I’ve been trying out some new Bontrager tires this summer and although I’m still developing opinions on the 3 tires I wanted to share are some impressions. I got a few of the 29-0, 29-1, and 29-2 Bontrager tires, 2012 version since this year the tires name starts with an “XR” instead of a “29.” The numbers generally indicating the size of the tires, with the XR-0 starting at 1.9 and on up to 2.3 for the XR-4. I also had bought a 29-2 (2.3″) earlier this year that I added to the mix as well.
I’ve still yet to mount the fast and lightest XC tires — the XR-0. I’m going to mount them on my Mountain Cross (“monstercross”) bike that I ride mostly on dirt roads and smoother trail. They aren’t meant to be run tubeless but because I have only Stans rims i run all my tires tubeless. You can see the tread is super low profile and for dry-conditions. These are crazy light at 418g and I’m not sure how they’ll last but I’m going to have to update on that later. I heard from a friend that they hook up better than you’d think and are indeed super fast tires that you can rail.
I’ve been mostly riding the XR-1 tires and have found that they’re best for my style of riding, especially as a rear tire. Lots of road ‘approaches’ to dirt in this area and it’s nice to have a fast rolling tire that also hooks up well on the mostly hardpack trails, hardpack with duff on top, and moderately rocky trails. I don’t like the XR-1 as much in the front but it does do really well and makes for some low rolling resistance. But instead of using it on the front, I have been using the 29-2.
I really like the 29-2. It’s got a great round profile, rolls fast, the knobs are a bit wider and longer than the XR-1. It hooks up really well on the front, predictably. The XR-1 on the rear I replaced just before the tour and after 350 or so miles it looks worn being on the rear but not too bad. We rode a bit of road on the tour so with that much weight on the bike I’m not surprised. Using digital calipers, they measure what they claim to be = 2.2″ at the widest part of the tire (knob to knob).
For the last few months I ran a XR-4 on front with Stans even though it easily mounted up without sealant. I put some in just for thorn and sidewall protection. Both tires were mounted on Stans Flow rims. On the tour I got no flats and had no problems at all, they worked great and I’d run that same setup again. The XR-4 is a true tubeless ready tire and because of that has a thicker sidewall. It’s noticeably stiffer and in my experience a bit harder to hook up on corners since the knobs are stiffer and casing is thicker. I ran it at lower a lower pressure than the lighter XR-1 or 2’s. The main reason I took that tire for the front on this bike tour was its beefiness. You’d be hard pressed to slice that sidewall and i wanted that security. After a couple of months of riding it looks nearly new. It’s not the fastest rolling tire but what do you expect, always a trade-off. They l measured up at 2.3″ at the outer knobs.
I know many if not most XC riders ride non-tubeless ready tires tubeless because of weight and the ability to run low pressure and not flat, but I also think non-“tubeless-ready” tires ride better because they tend to have a less rigid sidewall. I did slice a sidewall on the XR-1 but that was when i had it mounted on a Blunt 35 rim so the tire’s sidwalls stuck out more than the tread when run on such a wide rim.
If i was going to ride the Tour Divide I’d likely choose the XR-1’s. They make a great all-arounder tire – fast rolling, hook up really well, they’re light, and pretty bomber even though they’re not officially tubeless-ready. If they came in a tubeless ready version they’d by my anywhere tire since the sidewall would be stronger. The XR-4 would be my tire for a slack-geometry AM riding. But those tires are beyond what I need, I just don’t ride that aggressively downhill.
In my opinion these Bontrager tires deserve a solid try and to be in the same “box” as the Ardent and other all around MTB tires.
A tire that is worth comparing the XR-1 and XR-2 to is the Surly Knard. The Knard tire is one of my new favorites with its block tread pattern and even rounder profile than the XR-1. I like how the tread goes very low on the sidewall. At low pressures these tires hook up just fine and still roll fast. I love that they have them in each platform (right term?) — 29+, monstercross/touring (700 x 41mm), as well as a 26 x 3.8 Fatbike size.