Since 2001, NoTubes has been producing affordable, performance-oriented rims and complete wheelsets using its proprietary tubeless-compatible rim profile. The US$595 Iron Cross wheelset is aimed squarely at cyclocross and gravel road racers in need of a lightweight, tubeless-compatible, disc-specific wheelset.
The name pays homage to a grueling 62-mile 'ultra cyclocross' race held every October on the rocky trails and gravel roads of central Pennsylvania. The rim is a 700c version of NoTubes’ ultra-light, 26in Alpine rim.
In its 700c form, the Iron Cross tips the scales at 385g. It has an internal width of 20mm – 3mm wider than the company’s Alpha 340 and 400 road rims, both of which can be used for cyclocross but are designed with road tubeless compatibility in mind.
NoTubes advises against attempting to run tubeless road tires on the Iron Cross rim, citing its slightly larger bead seat diameter (intended to prevent tubeless ’cross tires from burping at low pressures), which makes mounting carbon-beaded tubeless road tires nearly impossible.
The Iron Cross wheelset is built using rims with a 24-hole front and 28-hole rear drilling. DT Swiss Supercomp spokes with alloy nipples are laced in a two-cross pattern on both the front and rear wheels. NoTubes offers the US$88 / £70 Iron Cross rim in a 32-hole drilling for those who wish to build their own wheels.
Both the front and rear wheels use a two-cross lacing pattern
The hoops are built around NoTubes’ 3.30 hubs, which are used on many of the company’s mountain bike wheelsets. The 3.30 designation alludes to mechanics of the rear hub – three pawls engage a 30-point ratchet, which results in 12 degrees of engagement. Not lightning fast but quick enough to get the job done with very little drag.
The 3.30 hubs spin on cartridge bearings that are preloaded by securing the wheelset in the frame. Up front, the stock 9mm quick-release end caps can be swapped to make the wheelset compatible with 15mm thru-axle systems. Similarly, the 135mm quick-release rear hub is compatible with the increasingly common 142x12mm standard.
This versatility could make the Iron Cross a contender as a race-day wheelset for a 29er mountain bike, though the rim’s profile and low spoke count make it less than ideal as a mountain bike wheelset for heavier riders.
“It will work,” Rich O’Neil of NoTubes told BikeRadar. “But I would personally use [a wheelset built with] Crest or Gold rims – something that is wider, in a 32-hole drilling, with a more pronounced box section.” O’Neil notes that the Iron Cross wheelset has a suggested rider weight limit of 200lb.
The claimed weight for the Iron Cross wheelset is 1.52kg (3.35lb). With tubeless tape and valve stems installed, our test wheelset tipped the scales at 685g for the front wheel and 805g for the rear. That adds up to a total weight of 1.49kg (3.28lb). Sometimes getting less than you paid for is a good thing.
On the racecourse, the Iron Cross wheelset proved stiff enough for the task – not the equal of carbon rims, but far from flexy. The wheels have remained true and, despite repeated power washings, the bearings still spin smoothly. Our only criticism is that we wish the engagement of the 3.30 rear hub was quicker when stomping on the gas out of turns.
A viable alternative to tubulars?
Tubeless systems for cyclocross have had several false starts. Although the ability to swap tires to suit course conditions, rather than carrying a quiver of expensive tubular wheels, is alluring, the dependability of tubeless systems has been spotty.
NoTubes is a proponent of wide rim profiles, which do a better job of supporting and stabilizing tires than narrow rims do. This wider profile, combined with NoTube’s patented Bead Socket Technology, is intended to provide more support when you run cyclocross tires at very low pressures, with less tire squirm and a decreased likelihood of burping air.
In use, the NoTubes tubeless system worked as advertised. Tubeless-compatible clinchers such as Vittoria’s Cross XG Pro had to be muscled onto the rim, but could be ridden at pressures in the 24/25psi range without any issues.
Cyclocross tires without tighter (and sturdier) tubeless beads were hit or miss in terms of performance; some tires seated easier than others, and some could be run at lower pressures than others. This is less a criticism of the Iron Cross wheelset’s performance than it is an observation of the hit-or-miss nature of running traditional cyclocross clinchers tubeless.
In every instance – and while running tubeless and with tubes – the wide rim profile provided substantial support, particularly while cornering, allowing us to ride harder into corners with less tire squirm than we experienced with narrower rims.
Will tubeless technology oust the venerable tubular? Only time will tell. In the meantime, the combination of low weight, reasonable price and tubeless compatibility makes the NoTube’s Iron Cross an ideal option for privateer racers looking for a great clincher wheelset.