At the Sea Otter Classic earlier this year we looked at the Irwin Aon DX 38 carbon tubeless-ready wheels, but another offering from the California handmade wheel builder that caught our attention was the Irwin Kova XC 29er carbon tubeless disc wheelset. The Irwin Kova XC 29er is a 24mm wide, 22mm deep tubeless-ready mountain bike wheel that we think could be worth a look for low-pressure cyclocross and gravel riding.
Mountain bike wheels for cyclocross? Given the focus on weight saving among road racers, one would expect road rims to be lighter than their mountain bike counterparts. However, carbon road rims must withstand up to 125 psi of tire pressure, and thus they often require more material to maintain their shape and strength. We have found that for cyclocross and big-tire gravel and mixed terrain use, mountain bike carbon rims are often a lighter option, and they tend to be wider, adding welcome volume to cyclocross and gravel tires.
The tubeless-ready Kova XC 29er rims have an internal 24mm width, external 30mm width and 22mm depth. For comparison, the Aon DX 38 has an internal width of 19mm, which means the Kova XC 29ers provide a wider base for tubeless cyclocross tires.
As we noted with the 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 wheelset is available with a front 15mm thru-axle and rear 12x135mm or 12x142mm thru-axle. End caps are provided to convert both the front and rear to quick release and Boost sizing is available.
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.
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 Irwin Kova XC 29er. 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.
There are two schools of thought on rim material when using disc brakes. Light alloy rims can dent but can often be repaired, while carbon rims, especially in clincher form, may not even save weight but can survive rim-denting forces. However, when they fail, it can be more catastrophic.
It goes without saying that finding the right wheels for your needs takes way more than just counting grams. How will they hold up? How wide are they and will they remain air-tight using different tubeless tires? Stay tuned as we put the Irwin Kova XC 29er wheels to the test and find out how they respond to these questions cyclocross and gravel riders want answered of their wheels.
Irwin Kova XC 29 Carbon Wheelset Specifications
Weight: 780g front, 896g rear, 1,672g total (actual)
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
Included: Pre-installed TLR rim tape
More info: irwincycling.com
Andrew Yee and Zachary Schuster contributed to this report. See our full review of the Irwin Cycling Kova XC 29er Wheels here.