Tire Concerns: Tire Pressure and Speed rating charts

by Bernie@Beleskey.com
(Kitchener, Ontario Canada)

It is my information from doing accident insurance investigations, that a lot of accidents involving RV's are related to tire problems.

When the tire pressure is 20% + below the maximum rating on the tire, rather that the rating on the RV or Pickup/Tow unit.

NB the rating on the vehicle unit is usually 25 - 40% below the rating on the tire.

It has been proven that lower pressures on the maximum rating on the tire cause the following:

Lower fuel economy
Lower control and braking
Lower speed rating
Poor steering control in wet and windy weather
Excessive bouncing of RV
Over heating

All leading to blowouts and possible accidents.

Upon contacting all the major tire manufacturers I found out that their posted speed ratings are based on their maximum recommended posted tire pressure "Cold."

They all indicated that a reduction of tire pressure relates to a reduction in the "Speed Rating."