The Project XC Race Rocket bike would be nothing without some lightweight wheels to complement the frame, fork and cockpit. So, for the rolling stock, we pulled in parts from Nox Composites (with Project321) and Schwalbe.
That combo yielded a sub 1,500g wheelset with all the accoutrements necessary to mount the tires, and if you know Schwalbe, you know they make some of the lightest full featured tires on the trail…
The wheels came in at 690g front and 806g rear for a total of 1,496g with rim tape and valve stems installed.
Claimed weight for the Skyline 29er rims is 340g and wheelset claimed weight is 1,472g with these hubs, so our weight shows how much weight rim tape and valve stems add. They also offer the wheels built with Chris King (1,548g), DT Swiss (1,440g), Hope (1,528g), and Industry Nine (1,468g).
Initially, carbon rims’ main selling point was stiffness. As layups and designs evolved, they’ve also added durability, able to take far more punishment than an alloy rim under extreme conditions.
While we’d all hoped they’d have also bested alloy rims in weight, we simply haven’t seen the same drastic difference found between carbon and alloy frames. What it has done is given us rims that are far stiffer and tougher at the same weight as the lightest alloy rims. And among these, Nox Composite’s Skyline rims are among the lightest. Win, win, win, win, win.
The rims have an asymmetric profile with a bonded valve stem platform to give it a level surface. First generation rims had a small plastic platform that could crack and cause air to leak around the valve stem (we had it happen on our first set of test wheels). Fortunately, these new designs seem to be much burlier.
They measure in at 23mm internally and just shy of 29mm externally. Narrow by today’s enduro standards, but plenty for an XC width tire where weight savings is as important as spreading the tire wide. And it gave the 29×2.25 tires a nice round profile.
The Skyline and its kin are the second generation of rims from Nox, switching to a hookless bead. One of the main reasons for the switch was to increase the impact strength of the bead wall. Since most carbon rims get their bead by first molding a thicker-than-necessary sidewall then machining the bead hook into it, you end up with broken fibers and a compromised design. By running continuous fibers and having complete control over the layup of the entire rim bead and bed, they can make it much stronger.
The bead wall is made using multiple types of carbon weave, too, which means if you do crack it, it should still hold together (and hold air) well enough to get you home. More importantly, it should hold together well enough that the wheel doesn’t disintegrate on impact and amplify personal carnage.
The concept of hookless rims works because the tire is pushing outward against the sidewall and can’t expand upward thanks to the tire’s bead preventing stretching. To keep the tire from rolling inward if pressure gets too low, there’s a small “Anti Burp Bump” to lock the bead against the sidewall. So far, it’s held the tire in place well. Setup was also easy. I did use a compressor, but the tires snapped into place quickly.
I chose the Project 321 build because I wanted to try their hubs. All wheels are built with bladed Sapim CX Ray spokes and alloy nipples. Stock builds use 32 spokes (tested), but you can opt for 28 hole rims and wheels if you don’t mind waiting up to three weeks.
All wheels are handbuilt in Knoxville, Tennessee. Our wheelset arrived spinning true and balanced, but with one spoke on each wheel slightly twisted. Nox sent a few replacement spokes in all sizes and I had Revolution Cycles replace them. Nox says this has not been a common issue and there’s a chance they just missed a QC step as I was bugging them to get these in quickly in time for the 6 Hours of Warrior Creek Race. Either way, it’s a warranty issue that would be taken care of and my hunch is it’s unlikely your wheelset would have any problems. Other than those two spokes, everything has held solid and true so far.
Project321 hubs are machined then polished before anodization, then CNC’d to create the logos. The result is a beautiful, shiny hubset hiding quality internals. Up front there are two Enduro ABEC5 bearings…
…and in the back they use two angular contact Enduro bearings to allow for preload adjustment, plus two standard Enduro ABEC5 bearings in the freehub body. My wheelset came perfectly adjusted and I haven’t had to fiddle with the preload at all.
The P321 G2 rear hub’s drive mechanism is handled by an Industry Nine Torch Freehub body and pawl system, which gives it the trademark whizzzz sound of I9’s 120 points of engagement hub. They designed it to hold a bit more oil – add extra if you want to make it a bit quieter.
Claimed weights for the hubs are 169g and 274g, available with QR and 15/20mm thru axle up front and QR, 135×10/12mm thru axle, 135 bolt on, and 12×142 thru axle in the rear. All axle systems are interchangeable, you can swap between standard freehubs and XD driver, and choose from nine different colors.
So, if the P321 hubs use the same drive mechanism as I9, and both are available in tons of colors and both are made in the USA, which should you choose? Complete wheelsets are within $10 of each other (about $1,640), so it mainly comes down to whether you want the preload adjustment or have a brand preference. Or whichever hubs they can get into stock the quickest if you’re in a hurry.
The wheels come pre-taped with Stan’s NoTubes yellow tape, so the last piece of the puzzle was tires.
I reviewed the prior version of the Rocket Rons in 2012 and loved them. Since then, I’ve had two sets of the newer version in the office. One’s been on a bike and the other being saved for a build like this. Originally, I reviewed the Evo version, which was somehow lighter by about 100g per tire than these new Evolution versions. Current claimed weight is 605g rather than the low 5XX figure from the original PR they sent, and mine came in a bit heavier.
Still, 635g and 651g is very good for a full knob, large volume (for XC) 29×2.25 tire.
The trails at Warrior Creek in Wilkesboro, North Carolina, in April can be anything from perfect hero dirt to a Slip ‘n’ Slide of mud, and the Rocket Ron’s well spaced but susbstantial knobs were a good choice given that weather forecasts in the Carolinas in spring are about as reliable as Microsoft Windows. theyre fast in good conditions and capable in bad, making them about the perfect choice for varying conditions. The only caveat being they have no puncture protection under the tread, the tradeoff for being so light. It does get their Snakeskin sidewall barrier, which offers some cut resistance and helps hold air inside better than prior versions.
As fate would have it, I did get a pinprick in the rear that mysteriously defeated a healthy dose of Orange Seal sealant. I’ve had other tires develop similarly small holes and had the sealant fail to plug them, but have had it work just fine in other situations with multiple punctures. It’s a real head scratcher, and I’ll be cleaning out the tire and testing another sealant’s ability to fix it.
Barring that, the Rocket Rons performed as well as expected, offering excellent traction throughout the fast, swoop Warrior Creek trail, on wet Pisgah rides and around dry local trails. And they roll very fast for a knobby, too. Schwalbe reviews are typically littered with complaints of shorn off knobs, but so far these have held up well, and I never experienced undue wear and tear on the prior version either.