THE ULTIMATE TRAIL TIRE - Pirelli MT43 and IRC TR11 or Shinko 255 Trials Tires

There is a buzz about how great Trials tires work. They have about 5 times the contact patch compared to knobbies and form to rocks, roots to stick like glue. The Pirelli MT43 Trials tire offers the best of both worlds. Constructed with a stiffer sidewall than any other Trials Tire the Pirelli handles pavement riding at 8 psi, but still works phenomenally well on trails including gnarly technical trails also at 8psi. No more stopping to change pressure. Since pressure gauges are not very accurate at these low pressures the best way to ensure you have the correct pressure is to push with your thumb in the center of the tire and it should give a bit. The tire will not work well unless the pressure is low enough to deform. The Pirelli is also DOT approved so you can use it on the street!
The Pirelli was ridden sitting down at 8 psi on a softly sprung KTM 450EXC with a 180-pound rider through sharp edged
rocks with no flats or rim hits. Whoops are no problem although airing up to 12 or more psi would be recommended for extended whoop riding, consistent higher speeds, heavier bikes, heavier riders or stiffly sprung bikes. Keep in mind Trials Tires have taller sidewalls than a knobby so they can be run at lower than Knobby pressures and requires a lower pressure for maximum performance.
The MT43 shows minimal wear after 600 miles of hard riding. You can still see sip marks on some tire blocks. The longer tire life is probably due to the greater contact patch even though the grippy rubber is softer than a knobby. This bike, rider, tire combination ran 2500 miles before needing tire replacement. You may not get 2500 miles out the Pirelli, but you can expect to get at least twice the mileage from the MT43 than you get from a motocross knobby. The mileage you get out of the MT43 tire will depend on how heavy handed you are with the throttle. In dry riding conditions Trials Tires can be used until all the knobs fall off because they rely on surface areas not the edges of knobs.
Knobby spinners will find the MT43 wants to stay hooked up far better, providing more predictable lines with less effort. However spinning the MT43 is counterproductive since it will reduce traction and increase riding effort while reducing tire life.
Being a very poor hill climber I was really surprising when my MT43 shod bike repeatedly out
climbed an excellent hill climbing rider on new knobbies. The MT43 works well in the wet or dry, roots or rocks, hills or
If you want the Ultimate in Trail Traction then the IRC TR11 or Shinko 255 are an even better choice. The IRC and Shinko tires are much softer than the MT43 and is meant for trail riding not pavement. It should only be used with a Pinch Protection device like TubeLiss or TubeSaddle (more on this later) and would need to be aired up if ridden on the street and it is not DOT approved, but at 6-8 psi WOW does it hook up. It also lasts quite well when used on trail getting about 1500-2000 miles.
Trails tires will not create whoops or braking bumps. With more riders riding fewer trails, stopping the trails from getting worn out rates a ten for me. The bike easily goes over rock ledges with dirt below, most knobby tread riders would dig a hole. The MT43 or TR11  or Shinko hook up on step up roots and rocks that leave knobbies spinning and smoking. Trails tires have incredible traction all the time unlike knobbies that are often described as clawing for traction or searching for traction. Who wouldn’t rather have traction than be searching for it?
Trials tires have a taller sidewall to allow for compression over obstacles. The lower pressures will provide a softer ride that is less fatiguing. Depending tire pressure the taller sidewall may increase your overall gearing slightly.
Running a normal tube or the Michelin tube works fine. Slime is a good idea. There is no need to run heavy tubes or wrap the tube with another tube as this would increase the stiffness of the tire reducing flexibility and performance, as well as increasing unsprung weight.
However the best setup is to use a Tubeliss Kit, which replaces your tube with a special internal carcass and makes it virtually impossible to pinch flat while reducing unsprung weight and providing 360-degree rimlock. With the Tuebliss kit you can run lower pressures for increased performance. I now run 6 psi with the Pirrelli MT43 for ultimate traction and can still drive 60mph on the pavement or air up for whoops.
A less expensive option is the TubeSaddle which places a piece of foam between the tube and rim. When using these pinch flat protection systems you can run lower pressure to get maximum performance from these tires. In snow or mud you can air down to 3 psi providing traction unlike any other.
The Pirelli MT43 and IRC TR11 and Shinko 255 are truly outstanding tires making it easier for you to ride sections of trail that were difficult on knobbies. Both are easy on the trail and lasts twice as long as a knobby. At a price of less than $125 each they are a real tire bargain too. Try one out and see for yourself.
~Chris Horgan
Here is a short video showing how to properly air down for The Most Overlooked Performance Gain