Last year at Sea Otter, the Irwin Kova XC 29er carbon tubeless disc wheelset caught our eye as a cyclocross and gravel option. When we first looked at the Kova XC 29er, the low-profile, wider carbon rim appealed to our low-pressure tendencies more than an aero, road tubeless-ready option.
Given the focus on weight in road racing, many of us would expect road disc wheels to be lighter than mountain bike wheels designed to withstand drops, jumps and rock gardens, but carbon road wheels have to withstand pressures up to 125psi, and thus typically require more material to maintain their strength and shape. They also tend to have a deeper profile, aimed to cheat the wind. The extra material adds grams.
While aerodynamic concerns are not irrelevant in cyclocross or gravel, an airtight, reliable tire interface and confidence-inspiring tire profiles are typically higher priorities for gravel and cyclocross. For the constant accelerations of cyclocross, we welcome gram savings as well, especially at the rim.
We put our test set of $1,300 (Updated price as of summer 2018) Irwin Kova XC 29er wheels to work on the cyclocross course and gravel roads this past season. Read on for our full impressions of how they performed and how they compare to some of their carbon road counterparts and other wheels such as the Boyd Jocassee, FSE EVO and Derby CX 23i we have recently reviewed.
The $1,300 Irwin Kova XC 29er carbon tubeless disc wheels provide a low-profile option for the low pressures of cyclocross. © Cyclocross Magazine
Irwin Kova XC 29er Wheelset
The carbon, tubeless-ready Kova XC 29er rims have an internal 24mm width, external 30mm width and 22mm depth. For comparison, the Irwin's Aon DX 38 has an internal width of 19mm, which means the Kova XC 29ers provide a wider base for tubeless cyclocross tires.
Irwin Kova XC 29er carbon tubeless disc wheels. © Cyclocross Magazine
The wheelset is available with a front 15mm thru-axle and rear 12x135mm or 12x142mm thru-axle. Irwin provides end caps to convert both the front and rear wheels to quick release, and Boost sizing is available.
The front hubs come with 15mm thru-axles and end caps to switch to quick release. Irwin Kova XC 29er carbon tubeless disc wheels. © Cyclocross Magazine
Both the front and rear wheels have 32 Sapim D-light spokes with external nipples to assist with maintenance. The wide rim width provides a base for running low pressures, but if you want to run the wheels at higher pressures for gravel adventures, Irwin does not specify maximum tire pressures based on tire width and instead recommends running the maximum tire pressure recommended by tire manufacturers.
As we noted with the narrower Irwin Aon DX 38, one aspect of Irwin’s wheels that really stands out is the quick freehub engagement provided by Irwin’s proprietary 6-pawl, 3-degree engagement freehub that comes with enduro bearings, is Shimano and SRAM-compatible and is also HD driver-compatible.
The Kova XC 29er wheels come with Irwin's proprietary 6-pawl with 3-degree engagement freehub. Irwin Kova XC 29er carbon tubeless disc wheels. © Cyclocross Magazine
The Kova XC 29er is one of several tubeless cyclocross/gravel wheelsets we have recently looked at. Several aluminum alloy wheelsets, including the Crankbrothers Zinc 3 and American Classic MTB Race wheels, provide a good comparison to what the Irwin carbon wheelset offers.
We measured actual weights of 780g front, 896g rear and 1,672g total for the $1,600 $1,300 Irwin Kova XC 29er. The rims alone weight 425g. To put that into perspective, the carbon set is a few dozen grams lighter than the alloy $750 Crankbrothers Zinc 3 gravel wheels that are also under review but almost 250g heavier than the 1440g alloy American Classic MTB Race wheels we have become fond of for their value-oriented gram shedding.
Tubeless Setup
We took full advantage of the wide rim and mounted several high-volume tires during our test riding, including Terrene Ellwood 700cx40mm Light, Vittoria Terreno Wet 700cx40mm and the WTB Nano Race 29x2.1" mountain bike model. The Kova XC 29er rims came from the factory pre-taped, and the blue tape was tightly stretched across the rim channel.
One of our team members had trouble getting tight tubeless tires installed when we first received the test wheelset, and another experienced some trouble mounting tires as well, albeit for a different reason.
Irwin Kova XC 29er carbon tubeless disc wheels come pre-taped, but the factory tape covered the center channel, which made it a little harder to mount tight tubeless tires. The tape needs to conform to the channel, and as shipped from the factory, proved to be problematic as it stretched, pulled away from the sides and cracked, but a new tape job solved our issues. © Cyclocross Magazine
He was able to mount the test tires, but once on the rim, he initially had trouble getting them to stay inflated, which appeared was from movement of the factory tape during tire installation. After removing the pre-installed tape and replacing it with Gorilla tape, installing the tires and keeping them inflated was straightforward.
A look at the deep rim channel shows how the factory tape does not adhere to the deep rim bed. photo: courtesy
Ride Review
We primarily rode the Kova XC 29er wheelset for Wednesday Worlds cyclocross practices and races during the past season. They saw some fairly rough mixed terrain during the week and then smoother more consistent courses when it counted on the weekends.
We have dented some alloy rims in the past when running low pressures, but the Kova XC 29er rims showed no such damage after a season of riding, despite some palpable rim strikes. They held their true and had no cracks from any of the rough terrain riding.
Irwin Kova XC 29er carbon tubeless disc wheels feature external nipples for easy truing. © Cyclocross Magazine
The 6-pawl, 3-degree of engagement Irwin hub worked as advertised in the field. We immediately noticed the engagement of the hubs and reported feeling faster thanks to the increased responsiveness. While riding, the wheels felt light and stiff and helped mask some of the shortcomings of our bikes and perhaps own ability.
The wide rims were a good match for the 40mm tires we ran while testing the wheelset, and not surprisingly, they also fit well with the mountain bike tires we tried. Although we tested primarily for high-volume cyclocross racing, the performance suggests they are also suited to riding gravel with high volume tires.
The Verdict
When we started our review of the Kova XC 29er wheelset, we asked if mountain bike wheels were a good choice for cyclocross. The wide rim proved a good match for the high-volume 40mm tires we mounted for both cyclocross racing and gravel riding. The carbon rims withstood audible rim strikes, and the wheels stayed true despite the rough terrain at our tester's Wednesday Worlds venue.
The most noticeable aspect of the ride was the responsiveness of the 6-pawl, 3-degree Irwin hub, which made us feel faster and more nimble on the bike.
The Kova XC 29er wheels are cyclocross-ready, but the question that remains about the Kova XC 29er wheelset is if it is a good value. At $1,300 and a measured weight of 1,672g, the Kova XC 29er wheels are similar in cost to some of the tubeless road clinchers we have looked at recently, but are between 60 and 120 grams heavier. For example, the Bontrager Aeolus 3 wheelset weighs 1,616g at a cost of $1,200 and the Williams System 45 wheelset has a claimed weight of 1,558g and a cost of $1,400.
Our time with the Irwin Kova XC 29er wheels suggests the wide mountain bike rims and responsive 6-pawl hub positively impact responsiveness and durability, so the ultimately, the issue for a rider interested in the Kova XC29er is if those are qualities you are willing to pay a small weight premium for.
Irwin Kova XC 29er Specifications
Cost: $1,300
Weight: 780g front, 896g rear, 1,672g total (actual); rims: 425g front/rear
Rim: 24mm/30mm Internal/External width, 22mm depth
Axles: Front: quick release or 15mm thru-axle; Rear: QR, 12x135mm or 12x142mm TA; boost sizing available
Freehub: Irwin proprietary 6-pawl, 3-degree engagement Shimano/SRAM 11-speed, XD-compatible
Spokes: 32 front and rear, Sapim D-lite, external nipples
Rotor: 6-bolt
Included: Pre-installed TLR rim tape
More info: irwincycling.com
Zachary Schuster and Lee Slone contributed to this report.
Photo Gallery: Irwin Kova XC 29er Carbon Tubeless Disc Wheelset
The hubs are built for 6-bolt disc rotors. Irwin Kova XC 29er carbon tubeless disc wheels. © Cyclocross Magazine
