| T O P I C R E V I E W |
| CatDude | This link is useful if you are changing tire size on your vehicle. You can use this to see how much your speedometer may be off. http://www.miata.net/garage/tirecalc.html |
| cnote6 | I run a 295-30-22 on my Chevy truck. stock is a 235-75-16. this is the largest tire to fit, with the truck lowered. This message has been edited by cnote6 on 12-07-2003 at 05:04 PM |
| CTProwler | I've used Tirerack.com and it has a place where you can do it online, or call them they will tell you what will work on your car ------------------
 |
| Kurtis | Comparing various tire/rim combos is really quite easy. Here's how: First, determine the height of your current setup. Say you have a 205/60 on a 16" rim. The height would be equal to 205 millimeters multiplied by the 60% aspect ratio (=123mm). Next divide this by 10 to get centimeters (=12.3cm). Multiply this by .394 to convert centimeters into inches (=4.85"). Now (stay with me here) you have the height of one sidewall. Multiply by 2 to account for the sidewall below the rim and the sidewall above the rim (=9.7"). Add your rim height (16") and you have the total height (=25.7"). Now you can use the same formula to compare other combos like 225/55-16 or 215/50-17 or 235/35-19. Anything that falls within .25" is not going to impact the speedometer greatly. Formula: tire width x aspect ratio / 10 x .394 x 2 + rim diameter = tire height. |
| CatDude | 295/45 18 height = 295 mm x (45/100) x (1 cm/10 mm) x (1"/2.54 cm) x 2 + 18" = 28.45" Yep!! works!.... although, I would add "/100" next to aspect ratio and I would replace .394 with "1/2.54", which is an exact conversion rather than a rounded number: height (") = (wheel width in mm) x (aspect ratio)/100 x (1 cm/10 mm) x (1"/2.54 cm) x 2 + (wheel diameter ") Don't blame me... I'm an Engineer and I have to check these things out...  |
| Gary C | the Dunlop and Goodyears numbers are the same for the rears but they are not the same size. Go figure...... |
| Kurtis | Yes, Gary is right. For some reason tires with the same exact size markings CAN vary in actual size. The guys over at Dunlop must have an old tape measure that is worn, because their tires are notoriously small when compared to other brands of the "same size". So, once the formula has been used to narrow down your choices it is best to look up the manufacturer's actual height and width measurements on their website just to make sure you are getting what you expect. |
