Originally Posted by nielsensmn
So, logically, with 18 X 10 Shelby Torque rims...I should be able to put a 275 to 295....possible a 305/40 or 45 ZR 18 tire on that rim and fit on my car......depending on the maker of the tire?
It all depends on the tire manufacturers recomendation for rim width. There is a pretty big spread, that's why it needs to be researched. 275's-295's are pretty reasonable. A lot of tires will work with a 10" rim.
I doubt you will find a 305 that is recomended for a 10" rim though.
And keep in mind that no matter how wide the tire you put on is its "net" width will be determined mostly by the rim width. For example, you could get a 335mm tire to bead up on a 10" rim but the tire will not measure out to 335mm wide anymore. The sidewalls will be pulled in A LOT which will make the tire narrower and the center of the tread will baloon out in the middle so the tire will wear out a strip right down the center of the tire real fast and your effective contact patch will be greatly reduced.
I deal with "wider tires are better" dumbness constantly at the track. On a motorcycle the hot size tire is 190mm wide. That tire needs to be on a 6" rim but a lot of people put them on 5.5" rims. By only changing the rim size 1/2 inch the 190mm tire gets pinched down till where its about 182mm wide and the center of the tire gets taller, the contact patch gets smaller and the sidewall performance while on the edge of the tire (which is basicaly the only "suspension" you have) goes to crap ad there is a major loss of traction. I get these guys all the time saying there bike "feels funny" ad can I do something about it and i say yes.....and point them to the tire vendors with istructions to go get a 180mm wide tire.
The change is so dramatic that I can tell a bike has a tire o it that is too wide for the rim within the first 2-3 corners of my out lap which is at a very slow pace because I am waiting for the tires to come up to temp. If I had to guess I would say that a tire 10mm too wide would impact my laptimes by about 5 seconds.....which may as well be a year.