OK well for all the ppl wondering how big of wheels and tyres u can run on ur car without getting defected. Heres the solution or problem for everyone to work out.

Heres the Steps to work it out.

1) Find the tyre placard on ur car and get what size tyres are specified for ur car or what ever is the largest or smallest tyres that come out on ur car.(eg VL COMMODORES COME OUT WITH 14,15 & 16inch wheels and tyres)So u can use what type of combination works best referring to the the
a) LOAD INDEX
OVERALL DIAMETER

2) The load index must be the same or bigger than the factory wheel/tyres specs

3) The overall diameter must not vary by more than +15mm or -26mm from factory wheel/tyre specs

4) The max tyre width must not be more than 1.3 times wider than the vehicles manufactures widest optional tyre.

5) The nominal width of the narrowest tyre fitted must not be less than 70% of the nominal width of the largest tyre fitted and never less than the vehicle manufactures narrowest optional tyre as indicated on the manufactured tyre placard.

6) The rims and tyres must not protrude beyond the bodywork of the vehicle including flares when viewed from above and when the wheels are facing straight ahead.

See the tables below for the LOAD INDEX & OVERALL DIAMETER and then compare them to the manufactures specs of ur car to get what is the biggest tyres u can fit,

QUOTE

4) The max tyre width must not be more than 1.3 times wider than the vehicles manufactures widest optional tyre.

so this means that cause the ss has 235's you can put 305's on a gemini as long as it stays in the gard ?

i get it.....

eg vl commodre came out with 16 in wheels

225/50/16's on walkies.

therefore if i want to run 18's on my car i can use

225/50/16 = load index = 92 & overall diamter = 632

So i can use

265/35/18 = load index = 93 & overall diamter = 643

refer to -

2) The load index must be the same or bigger than the factory wheel/tyres specs

3) The overall diameter must not vary by more than +15mm or -26mm from factory wheel/tyre specs

QUOTE (TwinCam16 @ Jul 23 2003, 08:55 PM)

QUOTE 4) The max tyre width must not be more than 1.3 times wider than the vehicles manufactures widest optional tyre. so this means that cause the ss has 235's you can put 305's on a gemini as long as it stays in the gard ?

as long as the 305's come in under all the other specs load index and overall diamter specs

which i highly doubt

ehehehehe

im lost... :S

waaay to technical for home time...


/me goes back to blowing shit up and shooting people. ( computer images of people... not real people.. duh).

thanks for the tip

cheers for the info ovl666, very helpful.

interesting

well im putting that one in the "too hard" basket

Thanks man need to know abou this kinda shit

For those too lazy to use a calculator, try here

The wheels on my car are so far illegal it is not worth even trying to do the calculation!!!!

swoit, by that rule the proton can have 19s, gunna have to try fitten em in now, who wants some 17in chromes?????

Further to OVL666, here is a web site that will calculate the maximum wheel/tyre combination for you and compare it to the standard fitment......

http://www.tyresave.co.uk/tyresize.html

OVL66....nice icon...I'll have it back when ur ready...lol

Isnt it that you can run 2"bigger diameter than YOUR car came out with. ie if its not a walkie, you cant run 18s without engineering certificate.

would make more sense this way, as going from base model to "sports" model in many cars means not only bigger wheels, but the suspension has been changed for the change in wheel diameter (bigger rims means lower profile tyres=stiffer spring rate in tyre, usually different tyre corner stiffness (how quickly the tyre reacts to lateral acceleration inputs), etc)

ie, Vx executive commodore with 15" steel rims, but GTS runs 19s, so if that was right you could run 21"s

from 15 inch to 21 inch means a huge change in the dynamics of the tyre/suspension package. I dont think that is legal

yeah thats way to technical and yeah i just stick to what tyre size my car came out with,and yeah no need to worry about that..

for you hardcore bling bling ppl take note as it might be you the cops might defect for your tyres/size etc..

At the end of the day as long as the overall diameter is not more than 15mm over the stock diameter you are pretty safe although generally it's 2 inches bigger than the largest wheel that was available on that model
ie 93 Prelude had 15 inch so you could go to 17 inch although if you put 215/40 rubber on 18's it was still legal!

QUOTE (neil_se @ Jul 24 2003, 01:34 PM)

For those too lazy to use a calculator, try here

Very interesting to note the difference in speedo ratings!

I personally know my tyres are illegal.. Slicks have more tread then my tyres at the moment