Fitting Wheels 2" bigger than standard

[trd_st184]

Hi Toymods,

I've got a new purchase that i'm pretty excited to work on at the moment.

Its a 1990 Toyota MR2, unfortunately though the model that I bought came out with 195/60/14" and I'm hoping to put my spare set of Rays 17" on it.

I'm looking at going about things legal, is there a place that would be willing to certify this sort of thing?

The later model MR2s came out with 15" standard (turbo models came out with 15")

Any advice would be taken on very highly in my times of trouble

[river]

Hi,

If you are going with larger diameter rims you will need lower profile tyres so the external circumference (on the tyre) is not too large over the stock value.

For example, Trini in stock form had 14inch rims with 70series tyres. She now has 16inch rims with 45series tyres.

To go from 14 to 17 inch rims you may need to look for 40 series or even lower profile tyres.

Not sure how 17s would look on an MR2, but if it's been done I'm sure someone here has done it and can advise you.

seeyuzz
river

[trd_st184]

Hi,

If you are going with larger diameter rims you will need lower profile tyres so the external circumference (on the tyre) is not too large over the stock value.

For example, Trini in stock form had 14inch rims with 70series tyres. She now has 16inch rims with 45series tyres.

To go from 14 to 17 inch rims you may need to look for 40 series or even lower profile tyres.

Not sure how 17s would look on an MR2, but if it's been done I'm sure someone here has done it and can advise you.

seeyuzz
river

Hey mate,
Thanks for the heads up. I worked out I would need a 40 series tyre to get the car doing 101km at 100km (close enough)

Apart from this aspect (hypothetically if the 14" wheel and the 17" wheel were identical) is there any legalities to physically having a larger size rim which would be 2" more than what was standard on my particular model?

I read something once on the vicroads site that there is a limit of 2" bigger than what the car came out with, the other thing I saw was that it could be 2" from any model in that "series".

[roadsailing]

http://www.vicroads.vic.gov.au/NR/rd...340/0/VSI8.pdf

page 3 is what you are after, overall diameter is an issue, rim diameter isn't, sticking to the letter of the law you should be more concerned about rim width and offset, as you can only got 25mm wider and change track by 25mm (offset can only be different by 12.5mm)

there is a good calculator for finding different tyre sizes for a given overall diameter, something is wrong with my internet but just google "miata wheel calculator" and you will find it.

[thechuckster]

I read something once on the vicroads site that there is a limit of 2" bigger than what the car came out with, the other thing I saw was that it could be 2" from any model in that "series".

that would have been referring to outside tyre diameter or width, not rim diameter.

[AndyTTR]

The guys are right, it's overall diameter that matters most.

When I got my car engineered I was told me that 15 mm larger than the largest tyre diameter on your placard is the legal limit... so it would be handy if you could get your hands on that later model placard.

[CrUZida]

That 15mm refers to the tyre height, or rolling diameter, not the width.

[CrUZida]

http://www.vicroads.vic.gov.au/NR/rd...340/0/VSI8.pdf

page 3 is what you are after, overall diameter is an issue, rim diameter isn't, sticking to the letter of the law you should be more concerned about rim width and offset, as you can only got 25mm wider and change track by 25mm (offset can only be different by 12.5mm)

there is a good calculator for finding different tyre sizes for a given overall diameter, something is wrong with my internet but just google "miata wheel calculator" and you will find it.

Are Victoria even following those rules anymore?
I thought they had come on board with the new NCOPs?

[roadsailing]

Are Victoria even following those rules anymore?
I thought they had come on board with the new NCOPs?

dunno, i think the NCOPs make more sense. thats current info from the vicroads site though.

[AndyTTR]

That 15mm refers to the tyre height, or rolling diameter, not the width.

Yeah... that's what I said.

[CrUZida]

So how does the later tyre placard come in handy?
There is always the chance it has smaller height tyres on the newer car.

[AndyTTR]

Because the diameter is determined by the largest profile on the placard.

Eg, with the Supra the later models came with a 255/40R17 with an overall diameter of 635.80mm, but the early model came with a 245/50R16 which had a larger overall diameter of 651.30mm.

So sticking the early model placard to your car (like you can get away with on grey imports) would technically allow you to run a tyre ~665mm in overall diameter.

Edit: It'd help if I fully read the question...
You're right, it would depend on whichever had the largest overall diameter. IIRC the later SW20 did have larger tyres.

[jonathan yee]

i hope these spare 17in wheels aren't ones off your celica cause they won't fit. wrong PCD 5/100 vs 5/114.3 unless they're multift.

[trd_st184]

i hope these spare 17in wheels aren't ones off your celica cause they won't fit. wrong PCD 5/100 vs 5/114.3 unless they're multift.

Luckily they were PCD 5/114.3 as well as PCD 5/100

They look awesome thanks very much for all your help.

[old_mr2]

nice rims buddy!