After close to two hundred miles logged on the Bontrager XR-1 Team Issue tires, I have some thoughts and comments to share. These are the race inspired treads from Bontrager’s new design team. Not meant to be run tubeless, I have gone ahead and set them up that way and my comments should be taken in light of that. Please keep in mind that doing as I have done will void any and all warranties. Let’s get on to the notes here…….
Test Conditions: Dry terrain, loose gravel, sand, hard pack dirt and gravel surfaces, roots, and some tacky to muddy trail. The XR-1 is meant for dry terrain, and as such, I kept the tire to these sorts of conditions as much as I possibly could. These tires were used on single track, and on a gravel/back road event recently.
Notes On Mounting And Tire Pressure: While I must repeat that these tires are not meant to be tubeless, and are not part of Bontrager’s excellent TLR System, they did mount up and seal up very well. I used a Race X Lite rim with a TLR rim strip and a TLR valve stem. The sealant was a mixture of CaffeLatex, Slime Tubeless, and some “homebrew” latex solution. The tires required a bit of soapy water around the bead interface to aid in airing up and to set the bead properly. This was accomplished with a small air compressor. Riding the tires aided in keeping air pressures maintained, but I did note that these leak down a bit faster than a “true” tubeless ready tire does.
I tried the tires running at around 30-35 psi, but this resulted in a higher rolling resistance and a bit of flexiness side to side which indicated that tire pressure was perhaps too low. The 120TPI casings were also likely contributing to the feeling here. The higher thread count usually results in a more supple casing and would also point to a need to run a higher pressure. On the next ride, I bumped up the pressures to 39psi front and rear. This nominal change made a really big difference. The tires really came into their own at these pressures and I have continued to run them at 38-40 psi since then.
Performance Notes: Once I reached the pressures that started working the best with the XR-1, I could really feel a big difference in performance. The rolling resistance, which was higher than you would expect from a sub-two inch race tire, went away at the 38-40 psi range and then these tires felt very fast. Pavement riding was above average, but off road anywhere these tires really come into their own. As long as it is dry, that is, and as long as you don’t have some loose layers over hard pack. Mud isn’t part of this tires vocabulary and loose over hard pack will find this tire skating a bit. The rounded profile and skinny knobs just are not suited to loose over hard, in my opinion. I had to ease up in corners in those situations.
Where it does work fantastically well is on grassy tracks, gravel, and of course, anything hard packed or stone. I especially liked riding these tires on grass track where you had a Velcro-like adhesion to the dry grass and the supple casing just erased the small bumpy surface. Hard packed dirt was also a treat, and I railed these tires through twisty-turny trail at higher speeds than I was expecting to since the grip was so good. Again, the rounded profile and small knobs with the supple casing as a foundation were working well. Almost tubular like. I would suspect this pattern would be phenomenal in a tubular configuration.
Standing climbing resulted in great grip on sandy, gritty roads. I never spun a tire. Going over loose sections of deeper gravel and sand were met with a higher degree of float than I would have expected from a tire this narrow and this rounded. Tacky dirt that allowed the tread to bite in was also great, but I noted that the tires made a weird sound when hitting these tackier patches. Nothing bad, but noteworthy. Mud would instantly pack in the diminutive knobs and there wasn’t any traction at that point. I do not recommend doing a muddy course with these tires! But then again, they are not designed for those conditions either.
Finally, I noted that the tires were very consistent and predictable when breaking free, and drifting these tires a bit was not a fear inducing event. In fact, I almost wished for it in some cases. Laterally, these tires will drift into ruts or slip down off cambers a bit as well, so that is something to watch out for. Overall, wear has been low. I was looking for these tires to wear more quickly, being they are designated for racing, but so far, they have impressed with their ability to wear well.
I’ll be back with a Final Review in a few weeks to a month or so. Stay tuned!
Note: These tires were purchased by Guitar Ted for test/review. Twenty Nine Inches is not being paid, nor bribed, for this review. I will strive to give my honest opions and thoughts throughout.
Scary tire for tubeless in a true mtb application, IMO. I’ve got two brand new ones that could be had VERY cheaply.
OTOH, if I ran tubes, I’d race one on the back in a heartbeat!
@Kosmo: Depends upon what your definition of “true mtb application” is and if that matches up with the design intents of the tire.
If you use this as intended- on race type courses in an XC type manner- I don’t see any issues. Of course, this implies that you are also using a reliable tubeless application as well.
Again, these tires are not meant to be run tubeless, so anyone doing so will be running a risk of failures. That said, I have confidence in this tire on the TLR rim strip so far. No burping, or other weirdness at all with trails that are littered with roots and some embedded rock.
I would agree with you in your assessment of the tire as a rear and with regards to tubed use.
Interesting comments…Bottom line, how do they compare with the SB-8 and the Vulpine? I guess they would be the closest competition.
@Willie: The Smallblock8 was the foundation for Bontrager’s design of the XR1, so they are similar in performance and intended use. I have heard Smallblock8′s are tough to set up tubeless though, but it has been done with success. The Smallblock8 is also a bit larger in volume than this tire, with a slightly squarer profile.
The Vulpine is definitely as fast, but it lacks the “Velcro-like” center grip. Vulpines do have a more aggressive cornering knob arrangement and therefore work better in more tacky, loamy conditions. The tire is easily set up tubeless, and has a nice, large volume for a 2.1″ tire. I would say that the Vulpine has a stiffer casing, and can be run at lower pressures without rim hits occurring better than the XR1 can. It should be noted that the Vulpine is a bit heavier tire as well, so in terms of weight, the XR1 wins there.
The Vulpine is definitely a more versatile tire in terms of uses and terrain types to my mind, so if you have to have a versatile racing tire, the Vulpine, or the classic Nanoraptor are the “go to” tires in my opinion.
For all out XC dry conditions racing, the XR1 is hands down the tire to run, with another nod to Maxxis’ excellent Aspen tire, which I will be reporting on again here soon.
The SB8 is a PITA to set up tubeless. Lots of small pin holes in the thin sidewalls. But, once you get it sealed it’s good to go.
Kosmo, not sure if this is why you said it, but I’m interested in your set of XR1s if you’re serious about selling them.
Excellent review, GT.
In other words: For its intended use, the XR1 (or call it SB7
) is perfect. It is just that its intended use range is quite small.
I also had no trouble setting them up and riding them tubeless. In fact, they sealed allmost instantly, apart from a few pinholes.
What you say about tire pressure is interesting. A lot about that is rider preference, I guess. My initial preferred tire pressure resulted in a dinged rim. To be safe, I ran a bit more pressure, which -to me- compromised rolling and grip.
The Aspen has the volume and the grip, at little more weight. How about a racing tire comparison like you did some time ago? Be sure to include the Bontrager 29-2 Team Issue. They are big, have some knobs and are 600gr-ish. OK, sounds like a SB8, but this one is truly TLR!
My experience with these this past couple weeks has been exactly as you describe, GT – easy tubeless set up with compressor, and a little more pressure than usual (34 front, 36 rear for me). And yes, at that pressure, they still have some plush left. Also surprisingly long wearing, even on pavement as I ride to the trail.
What I find delightful is the decreased weight – the geared Superfly came alive on these things, especially after the 29-3 front/XDX rear I had on it before. A bit more skittish in turns, but very predictable with practice. So far no major issues with Socal rocks, but part of that is I can steer more quickly and hold a more precise line. Deep sand is not your friend on these, though – I haven’t lost it but they require more attention and some furious pedaling in granny gears to get through the really deep stuff without fuss.
X2 to JeroenK – this would make the start of a good comparison. I would suggest the 29-0s as another good one to run off against these – they are even lighter, according to Bonty’s site, and in keeping with the XR1 purpose.
interesting to read that others are getting good wear from their XR-1s. looks like i pulled a short straw on mine
my pressure experience (only running them with tubes) is that due to their subtle casings the tyres feel very ‘soft’ even up to high ( 35psi ) pressures but hang in there in the low 30s and you will find the grip levels, speed and comfort fantastic once you get used to the ‘squirmy’ feel.
GT, another vote on a race tyre comparison from this reader if you can manage.
perhaps also include the silly furious fred’s, i am interested to hear other peoples experiences with these tyres as all i have heard is that their durability is non existent – ie: riders cant get to the start line with them as they puncture on the way there !
These tires are very surprising to me. I ran them tubeless for a couple of months on front and rear. I got my first flat in several years and decided to swap them out for more “durable tires”. I threw a Kenda Karma on the rear, which was absolutely horrible. I now have the XR1 on the rear with a tube in it. I run it at 37 to 40 and it sticks to everything. I have a 2.2 Nevegal up front for moon dust season, but will be putting the XR1 up front again, just so fast. They look like road bike tires next to the Negegal, but they stick and roll fast. I can’t mount them up tubeless again as I don’t have a compressor and after an hours battle, I threw a tube in. I really don’t notice the tube and it took me 3 minutes to get set up.
I run one of these on the rear set up tubeless. With my wieght of 165, I run it at about 34psi, as the supple casing and rounded profile makes up for the extra pressure. I race on this set up regularly and have never had a problem with burping, gashes, or any problem at all for that matter. I run the tread in the reverse of its intended direction for a bit of extra bite.
Hmm… I had a pair of XDX TLR 29er tires that wore terribly fast, and wonky traction on loose pack/mud/leaves/anything but hardpack… Maybe I am over-exaggerating, but you get the idea.
Currently reviewing IST solutions System 29′er tire. Very low rolling resistance with the design of their tread.
Almost interested in these tires, but I run into way too much mud, here in West Virginia. :\
Care to suggest a tire?
Anyone have a long term test of these tires tubeless?
I am looking at them as more or less a race-only tire.
@Jon: I ran these tubeless for over six months and had zero issues. This was on the TLR system, Race X Lite wheels.