Quote:

Originally Posted by **vinodkumar** I feel there is some error in the calculation. 195 X 65 R15 will be a right upgrade with 6 mm increase in ground clearance and 2%^ error. We are using that from the beginning. |

Hi Vinod

Both our calculations are similar to a large extent, except for the 'error calculation' part. I guess you have used height for the calculations. But

IMO, odometer error has to be calculated based on circumference of the tire since odometer will be calibrated based on rotations of the wheel (i.e., for each rotation of the wheel how much linear distance the tire will travel). Have included that also in attachment with this response.

Even if I use your calculation, errors are as follows:

> 195/60/15 :

**-1.05% &**
> 205/60/15 :

**0.88% **
> 195/65/15 :

**2.09%**
Among the 3, error is more in 195/65/15 than others.

To put things in perspective, if we use tires with +ve error, odometer will show lesser kms than what the car actually travelled (since car will travel more distance per revolution). Assuming error is +4%, if car travelled 100kms odometer would show 96 kms only. It could appear small for 100km example - but if you use car of 1,00,000kms error will be 4,000kms which is significant.