MXA TEAM TESTED: DUNLOP GEOMAX MX71 HARDPACK FRONT TIRE

December 6, 2011
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WHAT IS IT?
The MX71 is Dunlop’s new hard terrain tire, and the final model in Dunlop’s new Geomax line (which includes the MX31, MX51 and MX71).
       
WHAT’S IT COST?
$95.76 to $98.15 (mini sizes start at $45.00).
       
CONTACT?
www.dunlopmotorcyle.com or your local dealer.
        
WHAT STANDS OUT?
Here’s a list of things that stand out with Dunlop’s Geomax MX71 front tire.

(1) Target. The MX71 is designed to take the place of the D745. Dunlop felt the D745 could have worked a little better on pure hardpack and in blue-groove conditions, so with the MX71, Dunlop set out to make some changes. Dunlop tested the tires with many top pros through the ’08 and ?09 Supercross seasons and used them a lot in the 2010 Supercross series; but since Dunlop has a virtual monopoly on AMA Pro racing, the fact that pros use them can be discounted.

(2) Tread pattern.
The MX71 has all the important hardpack design features that the D745 lacked. The MX71 has a bigger land/sea ratio (more knobs on the ground than gaps between them) and beefed up shoulder knobs for better traction when leaning over. You can also see that the MX71’s center knobs are interconnected and braced. The bracing cuts down on knob wiggle on hardpack. The interconnected knobs help fight off the dreaded knob roll-over, which can be scary. The center row of knobs has varied spacing. Finally, the recessed area on top of the knobs provides more biting edges (and is a telltale hardpack feature).

(3) Construction. Dunlop used a stiffer carcass to allow for lower tire pressures and went with a wider footprint. These elements are more beneficial for a hard terrain tire than a soft one.

(4) Testing.
The Dunlop MX71 front worked very well from blue groove to shallow loam. The MXA test riders reported predictable transitions onto the side knobs and good traction until the dirt got softer or deeper. In dirt that bordered on full intermediate conditions, the front tire tended to float. We wouldn’t use this tire as a Dunlop D756 replacement unless the track was at least 30-percent hardpack. If the track had less than 30-percent hardpack, we would opt for the Dunlop MX31 soft terrain tire. Under no circumstances would we voluntarily choose to run the MX51 front tire.

(5) 80 vs. 90. In addition to testing the MX71 against a control front tire, we tested the 80/100-21 against the 90/100-21 front. Most MXA test riders don’t like the wide 90 front tire. The larger contact patch tends to offer a little more grip on rock-hard dirt, but it doesn’t like watered tracks, deep ruts, loose dirt on top of hard dirt or loam. The 90 floats rather than digging in. It also creates a much heavier steering feel. Given our choice, we would almost always run the 80 version of the MX71.

(6) Options. The MX71 front is available in 80/100-21 and 90/100-21 for full-size bikes and 70/100-17 and 70/100-19 for minis. Naturally, a MX71 rear is also available. It has a borrowed-from-Bridgestone “double wave tornado tread pattern” and is both directional and asymmetric.
       
WHAT’S THE SQUAWK?
Tire selection is always a compromise, and there were a few compromises with the MX71. Taking full advantage of a hard terrain tire like the MX71 is difficult. Even hardpack tracks are usually ripped and watered at the beginning of the day, so a switch between motos is often ideal. Also, the tire is directional, so if you are in the habit of flipping tires to get a little more use out of them, think again.
    

The Dunlop MX71 front tire worked well on hardpack and is better than the D745 it replaces. It worked well in light loam, but struggled to paddle through anything loose. For prepped tracks, we usually prefer the MX31, but the MX71 does what it was designed to do.

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