Photo: Wil Matthews

How much testing is required to adequately review a product? Even for most complete mountain bikes, a month or two is sufficient time to get fully acquainted. For others, it can take an entire riding season to achieve a fully-informed opinion of a product.

This review of Michelin’s Wild AM tires is one such ultra-long-term review–I’ve gone through four Wild AM tires between March and October. Here are my detailed thoughts on Michelin’s latest mountain bike tire offering.


Photo: Wil Matthews

I tested the 27.5″ diameter, 2.35″ wide Michelin Wild AM tire. This model weighs a claimed 760g and retails for $74.99. They are also available in a 29×2.35″ size, weighing 800g and retailing for the same price.

The tires feature what Michelin calls “Gum-X3D” technology. Basically, this is a triple rubber compound. The first, “Race Compound,” is a hard sub-layer. The outer Traction compound is softer, providing grip “without sacrificing propulsion,” according to Michelin, and is placed in the middle of the tread. Finally, the softest GRIP compound is used on the side knobs, and provides even more traction.

The casing is 60 TPI, and Michelin dubs the construction “Trail Shield Technology,” saying “the Michelin Wild AM is extra tough and durable and therefore perfect for trail and all-mountain riding.”

Out on the Trail

Michelin tire launch in Santa Barbara, CA. Photo: Wil Matthews

I began my lengthy test of the Wild AM at Michelin’s stateside launch in California. The tires showed promise, so I brought back a set with me for long-term testing.

Tire Set #1

Photo: Marcel Slootheer

I first mounted the Wild AM tires front and rear on my Mavic Crossmax XL WTS wheels, which measure 23mm wide. While this is getting to be an outdated rim width for an enduro bike like my GT Force, the Wild AM tires formed a nice, rounded profile on these rims, which led to pretty good engagement and hook up right off the bat.

Photo: Nathan Wentz

However, when running pressures in the low to mid-20s, I experienced a significant amount of tire squirm. Most notably, the front tire would collapse under hard cornering, particularly in berms. Landing drops and jumps would also cause the casing to deform, creating unpredictable landings when I needed reliability most.

While the weak casing was most evident with the front tire, I could feel the rear deform and slide around under really hard cornering in high-speed berms. So, I decided to bump up my tire pressures.

Photo: Nathan Wentz

I slowly worked my way up until I reached a tire pressure of about 28-29psi. The high pressures led to a very hard tire but at that point, I had successfully tuned out the squirm based on my weight, terrain, and aggressive riding style.

Technically the Wild AM does dip its toes into all-mountain territory, albeit on the lower profile end (despite currently being the burliest tire in Michelin’s line). The tire features relatively small knobs, but thanks to the grippy rubber I found the Wild AM to provide decent hookup, considering its lack of over-the-top burl.

But once I hit 29psi and tuned out the tire squirm, the traction I was able to achieve from the Wild AM largely evaporated. The lugs on the front tire weren’t big enough to find purchase in extremely loose, rocky, aggressive terrain. And the hardness of the tire didn’t allow it to fully grasp the ground by bringing the softest GRIP compound into play.

Consider these tires thrashed. The grippiness of the rubber provided a medium-length lifespan–not the longest-wearing tire, but not the shortest either.

About the time I was ready to finish my review, having thoroughly worn out these tires, I was washing my bike and spotted a crack in the casing of the rear tire.

The crack in the casing.

This wasn’t a tear or abrasion, but rather a fracture beginning on the outside of the casing. The inner casing was still intact and the tire was still holding air, and I even rode it another time or two with the cracked casing (without straying too far from town), but the crack was pretty disconcerting.

Hard to believe, but as I was going through my images I spotted another casing crack in this picture. The intended subject matter of this photo was the tread wear, not the crack. It appears that this crack starts higher and ends higher than the other crack pictured above. I’ve since sent these tires back to Michelin for review.

Michelin’s team had seen this issue before, so they sent me a second set of tires to test.

Tire Set #2

Photo: Alexander Bowers

By this time, mid-summer, big mountain riding season was in full swing, and I knew that a 29psi Wild AM wouldn’t suffice for the front of my bike. So, I decided to run it as a rear tire, installing a tried-and-true Maxxis Minion DHF 2.5″ WT tire up front.

At this time, I also installed Spank’s Oozy 345 wheels, with a modern 30mm internal rim width. (Stay tuned for the review.) The wider rim squared the Wild AM off a bit, but as a rear tire, it still looked passable. I would avoid running the 2.35″ Wild AM as a front tire on a 30mm internal width rim.

On the rear of the bike, the Wild AM proved its mettle. The relatively low 760g weight was a blessing while climbing and pedaling, and even at 29psi the knobs provided adequate traction and predictable drifting as a rear tire. The ride quality still suffered at that pressure, but at this point, I’d rather have a bit harsher ride and not be changing flat tires all the time. While I was tempted to drop my tire pressure due to the wider rim width, I was nervous to drop below that level, as I had recently pinch flatted a 2.6″ Maxxis Rekon set to 26psi on a test bike.

Despite a few close calls, over a month of down-and-dirty summer riding passed uneventfully, until a fateful day spent shralping the Cottonwood trail with Alexander Bowers, AKA the Singletrack Sampler.

Photo: Alexander Bowers

I have a long history of pinch flatting tires on the Cottonwood trail due to its sharp rocks and high rates of speed. Getting in front of a camera only egged me on to ride a little faster, but with roughly 28psi in my rear tire, I was feeling confident. About halfway down the trail, I rammed into the gnarliest of rocks at top speed, smacking the rim hard, and heard all of my air rush out. Despite running tubeless at high pressures on a high volume rim, I still pinch flatted the Wild AM tire.

Pinched it good

I had one tire left, so I installed a fourth Wild AM. However, I couldn’t bring myself to pump my pressures up above 29psi–the ride quality was already pretty rough, and only got worse at higher pressures. So, I opted to ride a bit more carefully.

Full disclosure: I hate riding carefully. But unless you want to haul around boat anchors for tires, sometimes you have to tread lightly to avoid flats. Sometimes I do opt to haul around boat anchors, though. The Maxxis Minion DHF 2.5″ WT with DoubleDown casing currently on the front of my bike weighs a whopping 1,170g, literally 54% heavier than the Wild AM. It feels like a boat anchor in comparison, but I have yet to flat it.

Photo: Marcel Slootheer

After deciding to (mostly) take it easy, I still proceeded to rally this rear tire. Basically, the only place I’ve truly throttled back is that same spot on Cottonwood where I flatted, opting instead for the newer bypass. In the two months since that fateful flat, the Wild AM has performed well at the 29psi pressure, proving to be a capable rear tire at a relatively low weight.

Finish Line

Photo: Marcel Slootheer

What started off as a mere tire review turned into one of the most exhaustive gear reviews I’ve ever conducted. Having thrashed four tires on a variety of terrain across the nation, on two radically different rims, while experimenting with a variety of tire pressures and tire combinations, this depth of testing is rarely possible for most products.

I’m sure this review reads as largely negative, but please don’t take it that way. After all of this testing, I found the Wild AM to perform quite well for my needs as a lightweight rear tire in aggressive big mountain terrain. 

Also, consider what issues I did not encounter: I didn’t tear a sidewall, suffer any punctures, or rip off any knobs–common issues that strike many tires. I also didn’t find any more casing cracks in the second set of test tires: they have been defect-free.

Photo: Nathan Wentz

Your mileage may also vary. If you don’t find yourself pinning down highly-technical black diamond trails in the mountains at breakneck speed, the Wild AM might be sufficiently aggressive and burly enough for your every need. You might not corner hard enough, or weigh enough, to deform the casing. Personal preferences and riding styles will play a big role in how this tire performs for you.

If you’re looking for dependable durability and consistent performance in high-consequence terrain, I’d personally recommend a tire that you know will perform the way you want it to, instead of spending an entire riding season trying to figure out the best use case for an unproven entity. But if you’re ok experimenting with a new tread as a lightweight rear tire on your trail bike, consider giving the Wild AM a spin.

Thanks to Michelin for providing the Wild AM tires for review.

# Comments

  • MTBrent

    Greg – Did you happen to take “as-installed” measurements (actual widths) on each rim?

    • Greg Heil

      That’s a really good question MTBrent. I didn’t take measurements because every brand seems to measure their tires a bit differently and as you alluded to, the tires would measure differently on different rims. But I just went out to the shop to grab at least one measurement for you.

      Mounted on the Spank 30mm internal rims, the tire measures 2.5″ from outside edge to outside edge of the outer cornering knobs. The carcass would measure narrower than that.

    • MTBrent

      Awesome, thanks. I thought they looked like pretty fat 2.35s!

      Looking forward to the Oozy 345 review, too.

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