DUNLOP GEOMAX AT81 FRONT AND AT81 EX REAR
By Chad de Alva
Dunlop’s Geomax AT81 Frontand Geomax AT81 EX Rear tires are staple offerings in the world of off-road motorcycle tires. They’ve been on the market for several years now, yet they are still a great option for riders who are looking for well-rounded performance out of a front tire, and all of the traction out of a rear tire. After running so many different tires from other manufacturers, it’s always enjoyable to revisit a known tire combination that you haven’t used in a while. Like catching up with an old friend where you just pick up where you left off, it’s been great to get back out on the AT81F and AT81EX for many of the different types of riding that fall under the all-encompassing term of “off-road.”
The AT81F and AT81EX are part of the larger Geomax AT81 family which includes multiple compounds, ply construction, and sizes. The AT81 front is available in either 80/100-21 or a 90/90-21 sizing. The rear is available in three flavors: AT81, AT81 RC, and the AT81 EX. RC stands for Reinforced Construction, and AT81’s bearing the RC moniker have four Nylon plies as opposed to the normal two. AT81 and AT81RC rear tires are available in 110/90-18, 110/100-18, and 120/90-18 sizing. The EX in AT81 EX stands for Enduro Cross, and this rear tire is available in one size: 110/100-18. The AT81 EX uses the same compound as Dunlop’s D803GP trials tire, which is what makes this tire have so much grip.
When a tire has the word Endurocross affiliated with its name, using the tire in certain conditions is required. Since riding outside is always better than riding in a stadium, we made the quick trip up to Page, AZ, for the Grinding Stone Hard Enduro to get reacquainted with the AT81s. If you’ve never seen anything from this incredibly spectator friendly race – you’re missing out on some truly impressive and scenic riding, so go consult the internet. Grinding Stone takes place on slickrock mesas and in deep sand, and the course is full of insanely intimidating climbs and descents. Slickrock is like 80 Grit sandpaper, so there’s insane traction until sand is sprinkled on top of the slickrock, at which point its name makes much more sense. In the deep sand that became progressively more dry as the race weekend went on, the AT81s had no problem holding a line while pointing and shooting down whooped out sand tracks, or digging in to climb the steep slip faces of Sand dunes.
Riding on slickrock is where the AT81 EX started to show what it’s really capable of, and to be perfectly clear, the limiting factor was 100% what the rider was willing to attempt, and not the tire. The grip provided by the trials compound is most impressive, but the downside is that when used aggressively the tire will wear quickly. That being said, the AT81 EX inspires you to tempt fate in places like Page, AZ, so discipline is required in order to not gain firsthand knowledge of why the race is called Grinding Stone – Gravity has this nasty habit of making sure that what doesn’t make it up a climb comes grinding down on 80 grit slickrock. Walking away in one piece from our trip to Page, our next move was to get out for some proper dual sport / and exploration riding. On hard packed, decomposed granite roads and trails in Central Arizona, the AT81F provided consistent, communicative performance. The tire lets you know that it’s starting to slide instead of just tucking out from under you. The AT81 EX continued to provide all the traction, and on hard packed surfaces under hard acceleration or breaking, you could feel the blocks squirming around a little bit. When you exceed the traction of the EX in a power slide, the tire steps out and comes back in quite well, but doing this isn’t conducive to getting the most mileage out of this tire.
On our local singletrack which is currently in the hero dirt/muddy/extra rocky from all of the spring run-off stage of life, the AT 81 EX works great. Its combination of a trials tire compound with proper off-road proportions (not trials tire proportions) means that the AT 81 EX can party on singletrack like the best off-road or MX tires, yet it also provides top shelf levels of grip. The AT 81 EX is an awesome technical single track/enduro tire. The AT 81F on the other hand works decently, but it definitely does not provide the same levels of grip as gummy compound tires from other manufacturers. This was most noticeable when riding in the big rocks where I had to pick different lines, as my go-to move of sticking to the sides of some of the larger rocks in a few sections wasn’t working. Here is hoping that Dunlop comes up with a gummy front – based on what the AT 81 EX can do, I expect great things.
Dunlop’s Geomax AT 81 EX is a great tire for off-road riders who want a tire that provides top shelf grip across a wide range of surfaces and riding disciplines. We ran the AT81 EX (and AT81F) with standard tubes, but additional traction could certainly be found with a Tubliss setup, and flat-proof performance found with a mousse system. The AT81 EX’s impressive grip does come with a trade off however, and that is a short life span. On the other side of that coin is the AT81 Front tire, which provides consistent performance and respectable grip across a wide range of surfaces, but it trades top shelf grip for a longer life span. Going two or more AT81 EX tires to one AT81F tire would certainly be possible. I’ve enjoyed my time on the Dunlop AT81F and AT81 EX tires. They’ve never let me down or done anything to scare me, and I’ve really appreciated how much grip the AT81 EX is able to find across so many different riding surfaces. Tires are a personal preference, and if you haven’t sampled Dunlop’s AT81, it’s worth a go. For more information on Dunlop Motorcycle Tires, visit www.dunlopmotorcycletires.com