Question for the tire guys

[Alfetta]

so my rear tire is in need of replacement. and i have found a unit that i like, but it is a "front" tire.

I know that when i had the last rear installed, the tire shop said it was the same tire that they typically put on the front of Harleys.
The Harley "front" tire has worked well enough for 5K miles at the back of my 7, so I'm not shy of slipping another "front" at the rear,

But this gets me to wondering, and that's typically a bad thing.... Is there a construction or technical difference in tires that dictates the placement, or is this all marketing, or assumed based on size ?

[Vagrant]

What bike?

[twowheeladdict]

All you have to do is look at various front/rear tire patterns to know there can be a difference in traction profile which is why there are direction arrows.  There may also be a difference in load rating. 

There are universal tires that can be run front or rear.

The double darksiders typically run a rear on the front but reverse the arrow.

On some tires there is also a difference in lean angle before you run out of tire between front and rear.

[faffi]

Typically, front tires have between 2/3 and 1/2 the thread depth of a rear tire and a lower load rating. If a tire is fitted to the opposite wheel it was designed for, it is sensible to reverse the direction because the biggest forces will be in the opposite direction (braking vs acceleration).

[Bulldog9]

so my rear tire is in need of replacement. and i have found a unit that i like, but it is a "front" tire.

I know that when i had the last rear installed, the tire shop said it was the same tire that they typically put on the front of Harleys.
The Harley "front" tire has worked well enough for 5K miles at the back of my 7, so I'm not shy of slipping another "front" at the rear,

But this gets me to wondering, and that's typically a bad thing.... Is there a construction or technical difference in tires that dictates the placement, or is this all marketing, or assumed based on size ?

I'm NOT a tire guy, or expert by any means, but because I wanted the Shinko 705's on the Stornello, I went this route. Not ideal, but it works. I think most important is to check with the manufacturer that it is suitable/possible.

The difference is traction and expected load on the tire. The forces on a rear tire are opposite to those on the front, and why if putting the correct rear tire on the front it has to be reversed, so on the front you have max traction for braking.

[Brand X]

The difference is traction and expected load on the tire. The forces on a rear tire are opposite to those on the front, and why if putting the correct rear tire on the front it has to be reversed, so on the front you have max traction for braking.

I am doing it now with a BT-46 rear going on the front.. Talk about force...The Rear tire on the front of it now is going in the wrong direction

[John A]

I’d use a tire with a square profile on the front of about any three wheeler. It will give the front less under steer, and more authority.
https://www.revzilla.com/motorcycle/metzeler-sidecar-tire
Like this, I just picked one arbitrarily, don’t know what size you need

[wirespokes]

One of the differences is in the construction of the belts. When they make a tire, the belts overlap - applying force in one direction (braking up front, acceleration on the rear) will wrap the belts tighter, the other direction wants to unwrap them. That's the reason for reversing the rotational direction if using a rear on the front, or vice versa.

[PeteS]

With bias ply tires you just reverse the arrow as mentioned above. Not sure if that works with radials though. Should be OK on older Tontis that came with bias plies.

Pete

[faffi]

One of the differences is in the construction of the belts. When they make a tire, the belts overlap - applying force in one direction (braking up front, acceleration on the rear) will wrap the belts tighter, the other direction wants to unwrap them. That's the reason for reversing the rotational direction if using a rear on the front, or vice versa.

That was something new to learn. I have only heard about the rubber joint of the thread overlapping, and since the biggest forces on the front are reverse of the rear, the overlap goes in opposite direction to prevent it from opening up. These days, several tires do not have a joint because the rubber is put on as a full circle/circumference.