Date: 25/11/2013 00:01:18
From: robadob
ID: 437254
Subject: tyres on cars
:)
do low profile tyres give you more performance ?
mostly thinking older car with out traction control.
:)
do low profile tyres give you more performance ?
mostly thinking older car with out traction control.
robadob said:
:)
do low profile tyres give you more performance ?
mostly thinking older car with out traction control.
To a point, yes. Normal road cars have high profile tires in order to make the ride smoother, but it makes the steering mushy.
Race tires have no interest in comfort, so use a wider tire with a lower profile which makes the steering more accurate.
Some idiots buy stupidly low profile tires that are too stiff to get much grip, so they don’t have comfort or performance.
as i thought :)
robadob said:
as i thought :)
Less sidewall on the tyre means less distortion during cornering giving sharper steering, but most purchases for on-road cars are just for show
Good Morning
Gosh where is everyone this morning?
A steamy 24 degrees and 95% r/h this morning… aaaah wet season I do so love you :)
A sad week for us and will be organising a couple of days off work to travel for a funeral this week, never a nice time :(
Enjoy Monday everyone, it’s a good day to start the week :D
Less ‘tyre roll’ sideways on the rim during cornering, but less cushioning on bumps before tyre fully compresses and ‘bottoms out’ on the rim, pneumatic tyres being an important part of suspension.
Helps lower centre of gravity of the vehicle also, so assists keeping vehicle horizontal to driving surface.
parallel to driving surface, should have said, but reduces undervehicle clearance.
Why are F1 tyres so fat comparatively? They corner pretty well.
>Why are F1 tyres so fat comparatively? They corner pretty well.
They don’t have to fit tyres into wheel arches of the body of the vehicle.
Next question will be why aren’t they more low profile tyres.
Some sideways ‘tyre roll’ or give is probably not all bad when you think about it, and with high pressures may even be beneficial, because absolute rigidity of two tyres that roughly track the same line would not help ‘equalization of grabbing’ the surface. So I suppose you could see this as sideways suspension to do with sharing of sideways grip, or shifting sideways traction one tyre to the other. Typically you’d get some flex in the tread to do this maybe, but they run no tread in dry conditions, but I know little of this type of vehicle to be honest.
give in the side wall stores energy
when pulling away if there is give in the side wall it will store some of the energy and is less likly to spin the tread on the tarmac, then will release that energy as the car moves forward.
give in the side wall also has some give on cornering having the same result.
if there is not enough give then the trye tread will slide earlier
transition said:
Helps lower centre of gravity of the vehicle also,
Overall diameter remains the same, so no.
I saw an AMG Merc at Canberra that had come down for the Summernats. Its tyres looked like a smear of rubber over 20inch rims. Never seen a tyre so low profile before. I dunno how he got down without buckling his rims.
Skunkworks said:
I saw an AMG Merc at Canberra that had come down for the Summernats. Its tyres looked like a smear of rubber over 20inch rims. Never seen a tyre so low profile before. I dunno how he got down without buckling his rims.
If you look at the sidewall markings you can see the aspect ratio which is a percentage of the tyre height to width e.g. a 200/50 tyre would be 200mm across & 100mm deep.
>Overall diameter remains the same, so no.
Well I suppose if the diameter is the same, yes you are correct :).
transition said:
>Overall diameter remains the same, so no.Well I suppose if the diameter is the same, yes you are correct :).
And that’s why you use larger rims on lower profile tyres to keep the over-all diameter the same. It is generally a legal requirement, as well as a practical one that keeps the speedo within spec.
>And that’s why you use larger rims on lower profile tyres to keep the over-all diameter the same. It is generally a legal requirement, as well as a practical one that keeps the speedo within spec.
I don’t think an overreading speedo is going to get anyone into trouble. Going higher profile to lower profile.
transition said:
>And that’s why you use larger rims on lower profile tyres to keep the over-all diameter the same. It is generally a legal requirement, as well as a practical one that keeps the speedo within spec.I don’t think an overreading speedo is going to get anyone into trouble. Going higher profile to lower profile.
The absolute tyre diameter is a legal issue, the speedo issue is just a practical one.
Though doing trip distances from your odometer may have you turning off short of your real destination, but it’s not like the shuttle calculations for a reentry orbit.
robadob said:
:)
do low profile tyres give you more performance ?
mostly thinking older car with out traction control.
They can do, though it’s usually because the lower-profile tyre is made from a better (softer) compound and so is stickier, and a slightly better carcass construction.
poikilotherm said:
Why are F1 tyres so fat comparatively? They corner pretty well.
Because the rules state that they have to use 13”: diameter wheels. It was intended to keep the brake disc diameter down to increase the braking distances to provide for more passing opportunities, but they haven’t been brake limited for quite a while now.
everyone said:
Rims.
They aren’t rims, they’re wheels.
They aren’t rims, they’re wheels. :) cool