Rennie Scaysbrook | April 13, 2018
Everyday Adventure
Own an adventure bike but do stuff other than hard-core off-roading? Then, listen up: Bridgestone has a tire that might be perfect for you.
It’s one of the big problems facing the modern adventure rider: what’s the best rubber that lasts a long time and performs well on the street, with enough dirt prowess to get you to most of the places off the beaten track that you bought the bike for in the first place?
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Photography by Bridgestone
Bridgestone’s Battlax Adventure A40 has been a leader in this area of quasi-adventure since the first 110/80R19 front and 150/70R15 sizes were launched back in 2015, noted for excellent wet-weather grip and long-lasting mileage from bikes that spend a large part of their time on tar getting to the dirt. The problem with the A40 was there were only four sizes in the rear tire, meaning a large portion of the market missed out. Now, there are 16 sizes in total, so every adventure bike, from a BMW G 310 GS to a KTM 1290 Super Adventure, will be able to get some Bridgestone adventure love. And if you’re a lucky ducky buying a new Honda Africa Twin, BMW F 750 or F 850 GS, or BMW R 1200 GS or GSA, you’ll get these A41s as standard fitment.
Here’s the chart, does your tire fit in here?
For the new Battlax Adventure A41, it was more a case of improving the breed, rather than reinventing the wheel, so Bridgestone’s focus was to further improve wet-weather grip, increase mileage, gain better high-speed stability and increase the rider feel via a new tread design and compound construction.
These kinds of dirt roads are about the maximum you’ll want to push at A41—and it will perform brilliantly when you do.
Tire Time
Bridgestone classifies the A41 as a 90:10 for more road-focused riding but still with the ability to traverse most of the dirt roads you’ll encounter on your next adventure.
The biggest visual difference between the A40 and the A41 is the vastly different tread pattern, with the A41 sporting a much more aggressive design. The aim here was to disperse more water via an increased sea/land ratio in the shoulder, while spacing out the grooves in the center of the tire and allowing for the use of the dual-compound front for longer mileage, which is a first for any Bridgestone adventure tire.
The rear compound here shows the three compound Cap and Base design. The harder center compound (yellow) forms the foundation for the softer sides to be layered over the top, increasing carcass stability and stiffness when cornering.
“For Bridgestone, this Adventure A41 was a complicated development,” said Fabian Francois, Field and Product Planning Engineering for Bridgestone Motorcycle tires. “What is difficult in this segment is, most of the time, the maxi trail bikes the have fully loaded luggage and a high front end, with 19- or 21-inch wheels, and this makes it quite complex in terms of tire setup.”
One of the biggest development goals with the new Adventure A41 tire was to increase the high-speed stability, an area the old tire was not exactly lacking but needed a little boost.
The A41 was a good companion for the big GS, offering excellent braking and high-speed stability on Ouarzazate’s albeit excellent (when tarred) roads.
“High-speed stability is absolutely crucial in the adventure/on-road segment,” says Francois. “We have achieved a better result in the A41 compared to the A40 by changing the tire tread pattern and the block design between the treads. This happens by the changes in the pattern but also by the block rigidity. The block design between the grooves is really important for this tire.”
Notice the increased sipes on the tire’s sidewall for better water dispersion.
The Adventure A41 is constructed using Bridgestone’s MSB (Monospiral Belt Construction), with a stiffer case construction to aid in the high-speed stability desired by the engineers. The rear compound (and most of the fronts, save for 21-inch tires, for example) uses a Cap and Base design. That allows for the harder center compound to be run underneath the softer side compounds, thus giving the carcass extra stiffness, more rigidity and better stability when braking and cornering. This allows the softer compound to flex, bend and grip to the road and trail conditions, resulting in a five-percent-larger contact patch.
Here you can see Bridgestone’s Monospiral Belt Construction (in blue) for the A41.
Wet-weather performance was also improved, with Bridgestone claiming an eight-percent-faster lap time around their wet testing facility in Rome, Italy. Unfortunately for us, this was an area we simply couldn’t test in the arid, near-Martian landscape of Morocco, the one of the most northern points of Africa.
Quick Tests in Paradise
Not often in any westerner’s life do they get the opportunity to ride the motorcycle in Morocco, so we jumped at the chance to put the new A41s through their paces in a land seemingly built for them.
Water testing was sadly off the agenda, as was any form of long-distance testing, but we did get a good 180 miles in with about 70 miles of pothole-riddled dirt roads where the new A41s made a good initial impression.
Here’s the video:
Bridgestone Battlax T31 and A41 Tire Review
My rides for the day were the two big dogs in the KTM 1290 Super Adventure R and BMW R 1200 GS, right up there in terms of vehicle weight. We left the small city of Ouarzazate in central Morocco and within five miles, hit the dirt. Remembering this is a 90:10 road-focused tire, the front-end grip was predictable and good for medium-speed cruising, however, if you really tried to push it off-road, the grip would give way pretty quickly.
Where the A41 shined off-road was when it gave a surprising amount of braking grip and importantly, feel, for a tire that had zero knobbies. The road was a graded dirt pass, so nothing too gnarly in terms of off-roading, yet still, the grip and feel at the bar was very good.
Direction changes were likewise smooth and predictable, and it served as a good omen that no one in our group had a front-end crash despite a wide range of riding abilities and bike sizes.
Rear traction was very good off-road but it was on the tar where the grip and stability was obviously at its best, and I could get seriously aggressive with the throttle on the big KTM with all the rider aids turned off and the rear tire would still hook up and lurch me forward. It’s here the designation as a more street-focused tire begins to shine through, as high-speed stability was excellent for when we decided to wind the bikes out and test the outer limits of the Moroccan speed zones.
Just like on the dirt, front-braking stability was excellent on the tar—although this time it was extra impressive given how hard I would slam on the front-brake lever on the GS when leaned over.
As a quick spin of one day, the Bridgestone Battlax Adventure A41s measured up very well, although we have one omission from the test, and that is wet-weather performance and longevity. If they perform as good in the wet as they do in the dry, Bridgestone will have a winner on its hands. CN
Have tire, will ride: If Bridgestone’s A41 retains the longevity of the A40, there will be plenty of miles in your near future.
