WHAT IS IT? Pirelli has revamped their Scorpion MX line with changes to the Hard 486, Mid-Hard 554, Mid-Soft 32 and Soft 410. Since the MXA wrecking crew typically races on hard-to-intermediate SoCal dirt, we wanted to try the new Mid-Hard 554.

WHAT’S IT COST? $107.00 to $127.00.

CONTACT?, (800) 747-3554, or have your dealer call Parts Unlimited or Western Powersports.

Here’s a list of things that stand out with Pirelli’s Mid-Hard 554 tires.

(1) Tire updates. On both the front and rear tires, Pirelli engineers changed the knob layout and increased the number of knobs in contact with the ground at any given time. Bridges between the center knobs and side rows were used to not only ensure knob strength and stiffness, but to maintain footprint shape under heavy lateral loads. The engineers also changed the knob-wall inclination to prevent tears, which can happen to any tire on hard surfaces.

(2) Compound. Pirelli chemists tweaked the formula for the Mid-Hards in search of a compound that would provide a good chemical adhesion to hard dirt, maintain stiffness and strength as the tire heated up, and not wear out too quickly. The Pirelli compound is a new blend of synthetic polymers, resins and heat stabilizers combined with natural rubber and silica.

(3) Trends.  As the sport switched from two-strokes to four-strokes, tire manufacturers found that they needed stiffer carcasses, less flexible sidewalls, increased knob strength and larger contact patches. In a previous test of the older-style Mid-Hard 454, we noted that we could feel the carcass and sidewall soften up right away. The new Mid-Hard 554 remained firm. In fact, we had to put about 30 minutes on the tire to get it to be more compliant. After this break-in period, the rear Mid-Hard worked well in whoops and on square-edged bumps. We never felt any unpleasant sidewall roll-over on the front, which can happen on tires with unsupported knobs, weak sidewalls or overly soft-rubber compounds.

(4) Traction.
On hardpacked dirt with loose gravel, the 554s performed very well. The front tire stayed predictable as it clawed through thin layers of loose stuff on hard ground. Leaning onto the side knobs on softer terrain, however, the front was less predictable than our control tire. Similarly, the rear tire put the power to the ground very well on harder, but still intermediate, dirt. In over-watered corners and sloppier mud, however, we always seemed to get a bit more wheelspin with the 554 than our control tire.

(5) Weight. Twelve pounds is a good weight to shoot for with a 110/90 rear tire. The old Pirelli 110/90 Mid-Hard 454 was one of the lightest tires in its class at 11.7 pounds. The new Mid-Hard 554 weighs a hefty 13.1 pounds. An extra pound can be felt on the track during acceleration and in rear-suspension performance during high shock-shaft speeds.

(6) Sizes. The available sizes and MSRPs are 80/100-21 ($107), 90/100-21 ($109), 110/85-19 ($121), 110/90-19 ($121) and 120/80-19 ($127).

Adding features and strength comes with a weight gain. Pirelli claimed that the new models were lighter than the old models. Perhaps different sizes may tell a different story, but on our scale, the 110/90 bulked up.

When the conditions were right?and the Mid-Hard is an accurate description of the kind of dirt the Pirelli likes?the Pirelli Mid-Hard 554 worked like a dream. But as with any terrain-specific sneaker, when you get out of the window, you have to make adjustments.