These days, it seems like every Tom, Dick, and Harry has their own carbon wheel company, and there's also a load of house-branded carbon hoops out there, too. Many of the big bike brands now include their own carbon wheels on high-end builds, usually with a different name on them so you still feel special after handing over so much money, and the once-exotic rim material is now a relatively common sight at many trailheads. Unless you're on Quai's unique looking ISOS 33 Pro+ enduro wheels, that is.
The 1,779-gram wheelset can be had with DT Swiss' 350 hubs in the Pro+ spec for $1,599 USD, as tested below, or with Quai's hubs if you're okay saving $300 and adding 30-grams.
ISOS 33 Pro+ Details
• Intended use: Enduro / all-mountain
• Rim material: UD Carbon fiber
• Rim width: 33mm (internal)
• Diameter: 27.5" or 29" (tested)
• DT Swiss 350 hubs
• 28 straight-pull spokes
• Rim weight: 490-grams (claimed)
• Weight: 1,779-grams (actual)
• MSRP: $1,599 USD
• More info: www.quai-bicycle.com
With their strangely shaped RSL rims, the ISOS 33 wheels are anything but ordinary... But does the unusual design actually make a difference in the dirt? We've put 30,000-meters of descending (and climbing) on them to find out.
Quai's $1,599 USD ISOS 33 Pro+ enduro wheels use their RSL stepped rim that's said to provide more equal spoke tension. In theory, that should make for a stronger wheel. It also looks pretty neat.The Details
No reason to beat around the bush: What the hell is up with the funky stepped 'RSL' rim shape that Quai is using? Those three letters are short for Radially Staggered Lacing, and the idea is to have the spoke tension be as even as possible from left to right. Equal tension, or close to it, is a key ingredient if you want your wheels to be as durable as possible, but because there are a bunch of cogs on one side and some important braking stuff on the other, and the rim can't be dished centrally over the hub, it's not an easy thing to do.
One of the most common ways to approach the problem is to have the hub's spoke flanges be a different height, with the drive-side taller to help equal the tension and provide a better bracing angle. The other common route is to offset the spoke holes to one side of the rim bed, which Quai does, and that can help in the same way as offset flanges.
The 33mm-wide rim bed requires tape, and Quai has gone with a hookless bead design.
Quai uses offset spoke holes for their ISOS 33mm wide (internal) carbon rims, but they've also gone with a wild-looking stepped rim shape that's said to help equalize spoke tension in much the same way that a taller drive-side hub flange would. In effect, the drive-side spokes are shorter because the rim is taller where they connect, and the spoke tension on both sides should be closer to being even.
So why didn't they just use hubs with differing flange heights? Steve Metz, the RSL patent owner, explains his thinking: ''Although I was looking for a technical advantage to the rim, it was also the need for visual differentiation that I was interested in. Black anodized alloy rims and carbon rims of all types do not differentiate or enhance bikes from one another visually. I was also after something that would communicate the unique quality of the rim/wheel and therefore bike.
On top of that, making the difference at the rim means that you can use hubs with equal height flanges, like the DT Swiss 350s on these test wheels, but hopefully still benefit from left and right side spoke tension being closer to equal. ''We don’t want to claim that Quai wheels and/or RSL tech is the endgame design for cycling wheels,
'' Frank Chin, Quai's USA brand manager, explained. ''Our goal is to give our customers the ability to stand out from the crowd with a sick looking wheel while having the advantage of great tech.
Moving inwards from the strange rims, Quai uses 28 straight-pull butted (2.0-1.8-2.0mm) spokes, and ours showed up with a set of DT Swiss' 350 hubs in the middle. You can get them with Quai's hubs, too, as well as rim decals in a bunch of different colors so you can pop or blend in. They also come with rim tape and some nice aluminum valve stems that save a few grams over cheap steel ones.
All that comes in at 1,779-grams on my scale, which is reasonably light for a set of $1,599 USD wheels intended for enduro use and smashing into things. Some more numbers for you: Crankbrothers' Synthesis E11 enduro wheels weigh 1,825-grams and cost $2,399 USD, and Specialized's Roval Traverse 29ers come in at 1,840-grams and $1,200 USD.
You can spend way more if you want to, and there are both lighter and heavier options out there, but Quai's ISOS 33s seem reasonable on the price-to-weight scale when it comes to today's carbon wheels. If you want to compare them to an aluminum option, though, Newmen's Evolution A.30 wheels weigh 1,760-grams and cost €698.
The ISOS 33s saw plenty of action in Whistler and Squamish while bolted to a Santa Cruz Megatower.How'd They Perform?
Our ISOS 33 29er wheelset has been through more than 30,000-meters of climbing and descending while bolted to a Santa Cruz Megatower over the past few months, all of that with either a set of Minion DHF/DHR2 EXO+ or IRC's new Tanken enduro tire (review soon) mounted to them at 20 to 24 psi depending on the conditions. The wheels arrived with a roll Quai's tape and their valve stems, and it all went together without any sweating or swearing.
Both companies tires mounted, seated, and sealed on the hookless rim near-instantly with just a standard floor pump - the fit is snug enough that no compressor or air canister was required. And since we're speaking of tires and air, there were no rude burping incidents, either, even with a 180lb rider going as low as 20 PSI.
The rim's shape sure does look neat, but does it make a difference on the trail? I'm not so sure...
Many riders are wary of carbon rims for a good reason - they're damn expensive and if/when they fail, they're usually going to do it in a shower of black splinters and a mix of crunching and flushing sounds, the latter somehow coming straight from your wallet. It's not all that of an uncommon sight, either, with most of the Pinkbike editors managing to at least crack, if not completely destroy, a carbon rim or three over the years. Quai's carbon hoops are still running strong, though, despite a handful of rock strikes and tire bottom-outs that felt harsh enough to leave some lasting damage behind if it had been an aluminum rim on the back of the Megatower.
Both the front and rear rims have seen some of the rockiest, nastiest descents that the Whistler area has to offer, and they've both shrugged off that sort of rim-eating terrain without issue. Carbon fiber rim beads often get scarred and gouged, even if they don't ever crack, but the ISOS 33's show next to no impact damage whatsoever. In fact, they look nearly unused, even though they've seen more than their fair share of sharp edges and low air pressure.
Unfortunately, I can't say the same thing about the tires that have been mounted to the rear wheel.
While I can't be 100-percent certain that the rim's bead shape is at fault, especially because it appears to be similar to everything else out there, we did manage to put three different slices into a poor Maxxis EXO+ rear tire, all of which seem to have been caused by pinching it between the rim and the ground.
Thing is, this wasn't happening before or after with the same EXO+ casing tire pumped to the same pressure on a different wheelset, which has me believing that the rim might be to blame.
My other concern, albeit one that hasn't been an issue yet, is the silly straight-pull spokes. Not only can they be tricky to find (or make) if you don't have a decently stocked bike shop close by, it also makes truing the wheels trickier as you might need to keep them from spinning in the hub flange while turning the nipple. It's not a deal-breaker, but something to keep in mind.
Want carbon wheels that stand out from the crowd? These will do that for you.
How do they feel out on the trail? In a lot of ways, they deliver that stiff, precise sensation that stout carbon rims are known for. No, you won't ever mistake the ISOS 33s for a set of aluminum, low-profile Stan's wheels that are obviously more forgiving, but it certainly doesn't feel like you're sitting on a paint mixer while riding them, either. The 28-spoke lacing surely adds a bit of suppleness to them, and I suspect that most riders will find them to feel a lot like, you know, wheels rather than being too harsh or not stiff enough.
Alright, let's answer that question I posed at the top of the review: Does the unusual RSL rim design make a difference in the dirt? I want to say that the answer is no and that they're different just for different's sake, but the Quai wheels have also shrugged off some very hard impacts that might have troubled other rims. I doubt that the stepped design provides much as far as ride experience goes, but it might be a factor in their reliability.
Regardless of how they look, the ISOS 33s proved to be very reliable and were trouble-free.
Relatively light given their enduro intentions +
Unique appearance +
Durable carbon rims
Rim bead might be cutting tires-