Mr. Spadoni 

The Neighbor, the one who is driven to undertake all tasks to perfection, wanted to put new tires on bikes that will be used by family members. One of the bikes is a Trek ATB. After weeks of picking my brain on what tires to buy, where to buy them, and other details, he calls me last night to ask I how he should mount the tires on the Trek so that he can get them asynchronous. Now keep in mind that he got road style tires and this bike will never see more than five feet of dirt in a row.
I had to admit that I had never heard of asynchronous mounting, but he pressed on about how he should perform this task.
Curious, I did some googling on the subject and found nothing on the subject, at least as far as bicycles are concerned.
So, is asynchronous orientation of tires actually a thing or was the guy at the bike shop pulling The Neighbor’s figurative chain?

Narhay

Directional tires should be aligned so. If not, I put the label on the drive side aligned with the valve stem.

I dont know what this asynchronous idea is.

Bianchi84

Maybe it means mounting a directional tire backwards on the rear in the belief it will give more traction. I remember people mounting mounting Farmer John's with the chevron pattern in the "wrong" direction back in the day for that reason.

dweenk

On Tuesdays, Thursdays, and Saturdays I would turn my bib overalls around. I only needed to wash them once a week.

AeroGut

Since "asynchronous" refers to time, I interpret it as a reference to whether you replace both tires at the same time or one at a time. Some people opt for putting a new tire on the front and moving the used front to the rear when the rear wears out. That would be the asynchoronous approach perhaps? But that doesn't seem to apply at all to a switch from knobbies to street tires, where you'd obviously want to put both new ones on at the same time.

nlerner

Tell him to put the damn tires on and ride the damn bike.

natterberry 

Why not ask him to explain what he means?

randyjawa 

And turned inside out cuts the wash time in half!-)

T-Mar

+1. I think he's talking about the rotation direction of the tread pattern. In the early 1990s it became popular to mount lugged ATB tyres with tread patterns facing opposite directions on the front and back (i.e. not synchronized with each other). The claim was one direction offered more directional stability while the other offered better traction. Manufacturers saw an opportunity and started including directional arrows for front and back mounting and then started offering matched pair tyres with different lug patterns on the front and back. The importance of this is relative to the hardness of the surface, with it being more important of softer, looser surfaces.

Directional mounting mounting of road tyres is not as critical, especially on dry surfaces. However, I always observe directional mounting arrows, if present, as it can make a difference for water dispersal in wet conditions. I don't believe that I've ever seen a road tyre with different directional arrows for front versus back mounting.

Mr. Spadoni 

Yes, he was talking about the direction of the tread pattern.
But what I was looking for was some sage advice for when he asks me about this again, which he will. I have found it...” Just Ride The Damn Bike...”

zukahn1 

I would say go with manufactures markings arrows pointed forward and label above the valve stem on drive side. Most quality new tires actually marked how to mount the tires. As for a semetrical or none synced mounting this is really only for certain tread pattern 90's MTB tires aas said and not really relivant to modern road tires.

Salamandrine 

If you have 36 rows of knobs on your front wheel and 37 rows of knobs on your back wheel, your tires are asynchronous. This will cause an interference beat frequency that can lead to a sympathetic oscillation in your top tube. If this happens you can experience extreme shimmy and a very dangerous scenario...

Seriously now, there is no benefit to mounting the rear tire backwards on a road bike. IMO if you're going to use a fancy word, best to know what it means. ( I refer to the OP's neighbor, not the OP)

Frankly, I doubt that the direction makes any significant difference with road tires at all. However, I give the design engineers the benefit of the doubt, and I assume that there is at least some tiny benefit to installing tires the way the arrows point, so I do.

noobinsf 

This sounds like your neighbor politely listened to someone's opinion about how to improve tire performance and doesn't have the necessary background to distinguish a unique opinion from an accepted practice. Here's hoping nobody talks to him about chain lube.

old's'cool

Or filling your tires (tyres) with CO2/Nitrogen

nomadmax 

Directional motorcycle and car tires are that way for a reason; tread splice. The tire carcass is layered so the primary forces (either braking or acceleration) don't separate it. That's a big deal.

I can't say that I know if bike tire carcasses have a tread splice.
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Salamandrine 

That's actually a fair point. Maybe I should not be so glib about it. However, in the many decades during which bicycle tires did not have indicated directions, I've never heard or seen of this type of failure. I have seen treads come off the carcass in one piece.

Yes, bicycle tires do have a spliced tread, but it's spliced before vulcanization and molding. Maybe some older traditional construction techniques are different. I remember watching people make tubulars by hand when I was a kid, but I don't remember what the treads looked like before they went on.

Lascauxcaveman 

I fill mine with Oxy/Acetylene. That way if I pinch-flat hard enough to make a spark, I go out with a bang.

RobbieTunes

I thought this was about orbits.

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