will getting 225/45/18 or 225/40/18 tires affect your speedometer?

[stageup]

just wondering,

i'm leaning towards 225/45/18's right now

 

[CWPspeed3]

yes, anything different than the stock size will put the speedometer off slightly in one direction or the other. I'm running 225/40/18 and at 70mph your actually doing 67-68mph.

I dont have the link at the moment but there are tire/rim size calculators that will show you how much it will be off.

 

[Kain]

Clicky linky thingy.http://www.miata.net/garage/tirecalc.html

 

[007ms308]

the 225-45-18 would probally be the worst idea cause the height of the sidewall

 

[cleancutx]

Would this effect my MPG? Or would I have to take into consideration the 2% change in size when calculating my MPG?

I just put on my rx8 rims with 225/40/18 Dunlops, LOVE them.
This means my mileage will be off, also trip meter will be off, and my warranty =(
What we do for 5 spoke....

How do you like?

 

[dwc]

I just put on my rx8 rims with 225/40/18 Dunlops, LOVE them.
This means my mileage will be off, also trip meter will be off, and my warranty =(

Wait, what?

 

[khoney]

I think he meant that actual miles on the vehicle will be less than what the odo reports at 36K/60K.

 

[manselainen]

My tacho reading is about 4% off with stock tires so 235/45-18 would almost correct it.
3 MPS -07

 

[charlessss]

45 series is tall IMO. Had them on for a couple days, felt sidewall flex, and since I am lowered had some major rubbing too. But it was more comfortable though.

 

[Kyrosfactor]

I dont have the link at the moment but there are tire/rim size calculators that will show you how much it will be off.

Here you go-----http://www.miata.net/garage/tirecalc.html

 

[event]

Would this effect my MPG? Or would I have to take into consideration the 2% change in size when calculating my MPG?

I just put on my rx8 rims with 225/40/18 Dunlops, LOVE them.
This means my mileage will be off, also trip meter will be off, and my warranty =(
What we do for 5 spoke....

How do you like?

you mean I'll have to put my stockers back on when going in for warranty work? that's dumb

 

[meicalnissyen]

I think he meant that actual miles on the vehicle will be less than what the odo reports at 36K/60K.

No, sorry, I think he thinks it will change his fuel efficiency