Tubeless 29".

No ho sé, Crossmark LUST 29", Ardent LUST 29"?:

"I've been running the Ikons converted to tubeless on my Crest rims on the JET 9 this summer as well as an Ardent UST 2.25 up front on my RIP and a Crossmark UST on the rear of my RIP (on Flow rims). Both the Ardent and the Crossmark fit on the Flows very tightly. I had to use tire levers and vocal grunts to mount them. I also have not added any sealant and they have held air all summer. That's it. No sealant. Flows with yellow tape and valves. They have been bombproof on the RIP.

Mounted on Flows on the RIP....

They do very well in mud. And it has been a very, very muddy summer. Historic mud and rain in fact.

I've bashed these as hard as I could on every rock I could find in the Black Hills and here in the Midwest trying to get a flat. I can't do it. Lately, I've been running them through thorn infested trails hoping to pick up some thorns and get a flat (to test the limits of running with no sealant). But no flats yet and no sealant. If I do flat, I'll just add some sealant.

The Crossmark and Ardent UST or LUST as Maxxis calls them are not light. But if you factor in not having to use 2 ounces of sealant, you cut out 57 grams of rotating weight for each tire - it's not terrible for the security and performance. And the beefier sidewalls are worth their weight in gold. As I said - I've been pointing these things at every sharp rock I can find trying to find a fault and tear them. No such luck. Not sure these tires will appeal to everyone for their particular needs, but they have been a mount 'em and forget about 'em tire on my RIP this summer. I'll probably get a second Ardent UST and run 'em front and rear on my RIP. Although the Crossmark traction has really surprised me in a good way. Crossmark's in the LUST version are around 840g and the Ardent LUST is 900+. The exact weight is written on the side of the prototypes I've been testing, but they are so covered in mud at the moment I can't read the Ardent's weight. In terms of the weight, the two XC series races I did using these heavy tires, I placed the highest I have all season in spite of running tires that weighed 300 - 400g heavier each than my usual XC race tires. So go figure - heavier wheels, heavier tires, heavier bike and I do better against the same guys I compete against with my lighter JET 9 or Dos set up. Hmmmm....

The Ikons are a legitimate 2.2 XC race tire. Light (mine are around 510-520g) and are more aggressive than the Aspen since the knobs are taller. I consider the tread pattern to be a baby version or "lite" version of the Ardent. Very similar tread pattern, just shorter knob height and size minus the additional pair of center knobs between each row of tread blocks. I like the additional volume over the Aspen and they roll just as fast IMO. Like the Aspen, one has to be careful to find that sweet spot psi where you don't go so high that you start spinning out on climbs and losing cornering traction through the turns, but not go so low that things get squirmy and burping can happen. I've messed around between 18 and 26 with the sweet spot somewhere in there for my weight and needs.

They got a little sketchy on me in a race this summer when it started raining near the end of the race as the trail quickly turned to grease. But the Aspen or any other XC race tire would have reacted the same way in those conditions. Dry, tacky, loose, thick mud, gravel, grass, hardpack, pine needles, etc.... - the tire rocks for XC racing.


Red Wing by singingsingletracker, on Flickr

I have not tried these out on my wider Flow or Blunt rims yet, as I've been running them since June on my Crest rims with 2 ounces of sealant in each tire. Possibly an IKON on front with an Aspen in the rear would make a good racing combo, but I'm pleased running them front and rear for my needs. It's a bit more aggressive than the Aspen, but not enough to slow the tire down at XC speed. It's a nice tall tire with the extra volume over the Aspen. No flats, burps or roll offs with all the riding/racing I've done on it. A couple of loud "pings" or "boings" out on the trail as the tire sidewall rubbed a rock or root that I at first mistook for a burp, but they were not burps. I guess, if I had to pick something in my tire collection that it closely competes with or feels like out on the trail, it would be the Continental Race King 2.2's, Schwalbe Racing Ralph 2.25 and the Bontrager XR 2.25 front tires.

If you are looking for a real UST tire, the beefy nature of the Ardent's are golden out on the trail for full suspension bikes. I've run crazy, crazy low air pressure on these UST tires without any squirm. They are pretty amazing out in the chunk doing that for grip and no squirm thanks to the ultra beefy sidewalls. Gobs of traction. I can imagine what a pair of the Ardents would be like with low pressures. But - I only have one of them mounted on the front for now. The Crossmarks UST are good for racing with the beefy sidewalls giving you protection for the weight penalty. If you want a more aggressive XC race tire, yet light and with more volume - then the IKON edges the Aspen. And I love the Aspen - especially on wider rims. It's a very supple tire that I have really enjoyed. So much so, that I have worn my pair out (took 13 months to do so). I actually would really like to see a 2.25 Aspen for the terrain I ride. Both the Aspen and the IKON should satisfy the needs of XC racers whether run in combination or in like pairs.

BB"

http://forums.mtbr.com/showthread.php?t=648447

I a Pinkbike:

http://www.pinkbike.com/news/maxxis-aspen-tire-review-2010.html?trk=rss