Trials tires?

My partner in ThumperTalk, Steve has a friend who is an accomplished rider/racer. He may be pro (not quite sure on that). Regardless, he installed a trials tire on the rear of his KTM 400 exc RFS and says it is amazing the kind of traction he gets. Even in the mud. He swears by it for woods riders. Has anyone else tried this? Comments? I'm toying with mounting one up to see what it's like and share the results with the community.


1999 WR400, IMS Seat/Tank, Pro-Tapers, Enduro Engineering Hand Guards, FMF MegaMax II Exhaust, Panoram Computer, MSR Skid Plate, Dunlop 756 front/back, Throttle Stop Cut, Air Box Lid Removed, Forks Raised 3/4 Inch

[This message has been edited by Bryan Bosch (edited September 09, 2001).]

Bryan, I am getting ready to get new tires for my 00WR400. I was strongly leaning towards the Dunlap 756's. Are they not working for you? I do mostly woods riding but plan on doing more desert this year. On the way to work I got to thinking more about the trials tire idea. Sounds very interesting especially with winter approaching. Heck, maybe I will try it too. Thanks, P

[This message has been edited by PMAUST (edited September 09, 2001).]

[This message has been edited by PMAUST (edited September 09, 2001).]

I'm not complaining about my 756 Dunlops. I'm pleased with their performance. Especially over stock. I wouldn't think twice about buying another set. I'm just curious about trying a trials tire on the rear. My understanding is that they last a long time because the tread blocks are all the same highth. I also understand that the compounding is quite a bit more complex than an MX tire, hence the grip. Actually, the profile is much beefier as well. It might look a little stupid on the bike, however, performance over looks is what I say.


1999 WR400, IMS Seat/Tank, Pro-Tapers, Enduro Engineering Hand Guards, FMF MegaMax II Exhaust, Panoram Computer, MSR Skid Plate, Dunlop 756 front/back, Throttle Stop Cut, Air Box Lid Removed, Forks Raised 3/4 Inch

Yes, performance over looks. I guess the best way to find out is to try it. Since I need to get tires anyway i'll give it a shot. I'll wait a few days to see what kind of feed back we get on this. This sounds very interesting though. :)

I believe Michelin is what Steve's buddy is using. I'll see If I can get more specific model/size info.


1999 WR400, IMS Seat/Tank, Pro-Tapers, Enduro Engineering Hand Guards, FMF MegaMax II Exhaust, Panoram Computer, MSR Skid Plate, Dunlop 756 front/back, Throttle Stop Cut, Air Box Lid Removed, Forks Raised 3/4 Inch

Sounds like a great idea... but what's a trials tire like? I would assume a really soft compound and not much tread.


2000 WR400F - Throttle stop shortened, Grey Wire Cut, Filter Cover Removed...

It'll be interesting to see how they perform, I wished I had a set on during a wet dual-sport event up at Sequioa a couple of years ago. It was amazing to see how little traction our knobbies got on muddy rocks, rocky hills, and stream crossings. The whole day I was wishing I was on my trials bike! Since trials tires are designed to run 5-7 psi, mounted on 170 lb. motorcycles, I'd expect we would run higher pressures on our WR's. The sidewalls are very soft so that the tire can make a big footprint as it conforms to the terrain. Due to the soft sidewalls, they are a definite hazard on the street. The tire compound is so soft that you can easily twist each knob 90 degrees with your fingers. Gumbo mud (clay) will turn them into slicks, since they won't self-clean unless it's really wet. Keep us posted :)

[This message has been edited by Steve Morgan (edited September 10, 2001).]

Steve Morgan, do you think the WR would tear up the side walls during hard riding. I was kinda wondering about cornering with them? Isn't the tread pattern similar to the old universal knobbies? Is this something you would try? Thanks in advance, Paul

I was talking to sclaus the other day about trials tires. I used to own a '99 WR400F. I now own a two-stroke '01 GasGas 300XC, on which I installed a Michelin X-11 trials tire. Since I once was active as a TT member and received much valuable insight, I wanted to share my observations on the trials tire.

The GasGas XC300 weighs about 250 lbs ready to ride. I weigh about 240 lbs ready to ride. The GasGas puts out about 44 HP at the rear wheel. Most of my riding is on trails in wooded areas. Most of the soil is hard clay, dry or wet. When wet it is very greasy. There are plenty of rocks and tree roots sprinkled in as well.

I installed the Michelin X-11 trials tire early spring ’01. So far, I have over 750 miles on it and I have just noticed it starting to loose some of its grip. It has worn down about 40%, but not a single knob has ripped off or chunked, even with full throttle on rocks and gravel/rock logging roads. There are cracks at the base of the knobs where the knob meets the tire, but they are all intact. As a reference, I would normally get about 300 miles on a 756 before knobs were so well rounded, worn down and missing/chunked out that I changed it.

To make sure that I objectively evaluate rear off-road tires, I run them on a couple of nearby hills in the woods of Western Washington. In the fall, winter and spring these hills are wet and muddy, making them very challenging to climb. They are a clay base covered with greasy mud and rocks sprinkled about. I have had the best knobby tire performance out of the Dunlop 756 and Michelin S-12. With either a new 756 or S-12, I can just climb the hills as long as I maintain momentum and a good line. Often, I have just enough momentum to make it to the top of the hills.

With the Michelin X-11 rear Trials tire, it is dramatically different, I can accelerate up these hills now and even lift the front wheel. It was SOOOO amazing!!!!!!!!!!!!!!!!! (For all you skeptics it had rained quite a bit the prior day and I was riding at 7:00 AM, so it was WET and MUDDY).

I have climbed a muddy root and rock infested hill with the trials tire that I could not climb with a fresh Michelin S-12. In the snow, the trials tire hooked up well on 3 inches of wet snow on a base of slimey clay soup. Further it hooks up very well on snow covered rocks.

The key to forward progress with a trials tire in slimey or soupy mud is NOT to spin. Get it to grip by starting real easy, torquing along a gear high and steadily roll on the throttle without spinning. The bike will move forward surprisingly well. If you just nail the throttle it will spin just like anything else. A trials tire grips, where a knobby digs and throws dirt/mud.

Much easier to maintain a line, up or downhill

Outstanding rut crossing – crossing a muddy clay rut with the Trials tire was as easy as a crossing a dry clay rut with a knobby.

Much improved rear braking control especially on downhills.

Much smoother rear tire ride, especially on rocks. Less bouncing and chattering.

I have inadvertently knocked the GasGas into neutral in the middle of a swampy mud hole. I put it back in gear and got out very easily. WOW!!!!!

The tire easily clears clay mud at speeds above 10 to 15 mph as long as you are going forward at 10 to 15 mph. It clears mud much better than the Dunlop 756 on the front!!.

I have found about 8 psi works best all around. For very muddy conditions you may want to go a little lower, like 7 psi. You may wonder about rim protection – no worries. I regularly smash thorugh rocks mile after mile. The front rim with a 756 at 15 psi comes back with black rubber marks all over the edge of the rim from the severe impact of the tire on the rim. The rear rim has not a single rubber mark at all when running at 8 psi. It is amazing. I run a heavy duty tube. So far no flats, in spite of all rocks I have hit.

A few additional notes: They are DOT approved. TT designates Tube type TL designates Tubeless. Either will work, as you will need to use a tube anyway.


1) A trials tire may require some change to your riding style, as it gets its traction from gripping as opposed to the digging and throwing done by a knobby. Try not to spin as much and it will reward you very nicely.

2) On hills be careful as you may find your front end going up much easier and looping out.

3) Tighten down the rimlock(s) very securely or it will slip on the rim due to the exceptional grip and low pressure.

4) Cracks will likely appear first at the back side base of the knobs, due to braking. Cracks will also likely appear first at the front side base of the knobs, due to acceleration. Do not panic, the knobs are quite secure for offroad. On pavement, I do not have experience.

5) The tire works OK in sand as long as you do not try steep hills. It does not work well on steeper hills in deep loose material like sand or cinder.

Eric in WA

’01 GasGas 300XC


Thanks for the write-up on the performance pros&cons of running a trials tire. Bryan and I will add this article to the "Tech Tips" section of the site.

Thanks again...and I'm on my way to buy one this weekend for my '01 WR426! :)


Eric, thanks. I have decided to pass on the idea for now but may give it a go after this winter. Great info. Paul

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