I posted a few days ago about the buildup of my Stan’s Crest rims, Sapim CXRay spokes, and Bontrager CX0 700×38 tires (tubeless), by Hand of Midas at NCC. Here’s an update.

I’ve run a lot of tires on the Vaya. The most miles were on Continental Cyclocross Speeds and Schwalbe Marathon Mondials. The Speeds are 35s, and the Mondials are 40s.
The Speeds, at 35c, weigh 350 grams. These CX0s, at 38c, weigh just under 370 grams. They’re pretty true to size, too (while the Speeds are a bit under 35mm). Here’s the skinny on the CXOs thus far:
- The CXOs roll just as fast as the Speeds on gravel or pavement. I notice no greater rolling resistance, even with the wider tires. They’re fast on hard surfaces.
- With my light weight, 35c tires are plenty for the vast, vast majority of gravel riding conditions…that said, there doesn’t seem to be a penalty to running 38s under ‘normal conditions’, and when the gravel is soft, the 38s have a clear edge. I’m impressed.
- With the Speeds, I was running tubes and typically around 50psi. If it was going to be a road-ish ride, I’d run 65psi. The CX0s, tubeless and larger, are interesting in the pressure department. I’ve settled (for right now) at 37psi in the rear, and 30-32 in the front. With the rear weight bias of the Vaya, that works well. Yes. That is low pressure. But tubeless, they roll FAST, even at that pressure. I’m very, very pleased with tubeless thus far. And of note, even though the CX0s weigh 20 grams more per tire than Speeds, without tubes, the CX0s come in lighter. The lowest pressure I could run with the speeds was 40psi. That was only in very soft conditions, when there were no pinchflat concerns (e.g. wet limestone path). The CX0s, even at 30psi, have not had any problems with burping. That includes singletrack expeditions on roots and ruts.
- In the realm of unfair fights, comparing the Speeds to CX0s on singletrack just isn’t fair. The CX0s do much, much better on soft ground. At the pressure I’m running, it’s like riding a 29er on skinny tires. In mud, the more aggressive side knobs on the CX0s do a good job of providing significantly more traction than the Speeds. In other word, the CX0s are just as good on hard surfaces and better on soft surfaces. I love my Speeds…so that’s saying a lot.
- That note aside, I’m absolutely, steadfastly convinced that the CX0s will wear much faster than the Speeds. I’ll keep updating on the wear…I only have a handful of rides on them thus far.
This next point has been made by many, and it is one that I strongly agree with: the single best upgrade to a bike is better wheels and tires. The drop in rotating mass and increase in traction on adverse surfaces, coupled with the greater comfort at lower pressure running tubeless…it’s amazing. I’ve always loved the Vaya. This is like falling in love all over again.
It’s a great build, and they ride swiftly.
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what is the actual width of the Bonty CXO 38c mounted up?
Mounted on my Stans Crest rims, at 30psi, they’re a healthy 40mm wide. They don’t grow much more than that, though.
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