Manufacturers of wider (clincher) rims claim many benefits–improved aerodynamics, better handling, and the ability to run (wider) tires at lower pressures. I, myself, have ridden wider rims for many years, but they have typically been heavier, and less aerodynamic than the rims currently on the market. Recently, however, I was given the opportunity to test the new Pacenti SL23 rim.
Kirk Pacenti–the man behind the SL23 rim–is a 20-year veteran of the bicycle industry, working with the likes of Keith Bontrager, Giro, and Manitou’s Doug Bradbury. The SL23 is not Pacenti’s first foray into the rim market–has been one of the driving forces behind the industry- and consumer-adoption of the 650B (27.5″) wheel size, and lead the charge towards wide-but-light rims by designing Velocity’s P35 rim.
Exactly how does one test a rim? If you have a huge budget, you spend time (and dollars) in a wind tunnel, or you develop machines and fixtures that can measure deflection and other esoterica. But if you’re an enthusiast-run blog like GRAVELBIKE, you ride them, think about them, ride them some more, and then share your thoughts and findings.
Due to the fact that I possess the wheelbuilding skills of a chimpanzee (apologies to any wheelbuilding-chimps reading this), I enlisted the services of Ergott Wheels‘ Eric Gottesman. He spent several months riding and testing pre-production SL23 rims, so I was able to take advantage of his familiarity with the new Pacenti hoops. I gave him a summary of my riding style, weight, and tire/gearing preferences, and told him to build whatever combination he thought would best highlight the SL23s’ features.
One week later, a pair of Gottesman’s GT Signature wheels arrived at my doorstep. The SL23 rims had been laced to White Industries T11 hubs using Sapim bladed spokes and alloy nipples. While the majority of my wheels tend to be fairly conservatively, the GT Signature wheels are anything but. Gottesman chose to go with 24 radially-laced spokes for the front wheel, and 28 spokes in back (using slightly thicker spokes for the drive side). Weight for the front wheel was 671g, with the rear wheel coming in at 871g (weights include rim tape).
Constructed of 6061-T6 aluminum, the SL23 features machined sidewalls with wear-indicator “dimples.” The Pacenti’s 24mm outside width is paired with an inner-bead width of 18mm. For comparison, a Mavic Open Pro rim has an outer measurement of 20mm. By increasing the rim’s width, the tire’s profile opens up, and it takes on more of a “U” shape. This reduces the tire’s “lightbulb” profile, and increases the tire’s effective width. That translates into the ability to run lower pressures (without increasing rolling resistance), which means more traction and comfort for the rider.
During the course of my testing, I rotated through three different sets of tires: Panaracer Pasela (700×28), Schwalbe Durano (700×28), and Vredestein Fortezza (700×25). With two layers of Stan’s yellow tape installed, I could mount (and remove) all three tires without the aid of bead lubrication or bead jacks. Inflated to 100psi, the Duranos measured the widest at 28.65mm, but it should be noted that the 25mm Vredesteins plumped out to 26.5mm wide.
Over the past few months, I’ve ridden the SL23-equipped wheels over a range of terrain that’s included lots of broken pavement and dirt roads and trails. The wheels are as true as the day I unboxed them, and aside from the buzz of the rear hub’s freehub, they’ve been blissfully silent. I’ve been unable to detect any “pulsing” or vibration from the welded seams or wear indicators, and braking has been smooth, quiet, and predictable.The end result is a pair of lightweight-but-sturdy wheels that I can ride hard over a wide variety of surfaces, without having to baby or constantly true them.
At 450g each, the SL23s are anywhere from 25g to 50g lighter than the rims I normally use, but the rims’ light weight doesn’t come at the expense of durability or compatibility with wider tires. I’m no speed demon (especially at 195 pounds), but I really appreciate the wheels’ liveliness when climbing (which there is no shortage of here in Colorado).
Disclosure: Pacenti, White Industries, and Ergott Wheels provided review samples and services for this article, but offered no other form of compensation for this review.