is this correct? aren't our wheels 18" so spares should also be 18"!!!!!

 

Think before you type......it is a get you home spare that has a higher profile than your road tyres so it equates to approximately the same rolling diameter. Just about every manufacturer does this with these spares (even shitty old Ford uses a smaller diameter but higher profile spare on its sports models)

 

sorry but I am total newbie when it comes to cars so I don't even know what you mean by Higher Profile. Can someone please elaborate this for me..

Also how often do most people need to change their tyres?

 

The profile height is the width of the tyre wall ID to OD.

Its hard to say how long a tyre will last as that is governed by how the tyre is treated (pressures, spinning and so on).

Ive usually get about 40 - 50K kms but it really depends on how you drive.

As always

H

 

*****! - Even only drinks old also!

FROGGLEZ

 

Mmmmmmmmmmmmmmmmmmmmmmmm, OLD! (and Tequila!!)

As always

WORM

 

ah 17" width! now i get it.. me bit thick i though it was like diameter size (like the rim size..)

 

Hey! Don't knock Too's Old, thats good stuff, it puts hairs on your chest (not that I don't already have too many as it is).

Jim

 

Gianniz - to clarify - a 17" wheel (like on my Touring), that is the wheel diameter, has a 50 profile tyre (profile is the height of the tyre measured from the outer edge of the wheel).
The Track model has a larger diameter 18" wheel, but a lower profile 45 series tyre.
So if you measure the total diameter of wheel + tyre, the Touring and Track measure the same.
I don't know the size of the T spare, but it looks to be about a 14" steel wheel, with a large profile tyre.

PS - The specifications of the tyre are stated on the side of the tyre wall.
IE Bridgstone Potenza 225/17/50 means that the tyre has a width of 225mm, that goes on a 17" wheel and the tyre has a profile of 50 .
Hope this helps.

 

Potenza 225/17/50 means that the tyre has a width of 225mm, that goes on a 17" wheel and the tyre has a profile of 50.

Spot on, but you got the numbers the wrong way around it's WIDTH/PROFILE/RIM (ie. 225/50/17). Which, like you said would be a tyre that fits on a 17" wheel, is 225mm wide and has a 50% profile (ie. 112.5mm).

 

Thanks David - could not be bothered going to the garage to confirm.

 

height of sidewall (mm)/width of tread (mm) x 100 = profile in %

i.e 112.5mm/225mm X 100 = 50 profile

 

Thats a bit of a 'brusque' response, we all have varying knowledge....