To those who can answer my question...

Which of these two tyre sizes are lower profile?

205/45/16

215/40/16

I'm trying to decide which set of tyres to get and I'm kinda lost on profiles in general at the moment, especially with these two. Calculating normal percentage, 215/40 seems to be the lower profile tyre...

Sidewall Markings...

205

Width of the tyre in millimetres

45

Height of the tyre sidewall as a percentage of the width. In this case 45% of 205mm. Also know as the aspect ratio.

I'd got option b, *if* I'm calculating it right.

205/45 16 = 92.25mm sidewall

215/40 16 = 86mm side wall

So the 215's are smaller in rolling radius by 39.27mm (2.12%) meaning at a true 70 mph your speedo would read 68.52 mph

205/45 16 = 92.25mm sidewall

215/40 16 = 86mm side wall

So the 215's are smaller in rolling radius by 39.27mm (2.12%) meaning at a true 70 mph your speedo would read 68.52 mph

Yeah but dude you gotta remember I had 195/50/15 wheels before, which is the standard for 2.0s...

I don't have a calculator with me at the moment so I'm hoping you can show me the 195/50/15 diameter...

BlueRobin that's what I got too this afternoon...just need the final advice from the real deal like Ross...

EDIT: Okay Ross, so 195/50 from what I'm getting on 15 inch rims has 97.50mm sidewalls....

But then when we add this figure to 15 inches of rim diameter, and we add 86mm to 16 inches of rim, what are the final results?? I know you gotta convert MM to inches but I ain't bothered at the mo...too much for such a late night..

Use this mate..

http://www.carbibles.com/tyre_bible.html

About half way down there is a simple fill in and click box that does the maths for you.

OH MAN THANKS SOOOOO MUCH! 215/40s it is!!!!! It's the closest I can get to the original overall size

6mm difference? Poseur!

6mm difference? Poseur!

More like 0.42% difference from 195/50/15 (The original standard setup I had) and 215/40/16