My super-sweet Superfly came equipped with Bontrager XR1 tires but I recently switched over to the Bontrager 29-3 TLR. Here are my micro-blog thoughts.
XR1 - Very fast, light tire. A great, great tire for a mountain bike race on a course that is not too muddy or too rocky. I rode these at the 24 Hour Race and the Mad Dash 8 hour race. They worked well, but I had a pinch flat at one race and a mysterious stem blowout on the tube at one. If I was under 180 lbs, I don't think I would have the pinch flat issue and I might still be riding these tires. The front tire isn't really grippy in loose stuff, but it is a great hard pack tire and a perfect race tire for someone light on the bike and competitive at the front of the pack.
For the Leadville 100 I wanted to make sure that I had a tire that would stand up to the abuse my size and the course dishes out. The course actually doesn't dish out too much to the tires themselves and I have it on good authority that the Trek supported riders will be on the XR1 at Leadville, but Two Wheel Transit mechanic extraordinaire Tom suggested a tire with more volume would be better for me.
Passing over the multiple conversations and hundreds of tires checked out, Tom helped me land on the Bontrager 29-3 in a 2.25" width.
29-3 TLR - This tire comes in a couple of different tread patterns and widths. Looking for the right combination of weight and volume, I got the Team Edition 2.25", which say is it 600 grams. This compares to 495 grams for the XR1, but it is a lot less than a lot of other rubber I was looking at. I got them mounted tubeless and rode them this weekend for the first time. I am super happy with the superfly and these tires.
The do have a lot more volume or mass than the XR1, which absorbs a lot more impact without hitting the rim or feeling like it might. In the rock garden sections I went back to feeling like I could just rip right into them without a problem and after six hours on Sunday of no-holds barred banging on them, they held up perfectly. They have more grip on the front end for looser stuff and they do have more weight for spinning up or going uphill, but I felt confident and good on them, which really is the mark for these things.
I would rather have 200 more grams to haul up the mountains in Colorado and not have a roadside repair so I think I got the right combination. I did, by the way, by-stop at the Kenda Small Block 8's. I voided the warranty by using Stan's and then promptly split the rear tire on the centerline on a rock, which Stan's wouldn't stop (nor would I expect it to). I was disappointed with the casing on the Small Block 8's as they seem to be twisted somehow so that they rode oddly on pavement. I have heard a lot of good things about them, but they didn't work for me. I am looking forward to many more miles, and hopefully 103 of them at Leadville, on the 29-3's.