Wheels and Tyres. Clarification needed please?

Le_Petit_Lapin · 30 Jul 2007 at 16:37

Right, wheels and tyres, they confuse me. I've been sitting in work being highly productive over the last 1/2 hour by looking at alloys online....then looking at tyres.

The tyres on my car are 165/65/14 (I think), the 165 is the width in mm...the 65 is a percentage of the width, and tells you the height of the sidewall (107mm)....and the 14 is the radius/diameter of rim that the tyre is designed to fit on....am I right so far?

Right.....so what is the offset? someone was saying that if that is wrong it results in "scrubbing"...what does that mean?

Another thing thats been bothering me...say (for example) I wanted to get a rim on my car that was ....I dunno.....17" or so, but at the same time I wanted to get a tyre with a narrow sidewall (you'd buy something like a XXX/40/17, yes? how would you know if that wheel and tyre combination would fit on your car before you purchase it?

Also....for that look that Penski advocates, stretched tyres, I assume you just buy a tyre that is too small for the rim?

Sorry its a bit of a rambly post, but its been bothering me. Be glad if you could clear it up a bit.

avrc · 30 Jul 2007 at 16:41

Can't answer the above, but be aware if you are fitting non factory standard alloys (wheels that were not fitted to your car in the factory), that you need to inform your insurance company and the premium may increase.

Some insurance companies won't even allow that kind of change.

michael baxter · 30 Jul 2007 at 16:46

Offset is the distance between the mating face of the wheel and the centre of the wheel.

Scrubbing is where the tyre touches the inner or outer wing, which can occur when a car is lowered and/or with alternative wheels/tyres.

Until you fit a new wheel tyre combo', you can only guess if scrubbing will occur.

Muban · 30 Jul 2007 at 16:58

What car do you have? If you do a google you should be able to find the offset.

Liverpool-Lad · 30 Jul 2007 at 16:58

Is this for the Corsa? Offset ET45-49 is the best best. Find some Vauxhall 15s and stick 195/50/15s on them, mega cheap.

Le_Petit_Lapin · 30 Jul 2007 at 17:06

Liverpool-Lad said:
Is this for the Corsa? Offset ET45-49 is the best best. Find some Vauxhall 15s and stick 195/50/15s on them, mega cheap.

Oh, I'm not actually going to change them, I'm just curious as to how people figure out what works....basically it seems to me that its a "try it and see" process unless you know of someone else having made the same fittment before.

Does each rim have a specific offset?

Firegod · 30 Jul 2007 at 17:39

Have a read here mate, very useful site.

http://www.carbibles.com/tyre_bible.html

Bear · 30 Jul 2007 at 17:39

You can buy most rims at many different offsets. The lower the offset the more the wheel will stick out further from the car. The higher the offset the further inset the wheels will be on the car.

If you choose too low an offset, the wheels will foul on the edge of the arches when going over bumps unless you get the arches rolled or flair them. Too high an offset, then the wheels will start to foul on the suspension struts or what ever you have and you'll have to use spacers.

If you go to certain shops then they will trial fit a wheel on for you to see if they foul on anything, else its following a well trodden path by going by what the owners club members have used

Jonny ///M · 30 Jul 2007 at 18:32

avrc said:
Can't answer the above, but be aware if you are fitting non factory standard alloys (wheels that were not fitted to your car in the factory), that you need to inform your insurance company and the premium may increase.

Some insurance companies won't even allow that kind of change.

******** as far as i know. If they can prove that your wheels where a direct cause of the accident then yes you will be in trouble. Like putting tiny wheels on a car and cracking your sump on a speedbump or something.