I just put on a new set of 195-60-15 tires (a little bigger than stock for an xA) and I notice at 70 mph its still almost 3500 rpm's! What do you guys get? I have a 5 speed. Is 5th gear OD????

 

3500 with stock size tires in my '06 xB.

 

Ummmm....... why do you think it would change?

 

Because the tire is taller.

 

http://www.tacomaworld.com/forum/tir...0r15-195-60r15. Actually now when the the speedo says I am going 70 I am actually going71.5approximately.

 

The only way 70 would be 70 is if you are using a gps for speed. I almost wish I went with 205 60 15.

 

Let's start off with some basics here. Regardless of what size tire (or wheel) you mount on your car, 70 MPH on the speedo will still show 3500 RPM. Tire diameter has no affect on your speedo/tach reading. By going from a 185/60/15 to a 195/60/15 you induce a 2% speedometer error, so at 70 MPH observed, you're actually doing 71.4 MPH. Check it out here;
http://www.miata.net/garage/tirecalcold.html
If you wanted lower RPM at 70 MPH you should have bought an automatic.
70 MPH is 3000 RPM......no matter what size tire is on the car.

 

But if I were actually doing 70 w/ a GPS like I did today the rpm would be a little lower. Now I can set my cruise on 68.5

 

You should've used a GPS before your 1st post! But, I'm sure that would have confused you too.

 

Sorry to ruffle your feathers! I guess I should have said it was the first time on the highway because I just bought the vehicle. I just expected it to be a little lower. So I take it 5th isnt OD.

 

No need to apologize, no feathers ruffeled - but you left me scratching my head. As far as 5th being OD, probably not. Ask 5 speed folks 'cause I'm an AT guy.

 

I've got 205/60/15s on my Yaris and xA. They do rub on the plastic wheel well cover behind the tires if you go over a big bump, but they have about a 3% difference in speed so my "70" is actually like 75. Keeps up with freeways just fine.

And the handling is amazing.

 

yeah i hate the fact that the gearing ratio is 2 to 1, im running at 3500 rpm at 70 mph i was thinking on looking if there was a 5th gear swap or not, but im not sure if there is

 

problem with that though is that these engines have very low torque, so if you drop the gearing, it would require more pedal to stay up to speed. the only time that it would be of benefit is on flat road or very slight increase in elevation.

 

yeah, makes sense, It just sucks because when I drive to and from college its a 6 hour drive, and I hate having the engine revving like that for that long.

 

My Civic w/ a 5 speed is below 3K @ 70 mph. :?