help understanding foams
 

What are the shore #s bigger number harder or softer and how do you know when to change to a harder or softer shore?

Thanks for your help

The higher the number the harder the shore.
The lower the number the softer the shore.

softer for low traction low wear
harder for high traction high wear

Softer is giving most of the time more grip but that is not always true. In hot conditions a softer tire can give a slippery car and on dusty surfaces a harder tire will not hold the dust.

I was also informed that foam of the same shore, front vs rear, can be different as some manufacturers will use a softer foam for the rear. For example a 45 shore front vs a 45 shore rear from the same manufacturer, the rear would be of a slighlty softer 45 shore. Don't know if this is true but maybe someone could shed some light on this.

Its not softer foam. The foam is different, the front tires foam is denser and grips different.

We have a winner!!! Thank you Nitrodude for the clarification. I knew someone had a answer for that.