useless information: tyre sizes are deceptive

peasant

There's a Porsche parked in our car park ...massive wheels on that thing ...295/30/18.

Two cars down is my van with it's skinny cutting disks 195/80/14

Looking at both, I'm thinking that my tyres are actually bigger (in diameter). Sure, that can't be right ...

Checked here http://www.tyresave.co.uk/tyresize.html and yes, they are!

A full 5% or 34 mm.


now make of that what you want

MarkR

They are bigger, but your steel wheels are also far heavier. The 14 in your size refers to the outside diameter of your wheel, not your wheel plus type.

Gary ITR

Why do we not have pictures of said Porsche?

Do you mean that basically you have more rubber touching the ground at any one time?

Biro

80 profile are massive. Diameter of the tyre means nothing.
Your tyres are 80% of 195mm in profile, added to 14". The Porsche's are 30% of 295mm in profile, plus 18".
So 156mm times 2 plus 14" as opposed to 147mm times 2 plus 18".
The real crime is that they use metric and imperial measurement systems in the one line!

peasant

Onkle wrote: »

Do you mean that basically you have more rubber touching the ground at any one time?

No, definetly not. I'd say the Porsche tyres have two to three times as much contact area as mine. Mine are just taller, that's all.

Biro

Onkle wrote: »

Why do we not have pictures of said Porsche?

Do you mean that basically you have more rubber touching the ground at any one time?

I think he means that if you placed the Porsche tyre on it's side on the ground, and his tyre on top, then his tyre would actually cover the Porsche's one. Overall outside and inside diameter on his is bigger and smaller respectively than the Porsche's one. Or if you burned both tyres on a bonfire his ones would cause more pollution than the Porsche's ones!

peasant

Biro wrote: »

I Or if you burned both tyres on a bonfire his ones would cause more pollution than the Porsche's ones!

not so sure about that ...you forgot to factor in the width

maidhc

Biro wrote: »

The real crime is that they use metric and imperial measurement systems in the one line!

Wasn't there a move to metric wheels in the late 80s. I know jag fitted them at one point.

Gary ITR

peasant wrote: »

No, definetly not. I'd say the Porsche tyres have two to three times as much contact area as mine. Mine are just taller, that's all.

I was wondering that lol

<<<< in dumbass mode today

Seperate

Check the size of these...(you can make it out - top right)...

Anan1

MarkR wrote: »

They are bigger, but your steel wheels are also far heavier.

I wouldn't be so sure about that at all, the Porsche wheels are far bigger.

Owen

Anyone else think the subject line on this is a bit off? Should read "Useless information : If don't know how to read tire sizes, they could appear deceptive".

Not a dig at Peasant ... but ...