Parts

Trials Tires - Comparison - Dirt Rider Magazine

May 29, 2009

Once upon a time only tire you could get for your so-called dirt bike was a trials tire, and you ran a rear size on your front wheel, too. But that ancient history shouldn't completely disqualify the time-tested trials tire from being able to work in this day and age, should it?Dirt Rider set out to give four brands of trials tires a workout and see which ones grabbed us.First a caveat: These tires will not take over the earth. They are really good for trail riding,mostly for riders who do not spin or skid their rear wheel much. For racing applications, they are probably not the best choice-unless you race very mellowly! Another benefit is that they are good for the trails because they don't throw too much roost, they just hook up. These tires, even when we ran them at 12 psi, have excellent bump-compliance and all of them aided the suspension feel. Here's how they worked:Loam
About the worst place for a trials tire is where the traction is the best, so of course loam is far from home for these puppies. Here you are used to getting that full-on bite and dig of a true knobby, rewarding you with clawing action, and a trials tire is much more inclined to spin up with this much juice.Flats
You get pinch flats more readily on a trials tire due to the softer sidewalls, and it is a bit easier for sticks to stab through the softer rubber between the knobs. If you smack into rocks and nail square-edged bumps hard, you will pay in flat tires and in rim dings.Mud
They might look like they'd pack up and not grip, but the knob spacing is so close that they do not let the mud reduce the bite of the tire too much. And they seem to dig in deeper in soft stuff and float smoother on the slightly cakey mud than a normal knob.Spinning/Skidding
If you are the roost-skid-repeat kind of rider, a trials tire will frustrate you and put you on your head. They don't work when spinning, and they are even worse when in a full-lock skid.Great for Trails
One thing we've seen is that trials tires are great for trails. They don't displace too much dirt and since they hook up better in technical areas (the parts of trails that get beat up the worst), they help preserve soil conditions. And if you wonder how enemies of trail riders are going to go after us as soon as we conquer sound, I have one word for you: erosion. Something that guards against that is a happily-ever-after.

The Dos and Don\'ts of Trials TiresHardpack
As on rock, these tires squish down and lay rubber where knobs slide. This is one place where they grab traction, but here you also feel the tires flex and wallow.

The Dos and Don\'ts of Trials TiresHow they work in:Sand
You\'d think that trials tires would outright blow in the sand, but they don\'t. In fact, they may be way more consistent than even a sand tire in the soft stuff. They start out by spinning, and they keep spinning with a very consistent grab and never a harsh bite of traction. Sand was clearly the most impressive \"no way!\" surprise of these tires.

The Dos and Don\'ts of Trials TiresRock
Plain and simple, they flex, put down more rubber and let the tire conform to the shape needed to grip. They rock on the rocks.

Michelin
Model: 4.00R-18 TT(Rear) X11 Trial Competition Radial, $183.41Michelin is the preferred brand for most serious trials enthusiasts and comes standard on more trials bikes than any of the others. Trials riders prefer the tubeless radial tire (which is built largely for tubeless use), but we focused mostly on the tube type radial since it seems to work better at anything more than a crawling speed. Clearly, the rubber on the Trial Competition has more stick than the other brands, especially on the rocks. It also has a softer sidewall than the others and won\'t run when flat. It is easy to mount, though the sticky rubber likes to be lubed up to get over the rim.Tractionwise, the Michelin gave the best grip or bite just as the wheel got going, and most riders were really impressed with how far you could lean this tire over and still get bite out of it. It was slightly squirmier in sand than on hardpack but was still rated high by all riders. This tire was also one of the worst feeling when really

Dunlop
Model: 4.00R-18 D803, $118.98Dunlop\'s new 803 replaces the 801 and, for the trials guys, has been a huge improvement. The radial construction makes the tire very compliant yet not nearly as wallowy as the Michelin radial, but it does have that spongy feeling. It feels like the Dunlop has a bit more sidewall stiffness and, at the same time, has great bite under normal trail riding speeds. It worked well everywhere, and only a few riders thought it wasn\'t as grippy as the Michelin, mostly on ultrahardpack. It was noticeably better in sand, though. The tire was a little tighter on the rim during mounting and really needed lube. You cannot ride this tire flat.

IRC
Model: 4.00-18 Trial Winner Tube Type, $104.95IRC has the distinction of being very middle-of-the-road in every aspect. It gave decent traction everyplace, with no real standout points. It isn\'t noticeably wallowy or flexy, and at the same time, the tire is far from stiff feeling. It gets great marks for durability and, if anything, suffers a little in aggressive riding, where it doesn\'t bite as well right off the bat. That did allow it to earn high marks in sand, where it was constantly rated high. It has a good balance between being bump-compliant and not too soft. One of the strange things is that the IRC \"heats up\" on longer road stints; you can feel the tire become increasingly wobbly in turns. And it was the only one that chucked knobs off the carcass during extended high-speed running, but this was when riding 70-plus mph across a 10-mile-long dry lake bed. The IRC was stiff to mount but still installed easily because the rubber on the bead isn\'t so sticky. It, too, cannot be ridden flat.

Pirelli
Model: 4.00-18 MT 43, $80.95 The MT83 is the stiffest of the trials tires we tested and the only one that deviates from the standard square-only block design of the tread. The rubber is harder, and it is very easy to mount. Tractionwise, the Pirelli gives up to all the tires just a little on grip, mostly from the less-sticky rubber, but the tire is still compliant enough to flex and grab traction as only a trials tire can. It does most of the good things that the others do, such as stick where a knob would spin, help the suspension and last a long time, plus it is also the only one that you could ride for any distance on a flat tire. It is, again, just under the others a little in braking performance, and when it wears, it loses just a bit more performance than the others. But it does last a long time and is also the cheapest tire of the lot.

The Dos and Don\'ts of Trials TiresRock
Plain and simple, they flex, put down more rubber and let the tire conform to the shape needed to grip. They rock on the rocks.