New to 19" wheels

I guess that ///Ms and Non-///Ms are a bit different, so perhaps best to go by what those with Non-///Ms have found to make sure you don't get any rubbing!
 
Difference in tyre diameters compared to a 225/35/19 front are that 265/30/19 will be 1.5mm taller and 255/30/19 will be 4.5mm shorter - nothing much in it but neither is actually within 4mm circumference as the 265s have a circumferential delta of about 5mm more but the 255s have a delta of 15mm less. ;)
 
DLH said:
Difference in tyre diameters compared to a 225/35/19 front (641mm diam, circumference 2013mm) are that 265/30/19 will be 2mm taller (643mm diam, circumference 2019mm) and 255/30/19 will be 4mm shorter (637mm diam, circumference 2000mm) - nothing much in it but neither is actually within 4mm circumference. ;)
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Lets take the 225/35/19 as our example.
The diameter is 19'' or 482.6mm
The section height is 35% of 225=78.75mm
The outer diameter of the unladen wheel and tyre is, the diameter 482.6mm +2 section heights 2x78.75mm=640.1mm
The formula to calculate the rolling circumference is 0.96 x OD x PI so you have 0.96 x 640.1 x 3.14159265359=1930.49mm

If you care to do the same for a 265/30/19 wheel and tyre the rolling circumference will work out as 1935.02mm
The difference between the two is 4.53mm.
Close enough?
Have a nice day.
 
GJC72 said:
I have CSL reps. Fronts are 19 x 8.5 et40, rears 19 x 9.5 et 40. Front Tyres are 235/35/19 front and they have rubbed through the wheel arch liner. Rear tyres are 265/30/19, no issues of rubbing. Suspension is standard sport setup. Will switch to 225/35's for the fronts when I need to change.
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You answered my exact question before I got the chance to ask it? I got the csl rep wheels from Sam and are exact same size as yours, and I'm running the standardish m sport suspension, looks like ill but the 225/35's at the front, as a question tho gjc72, what the ride like?
 
Dav - My initial numbers were all 'near enough' and the sums done on the back of a fag packet, but if using more than 1 decimal place for everything the the outer diameter of 225/35/19 is indeed 640.1mm and that of a 165/30/19 is 641.6 i.e. a difference in diameters of 1.5mm which gives a circumferential delta of 4.7124mm which is greater than 4mm and if working to the nearest millimetre would actually be 5mm ;)

So, we agree that the circumference of your wheels isn't within 4mm front and rear although the 265/30/19 is nearer than the 255/35/19 to the circumference of the 225/35/19. :P

PS I've updated my original rough figures to be a little more accurate. ;)
 
I won't be posting on this thread again.
Someone simply asked for advice and I gave it to them based on my experiences. I wasn't expecting it to be forensically examined. :roll:
I'm sure based on this thread alone, people will be flocking to you for your advice on wheels and there fitment.
Enjoy the rest of your day.
 
Dav - you gave him good advice and the best option for his 313 reps appear to be 225/35/19 on the fronts and 265/30/19 on the rears. :)
 
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