Pacenti SL 23

Photo courtesy of Blacksmith Cycle

(updates at end in italics)

Over the winter I worked with Blacksmith Cycle in Toronto and their custom wheel program to design and build a set of all round clinchers. The requirements for the wheels were pretty clear, I wanted something that would brake well, be 11 speed compatible, strong, reliable, with a wide profile (for 25c tires), while being as light as or close in weight to the Dura Ace WH7900 C24-CL wheels they would be replacing. Oh and they needed to be as black as possible to match my new bike. So the requirements were clear, but it wasn't an easy list to satisfy. After some great questions and suggestions from Mike at Blacksmith, it was settled. 

We went with a Tune hub and Pacenti rim combo. Corey Wood from Urbane Cycle built the rims and supplied the necessary spoke counts. He also suggested that we use Sapim CX-Ray spokes for their low weight and high strength. Since I trust Corey, and only Corey to build or service my wheels I happily took his advice. 

Two weeks ago the wheels were ready and I picked them up and headed out for a first ride. Since then I've thrown everything at them. Sprints, headwinds, sidewinds, my nemesis climb, and a few club rides too. So here are my first impressions.

build specs

Photo courtesy of Corey Wood @ Urbane Cycle

  • Front - 659 grams
    • Rim: Pacenti SL 23 v1 all black
    • Hub: 24hTune Mig 70
    • Spokes: Sapim CX-ray 
    • Pattern: Radial
    • Nipples: 7075 aluminum
    • Rim Strips: Continental
  • Rear - 789 grams
    • Rim: Pacenti SL 23 v1 all black
    • Hub: 28h Tune Mag 170
    • Spokes: Sapim CX-ray 
    • Pattern: 2x
    • Nipples: 7075 aluminum
    • Rim Strips: Continental


So weighing in at a total of ~1450 grams with rim strips, the new wheelset hits every mark including the same weight as the Dura Ace wheelset. Incredible. Actually 2 grams lighter but who's counting.

The Ride

Of course what really matters is how they ride. That's where these wheels really impress me. The ride is fantastic. The relatively low weight of the wheels makes for great climbing and the build specs mean they don't flex while in or out of the saddle.  I have yet to feel any break rub, even when sprinting. They roll smooth and true.  Right now I have a set of 25c Michelin Pro 4 Service Course clinchers on the rims which are my regular tire choice. I'll admit that something about this combo feels a bit muddy while cornering so I'm going to try a 23c and a different tire to see if that changes. 

In comparison to my Yishuns or my ENVE 45s, the Pacentis seem to catch more wind, take longer to spin up, and with more effort to hold at higher speeds. But all of this was to be expected. The Pacentis are about 27mm deep and have an archetype rim profile while the carbons have a more aero profile. Hence the difference in how they handle cross wind. It's not bad by any stretch, but noticeable and worth noting. I'm not entirely sure why they feel harder to spin up or keep at speed because by weight they are nearly identical to the carbon rims and have the same spokes. While I'm not engineer, I suspect it's a property of the aero profile advantage of the carbon rims. Corey has noted that he thinks the bearings need to break in as well. We'll see.


Pacenti SL23 v1 black braking surface. Also with a 25c tire mounted

These wheels are my every day workhorse wheels and while I do love a light and aero carbon wheel set, it's not needed for every day riding across the city in traffic or slower club rides. So the choice for an aluminum brake surface was easy. The Pacentis brake like a dream, dare I say the best braking aluminum clinchers I've ridden. Probably due to the machining on the brake surface. The rims that Blacksmith chose for me have a black anodizing on the brake surface which looks hot, but I know that this won't last forever. In fact probably not that long, but it's fine by me. So to add to the braking quality and the longevity of the anodizing, I switched out the stock Ultegra brake pads for some extra Dura Ace pads that I had laying around. All in all, two thumbs up.


Pacenti SL23 v1 blacks sideview

With enough decent rides in on the wheels, it's fair to say I'm very happy with them. If you're in the market for an impressive set of no compromise aluminum clinchers, your search is over. Mike and Corey have outdone themselves one more time. These wheels have done everything I've asked and more with no sacrifices at all. This is what you get when you know what you want and you work with great people who you can just trust to make decisions for you. It's a true testament to the saying "Pick the right people, then get out of the way".

I'll continue to update the blog with any additional observations as time goes by. Mike and Corey are also building a nearly identical set for my wife on a pair of Alchemy ELF/ORC 10 speed hubs so I'll see how they compare too.

update #1

After a few rides of different lengths and variety I've gotten to know these wheels a lot better and learned a few things too. First, I had been feeling a sense of muddiness in the front and couldn't figure out why. I came across a similar post about this 'sluggish' feeling of a 25c tire on the Pacenti rim on a cycling forum. It seems that the combination of a 25c tire and the larger 18mm internal diameter of the Pacenti SL23 v1 rim makes for a chubby rubber. Too chubby in fact. The tire expands so much in volume that it creates this lack of responsiveness. I also noticed that the significantly increased volume at certain air pressures runs the tire too close or even bottomed out on the fork of one of my bikes. To be specific, if the PSI of the front tire on the 25c hits 90PSI the tire would have rubbed the underside of the fork. 

Looking around I found some suggestions to run a 23c on the front to alleviate both these conditions. Happy to say that the 23c on front does create plenty of clearance and improves responsiveness. Probably a better aero profile as a benefit as well but I've got bigger problems to save a few watts. I may try and run a 23c on the rear and see if rolling resistance improves with a more modest profile tire.

update #2

One of the biggest questions out there is how long does the black anodized brake track last. That's a tough question because it seems to depend. If you're a fair weather rider it's probably going to last a really really long time. From my experience the black brake showed almost no wearing until I rode 50 miles in the pouring rain with two fast descents that required hard braking. Over the course of that ride I seem to have done a really great job wearing the brake track right off the rear rim and in large patches on the front. Mind you I may have been over braking because I couldn't see the turns I was heading into but it was still done all in one ride. Now it's no fault of Pacenti because it's not designed to last forever, this update is merely to help illustrate that it does happen and what it looks like when it does happen.

Pacenti SL23 rear rim brake track after 50 miles in and hard braking on fast descents

Pacenti SL23 front rim brake track after 50 miles in and hard braking on fast descents