Tire size question

S

Santeeford

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Sep 12, 2006

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Dec 15, 2006

#1

• Dec 15, 2006

• #1

I have a 93 Gt with the factory wheels. The tire size right now is 225/55. What is the widest i could go on that factory wheel?

 

Whytry91

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Dec 15, 2006

#2

• Dec 15, 2006

• #2

Santeeford said:

I have a 93 Gt with the factory wheels. The tire size right now is 225/55. What is the widest i could go on that factory wheel?

Click to expand...

I have(had) 245s on mine, some people run 255s but that is pushing it...

 

04sleeper

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Dec 15, 2006

#3

• Dec 15, 2006

• #3

Whytry91 said:

I have(had) 245s on mine, some people run 255s but that is pushing it...

Click to expand...

I agree.

I ran 245-50-16's on the rear of my old coupe and 225-50-16's on the front.

 

S

Santeeford

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#4

• Dec 15, 2006

• #4

Thanks guys

 

Prime Lord

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Dec 15, 2006

#5

• Dec 15, 2006

• #5

245/50/16 is the widest you can drop w/o overstressing the sidwalls.

 

DucatiRdr

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Nov 22, 2006

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North of Boston, Massachusetts

Dec 15, 2006

#6

• Dec 15, 2006

• #6

What about speedo error for the difference in tire circumference? My 88 has 225/60-15 with a circumference of 153.54". A 225/50-16 has a circumference of 143.53 for a difference of 6.5%. Is there a new speedo drive gear to account for the change in circumference?

 

Mustang5L5

That is…until I whipped out my Bissell

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Dec 15, 2006

#7

• Dec 15, 2006

• #7

DucatiRdr said:

What about speedo error for the difference in tire circumference? My 88 has 225/60-15 with a circumference of 153.54". A 225/50-16 has a circumference of 143.53 for a difference of 6.5%. Is there a new speedo drive gear to account for the change in circumference?

Click to expand...

WHy do you want to decrease tire diameter?

If you want wider rubber for your car, you can use a 245/55/15. This will keep your diameter the same and not require a gear change.


For the original poster, a 245/50/16 will also keep factory tire diamter and not require a speedo change

 

Prime Lord

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#8

• Dec 16, 2006

• #8

FWIW, its not the EXACT factory diameter, but its pretty damn close. B/t the 225/60/15 and 245/50/16 There's a .79" difference in overall height, leading to a .05" difference in circumference. At 60MPH, your speedo will be ~2MPH off.

Remember, when changing wheel size or tire width, the middle number of the three is the sidewall height as a percentage of the overall tire width. So as the width (first number) goes up, the sidewall percentage (second number) must go down to keep the overall dimension the same. The same is true when going to larger rims w/ the same width tire. The sidewall percentage must go down to accommodate the larger wheel.

225/60/15 ~= 245/50/16 ~= 245/45/17 ~= 245/40/18 and so on

so if you're sticking w/ a 15" wheel keep in mind that the sidewall must be tall enough to make the stock 15x7 wheel width. A 60 on a 225 is plenty. You can go to a 245/55/15 which are rare as crap, but its the exact same overall size.

 

DucatiRdr

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Nov 22, 2006

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North of Boston, Massachusetts

Dec 16, 2006

#9

• Dec 16, 2006

• #9

For my '88 I wasn't looking to change overall wheel height, just tire width. I am going to pick up a set of 16" pony wheels and wanted to bump up the width from the OEM 225 to something a bit more asthetically pleasing. Remember, my '88 has the "old style" fenders/fender liners. I would like to avoid tire-fender contact and don't want to have to roll the fenders. Will a 245/50 16 fit the rear? Do I need to reverse the quads?

 

SMOKEDYA

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Dec 16, 2006

#10

• Dec 16, 2006

• #10

I run 275/45/17 in the rear and 245/45/17 in front of my 93 coupe. peace





john

 

Prime Lord

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#11

• Dec 16, 2006

• #11

DucatiRdr said:

Will a 245/50 16 fit the rear? Do I need to reverse the quads?

Click to expand...

yes they will fit, yes flip em around

 

Mustang5L5

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#12

• Dec 16, 2006

• #12

DucatiRdr said:

For my '88 I wasn't looking to change overall wheel height, just tire width. I am going to pick up a set of 16" pony wheels and wanted to bump up the width from the OEM 225 to something a bit more asthetically pleasing. Remember, my '88 has the "old style" fenders/fender liners. I would like to avoid tire-fender contact and don't want to have to roll the fenders. Will a 245/50 16 fit the rear? Do I need to reverse the quads?

Click to expand...

On my '88 i went from 10-holes to 16" pony wheels with 245/50/16 tires. The rear fit fine, the front had a little rub at full lock. Nothing major.

I know have 245/45/17" tires on it

 

Brett88lx

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Sep 3, 2006

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Dec 16, 2006

#13

• Dec 16, 2006

• #13

I have 255's on the rear and 225's on the front. Very little rubbing, nothing major at all. Good luck.