The "backwards" tread patterns started 5 years ago or so. MC tire tread has a minor part with evacuating water, the contact patch and profile of the tire, inherently "part" standing water, plus a MC has about twice the contact pressure of a car tire, so it is less likely to be able to surf on it.
Here is my tongue-in-cheek explanation. Some engineer at brand X drew it backwards in his CAD program, and no one caught it until it was too late. The other manufactures then saw that the tire was getting a lot of free press, with moto journalists that were perplexed, and at the local hang out everybody was laughing at the dolt that put it on backwards, until he bet them not. Upon showing his buddies it was correctly installed, a there was a crowd looking at this brand X tire (more free Advertising). So like any good marketing department they wanted to cash into to all the buzz, so they followed suit. Maybe a stretch, but as plausible as any other theory.
It's all about the details.
I know there are reasons. But I don't need to spend my money at places I don't trust (that emergency excepted) and I don't trust shops that keep the techs hidden and inaccessible to the customer - me!
I have had a few fellas TRY to mount the tires...then hand me the mounting bar and walk away Always fun!
SABMWRA MOA Club#62's Flat Fixer/ current forum moderator
It's not the breaths you take, but the moments that take your breath away-D.Dillon/G. Strait
When I change tires for friends, and I seem to have more of them now that I have a tire changer, I tell them I will change their tires for no charge. But... if they watch it will cost $50 a wheel, and if they help it will cost $100 a wheel.
Tm Pterodactyl MT Outpost
Have you ever been in a tire plant, do you design tires?
Unless something has changed, there is no tread pattern on a tire before it is cured, and the is no attempt to keep a certain orientation. The plies are symmetrical. The tire only get a pattern when they are molded. So they do not care which way they rotate, the pattern evacuates water better in one rotation, as narrow as a MC tire is, you would need to be rolling pretty fast to notice.
It was related to the wrap of the belts, and their overlap, not the tread material. Back when radial tires started to become popular, in the 70's, there was not so many directional tires, but the tire companies recommended against changing direction of the tires. Tire rotation previously was a crisscross pattern that changed the rotation, later recommendations went to just a front to rear rotation, on the same side. Tire tread separation use to be a common problem, where you got a "bubble" in the tread surface, and maybe this lead to some research. In my experience most tires today, car or MC have directional arrows.
I don't know if it is strictly the overlap direction of carcass components or if some layer of the tire is actually directional, but I know that even tires like the Michelin S-12xc rear, which is an offroad tire with a non-directional tread pattern, come with directional arrows on the sidewall. The information from Michelin was that the carcass was directional, even though the tread wasn't. I've never seen an issue from running the S-12 backwards (I'd flip it once the lugs were rounded to get more life out of it before I bought a knobby knife) but on front street tires, I've seen some ugly wear patterns from them being installed backwards.
Early radial tire carcass would take a set where the belts were slightly twisted with use. Before they were run in there was no directional set to the tire carcass.
Reversing this set would occasionally break the bond of the cords loose from the rubber. This was due to the primitive compounds and glues used at the time.
Now the compounds, glues, and cord treatments are pretty robust. Michelin was one of the first to solve this issue. There was a LOT of reverse engineering occurring.
So, since this tire has never been run, you are perfectly safe from a carcass point of view to run it reverse. If you reverse it early in life, you are also safe, as there will be little if any direction set. Beside, Michelin has great technology if the set had occurred I would not expect to to ever delaminate.. The only possible detriments would be water evacuation, as narrow as a MC tire is and with the low USA speed limits, I would just run it.
I currently have my front mounted backwards from a brain fart and I am leaving it that way.
I wanted to take a second and give kudos to Auto Tech Unlimited. They swapped the tire around on the spot for me Monday without charging me. I told them up front it was my fault and explained what happened. They said no worries and changed it for free. So if you are in the SW Ohio area and don't have your own changer yet give these guys a shout
Additionally, I really like these Pilot Road 3s. It transformed the ride and handling. My old Bridgestones had over 6.5k and had terrible a wear pattern with alternating raised and worn lowered corners of tread block down the centerline of the tire. Probably any tire would make a huge difference actually, but anyway, my bike rides a ton better!