Need suggestions from wheel gurus.
07-23-04, 03:43 PM
#1
"I see triangles"
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Need suggestions from wheel gurus.
OK, I finally decided on getting g-games 77W 2-piece wheels on my FD, 18X8.5 in front and 18X9.5 in back. What would be my best bet for offsets and tire sizes, that would give the least rubbing issues? The car is lowered a bit and I still have stock brakes( I may upgrade later though). Any help would be appreciated.
Ryan
Ryan
Last edited by Zyon13B; 07-23-04 at 03:46 PM.
04-01-05, 06:02 PM
#3
Super Snuggles
Wheel Offset
Anything between +38mm (1.5") and +45mm (1.8") will work.
Add 1" to the rated wheel width, divide by 2 to get the wheel centerline, and then add the offset (divide by 25.4 to convert to inches) to find back spacing. Subtract back spacing from the same overall width (rated width + 1") to find front spacing. Pretty easy.
8.5" + 1" = 9.5" / 2 = 4.75" + 1.5" = 6.25" (back spacing)
8.5" + 1" = 9.5" - 6.25" = 3.25" (front spacing)
So the 8.5s will have ~6.25" of back spacing and ~3.25" front spacing with a +38mm offset, which is pretty close in the front (about 3.5" max). +45mm would be better, which would give you another 1/4" of clearance in front, roughly (6.55" back, 2.95" front). That's plenty of clearance in the back, and should keep you from putting the tire into the fender with the wheels turned, unless you drop the car excessively.
In the rear, +38mm gives you ~6.75" back spacing and 3.75" in front (about 4.0" max) with a 9.5" wheel. +45mm gives you ~7.05" in back and ~3.45" in front, which is good too. +43mm would be about the perfect balance.
Tire Width
As far as tires, add 1" to the rated wheel width and multiply by 25.4.
8.5" + 1" = 9.5" * 25.4 = 241.3mm
Therefore, a P245 (245mm section width tire) would be just about right in front, although you could go with a P255 instead.
9.5" + 1" = 10.5" * 25.4 = 266.7mm
A P265 would work well in the back, but you can go P275 as well. Even a P285 might work, depending on its actual width, since tire dimensions vary slightly from one manufacturer to another and even between one tire line to another made by the same manufacturer.
Tire Height
Stick with a tire that keeps the overall height about the same as the stock P225/50-16s.
225mm (width) * 0.5 (50 series) = 112.5mm / 25.4 = ~4.43" (sidewall height)
4.43" * 2 = 8.86" + 16" (wheel diameter) = ~24.86" tall
To find the proper tire size for a 17" wheel, reverse the calculations...
24.86" - 17" = 7.86" / 2 = 3.93" * 25.4 = ~100mm sidewall height
100mm / 0.4 (40 series) = 250mm, so a P245/40-17 or P255/40-17 would work just fine in front.
If you want 18s...
24.86" - 18" = 6.86" / 2 = 3.43" * 25.4 = ~87mm sidewall height
87mm / 0.35 (35 series) = 248mm, so a P245/35-18 would work as well.
In the back, a P265/40-17 (~25.3" tall) would work. A P275/40-17 starts to get a little tall. This will affect the actual vehicle speed, although since the speed sender is driven by the tailshaft of the transmission, it will still read the same mph at a given rpm. You'll just be traveling faster (or slower) than the indicated speed if you have a taller (or shorter) than stock tire.
Anything between +38mm (1.5") and +45mm (1.8") will work.
Add 1" to the rated wheel width, divide by 2 to get the wheel centerline, and then add the offset (divide by 25.4 to convert to inches) to find back spacing. Subtract back spacing from the same overall width (rated width + 1") to find front spacing. Pretty easy.
8.5" + 1" = 9.5" / 2 = 4.75" + 1.5" = 6.25" (back spacing)
8.5" + 1" = 9.5" - 6.25" = 3.25" (front spacing)
So the 8.5s will have ~6.25" of back spacing and ~3.25" front spacing with a +38mm offset, which is pretty close in the front (about 3.5" max). +45mm would be better, which would give you another 1/4" of clearance in front, roughly (6.55" back, 2.95" front). That's plenty of clearance in the back, and should keep you from putting the tire into the fender with the wheels turned, unless you drop the car excessively.
In the rear, +38mm gives you ~6.75" back spacing and 3.75" in front (about 4.0" max) with a 9.5" wheel. +45mm gives you ~7.05" in back and ~3.45" in front, which is good too. +43mm would be about the perfect balance.
Tire Width
As far as tires, add 1" to the rated wheel width and multiply by 25.4.
8.5" + 1" = 9.5" * 25.4 = 241.3mm
Therefore, a P245 (245mm section width tire) would be just about right in front, although you could go with a P255 instead.
9.5" + 1" = 10.5" * 25.4 = 266.7mm
A P265 would work well in the back, but you can go P275 as well. Even a P285 might work, depending on its actual width, since tire dimensions vary slightly from one manufacturer to another and even between one tire line to another made by the same manufacturer.
Tire Height
Stick with a tire that keeps the overall height about the same as the stock P225/50-16s.
225mm (width) * 0.5 (50 series) = 112.5mm / 25.4 = ~4.43" (sidewall height)
4.43" * 2 = 8.86" + 16" (wheel diameter) = ~24.86" tall
To find the proper tire size for a 17" wheel, reverse the calculations...
24.86" - 17" = 7.86" / 2 = 3.93" * 25.4 = ~100mm sidewall height
100mm / 0.4 (40 series) = 250mm, so a P245/40-17 or P255/40-17 would work just fine in front.
If you want 18s...
24.86" - 18" = 6.86" / 2 = 3.43" * 25.4 = ~87mm sidewall height
87mm / 0.35 (35 series) = 248mm, so a P245/35-18 would work as well.
In the back, a P265/40-17 (~25.3" tall) would work. A P275/40-17 starts to get a little tall. This will affect the actual vehicle speed, although since the speed sender is driven by the tailshaft of the transmission, it will still read the same mph at a given rpm. You'll just be traveling faster (or slower) than the indicated speed if you have a taller (or shorter) than stock tire.
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