Tyre wear v/s Tyre graining

[Harinarayanan]

Hello all

A basic query. What is the difference between tyre wear and tyre graining in essence? As far as I understood, graining results in bits coming off tyres in the wake of over sliding of tyres and other handling issues. Is that right? How does tyre wear differ from graining?

I greatly appreciate your replies.

Thanks

[raymondu999]

I'm not a tyre person, but I'll do my best. When a tyre grains, it's like a bit of rubber gets ripped out, and this then forms a ball, but it's still attached to the tyres, and as they drive across the circuit, I believe the effect is akin to what you see when someone is scooping ice cream out of a tub. It kind of rips the rubber from the tyre.

wear, however, is more of a "natural" degradation of the tyre as it goes through constant heat cycles. I hope that made sense.

[Jersey Tom]

I believe the effect is akin to what you see when someone is scooping ice cream out of a tub. It kind of rips the rubber from the tyre.

That's really not a bad analogy.

[Lurk]

http://insideracingtechnology.com/tirebkexerpt3.htm

An article explaining tyres (and graining)

[Jersey Tom]

http://insideracingtechnology.com/tirebkexerpt3.htm

An article explaining tyres (and graining)

Except IMO, Paul incorrectly labels tread folds as "severe graining." Two entirely different things.

[Ciro Pabón]

According to one definition, tyre graining is when you overwork the tyres before heating them, or, if properly heated, you are using a soft rubber.

This (I think) creates small cracks in the tyre. The rubber is then rolled up at the edge of these cracks. For example, in a regular tyre this rolling up happens at the edges of the tread pattern.?

Graining


This happens because you steered too much without heating your tyres.

It is somehow the opposite of tyre blistering, which happens when you heat your tyres too much.

In tyre blistering the rubber melts at the interface between the ply and the rubber. Then you get the scoops mentioned (actually, they are globs of heated rubber, I think) because the tyre de-vulcanize, like this:

Blisters


The article mentioned by Lurk is not an article, it is part of this book:



This is the image provided by Paul (JerseyTom's friend) in this book, to show you how the rubber rolls when grained, also given in the link by Lurk:

A theory of graining


BTW, JerseyTom already gave several explanations (these are definitions number 2, 3 and 4). He claimed alternatively that this tyre was either having "a separate problem tied into the manufacturing of the tire" or "exceeding the tear strength of the material. Overstressing and abrading it and tearing it up. Can happen cold ("cold tearing") or hot ("graining") depending on the material properties". Now he explains it is "tread fold".

JTom says this is not graining but something else... bad manufacturing, lack of tear strength or tear fold, pick one


Anyway, if I see the tyre in the previous picture, I recommend to you to heat more your tyres before getting the car into speed, or, if they are heated, use a harder rubber (graining can happen with heated "grippy" tyres). JTom concludes you either need a new brand of tyres or a tyre with more tear strength or unfolding of the treads (just joking, J). You can pick one remedy (that is, the three provided by JTom or the other one, provided pretty much by the rest of humankind, including JerseyTom's friend, Paul ).

[raymondu999]

I believe the effect is akin to what you see when someone is scooping ice cream out of a tub. It kind of rips the rubber from the tyre.

That's really not a bad analogy.

Thanks

[ringo]

I remember the grooved F1 tyres in the tyre war days used to blister a lot. That problem seemed to disappear with the slicks.

[Jersey Tom]

Paul H.. friend might be a stretch. Distant acquaintance, sure. Likes learning and getting people's thoughts and opinions and experiences... I just don't agree with some of the specific conclusions and observations he has on tires.

That picture in Paul's book, you'll notice those separations are very smooth, almost perfectly circumfrential, and very regularly spaced. There's a reason for that.

[marcush.]

graining is in my view a combination of tracksurface and particular compounds combined with temperature .Drivers and tyre management have an influence but if it´s an issue it is an issue you can try to contain it but it´s always there.
Some compounds and tracks do not lead to graining whatever you do wrong .

[Harinarayanan]

Thanks guys. Once again, I appreciate your efforts. =D>

[Rideway]

Hi everyone

I am currently working as data engineer in a car series racing. I dont know a lot about tyres but i think we are not treating them properly. I took a couple of pics:
Cold tyres - i think that is graining, isnt it?

Hot tyres after race- might be an agressive camber setup? what are those tiny rubber bits on the left?


thanks a lot!!

[speedsense]

Hi everyone

I am currently working as data engineer in a car series racing. I dont know a lot about tyres but i think we are not treating them properly. I took a couple of pics:
Cold tyres - i think that is graining, isnt it?

IMHO This tire's grain is just slightly over abused and over worked. I would say this tire came from the end of the car that had a slight problem. And though I don't know if it's the flash, but the section to the right is "unused" and appears to have an excessive amount of camber.

Hot tyres after race- might be an agressive camber setup? what are those tiny rubber bits on the left?

This tire has excessive "pick up", most of the rubber on this tire, didn't come from your car.... You must be running high camber numbers as the inside edge is normal and the middle and outside edges have increasing amounts of pickup..IMHO

[/quote]

[Rideway]

First let me thank you a lot for your response!

IMHO This tire's grain is just slightly over abused and over worked. I would say this tire came from the end of the car that had a slight problem. And though I don't know if it's the flash, but the section to the right is "unused" and appears to have an excessive amount of camber.

What slight problem do you mean? Car balance? Brake problem? Grip? I fully agree with the excessive amount of camber, I've told them but as it was my first race, they didnt follow my advice.... But is good that you recognize those waves as graining as well.

This tire has excessive "pick up", most of the rubber on this tire, didn't come from your car.... You must be running high camber numbers as the inside edge is normal and the middle and outside edges have increasing amounts of pickup..IMHO

Again the camber excess, right. But those tiny bits on the left: do you think is also pickup? They look too tiny to me but you might be right.

Thank you very much once again

PS: just bought Paul´s book, lets see it if helps me a bit i will let you know

[marcush.]

Pick up is a fact of life..and at the end of the race -in lap -you will not push so the tyre will not be able to get rid of the pick up- i´d say.The inside is cleaner ,right? I fail to see if the inside of the tyre shows very slight pickup or it is the surface of the tyre that is ripped..maybe you give feedback if the small things can be peeled off.

the first tyre maybe is cold but shows quite a bit of deep routing and to me its a tyre that has seen it all and has seen -too much sliding-

but surely it would help to know what the tyres did (how many laps,heat cycles etc),if it´s front or rear

So maybe you ask your driver to try and be a bit more relaxed and not try harder when he feels the tyre is giving up on him. Reduce sliding the car ...if it´s not simply a out of balance issue... key is having the fronts and rears in the same temperature while having a good balance .

The second picture could also hint a little bit at a excessive toe issue more than a camber thing? But then your wear rate seems very low -when after the race the threaddept is still this much .....not enough info really yet.