Xxr wheels

[driver]

I have purchased some nice wheels xxr 527 zero offset wheels for my exocet, the brand new wheels have been sitting in the garage for over a year as I'm not sure which tyres to buy.... These wheels will go on my exocet soon now as I want to iva this summer. My issue is which tyre to buy as I need the same circumference as the standard mx5 wheels. This is in ordered to pass the speedometers test right? The wheels are 8.25 inch wide , I'm aware I will need to modify the wheel arches. Any one know what tyre size I should buy? I think the original tyres are 185/60-14.

[p5curly]

Any pics

[nm86]

Mar 1, 2016 22:37:07 GMT driver said:

I have purchased some nice wheels xxr 527 zero offset wheels for my exocet, the brand new wheels have been sitting in the garage for over a year as I'm not sure which tyres to buy.... These wheels will go on my exocet soon now as I want to iva this summer. My issue is which tyre to buy as I need the same circumference as the standard mx5 wheels. This is in ordered to pass the speedometers test right? The wheels are 8.25 inch wide , I'm aware I will need to modify the wheel arches. Any one know what tyre size I should buy? I think the original tyres are 185/60-14.

What is the rim size? 14" or 15".
If it's a 15 as I assume. You will be good with 225 45 15. I am running 8" wide rims and the 225 45 fits it well and keeps the speedometer correct. There are a few speed calculators out there and you should be able to double check with those.

[gl21133]

205/50/15 is close too I believe.

[driver]

I've never questioned the original alloy size I presume it's 14 as the tyre is 14? 185/60-14

[driver]

Whoops you mean the new alloys, they are 16's sorry it's getting late I'm seeing black circles after looking at tyres for the last 3 hours

[trident]

my car has 16" alloys and my tyres are 195/45R16

Your alloys are wider so not sure on width but 45R16 will be fine for speedo. I had no issues at iva with 45 on 16" alloy.

[driver]

Did a few online calculation, 215/40r16 seems to be the same match on speedo, not sure what to do now seen as you passed with 45.

[trident]

I'm no expert so please make your own mind up

I've just had a play with this site  www.tyresave.co.uk/tyresize.html  

With my tyre size 195/45R16 compared to the originals 185/60R14 size it showed
Difference in Diameter: percentage = 0.69% actual = 4mm

Change only the width to 225/45R16 and it jumps to
Difference in Diameter: percentage = 5.36% actual = 31mm

Now drop it to 225/40R16 and you get
Difference in Diameter: percentage = 1.38% actual = 8mm

I would go with the closes figure you can get to the the original. for me with my wheel width it was 45 as there was only 4mm difference in diameter but for on your wheel width it goes up a lot.. reduce to 40 with your wheel width and you get closer to original size again.  

I'm sure someone on here will be able to explain why the width also makes a difference.   

 

[nm86]

The first number is your tire width in mm. So 195 mm wide. The second number is your sidewall, this is a percent of the first number. So 45 % of 195=87.75mm that is how tall your sidewall is. Last number is your rim size. Essentially you can achieve the same outside diameter with many different combinations. 205/50/15 is the same as 225/45/15 is same as 245/40/15. Speedo will show the same with all those tires, but each one will have a different width. Just an example, I know your using 16in rims.

[driver]

Guys really appreciate your input in this thanks, 215/40/r16 seems to be best match. I just hope 215 tyres will fit the wide 8.25 rims. A little stretch is ok so long as it passes iva.

[gwnwar]

For 215/40/r16 rim width 7>8.5" best 7.5 per Tire Rack site..