New shoes (aka tires)

[cfg83]

caprice -

Originally Posted by caprice

yeah the best thing to do is verify the odometer with GPS. Instead of reling in the specifications.

On my old Daewoo, the speedometer was right on with stock size tires, odometer off, then with oversize diameter tires, the speedometer off a little and odometer dead on.

The road grove following is a side effect of higher TP. Im my experience, it gets worse with more air. That is when you know you have reached the limit for that tire. Also sometimes you can "feel" paint stripes though the handling.

I backed it down to 40 PSI and the road grooving diminished, so I think I will leave it there for now. I did another Odometer test and got the same result :

GPS:Car Odometer
32.83/31.80 => 32.8 / 31.8 = 1.031 => 3.1% error

CarloSW2

[cfg83]

Hello -

Here is a quick GPS update (in miles) :

              Car Odometer    GPS       GPS/ODO    % Correction
2007/12/01    30.4            31.2      1.0263     +2.6%
2007/12/05    31.4            32.3      1.0286     +2.9%

What does this mean? My one size larger tires, currently running at 50 PSI, are still showing a greater than 2% change when compared to the odometer. Since I use my odometer for calculating MPG, my +2% correction in my gaslog is still valid (whewwwwww! ).

CarloSW2

[8307c4]

You're supposed to lower sidewall profile a step when increasing width to help offset speedo miss-calibration, so those new tires should've been 195/60's...

Didn't the installer know this?

The wider tire will help some, I like them myself.
But I doubt it helps mpg any, I didn't see it hurt either thou.

[cfg83]

8307c4 -

Originally Posted by 8307c4

You're supposed to lower sidewall profile a step when increasing width to help offset speedo miss-calibration, so those new tires should've been 195/60's...

Didn't the installer know this?

The wider tire will help some, I like them myself.
But I doubt it helps mpg any, I didn't see it hurt either thou.

I told them I wanted this tire size, . The idea is to increase the diameter of the tires and thereby create a "taller gearing" for the car. I don't mind the odometer correction because it's "proof" that the tires are bigger (aka working) as intended. Orrrrrrrr ........... the odometer was off by X amount already, .

CarloSW2