Noob tire question on sizing
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From: Port St. Lucie, Fl
Noob tire question on sizing
I'm looking at getting 18 x 8.5 , 2" lip fronts,
and 18 x 9.5, 3.5" lip rears
Can I still use my stock tires
225/50-17
235/50-17
or do I need 4 new tires? and if so what size?
two 225/50-18?
and
two 235/50-18?
Sorry just a noob on tire sizing.
and 18 x 9.5, 3.5" lip rears
Can I still use my stock tires
225/50-17
235/50-17
or do I need 4 new tires? and if so what size?
two 225/50-18?
and
two 235/50-18?
Sorry just a noob on tire sizing.
Ok.. Quick Tire Sizing Lesson.
25.4mm=1inch
Example:
225/50/17
The first number is the width of the tire. (225mm Wide)
Second is one of the side walls as a percentage of the first number (50% of first number (225)=112.5.
The third number is for the wheel size. (17" wheels).
In order to find the proper size, you need to calculate the Overall diameter of the original tires.
17"~432mm. + two side walls (112.5) = 657mm.
In order to order the correct size, you need to find a tire that roughly matches 657mm OR SLIGHLTY LESS. More is usually not good for most people.
Given the new 18" wheel (457mm), you need 200mm of total side wall, or 100mm of side wall for each of the side walls. If you stay at a 50% sidewall rate, you need a 200mm wide tire. That is not going to work, because now you have 200mm wide tire (7.87") on a 8.5" wheel. No go.
At this point, you can keep calculating every possibility or you can use the tire calculator on 1010tires.com.
Inputting the original size of the front 225/50/17 and estimating a 245/40/18, you'll see the difference is VERY minimal. Thus, 245/40/18 will work. You'll also see that the rim width range on the site shows that a 245/40/18 will fit on an 8-9.5" wide wheel.
The rear tire, I recommend 255/40/18 or 275/40/18... Now you tell me why I recommend this size.
25.4mm=1inch
Example:
225/50/17
The first number is the width of the tire. (225mm Wide)
Second is one of the side walls as a percentage of the first number (50% of first number (225)=112.5.
The third number is for the wheel size. (17" wheels).
In order to find the proper size, you need to calculate the Overall diameter of the original tires.
17"~432mm. + two side walls (112.5) = 657mm.
In order to order the correct size, you need to find a tire that roughly matches 657mm OR SLIGHLTY LESS. More is usually not good for most people.
Given the new 18" wheel (457mm), you need 200mm of total side wall, or 100mm of side wall for each of the side walls. If you stay at a 50% sidewall rate, you need a 200mm wide tire. That is not going to work, because now you have 200mm wide tire (7.87") on a 8.5" wheel. No go.
At this point, you can keep calculating every possibility or you can use the tire calculator on 1010tires.com.
Inputting the original size of the front 225/50/17 and estimating a 245/40/18, you'll see the difference is VERY minimal. Thus, 245/40/18 will work. You'll also see that the rim width range on the site shows that a 245/40/18 will fit on an 8-9.5" wide wheel.
The rear tire, I recommend 255/40/18 or 275/40/18... Now you tell me why I recommend this size.
Last edited by iStan; Jul 11, 2008 at 01:38 PM.
Originally Posted by iStan
Ok.. Quick Tire Sizing Lesson.
25.4mm=1inch
Example:
225/50/17
The first number is the width of the tire. (225mm Wide)
Second is one of the side walls as a percentage of the first number (50% of first number (225)=112.5.
The third number is for the wheel size. (17" wheels).
In order to find the proper size, you need to calculate the Overall diameter of the original tires.
17"~432mm. + two side walls (112.5) = 657mm.
In order to order the correct size, you need to find a tire that roughly matches 657mm OR SLIGHLTY LESS. More is usually not good for most people.
Given the new 18" wheel (457mm), you need 200mm of total side wall, or 100mm of side wall for each of the side walls. If you stay at a 50% sidewall rate, you need a 200mm wide tire. That is not going to work, because now you have 200mm wide tire (7.87") on a 8.5" wheel. No go.
At this point, you can keep calculating every possibility or you can use the tire calculator on 1010tires.com.
Inputting the original size of the front 225/50/17 and estimating a 245/40/18, you'll see the difference is VERY minimal. Thus, 245/40/18 will work. You'll also see that the rim width range on the site shows that a 245/40/18 will fit on an 8-9.5" wide wheel.
The rear tire, I recommend 255/40/18... Now you tell me why I recommend this size.
25.4mm=1inch
Example:
225/50/17
The first number is the width of the tire. (225mm Wide)
Second is one of the side walls as a percentage of the first number (50% of first number (225)=112.5.
The third number is for the wheel size. (17" wheels).
In order to find the proper size, you need to calculate the Overall diameter of the original tires.
17"~432mm. + two side walls (112.5) = 657mm.
In order to order the correct size, you need to find a tire that roughly matches 657mm OR SLIGHLTY LESS. More is usually not good for most people.
Given the new 18" wheel (457mm), you need 200mm of total side wall, or 100mm of side wall for each of the side walls. If you stay at a 50% sidewall rate, you need a 200mm wide tire. That is not going to work, because now you have 200mm wide tire (7.87") on a 8.5" wheel. No go.
At this point, you can keep calculating every possibility or you can use the tire calculator on 1010tires.com.
Inputting the original size of the front 225/50/17 and estimating a 245/40/18, you'll see the difference is VERY minimal. Thus, 245/40/18 will work. You'll also see that the rim width range on the site shows that a 245/40/18 will fit on an 8-9.5" wide wheel.
The rear tire, I recommend 255/40/18... Now you tell me why I recommend this size.
so to the OP
245/40/18
275/40/18
not that 255/40/18 rears won't work
but 275/40/18 is the size that works best... its the size that carries the same diameter as stock 18s / 19s
Originally Posted by itsjiggajames
but 275/40/18 is the size that works best... its the size that carries the same diameter as stock 18s / 19s
Also, the 245/40 compared to the 255/40 almost retains stock stagger, where as the 245/40 275/40 almost doubles the size variances comparing front to rear. Because it's popular doesn't mean it's correct.
Last edited by iStan; Jul 11, 2008 at 01:44 PM.
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