Tires. Of all the parts on your bike, few play as big a role in performance and safety, and few need to be replaced as often. I like grip but I don't like to wield my Motion Pro tire irons more often than necessary, so I usually equip my bikes with sport-touring tires. They offer great performance and good longevity, and frankly, I think they're the right fit for the vast majority of on-road riding.

Bridgestone thinks ST tires are the way to go as well, which is why it's released the new T31 sport-touring tires in a staggering 22 sizes to fit pretty much any road-going streetbike this side of a cruiser. Alongside the T31s Bstone has introduced the A41 adventure-touring tires, which are (in my opinion) essentially sport-touring tires but with deeper tread grooves for a little more grip on loose terrain and made in sizes that fit the tall-yet-narrow wheels found on today's big-bore ADVs. Lucky for me, I got to roll around on both new models during a press event hosted in Morocco.

But first, a little about the rubber. The T31s replace the existing T30s, which have been demoted to a second-tier position. That means the T30s will be offered in limited sizes (120/20-17 front and 160/60-17, 180/55-17, and 190/55-17 rears) at a 10-to-15-percent price discount. As mentioned earlier the T31s will come in sizes to fit everything from a Ninja 400 to a K1600GT, and whatever you ride, the T31s are designed to offer the same key characteristics: solid sport performance and long-haul durability, now with improved performance in cold and wet conditions and a boost in feedback. Why does feedback matter? As Bridgestone North America’s Project Engineer Keith Willcome put it, “More feedback means more confidence, and that makes riding more enjoyable.”

Bridgestone T31
As is common, the T31s are essentially slick down the middle. Bridgestone added more siping to the tire’s shoulders to increase water drainage and fine-tune handling and feel.Bridgestone

To get improve tire-to-rider communication and up the ante with wet performance, Bridgestone redesigned the T31’s tread grooves to increase the block stiffness, enlarge the contact-patch size, and improve water dispersion. Compared to the T30s there are more grooves on the shoulders of the T31 and fewer sipes down the center. The T31s use a new rubber compound too, with more thoroughly distributed silica. That’s the stuff you wiggle your toes in at the beach, and it’s also what helps tires adhere to pavement when the road is cold and/or wet. According to Bridgestone, these new buns net measurably more friction and faster lap times at their test tracks, all without sacrificing the mileage that makes ST rubber so appealing in the first place.

The A41’s are a 10 percent off-road/90 percent on-road tire that will fully replace the existing A40s. Most of the same techniques and strategies that were applied to the T31s appear here, with one notable difference being the introduction of a three-compound tread design. (The T31s were already a multi-compound tire.) You can get the A41s in 16 sizes to fit most mid- to full-size ADVs, and as with the T31s the A41s emphasize grip and rider feedback in wet and cold conditions.

Bridgestone T31
Morocco has miles of this kind of well-graded dirt road.Bridgestone

Considering these new tires are optimized for frigid, rainy riding, it was odd that we went to warm, dry Morocco to test them. But hey, I am not complaining. If Morocco conjures up visions of rolling sand dunes, that’s only in the far south of the country. Everywhere else, Morocco is hilly or downright mountainous, which means loads of twisty roads. Stir in unbelievable landscapes, incredible food, and intriguing villages that time seems to have forgotten and you’ve got one heck of a grand place to ride a motorcycle.

What can I say about the T31s other than the fact that I didn’t really notice them? I don’t recall any loss of traction when I pinned the throttle rounding hairpin turns, no skidding when I hit the brakes at a stop sign I nearly missed, no weird handling behavior when bending the bike into or out of turns, and no greasy feeling when I went into race mode in the mountains. In my mind, not noticing the tires means they were doing everything right. I’d love to have ridden the T31s in the cold or wet to see how they perform in those areas Bridgestone targeted for improvement, but oh well. I’m also interested to see how they wear as the miles stack up, but that’s not something anyone is going to get to test during a two-day intro event. According to Bridgestone, a set of T31s should last between 5,000 and 10,000 miles. That’s a vague estimate, but hey, there are a lot of factors affecting tire wear.

Bridgestone T31
This is the road—and the bike—that netted me some power slides on the A41s. I don’t blame any tire for succumbing to full throttle in second gear on a 1,301cc V-twin!Bridgestone

I've got a little more to say about the A41s. These tires have a tough row to hoe considering most modern ADV bikes roll on relatively narrow tires yet pack stupendous power. My overall impression is that the A41s give the same neutral handling and surefooted feeling (on pavement) as the A30s, but I was able to get the adventure tires to spin and slide. Granted, they did it while I was riding the absurdly powerful KTM 1290 Super Adventure S, which channels its 85 pound-feet of torque through a relatively skinny 170-series rear tire. Can't really blame any tire of that size for succumbing to such force!

Bridgestone T31
The A41s have deep tread grooves and a quasi-aggressive pattern that’s a good match for today’s big-bore ADVs.Bridgestone

We did ride a few dozen kilometers of well-graded dirt roads on the A41s, and they worked as well as could be expected for a street-oriented tire. I got dusty on an Africa Twin and an R1200GS-A, both of which felt flighty and loose on the dry, dusty road. For the average ADVer looking to explore the occasional fire road or haul kit to a campsite, the A41s will do fine. Then again, so would the T31s! The point here is that these tires are the right size for today’s adventure bikes and have the kind of aggressive tread pattern that looks good on a burly big wheeler.

Looking to lever some new tires onto your ride? If the T31s or A41s interest you, head over to bridgestone.com for more info. And if you're still not convinced sport-touring rubber is the right fit for you, give our Streetbike Tire Categories Explained video a watch to learn what each of the five major tire groups are designed for.