Just something to consider when discussing larger tyres and the impact on fuel economy.

Your fuel consumption calculations you need to consider that the circumference of the large tyre is greater that the factory tyre (say 33 is 104 inch versus 31 is 97 inch) so the odometer will be out .ie a a larger diameter tyre will be turning the odometer over slower than a small diameter. Meaning that the larger tyre will have to travel say an extra 7 inches before it will complete a full 360° rotation.

Based on the above numbers it is about a 7% variation, so whilst the torque definitely takes a hit and will influence gear selection particularly for city/suburban driving, the economy will be affected but probably not as bad as calculations using odometer suggests, (particularly for highway driving.)

In this case you’d need to multiply the distance travelled by 1.07 first to work out a more accurate economy figure. Hope my maths are correct, I’ve only had one coffee..ps this assumes all other gearing remains constant.

nb the larger diameter will also impact on the speedo.. so watch your GPS.

Your fuel consumption calculations you need to consider that the circumference of the large tyre is greater that the factory tyre (say 33 is 104 inch versus 31 is 97 inch) so the odometer will be out .ie a a larger diameter tyre will be turning the odometer over slower than a small diameter. Meaning that the larger tyre will have to travel say an extra 7 inches before it will complete a full 360° rotation.

Based on the above numbers it is about a 7% variation, so whilst the torque definitely takes a hit and will influence gear selection particularly for city/suburban driving, the economy will be affected but probably not as bad as calculations using odometer suggests, (particularly for highway driving.)

In this case you’d need to multiply the distance travelled by 1.07 first to work out a more accurate economy figure. Hope my maths are correct, I’ve only had one coffee..ps this assumes all other gearing remains constant.

nb the larger diameter will also impact on the speedo.. so watch your GPS.

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