Tyre Pressure and Dyno Results

[Bill]

Just noticed that when my car was Dynoed they recorded the Tyre pressure.

Does Tyre pressure have much effect on Dyno results?

[MM2death]

The more pressure gives better grip on the rollers.

Scott

[Steg33]

Bill, tyre pressure won't have any effect on the power figure at all if there is no wheel slip. Only high powered or agressive boosting turbos need to worry about this generally.

The more pressure gives better grip on the rollers.

Scott

Correct me if i'm wrong, but lower tyre pressures are better for grip due to the increased surface area and allowed wall stretch in the tyre, eg: drag racing.

[MM2death]

Bill, tyre pressure won't have any effect on the power figure at all if there is no wheel slip. Only high powered or agressive boosting turbos need to worry about this generally.

Correct me if i'm wrong, but lower tyre pressures are better for grip due to the increased surface area and allowed wall stretch in the tyre, eg: drag racing.

But when they dyno your car, they strap down the rear of the car to anchor points. With this downward pressure and inflated tyre pressures at the rear, it would give better traction to the rollers. Correct me if i'm wrong...but that's the reason i think they do it.

Scott

[Steg33]

But when they dyno your car, they strap down the rear of the car to anchor points.  With this downward pressure and inflated tyre pressures at the rear, it would give better traction to the rollers.  Correct me if i'm wrong...but that's the reason i think they do it.

Scott

It's correct that they always strap them down for downward pressure (and also safety), but increasing the tyre pressure is only going to make it easier to break traction earlier due to the tyre wall being more rigid. A tyre will have a higher traction (friction coefficent) if it's pressure is lower and there is more 'tyre' on the rollers. This is how i see it but anyone else feel free to add.