Title: Wheels and tyres question - going from 16 to 17 wheels Post by: Lindsay on 29 March, 2011, 07:03:19 AM Morning all, not one for a Lancia per se but.... I am wanting to change the wheels on my R129 SL Mercedes from the original 8 hole alloys which are 16", tyres 225/55/16s to a set of 17" wheels which I have. They currently have 245/45/17 tyres on them. My reckoning is to keep the ratio correct, the 17"s should ideally have 235/45/17s. Is this correct?
Also, if I run it with the 245s will it make much difference - aside from changing the gearing slightly and making the instruments read slightly over/under? Lastly, if I change the tyres in pairs, would I be ok to change the fronts to 235 and keep the rears at 245 until they need new tyres? I would go on the Mercedes forum but I can't be doing with Mercedes folk!! thanks Title: Re: Wheels and tyres question - going from 16 to 17 wheels Post by: Neil on 29 March, 2011, 09:30:57 AM Lindsay,
I just looked up the tyre/wheel sizes, looks like you need 245/45 x 17 not 235/45 x17 - 245/45 x 17 has overall tyre diameter of 652mm and the original tyre size was 654mm, so not much in it, if you went for 235/45 x 17 it would be 643mm smaller overall wheel and tyre so the speedo would over read. I guess you could mix sizes front to to back as long as they are same per axle and four wheel drive :D Try this link: http://www.alloywheelworld.co.uk/page.php/tyrecalc.html Title: Re: Wheels and tyres question - going from 16 to 17 wheels Post by: Lindsay on 29 March, 2011, 12:07:42 PM Lindsay, I just looked up the tyre/wheel sizes, looks like you need 245/45 x 17 not 235/45 x17 - 245/45 x 17 has overall tyre diameter of 652mm and the original tyre size was 654mm, so not much in it, if you went for 235/45 x 17 it would be 643mm smaller overall wheel and tyre so the speedo would over read. I guess you could mix sizes front to to back as long as they are same per axle and four wheel drive :D Try this link: http://www.alloywheelworld.co.uk/page.php/tyrecalc.html Hi Neil, thanks for the reply. Too complicated for me! But your explanation is clear and makes sense so its good enough for me! cheers Lindsay |