18" wont fit!

[toks238]

Hey guys, I recently bought new rims for my VZ. Went to get some tires put on and they said that because the rims on my car are 15" I have to get the speedo
timed or something like that. They said the max I can go is 17" and the rims I got are 18". Has anyone had this problem before?

[Munz]

any rims that are more/less than 2 inchs in diameter will have an effect on your speedo

but it should be sweet F A difference

[one_and_only2004]

I went from 16's on my VY to 19's and my speedo was 100% dead on. You can get it checked on a dyno usually for $100.

[Munz]

or you can check on a GPS, it will give you a rough idea at least

[toks238]

Thanks for the help guys, going to get it looked at, thanks again

[Zeussy]

Holden can recalibrate it for you to suit what ever size wheels you put on, or someone handy with a tech 2 or similar.

Phreddy did mine on my old VY, had 15's on it and I put 20's on it - 5% increase in speed, they just change the PPM (pulses per minute).

[DylanWillo]

my Sv6 has 20's and its spot on.

[MY VZ]

ive got 18's and the tyres on them are 235x40 and my speedo isnt out, not noticeably anyway

[Jesterarts]

Don't need to re-calibrate anything so long as the correct tyres are fitted.

[toks238]

See that's what I thought, got told it would be roadworthy though :/

[Jesterarts]

You're in vic so the only tyre/wheel laws are:

MAX of 25mm increase in width, max of 15mm increase in overall rolling diameter when talking going UP in size.

Both these are also from values from the LARGEST wheel/tyre the manufacturer specifies for that vehicle.

In a nutshell, you can fit 18's without any legal issues as long as the correct width and overall diamater tyre is fitted.

If a tyre place tells you otherwise, go somewhere else as they don't know what they are talking about and I wouldn't trust them near your car.

Good luck with it mate.

[Surfwagon]

235/45x17 and 235/40x18 tyres have the exact same outside diameter so the tyre guy doesn't even know his own products very well and both are the sizes that Holden fitted to pre VE cars when fitting either 17's or 18's.