I"ve got an '89 XJS. Factory spec tires are 235/60R15 with a recommended V rating. Have only found one tire out there that meets spec. Has anyone tried increasing wheel diameter and reducing sidewall, say like 235/45R16 and going to Z rating. I'm curious as to effects on handling. Would appreciate any information or source of information for improving handling characteristics. Thanks, Mark
J. Mark Foley
1989 XJS
Submitted by wpblaw@juno.com on Wed, 03/12/2003 - 23:57
Submitted by dougdwyer@eart… on Thu, 03/06/2003 - 21:08
Re.: Tire Size / Wheels
The shorter, stiffer sidewall will give you a firmer ride and crisper steering response.
Cheers
Doug Dwyer
There is a general rule of thumb called "plus sizing". You simply add one tire size(to 235 from 225,for example)and reduce its aspect ratio by one unit(to 60 from 70, for example) for each inch in rim diameter increase(to 17 from 16 inches, for example). You'll note that with each successive size increase, the overall height(diameter)of the new combination is nearly identical to the factory wheels and tires.