wheels question

[red95r]

Since there are so many of you out there with rims that are most if not all bigger than your stock ones how does it affect the speedo? What needs to change to be accurate?

 

[joekd]

As long as you use the correct tire size (same diameter as the OEM) your speedo is fine

For instance the OEM tire size for a 17" wheel is 245/45/17, doesnt matter if you car had 15" or 16" wheels, as long as you use that tire size your speedo will be exactly the same

 

[red95r]

im looking at doing 17x9's (255/40-17) in front and the 17x10.5's (315/35-17) in rear.

I have the fuggly 15" tri-bar rims.

then by what you say it should be fine.

 

[atlanticblue98]

im looking at doing 17x9's (255/40-17) in front and the 17x10.5's (315/35-17) in rear.

I have the fuggly 15" tri-bar rims.

then by what you say it should be fine.

yeah you should be fine

 

[white98stang]

i have 17" oem rims and my speedometer is accurate...got a ticket found out the hard way lol

 

[atlanticblue98]

i have 17" oem rims and my speedometer is accurate...got a ticket found out the hard way lol

it depends on the size of the tire, not the rim

 

[white98stang]

yeah i know i had to get wider tires for the rims

 

[DEstang]

im looking at doing 17x9's (255/40-17) in front and the 17x10.5's (315/35-17) in rear.

I have the fuggly 15" tri-bar rims.

then by what you say it should be fine.

The correct size would be 275/40/17 for the front, and 315/35/17 for the rear. Will give you in the area of a 810revs/mile, which is as close to factory 245/45/17 as you'll get.

 

[98GTnSC]

so a 17" tire will fit a 15" rim?

 

[joekd]

so a 17" tire will fit a 15" rim?

No, not at all. The rim and the tire must be the same (15" on 15", 17" on 17")

 

[98GTnSC]

As long as you use the correct tire size (same diameter as the OEM) your speedo is fine

For instance the OEM tire size for a 17" wheel is 245/45/17, doesnt matter if you car had 15" or 16" wheels, as long as you use that tire size your speedo will be exactly the same

so as long as say the sidewall is the same size(45) in this case. then you can have a 15 or 17" wheel and the speedo will b correct? as long as the sidewall is (45) on both the 15 and 17" wheel and tires. i may b misreading ALL of this but it isnt making sense @ all. mayb im just running slow...

 

[joekd]

so as long as say the sidewall is the same size(45) in this case. then you can have a 15 or 17" wheel and the speedo will b correct? as long as the sidewall is (45) on both the 15 and 17" wheel and tires. i may b misreading ALL of this but it isnt making sense @ all. mayb im just running slow...

You just misunderstand what is being said, it's not that they need the same sidewall, they need the same overall diameter

Think about the tire as a donut, the 15, 16 or 17 is the size of the hole in the middle of the donut. The sidewall is the amount of tire you see from the side (rim to outside of tread)

245/50/16, 245/45/17, 245/40/18 are all pretty much the same exact diameter. 245 is how wide the tread is so you will notice the sidewall is dropping one ratio when the rim size is increased by an inch each time.

As long as you keep the diameter the same your speedo will be fine

 

[white98stang]

haha i like your comparison

 

[98GTnSC]

ahhh.... gotcha!