Confident front wheel tracking in the loose rocks and slushy gravel. Great rear wheel traction in the climb/descend in all trail conditions. Rolls very fast on the loose stuff. Handling is very sensitive to tire pressure; a 1-2 psi change will change how the tire handles, which can be used advantageously to tune the tire for various trail surfaces. Side walls seem to be reasonably tough. Tread knobs are not squirmy at all.

Rolls a little slower than I would like on the hard pack, but I realize the tire is not optimized for this type of surface. The XR4 can get a little bouncy in the rock gardens. Perhaps this is not such an issue with the heavier Comp version of this tire.

I'm 6'1, 170 lbs, and ride a size XL 26er hard tail with a very good XC front shock. I ride in the southwestern US where every rock and plant seems to conspire to rip your side walls open. I've been riding these tires tubeless for about six months now, and they have totally changed how my bike handles, so much so that it feels like I'm riding a different bike. The XR4 is light, reasonably fast rolling averaged over all types of trail surfaces, and confident in the corners. I can now climb up trails that I've never been able to climb with my old tires and run the descents much faster. I recommend these tires to anyone who wants an all-around good tire for all sorts of trail surfaces. The XR4 won't be particularly good at everything, but its a good middle-of-the-road tread pattern that will enable any rider to get through almost all trail conditions reasonably well. If you live in an read that is dry with lots of loose rocks and fine loose gravel, this is the tire for you. Go with the Comp or Expert version of this tire if durability is a forefront priority.

Similar Products Used:

Specialized FastTrak LK

Light, great traction for climbing, cornering, stopping, durable, more volume than expected, Rubber compound had great damping/rebound

Slightly Pricey

I recently upgraded my tires/wheelset to Bontrager Duster TLR and XR4 Team Issue TLR and the combo has made some crazy improvements on the overall feel, handling, and ability to shred on my hardtail. The Bontrager tubeless setup is quite the step up from my old system (low end bontrager wheel set and some kenda kinetics tires w/ tubes) I ride the 2.35 up front and the 2.25 in the rear and the 2.35 has some serous volume. The standard width and diameter of a tire is often the only stats given, but I think manufacturers should include total volume, because volume is a huge variable in how the tire will end up performing. I would consider these tires very floaty, as I ride them between 22 and 28 psi and have had no problems in the very rocky and loose conditions I usually ride in in Central Pennsylvania, specifically Rothrock State Forest. Pushing these tires hard in corners is very satisfying, as is climbing and braking down steep inclines. These tires were recommended by the local shop (Freeze Thaw Cycles) and I am very happy about my purchase.

Gread traction and cornering grip, great all round tire, light and fast
lightweight (750g for 26x2.35" and 680g for 26x2.2")
easy to mount as tubeless on Bontrager wheelsets, can be run without any sealant and pressurized with a small trail pump
great tubeless combination and bead holds on like hell

Not so expensive, £30 for 2,35", £25 for 2.2" on the rear.

thin sidewalls just like the Expert models (but when setup up as tubeless, not really a weakness IMHO as you don't get snakebites as with tubes)

Bought them after I decided to go tubeless with Bontrager Rhythm Comp Wheelset. Bought Bontrager tape, valves, Conti Revo Sealant and these tires.

First of all, mounted them easily with hands, and inflated them with a really small pump without any sealant. This was impossible afterwards with Continental Mountain King II 2.2 Protection (didn't even inflate with a compressor without sealant) and Schwalbe Hans Dampf.

I must say, these Bontrager Wheelset + Bontrager tires are one of the best tubeless setups by far.

Tubeless was done easy and lasted for 3 months until the first problem (read later on). During these 3 months, no problems with the pressures, tires getting on/off the rim easily by the hands. The bead to rim contact is perfect even on really low pressure (the tire didn't burp once; later on, with Conti MK II 2.2 Protection i burped the tire even on high pressures like 2.5 bars).
Then, at once this happened:
http://imgur.com/hidYg13

Conti Revo Sealant couldn't seal the hole, so had to put a tube in it. First real "problem" and the tire-sealant tubeless combo failed on me. Lost some confidence in tubeless, but later on bought a Conti MK II 2.2 Protection tire which had thicker sidewalls and everything else, but had a lot more problems while running tubeless than the XR4 (will make a review of the tire in the future; in short the MK II 2.2 Protection couldn't be made tubeless easily with out a sealant and compressor, couldn't hold air on the sidewalls during the rides, burped from the rim once in a ride if ridden hard and lost pressure...).

Think that if I had a different sealant I'd still have the XR4 on the rear, and not a new tire.

So, the summary is this:
Great all round tire (just like the Expert model), wide as spec'd, light as AM tire, great traction on the rear on all surfaces, also great braking on the front and cornering in all conditions except very muddy surfaces. They don't loose traction easily but when they do, you know they did all they could. Not a tire that need to be leaned a lot to get the grip again. Predictable I would say.

Main negative, just like on my review of the Expert model - thin sidewalls but they are not the problem while in tubeless setup. So not really a problem if you're not used to 2ply tires that can be run with really low pressure without bending in corners.

Similar Products Used:

XR4 Expert (non TLR) models, Conti MK II 2.2 Protection
all sort of cheap performance tires from Schwalbe, Continental and WTB

Good grip and control.

Durability

Tire de-laminated after 2 years.

Weight

you name it - no tread in middle of tire so everything sharp or even dull hits the main casing.

First ride - cut in middle of tread, second ride puncture that Stans would not seal. Third ride tore a kno vb off - 3 flats 3 rides on trails i ride my cross bike on!! Crap!!!!

handling, cornering

expensive

First tubless setup with all TLR supplies from Bontrager and took awhile to get them to hold air. The tires came with a couple of small holes in them so had to get the super juice to plug the holes first. The process wasn't as smooth I had thought but they ride great on the trails so far and are the best tires from Bontrager I've ridden on so far.

Grabs the dirt.

Does not like the mud.

Over all Its a good all around tire.

Light weight for its size. Open tread grips well and sheds mud very well. Rolls well for a AM tire.

Pricey

This is for the 2012 version of the XR4 Team Issue TLR. Different tire than what is pictured here. I became interested in these tires after Mountian Bike Action gave them 5 stars in a trail test. I had been running Maxxis High Roller II's all winter in the NorthWet and could not stand them. I set these up tubeless on my DT Swiss EX500 rims using Stan's strips and SlimePro. I have only ridden them for a month and the area is just starting to dry out, so the jury is still out on wear and durability. But so far, the roll well, hook up great on wet roots, rocks, and mud. Cornering is sweet and predictable, just lean over and go.

Relatively light weight. Good traction.

Mounting. Durability.

Bought these on the recommendation of the local shop to replace the terrible tires that come stock on the Fuel. Shop had a very difficult time getting them to seat right and hold air, but finally got it fixed. Took them out for their first real ride in the dirt and ended up tearing the sidewall on an little uphill climb. I've done this same climb at least a hundred times over the past 10-15 years with various tires and have never had any problems. Wafer thin sidewalls just don't cut it if you ride anywhere with any kind of sharp rocks (like most off-road trails). These are expensive tires and I have to say I am very disappointed. Definitely wouldn't recommend these tires and won't be buying these again.

Good grip, good tracking, rolls well for a knobby, relatively lightweight.

Sidewalls tearing

initially I loved these tires for their great compromise between lightweight, good volume, good rolling, and rail-like grip in the looser corners, but now I am not so sure. I ride in rocks and cactus in Tucson, and it is hard on the tires. In a year I have had zero issues with any tire I have run, but have torn 2 of these soon after new. This was in features I often ride, and a lot harder regularly. A friend has also torn 2 of these in quick succession, so I do not understand how other reviewers can praise the sidewall strength, just feeling them they seem flimsy to me, and this seems to have been borne out by our experiences here. I cannot recommend these for anyone riding in rocky conditions, but they would be great if sharper rocks are something you avoid successfully.

Similar Products Used:

Many different tubeless tires