Over the past two plus years I built and sold a lot of custom wheels built around the Pacenti SL23 alloy clincher rim. The SL23 purported to be a wonderful new rim from American Kirk Pacenti. Co-developed by Fairwheel Bikes, the SL23 is a wide tubeless ready alloy rim with many attractive characteristics, including weight, braking performance and wide comfort and handling. I recommended it for good reasons. I rode them too, for the past two years.
This is what Fairwheel Bikes had to say about this rim in their alloy rim roundup:
In the interest in transparency in our reviews I think it’s important to say we contributed to the design of this rim, producing what we feel is the most balanced rim on the market.
And here’s what one of the reviewers said about the then new Pacenti SL23 version 1 rim after riding it for a while:
Eric: I’ve been riding a pre-production rim for a while now and I’ve had no issues. It’s a new rim on the market, but very well designed and I have a good feeling it will test more aero than any other rim only option here.
I felt the same way about this rim. But after a year of riding it, approximately 4000km, the rim developed cracks around the nipple holes. Then, on a regular basis every single rim I sold that was built for a rear wheel came back to me with cracking around the nipple holes. The tension was always slightly below the recommended maximum tension, around 110 kg of force. Pacenti and his distributors were good about replacing them at first – sending out replacement rims having shown photos and serial numbers of the cracking rims.
Then in April 2015, Kirk Pacenti introduced the Pacenti SL23 Version 2 rim. This rim was meant to address some of the criticisms of the version 1 rim including addressing but not directly acknowledging the cracking by increasing the thickness of the alloy at the nipple bed to increase durability (well, to be more honest, to obtain durability). Here’s what Fairwheel Bikes said about this new version:
In April 2015 Pacenti released the first update to the rim to make three small changes to further improve building and riding. The rim is now 2.3mm wider internally — while only increasing .5mm externally — and has lower bead hooks further supporting the tire and increasing tire volume. The bead well is deeper making installing and changing tires easier. Finally the spoke bed is thicker allowing wheel builders to use higher spoke tensions and improving overall durability of every SL23 wheelset.
The downside of the Version 2 is its incredibly shallow brake track. While it works fine when pads are setup just right, some riders have complained it is just too narrow. Additionally, the some riders having ridden on version 1 rims that failed on them, had commented that the braking wasn’t as good on the Version 2 rim.
As of today, 5 months after ceasing operation of Zed Wheel Works, I continue to be dealing with cracked Pacenti SL23 rims with little over a year’s use. What’s worse, I am now also dealing with failed sleeves, on Version 2 rims and some cracking at the nipples on Version 2 rims as well. The sleeve is the metal shim that is peened at the rim joint. Pacenti suggests re-peening as a cure, but I’ve seen a few of these sleeves fall off completely, an indicator of quality issues.
No rim is perfect. I recently had the rarity of dealing with a cracked H Plus Son Archetype rim. But failing Pacenti SL23 rims, especially the version 1 rim was a pandemic. Any supplier in their right mind of ethical conduct would have recalled these rims or at the very least continued to honour the warranty, even extending it where rim cracking was occurring. Kirk has done neither. In a recent email conversation with him, he has announced that the warranty on all version one SL23s is no longer honoured. This is terrible for the retailer and customer alike.
For all of my former customers who selected Pacenti SL23 rims, I am sorry. You put your faith in me and I put my faith in Pacenti. This warranty nightmare was a large contributor to the decision I made to stop running Zed Wheel Works.
For your future rim choices, I have had great luck with HED Belgium C2 rims. I’ll be running these rims on my own bike very soon, replacing Pacenti SL23 Version 2 rims as I simply do not want to send the false message that I continue to endorse Pacenti SL23 rims.
The odd thing is that I have seen zero issues with the similar Pacenti SL25 disc rim, which is based on the SL23 rim brake rim, and I’ve built up and sold many of these too. Likewise, the TL28 disc mountain bike rim is also very good. No issues. You don’t have to stop riding Pacenti rims, but I would choose H+ Archetypes or HED Belgium C2s over Pacentil SL23 version 2 rims.