I'm not sure I'd believe the reviews that give this tire 1 star. Although these are on the more tricky side of mounting, it's definitely doable and actually easy once you get the technique down. It took about an hr for the first tire to work out the method. Then 15 mins to mount the other.
First, I'd watch this installation video by Challenge Tires https://youtu.be/1N9a1tqYky4 . Next, I'd pick up some tire bead wax (Shindy Tire Bead Wax).
The key is Japanese tire bead wax. You wax one bead and slide it over the rim so the whole tire is over top the rim and centered. Don't push any beads into the rim just yet. Then wax the other bead.
Now you can mount one bead making sure you're going into that center channel. Get as far as you can go using your body weight to stretch the bead as much as possible. Don't work too hard though. Once you can go any farther strap an old pedal strap to one side right where the bead is entering the rim. Basically you're trying to pinch that side so it doesn't move. Get the strap really tight but also make sure the metal parts of it aren't digging into the rim. Then you can work on the other side of the rim w a tire lever. If the other side migrates refit the strap so it pinches the bead so it can't move. Repeat on the other side.
Rode these at a not-muddy but also not-dry cx race and they performed excellent. Great traction despite small knobs. I ran them at 18 psi (138 lbs bike+body) which lower than the recommended pressure of 25-45 psi. No squirm. The rear rim kissed the ground a couple times with no issues. Great all-round tire that I'll be keeping on for the winter.
tire is so undersized out of the box that I was debating whether it was a mislabeled 650b. the TREAD needed to be stretched over the rim, let alone the sidewalls. I've mounted dozens of tubeless tires over the past decade and these were by far the most difficult. way harder than GP5000 TL.
once mounted, they were both very out of round. ok so I ignore that too because they just feel sooo supple. went for one ride at 40psi and they felt super fast and smooth on coarse gravel, even at that high of pressure. For reference I weigh 155lbs. but then on the following road descent they were unnervingly squirmy in corners. it was uncomfortable pushing them into a corner faster than 30mph. so basically, they're awesome in a straight line, on bumpy roads, as long as you don't mind them being wobbly and impossible to do a flat change roadside. can't speak to their durability since I returned them after 2 rides. when I removed them, bead had stretched so much that I could put it back on by hand. I suspect that challenge knows these unvulcanized tanwalls stretch a ton and thus intentionally undersize the bead a lot to account for that.
Conditions in the Marin headlands are dry dry dry these days. Fire roads are definitely hard pack. This supple tire is definitely helping to soften the blows. Low profile tread requires rider attention on downslopes butï¿½shouldnï¿½t that always be the case??
Definitely worth it.
One note about install: tight fit for sure. Patience and technique will reward and once on no issues with seating.
I bought these tires because they rated really well for rolling and puncture resistance. The tread looks like "just enough" for dry SoCal trails. The yellowish sidewall is kind of ugly, but I figured I'd eventually get used to it if they performed well.
Unfortunately I couldn't even get them mounted on my Rolf Prima Hyalite wheels (alloy rim). I knew something was weird when I took them out of the package and they were totally flat. Absolutely no roundedness to them at all. Then when I tried to get them on the wheel, The "fit" was so tight I needed to use tire levers to install the FIRST bead. Even with the first bead in the tubeless channel, I had to work the tire levers to get the first bead seated. Then I wanted to use a tube to set the tire up before adding the hassle of sealant. Well the tire was so tight I could barely get a fully deflated inner tube between the tire and the rim. Then, trying to install the second bead? Fugettaaboutit. I eventually got the second bead seated, but surprise, surprise, when I tried to inflate the tube I had obviously pinched it while wrestling with the second bead.
So now I have to try and get this thing off! Frankly I should have stopped when the first bead was so difficult to get on the rim. I can't even imagine what a nightmare it would be to try and deal with a bad puncture on the road/trail. What a waste of money.
I mean these are easily the most supple gravel tires I've ridden. All those Little Rock gardens disappear as I glide through the hills.
But I mean life span is crazy short. These tires are probably best saved for a race. As in one race. Well maybe two but don't forget the Dynaplugs.
These are pretty fast rolling tires and pretty light. I like them better than my Gravel Kings because they roll just as fast and don't throw pebbles at my fellow riders. They have a yellow sidewall, not tan if that matters to you. My 38mm version expands to 40 mm wide on my 25 mm internal rims. They require a no ammonia sealant apparently so just to be safe, I bought Challenge brand sealant instead of my normal sealant. Would give 5 stars if I could use my regular sealant. Maybe I can, but I don't want to experiment with these relatively expensive tires.