the pads then it stands to reason that there will be a sub-optimal contact from the pads on the rim surface, so proper set-up would be important.

Personally I don't get too hung up on wet braking on rim brakes; my riding on my 'best' wheels will be in the dry unless caught in a shower. 

Initially, but the pads will wear until such point that they make paralell contact with the braking surface. AS those parts whih are closer will contct foirst and hardest and suffer more wear than areas whih do no contact or contact lightly.

Avatar
Prosper0 | 3 years ago
4 likes

The jig is up with everyday brands offering carbon wheels. They're all made by the same people in the same factories in Taiwan/China. All that's applied by many western brands is marketing. Reduce your prices. 

Avatar
Chris Hayes replied to Prosper0 | 3 years ago
1 like

....nothing wrong with Taiwan....

Avatar
Gimpl | 3 years ago
1 like

Have a set of these on order and can't wait!

Gone with these due to their no rider weight limit and me being much larger than average. I have already trashed a set of Mavic Open Pro's (although that's also partly due to a motorist forcing his way through on my side of the road and me smashing into a huge pothole to avoid a head on).

I'm getting 28 hole hubs which are taking some time to arrive but overall Luke at Pacenti has been absolutely great and I'm really impressed. 

Avatar
Chris Hayes replied to Gimpl | 3 years ago
1 like

Did you smash a set of original Open Pros or the USTs? I've had some dealings with Luke at Pacenti too and he seems a genuine guy.  He actually advised my NOT to buy a set of his 36 spoke box-section retro wheels because they were weak (versus H+Sons or Open Pros) - which genuinely impressed me.  Have to say I'm a bit disappointed with the review - the wheel being 'out of true' is probably builder error (assuming it's not misuse) and I like the idea of bombproof 50mm deep section wheels.  But for not much more you can get a set up Fulcrum Carbon Quattros which are bombproof.  

Avatar
Gimpl replied to Chris Hayes | 3 years ago
0 likes

They were original Open Pro's - had issues with them right from the word go - they seemed to be very flexy! I have had those hubs rebuilt with H+ Sons and so far seem to be ok!

Agree the review is a little bit disappointing. Fulcrums look ok but really wanted to try a set with deeper rims this time. 

Avatar
Chris Hayes replied to Gimpl | 3 years ago
0 likes

Wow, I'm surprised - I have some 36 spoke Open Pros that have survived a couple of Paris-Roubaix, though I swear whilst my backside counted every chunk of pave I looked enviably upon carbon wheeled, carbon bikes seemingly gliding over them.

I tried some H+Son and found they required tension that my Chris King hub shells couldn't withstand.  I keep meaning to put the rims on eBay or in the bin.  Weird old world.  I thought the Fulcrums were 45mm....not much difference?

Avatar
Sriracha | 3 years ago
0 likes
Quote:

being tubeless – they can be run at lower pressures too

am I right in thinking tubeless enables lower pressures because you don't have an inner tube to pinch when your tyre bottoms out against the edge of a pothole leaving no air between road and rim? I would still have thought that was a situation to be avoided - punctures or no - especially on carbon rims.

Avatar
hawkinspeter replied to Sriracha | 3 years ago
1 like

That sounds right to me.

I've mistakenly run road tubeless at something like 10-20PSI (guessing by pinching the tyre) and didn't realise until I got out of the saddle to power round a corner at the bottom of a hill. The tyre moved under me in a disconcerting fashion so I took care to not throw the bike around for the rest of the ride. I've definitely heard a carbon rim bottoming out on things like drain covers when I've been running them too low.

Nowadays, I aim for around 70PSI in 28mm tyres.

Avatar
MattKelland replied to Sriracha | 3 years ago
0 likes

In theory, yes. In practice, I've had two major pinch flats from hitting potholes while running tubeless.

Avatar
Jez Ash replied to Sriracha | 3 years ago
0 likes

As others have commented, it doesn't *guarantee* that you can't ever get a pinch flat, but a tubeless tyre is massively less likely to have one than an inner tube, so lower pressures are less of a puncture risk. Of course, you're right that you don't really want to bang the rims down onto the road (through the tyre) more than you have to, although I've never had a set of carbon wheels fail due to that.

Avatar
Secret_squirrel | 3 years ago
0 likes

One bit I didnt get is the taper on the braking surfaces.  Does that mean it slants inwards as you move towards the tyre?

Does that not make toeing in brakes a bit more awkward?

Avatar
Dave Dave replied to Secret_squirrel | 3 years ago
0 likes

The sides of the rim are diverging. Making them parallel for the braking surfaces could be seen as 'tapering in', although it's an odd way to put it.

Avatar
Jez Ash replied to Secret_squirrel | 3 years ago
2 likes

Hi squirrel. It does taper in towards the tyre, yes. I've not seen that before, but it does sort of match the angle that the brake pads sit at when the calipers are opened that wide (given how much wider these rims are than many) so I wondered if that was the intention. Toe-in wouldn't really be affected, as far as I can see - you could still angle the end of the pad in a bit more. Geometrically, you'd think parallel brake track surfaces would be the most efficient, as none of the braking force from the pad would result in a radial force (relative to the wheel).

You can see a cross-section of the rim on Pacenti's product page here https://pacenticycledesign.co.uk/products/carbon-50-rim-brake-wheel-set

Avatar
Secret_squirrel replied to Jez Ash | 3 years ago
0 likes

Thanks Jez.  Nice reply.

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