tires directional and non directional

[snake123]

I have a hard time trying to figure why a asymmetrical tire marked this side out is even marked with this when it can be rotated in a non directional application.
here is one answer I received from attire maker below,

Asymmetrical Tires are those that the tread pattern on one side is different than the other side. They will always have something on the sidewall that says "THIS SIDE OUT" - or words to that effect.
The purpose of using asymmetry in a tread pattern is to allow the tire to be pretty good at 2 conflicting things. The tire to the right has large blocks, which are good for dry traction, and small blocks, which are good for wet and snow traction. Obviously, the large blocks should be on the outside.

Both asymmetrical and symmetrical tires can be cross rotated - meaning basically there are no restrictions as to what rotation pattern you CAN use.

 

[ammolab]

Marked so the Moron who mounts the tire on the rim puts "This side out" so it actually IS ON the outside when on the car.

 

[krzyss]

I am not sure who moron is here.
Asymmetric tire has inside (toward the car) and outside (the car) and has marking to this effect on sidewall.

Krzys

 

[Cardenio327]

Asymmetric tires are also different in the structural area, not just the tread design. The structure is more curved on the outside edge for better cornering and is more squarish on the inside edge for better braking. Some asymmetric tires have symmetric or nearly symmetric tread patterns.

 

[OneEyeJack]

Does this mean one should not backup at more than 25mph?

 

[bdcardinal]

Lots of ignorance in this thread. Asymmetrical tires are literally that, not symmetrical. The tread on the inside of the tire is different than the outside, both in design and sometimes in compound. They are designed to have a specific portion mounted on the outside, or that part of the sidewall facing out.

Look at a Michelin PS2 or Super Sport, those are an asymmetrical tread pattern. The original Pilot Sport was a symmetrical tread pattern.

 

[NMBurb02]

I think the root of the OP's question is based on a misunderstanding of terms:

A symmetrical tire has the same tread design on the inner half of the tread surface as it does on the outer half. The two halves are mirror images.
An asymmetrical tire's tread design is different on the inner part of the tread surface than it is on the outer part (the side labeled as needing to face out).

A directional tire means that the tire is designed to roll in only one direction and should therefore only be installed on one side of a vehicle.
A non-directional tire is designed to roll in both directions, can be mounted on either side of the vehicle initially, and can be rotated to any other wheel position.

So a tire can be symmetrical and directional, symmetrical and non-directional, asymmetrical and directional, or asymmetrical and non-directional. Or at least that is my understanding of the topic. Please correct me if I am wrong.

 

[mjoekingz28]

Thank you NMBurb02

 

[krzyss]

NMBurb02, you are correct.

Asymmetrical and directional tires have left and right models, just like shoes ;-)

Krzys

 

[Quattro Pete]

Originally Posted By: snake123
I have a hard time trying to figure why a asymmetrical tire marked this side out is even marked with this when it can be rotated in a non directional application.

It's marked like that for mounting (on the rim) purposes. Not for rotation purposes.

 

[HTSS_TR]

No, asymmetrical and directional can't be together. Asymmetrical is always non-directional.

Directional is automatically symmetrical.

Symmetrical can be either directional or non-directional.

 

[Quattro Pete]

Originally Posted By: HTSS_TR
No, asymmetrical and directional can't be together.

According to TireRack, they can be...

http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=180

There are some examples on this page:
http://www.car-tire.org/summer-tires

 

[bdcardinal]

Originally Posted By: HTSS_TR
No, asymmetrical and directional can't be together. Asymmetrical is always non-directional.

Directional is automatically symmetrical.

Symmetrical can be either directional or non-directional.


Negative. There are tires that are directional and asymmetrical. The factory Goodyears on the GT500s had specific left and right side part numbers.

 

[bdcardinal]

Originally Posted By: bdcardinal
Originally Posted By: HTSS_TR
No, asymmetrical and directional can't be together. Asymmetrical is always non-directional.

Directional is automatically symmetrical.

Symmetrical can be either directional or non-directional.


Negative. There are tires that are directional and asymmetrical. The factory Goodyears on the GT500s had specific left and right side part numbers.


Also to further complicate the GT500 tire thing, I am sure other vehicles are similar, the tires were a staggered fitment so there were 4 specific article numbers, one for each corner of the vehicle. The tires were both asymmetrical and directional.

 

[snake123]

Originally Posted By: NMBurb02
I think the root of the OP's question is based on a misunderstanding of terms:

A symmetrical tire has the same tread design on the inner half of the tread surface as it does on the outer half. The two halves are mirror images.
An asymmetrical tire's tread design is different on the inner part of the tread surface than it is on the outer part (the side labeled as needing to face out).

A directional tire means that the tire is designed to roll in only one direction and should therefore only be installed on one side of a vehicle.
A non-directional tire is designed to roll in both directions, can be mounted on either side of the vehicle initially, and can be rotated to any other wheel position.

So a tire can be symmetrical and directional, symmetrical and non-directional, asymmetrical and directional, or asymmetrical and non-directional. Or at least that is my understanding of the topic. Please correct me if I am wrong.


this is the most logical and understandable answer I have seen yet.

 

[HTSS_TR]

Originally Posted By: Quattro Pete
Originally Posted By: HTSS_TR
No, asymmetrical and directional can't be together.

According to TireRack, they can be...

http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=180

There are some examples on this page:
http://www.car-tire.org/summer-tires


Originally Posted By: bdcardinal
Originally Posted By: bdcardinal
Originally Posted By: HTSS_TR
No, asymmetrical and directional can't be together. Asymmetrical is always non-directional.

Negative. There are tires that are directional and asymmetrical. The factory Goodyears on the GT500s had specific left and right side part numbers.

Also to further complicate the GT500 tire thing, I am sure other vehicles are similar, the tires were a staggered fitment so there were 4 specific article numbers, one for each corner of the vehicle. The tires were both asymmetrical and directional.

I didn't know they exist. But it's very rare to have a tire that is directional and asymmetrical.

For the last 10 or so years, directional tires are rarer while asymmetrical are more popular.

I think there is very little advantage for directional tire, tirerack tested directional tires mounted backward on wet surface and found no significant adverse effects.

 

[Silk]

Originally Posted By: snake123
"THIS SIDE OUT" -


The ''outside'' marking is often in small letters and hard to find, but ''INSIDE'' often in huge letters and hard to miss.

 

[LubeLuke]

Originally Posted By: HTSS_TR

I didn't know they exist. But it's very rare to have a tire that is directional and asymmetrical.

For the last 10 or so years, directional tires are rarer while asymmetrical are more popular.

I think there is very little advantage for directional tire, tirerack tested directional tires mounted backward on wet surface and found no significant adverse effects.


Just because you don't know about something doesn't make it very rare.
Directional and asymmetric are used extensively in racing applications. Virtually every top gravel and snow tire is asymmetric and directional.
You will find most rally cars carry 2 driver side wheel and tires and 3 passenger side wheel and tires. 4 mounted on the vehicle and the 3rd passenger side wheel and tire in the boot as a spare.

 

[CapriRacer]

Originally Posted By: snake123
I have a hard time trying to figure why a asymmetrical tire marked this side out is even marked with this when it can be rotated in a non directional application.
here is one answer I received from attire maker below,

Asymmetrical Tires are those that the tread pattern on one side is different than the other side. They will always have something on the sidewall that says "THIS SIDE OUT" - or words to that effect.
The purpose of using asymmetry in a tread pattern is to allow the tire to be pretty good at 2 conflicting things. The tire to the right has large blocks, which are good for dry traction, and small blocks, which are good for wet and snow traction. Obviously, the large blocks should be on the outside.

Both asymmetrical and symmetrical tires can be cross rotated - meaning basically there are no restrictions as to what rotation pattern you CAN use.


First, the "tire maker" quoted is partially me. I have been in email contact with snake123 for a couple of days now, and some of that quote is from one of our email exchanges.

Second, Snake is having trouble with the difference between directional (and non-directional) and asymmetrical (and symmetrical) tires. He can't seem to understand that there is a difference. Any help you guys can give would be beneficial. Perhaps I am wording things in a way that is confusing.

And lastly, symmetry and directionality in tires are entirely different issues. While it is true that no one produces a directional, asymmetrical tire, it is possible to do so. They are NOT mutually exclusive.

(As a side note: If one were to produce such a tire, it would have to be produced in 2 versions - left and right. Why anyone would do so is a mystery, but I think the marketing departments of tire manufacturers do a lot of technically strange things.)

 

[LubeLuke]

Originally Posted By: CapriRacer
While it is true that no one produces a directional, asymmetrical tire, it is possible to do so.

(As a side note: If one were to produce such a tire, it would have to be produced in 2 versions - left and right. Why anyone would do so is a mystery, but I think the marketing departments of tire manufacturers do a lot of technically strange things.)


It has already been established that there are tires that are both directional and asymmetric. These tires have 2 part numbers, one for left and one for right. Yes I have even seen this on 'normal' road car tires. Not just race tires.
It is done to increase performance while driving forwards. Try driving with these tires on the wrong side and the difference is noticeable. I can guarantee that.

http://kumhotyre.co.uk/our-tyres/motorsport/
Look here at the tyre R800 you will see a quote "The R800 is DOT Approved and has an asymmetrical and directional tread pattern designed for intermediate and hard packed surfaces" This also applies for their R900 tire.

http://www.dmacktyres.com/pdf/en.download_motorsport_catalogue.pdf
Again we can see multiple tires that are both asymmetric and directional. These tires have left and right part numbers.