Project Wide Gravel Wheels: At The Finish
With the Spring over and Summer coming on strong it is time to revisit our long term test wheels. Dubbed “Project Wide Gravel Wheels” due to the wide, WTB KOM i25 rims, these wheels feature an inner rim width at least 4mm or more wider than what most wheels have on “gravel/adventure” bikes. This time I will relate what has happened with tires I’ve used and how they have performed on these wheels versus others I have here as test mules. The last update on the PWGW can be found here.
The intentions of this project were to find out what, if any benefits that a gravel rider might gain from using a rim with a significantly wider inner rim dimension. The KOM i25 fit this description being anywhere from 6mm-4mm wider internally than most wheels used on gravel road bikes now. Other riding disciplines have shown that a wider rim with a tubeless tire set up benefits from having a more stable feel at lower pressures and that the tires used tend to run and act like wider tires. The thinking here being that a rider might get a wider tire performance at a lighter weight by mounting a “narrower” tire on a wider rim.
Following are my list of findings both positive and negative for the PWGW set up. First, the good stuff……..
- Every tire set up tubeless gained, on average, 2mm of width overall versus what I could measure for the same tires on narrower rims.
- The profile of all tires tested was slightly flattened, making the tires act like wider tires than they were. This provided more stability, traction, and the tires exhibited a bit better comfort. (That last trait probably was affected most by the next bullet point though.)
- All tires could be run at significantly lower pressures with little or no negative effects while traction and comfort were enhanced.
- This same wheel set could double as your lightweight 29″er XC or bike packing wheel set.
While that all sounds great, there were some negative points to consider as well to running a wheel set like this.
- The wider tires, 40mm ones especially, could be spread out so wide that they will no longer fit your bike. I ran into this with the Twin Six Standard Rando and the Panaracer Gravel King SK 40’s, which ended up being 43mm wide on the PWGW set. That maxed out the Standard Rando’s clearances, so I had to switch that combination over to a different bike with more clearance. You may not have that luxury.
- While you can make a skinnier, lighter tire act like a heavier, wider one, the wheels are already heavier than wheels using narrower inner dimension rims. So the weight advantage may be a wash at best unless you use this idea with carbon fiber rims.
- If you are still running tubes, some of these benefits will be lost on you.
- If your gravel rig has to do double duty as a road bike, this idea may not make sense for road tires at all.
At The Finish: While almost any off road cyclist with a fat tired bike will be better off with a wider rim, the advantages aren’t quite so clear cut with gravel road cyclists. The boundaries we have to work within are often narrowly defined due to the nature of the bicycles being proffered as gravel bikes these days. Due to that and the changing field of tubeless tires available, the answer to, “Is this a good thing for me?“, as a gravel road cyclist is still an answer in flux. Even wheel size is being challenged with the 650B size becoming more prevalent in the gravel scene.
Still, I feel that if a cyclist chooses correctly, a lighter weight, wide carbon or maybe even an aluminum rim built up to accept tubeless tires could be a better mousetrap for gravel road use. The ability to run lower pressures, get great stability and traction, and eliminate pinch flats is almost too good to ignore. Short of running tubular tires, the PWGW set up shows me that wide rims and tubeless tires are a hard combination to beat if you get all the right boxes checked with your component choices.
Note: RidingGravel.com received the WTB KOM i25 rims at no charge for this project. All other wheel components are being paid for out of pocket by Guitar Ted. We are not being paid, nor bribed for this review and we will strive to give our honest thoughts and opinions throughout.