Tyre Profile

[B.S.F.]

If run at correct pressure ,should an identical used and new tyre have the same profile ? Tyres are 7.00-16 8Ply rating Recomended pressure 25lbs. I used to run the used tyre at 27 lbs. .W.

[loanrangie]

Well one is missing tread and the other isnt so of course the used tyre will lose height ?

[B.S.F.]

[QUOTE=loanrangie;1831709]Well one is missing tread and the other isnt so of course the used tyre will lose height ?[/QUOTE

I'm asking about the profile ,shape of the crown, worn more in the centre,not the diameter of the tyre. .W.

[steveG]

I wouldn't think so. Too many variables in the way the used tyre wears.

Edit: and if you used to run them above recommended pressure that would tend to wear the center of the tyre more - giving the reduction in profile you have shown.

Steve

[BreakingBad]

If run at correct pressure ,should an identical used and new tyre have the same profile ? Tyres are 7.00-16 8Ply rating Recomended pressure 25lbs. I used to run the used tyre at 27 lbs. .W.

Well one is missing tread and the other isnt so of course the used tyre will lose height ?


I'm asking about the profile ,shape of the crown, worn more in the centre,not the diameter of the tyre. .W.

I gather you mean the part that should be in contact with the road. In theory it should have the same 'profile' albeit somewhat shorter.

If a tyre is worn more in the middle it is a sign of over inflation. Having said that I would not have thought 2psi would make much difference.

[Tusker]

What's the tyre construction?

The size looks like a crossply, which run at lower pressures than radials. If the pressure's too high, the tread area crowns - blows up like a balloon - & wears in the centre.

A radial of course has reinforcing under the tread to keep it relatively flat.

But the pic looks more like a radial tread pattern, so I'm not sure what's going on.

Regards
Max P

[JDNSW]

These days most people are used to radials, where it takes fair bit of difference in pressure to make much difference to the wear pattern. With crossplies, it takes a lot less.

John

[B.S.F.]

What's the tyre construction?

The size looks like a crossply, which run at lower pressures than radials. If the pressure's too high, the tread area crowns - blows up like a balloon - & wears in the centre.

A radial of course has reinforcing under the tread to keep it relatively flat.

But the pic looks more like a radial tread pattern, so I'm not sure what's going on.

Regards
Max P

They're cross ply. .W.

[superquag]

Are we taling about the profile or the Rolling Radius?
- Worn tyres will have a lower Rolling radius, but hopefully will stay close to the original profile...

The profile is the relative proportions of sidewall height and width, such as a '50' is wider and shorter than a '70' . Also called Aspect Ratio. Bigger numbers = taller tyres, greater rolling radius and higher gearing when extreme... lower numbers = lower sidewalls...

But then there is the differant brand and their shapes... A classical illustration was the old Michelin X, and the Australian built tyres such as Uniroyal. (remember them ? Made in South Australia, also re-badged as Esso, both with a 40,000 km warranty)

- Michelins looked skinny and rounded alongside the 'wider' and flatter-treaded Uni's . - But both could be the same stamped size. Ride and handling were poles apart.

Wear may alter the apparant shape so that a brand new identical will not appear to be the same... depending on how abused -or not - the old one is...

Bottom line is, not good to mix your old one with a new on a car's axle.
Trailers are a differant matter.

Does that muddy the waters for you ? :p:p:p

[rick130]

Even within broad construction category (bias or radial) construction can vary markedly.