Best/Worst OEM Wheels
Discussion
2172cc said:
Yes....but in 1990 when they came out, they were awesome. My friends mum had the 1.4S, hot hatch for it's day, then when the RS Turbo came out it was just jaw-dropping and so futuristic (although never a match for the 5GT Turbo in my eyes)Tigger2050 said:
roverspeed said:
Have I missed something?
Is someone suggesting that changing the width of a tyre doesn't change its total contact patch?
It's not a suggestion, it is an absolute physical fact.Is someone suggesting that changing the width of a tyre doesn't change its total contact patch?
I used this tyre calculator to work it out:
http://paws.kettering.edu/~amazzei/tire_calculator...
The static radius is 326 vs 314.
Contact patch is 158.9cm sq for the 155 vs 230.37cm sq for the 245?
Ares said:
2172cc said:
Yes....but in 1990 when they came out, they were awesome. My friends mum had the 1.4S, hot hatch for it's day, then when the RS Turbo came out it was just jaw-dropping and so futuristic (although never a match for the 5GT Turbo in my eyes)roverspeed said:
So the 155/70R19 wheels that come on a BMW i3 has the same contact patch as the 245/45R18 tyres on my car?
I used this tyre calculator to work it out:
http://paws.kettering.edu/~amazzei/tire_calculator...
The static radius is 326 vs 314.
Contact patch is 158.9cm sq for the 155 vs 230.37cm sq for the 245?
I don't know what parameters he has used to program this so called 'calculator' but if they produce a significantly different figure for a similarly constructed tyre then they are obvious b....cks.I used this tyre calculator to work it out:
http://paws.kettering.edu/~amazzei/tire_calculator...
The static radius is 326 vs 314.
Contact patch is 158.9cm sq for the 155 vs 230.37cm sq for the 245?
Increasing the width of a tyre does not increase the area of the contact patch, just its shape, this is established physics.
However, on a smooth surface the wider lower profile wheel will have more ultimate grip. This won't hold if the wheel is heavier and the surface is ridged or bumpy as it will be in contact with road surface less than a lighter wheel.
Edited by Tigger2050 on Tuesday 19th March 21:16
Tigger2050 said:
Increasing the width of a tyre does not increase the area of the contact patch, just its shape, this is established physics.
As I said, whilst this is technically true, wider tyres will allow in practice for a larger contact patch, because they can be run with lower pressures without getting silly deformation. To get the same contact patch from a 155 tyre as from a 255 tyre, you're going to need somewhere north of 60% more deformation, which isn't good for many reasonsTigger2050 said:
roverspeed said:
So the 155/70R19 wheels that come on a BMW i3 has the same contact patch as the 245/45R18 tyres on my car?
I used this tyre calculator to work it out:
http://paws.kettering.edu/~amazzei/tire_calculator...
The static radius is 326 vs 314.
Contact patch is 158.9cm sq for the 155 vs 230.37cm sq for the 245?
I don't know what parameters he has used to program this so called 'calculator' but if they produce a significantly different figure for a similarly constructed tyre then they are obvious b....cks.I used this tyre calculator to work it out:
http://paws.kettering.edu/~amazzei/tire_calculator...
The static radius is 326 vs 314.
Contact patch is 158.9cm sq for the 155 vs 230.37cm sq for the 245?
Increasing the width of a tyre does not increase the area of the contact patch, just its shape, this is established physics.
However, on a smooth surface the wider lower profile wheel will have more ultimate grip. This won't hold if the wheel is heavier and the surface is ridged or bumpy as it will be in contact with road surface less than a lighter wheel.
Edited by Tigger2050 on Tuesday 19th March 21:16
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