What is this called and what is it's part number?

[DarkGti]

not right really.. what if you get a set of 18" wheels that are lighter than the standard wheels? carnt see any strain there plus if you use 225/40/18 tires on your 18" wheels the speedo wont be out http://www.kouki.co.uk/utilities/visual-tyre-size-calculator

[mowlamb]

It's all to do with the rolling radius (whatever that is). He said you should only go 2 inches more than your standard wheels. He told me the tyre size to keep the rolling radius the same if i used 17" alloys but said it couldn't be done with 18's which I don't think is correct.

[Rhyso]

an 18 inch wheel with the correct tyre will have the same radius as a 15inch wheel to within about 0.0001mm

Why do we have different profile tyres? 

[Wazzzer]

It's all to do with the rolling radius (whatever that is). He said you should only go 2 inches more than your standard wheels. He told me the tyre size to keep the rolling radius the same if i used 17" alloys but said it couldn't be done with 18's which I don't think is correct.

so if I wanted to go 18s that's fine (as I had 16's as standard) but you couldn't as you have 15's as standard?

What a complete arse

[mowlamb]

Yup that is what he reckoned lol!

[jamie16v]

Why do we have different profile tyres? 

because the tyre wall is narrower giving less roll in the tyre thus giving better road holding but less comfort 

[Ant1981]

Why do we have different profile tyres? 

because the tyre wall is narrower giving less roll in the tyre thus giving better road holding

Not necessarily 

[Rhyso]

Why do we have different profile tyres? 

because the tyre wall is narrower giving less roll in the tyre thus giving better road holding

Not necessarily 

You missed what I meant Jamie - I was on about maintaining the same rolling radius 

[mikemk4gti]

all those annis are gonna be dead soon then

What 

[richw911]

all those annis are gonna be dead soon then

What 

Because mowlamb said "any mk4 running 18 inch wheels will die soon"