is changing tire size a problem?

[JD22]

Right now I have 265/75/r15 and my dad hooked me up and he can get 4 new ones for under $400 mounted and balanced and what-not. The new tires are 235/65/r15 or something around there. Is that going to cause a problem with the speedometer or 4 wheel drive or anything? He wanted me to make sure before he bought them. Thanks guys

 

[TheTopher]

Those tires are gonna be a little smaller. It looks like you've got 30.6" tires now and with new ones you'd have 27" tires. So it'll make your speedometer read a little higher than you're actually going and your truck will probably accelerate a tad quicker. 4 wheel drive will work fine as long as all 4 tires are all equal sizes.


Here's the cool little website toys I used to find this out for ya. You can use the speedo calculator to figure out exactly how far off your speedometer will be.

Speedo calculator
http://www.therangerstation.com/tech_library/Speedometer_Change_From_Tires.html

Metric to inches tire calculator
http://www.therangerstation.com/tech_library/Metric_To_Inch_Tires.html

 

[Scotty J.]

Wow, that calculator is pretty cool, and I was right on with my estimation when I went from 30 to 33's. I used my chronograph watch and timed it at 1 mile, i estimated 66mph with cruise control at 60.

 

[Colin]

If the speedo wasn't changed when the 265's were put on, then going to 235's would make it more accurate. I had 215's and went to 235's and the difference was negligible.

 

[Mac]

I usually go out on the interstate for a 10-50 miles run, reset the trip mileage counter at one of the mile markers and then compare. I'm good at math but the OD on tires do change from one manufacture to another. Not saying the odometer corresponds with the speedometer but sure ought to be close.
Dave

 

[Jay FX4]

Why would you want smaller tires?

 

[Scotty J.]

Why would you want smaller tires?

I wasn't gonna go there, but since you asked, I'd like to hear also LOL.

 

[sloth69mustang]

If the speedo wasn't changed when the 265's were put on, then going to 235's would make it more accurate. I had 215's and went to 235's and the difference was negligible.

some rangers came factory with 265/75r15s. and the 215 to 235 depends on the aspect ratio. a 215/75r15 is the same size tire as a 235/70r15 just a little wide(by 20mm from bubble of sidewall to bubble of sidewall.) thats what the first number is the width in mm's.

 

[sloth69mustang]

Why would you want smaller tires?

agreed. i went from 215/75r15 to 31x0.5r15 which in metric is about 265/75r15.

 

[JD22]

If the speedo wasn't changed when the 265's were put on, then going to 235's would make it more accurate. I had 215's and went to 235's and the difference was negligible.

265 is was came on the truck originally.

 

[JD22]

Why would you want smaller tires?

Not my decision, It's what we can afford. Sorry.

 

[Toms01PSD]

Those tires are gonna be a little smaller. It looks like you've got 30.6" tires now and with new ones you'd have 27" tires.

Actually, 265/75 is closer to a 32" tire, not a "30.6".


To the OP: Look on your door jamb. I'm sure you'll find that 235/75R15 is the size that came on your truck from the factory. Most of the 98-00 4x4's did...

EDIT: Sorry, I didn't see your post. I was typing when you posted that...235/75R15 is what came stock on both the rangers I had. They are going to look small, and your speedometer will be off a bit if 265's were factory for your truck.

 

[JD22]

Yeah, i told my dad the 265's were stock and he didn't believe me till he looked at the sticker himself.

 

[sloth69mustang]

if they are the 265/75r15s buy 31x10.5r15. the same size but 31s are usually cheaper for some reason. people are usually too lazy to do the math and figure it out. the equation is really easy. convert the first number 265 to standard by doing 265/25.4=10.43307blah blah blah inches(25.4mm = 1 inch).so you know the width from bubble of side to the other bubble of the side wall is roughly 10.5" the second number is a percentage of the first number so 75% of 10.5=(10.43307 x .75)=7.8248" then you times that by 2 plus the rim size to get the height of the tire so 7.8248 x 2=15.6496+ rim is 15= 30.6496. so a 265/75r15 is 30.696 in height and 10.43307 in width. so sorry tom you are incorrect unless you are rockin a 16 rim it would be close to 32". (being a math major and working at a tire shop for too long)

 

[Toms01PSD]

if they are the 265/75r15s buy 31x10.5r15. the same size but 31s are usually cheaper for some reason. people are usually too lazy to do the math and figure it out. the equation is really easy. convert the first number 265 to standard by doing 265/25.4=10.43307blah blah blah inches(25.4mm = 1 inch).so you know the width from bubble of side to the other bubble of the side wall is roughly 10.5" the second number is a percentage of the first number so 75% of 10.5=(10.43307 x .75)=7.8248" then you times that by 2 plus the rim size to get the height of the tire so 7.8248 x 2=15.6496+ rim is 15= 30.6496. so a 265/75r15 is 30.696 in height and 10.43307 in width. so sorry tom you are incorrect unless you are rockin a 16 rim it would be close to 32". (being a math major and working at a tire shop for too long)

I overlooked the 15" rim part.