tire size?
Thread Starter
Racer
Joined: Mar 2006
Posts: 333
Likes: 0
From: NJ 448rwhp done by tommy @angermanagement nj
St. Jude Donor '10
tire size?
kinda stupid question but if im running a 35 series tire on an 18 inch rim in the rear what series do i run in the front if im using an 18 inch rim in the front. the car is already lowered so im not worried about adjusting the suspension.
thanks...
thanks...
Advanced
Joined: Sep 2006
Posts: 52
Likes: 0
From: Lewiston Idaho
Formula for figuring OD tire size
Hi guys,
I'm new here but I do know the formula to figure out the O.D. (outside diameter) of tires when you are changing to different size rims.
245 45 17 = 245mm divided by 25.6 = 9.57inches wide
multiply 9.57inches by .45 (aspect ratio) = 4.306 inches =
sidewall height
4.306 multiply by 2 =8.613 inches +wheel diameter 17inches
= Outside Diameter =25.613inches
245 = width metric
45 = aspect ratio = .45
17 = wheel diameter
You can use this formula the exact same way with different widths, aspect ratios, and wheel diameters to find a combination that will be the roughly the same outside diameter to keep from having clearance problems yet run bigger wheels.
example
245 40 18 =25.656 inches outside diameter and same width as stock.
Hope this helps
Sinister C5
I'm new here but I do know the formula to figure out the O.D. (outside diameter) of tires when you are changing to different size rims.
245 45 17 = 245mm divided by 25.6 = 9.57inches wide
multiply 9.57inches by .45 (aspect ratio) = 4.306 inches =
sidewall height
4.306 multiply by 2 =8.613 inches +wheel diameter 17inches
= Outside Diameter =25.613inches
245 = width metric
45 = aspect ratio = .45
17 = wheel diameter
You can use this formula the exact same way with different widths, aspect ratios, and wheel diameters to find a combination that will be the roughly the same outside diameter to keep from having clearance problems yet run bigger wheels.
example
245 40 18 =25.656 inches outside diameter and same width as stock.
Hope this helps
Sinister C5
Safety Car
Joined: Aug 2004
Posts: 4,734
Likes: 232
From: Youngstown Ohio
Originally Posted by Sinister C5
Hi guys,
I'm new here but I do know the formula to figure out the O.D. (outside diameter) of tires when you are changing to different size rims.
245 45 17 = 245mm divided by 25.6 = 9.57inches wide
multiply 9.57inches by .45 (aspect ratio) = 4.306 inches =
sidewall height
4.306 multiply by 2 =8.613 inches +wheel diameter 17inches
= Outside Diameter =25.613inches
245 = width metric
45 = aspect ratio = .45
17 = wheel diameter
You can use this formula the exact same way with different widths, aspect ratios, and wheel diameters to find a combination that will be the roughly the same outside diameter to keep from having clearance problems yet run bigger wheels.
example
245 40 18 =25.656 inches outside diameter and same width as stock.
Hope this helps
Sinister C5
I'm new here but I do know the formula to figure out the O.D. (outside diameter) of tires when you are changing to different size rims.
245 45 17 = 245mm divided by 25.6 = 9.57inches wide
multiply 9.57inches by .45 (aspect ratio) = 4.306 inches =
sidewall height
4.306 multiply by 2 =8.613 inches +wheel diameter 17inches
= Outside Diameter =25.613inches
245 = width metric
45 = aspect ratio = .45
17 = wheel diameter
You can use this formula the exact same way with different widths, aspect ratios, and wheel diameters to find a combination that will be the roughly the same outside diameter to keep from having clearance problems yet run bigger wheels.
example
245 40 18 =25.656 inches outside diameter and same width as stock.
Hope this helps
Sinister C5
Nice info and to ad to that here is a tire size calc. to make it even easier;
http://www.1010tires.com/TireSizeCal...?action=submit
and one for wheel offset;
http://www.1010tires.com/WheelOffsetCalculator.asp
as for front 30 or 35 depending on the width of the tire when compared to the rear, could go either way. Plug in the sizes you are interested in into the tire size calc and check for % of difference front to rear. Stock Z06 sizes return a 3% and stock coupe sizes return about a 3.5% diff front to rear.
Hope this helps,
Darion
Le Mans Master
Joined: May 2005
Posts: 6,366
Likes: 249
From: Fort Lauderdale, Florida
You didn't mention the width of your rims or the rear tire size you are running but here are my specs. I have 18" x 10" front and 11" rears. I have 295/35 rear tires which are the stock Z06 rear size. Up front I have 265/35 on the 10's which visually look good compared to the larger rears and also are the same diameter as the 17" front OEM tire size. You can also use a 275/35 in front also.
