My stock 245's are only 29" tall?

[ChevyHDGert]

WOW. No wonder they look small.

 

I can't wait to get my new 33" mud terrains on there. That'll give me a 4" taller tire and should raise the hieght of my truck roughly 2".

 

I thought 245's measured around 30.5-31"?

 

So what do your tires measure, whether you have 245's, 265's, 285's, 305's, 315's, etc.? Do they measure on the ground what the manufacturer says?

[snoman]

WOW. No wonder they look small.

 

I can't wait to get my new 33" mud terrains on there. That'll give me a 4" taller tire and should raise the hieght of my truck roughly 2".

 

I thought 245's measured around 30.5-31"?

 

So what do your tires measure, whether you have 245's, 265's, 285's, 305's, 315's, etc.? Do they measure on the ground what the manufacturer says?

 

<{POST_SNAPBACK}>

 

 

 

 

They vary with brand. mine are just under 30. When you go to 33 you will lower you effective axle ratio from a 4.1 to about a 3.73 or a 3.73 to a 3.42 so performance will suffer too especailly in OD.

[c5vetteman]

WOW. No wonder they look small.

 

I can't wait to get my new 33" mud terrains on there. That'll give me a 4" taller tire and should raise the hieght of my truck roughly 2".

 

I thought 245's measured around 30.5-31"?

 

So what do your tires measure, whether you have 245's, 265's, 285's, 305's, 315's, etc.? Do they measure on the ground what the manufacturer says?

 

<{POST_SNAPBACK}>

 

 

 

Check out BFGoodrich's site and look at the "tire tips" link. It will let you input different tire sizes and give you the result of axle ratio and speedometer changes.

BFGoodrich

 

Also, according to BFGoodrich, a 245/75/16 tire is 30.5" (even though I measure 29.5" myself) and a 285/75/16 is 32.8" in diameter. The axle ratio will effectively be reduced to 3.813.

[snoman]

WOW. No wonder they look small.

 

I can't wait to get my new 33" mud terrains on there. That'll give me a 4" taller tire and should raise the hieght of my truck roughly 2".

 

I thought 245's measured around 30.5-31"?

 

So what do your tires measure, whether you have 245's, 265's, 285's, 305's, 315's, etc.? Do they measure on the ground what the manufacturer says?

 

<{POST_SNAPBACK}>

 

 

 

Check out BFGoodrich's site and look at the "tire tips" link. It will let you input different tire sizes and give you the result of axle ratio and speedometer changes.

BFGoodrich

 

Also, according to BFGoodrich, a 245/75/16 tire is 30.5" (even though I measure 29.5" myself) and a 285/75/16 is 32.8" in diameter. The axle ratio will effectively be reduced to 3.813.

 

<{POST_SNAPBACK}>

 

 

 

 

 

The only way to measue tire height accurately is too measure the circumferance and divide by "pie" (rounded off to 3.14 if you like)

[dbunn]

I measured the circumference of my factory 245's and came up with 96 inches if I recall correctly. WHen I divided it by 3.14 it amounted to 30.5 approximately. Then I went to Michelin's website and theyt advertise 30.5 inches as the actual diameter for the factory tire. The 29 inches may be just the way it looks depending on where you measure it and your inflation. I measured an unloaded tire (the spare) circumference. The only reason I did all this was so I am going to be getting 285's soon - and I just sent my PCM to Wester's and wanted the speedo to be ready for the tire swap so I wouyld not have to send my PCM back.

 

Thanks for the math lesson a post or two up. Not that I am not familiar with the formula, but sometimes the simplest approaches to a problem are frequently the most overlooked.

 

Dan