Getting back to what the OP was concerned about: 65 mph max, I found the following in the "Goodyear (Marathon) Recreational Vehicle Tire and Care Guide". Has anybody tried raising their tire pressure to 75psi (if your wheel allows it) so they can go 75 mph?
I will never try it. 65 mph max. is fine by me. Just curious.
BEGIN QUOTE
IMPORTANT OPERATING INFORMATION
Industry standards dictate that tires with the ST (Special Trailer) designation are speed restricted to 65 mph under normal inflation and load conditions, unless a different speed restriction is indicated on the sidewall of the tire. Based on industry standards, if tires with the ST designation are used at speeds between 66 and 75 mph, it is necessary to increase the cold inflation pressures by 10 psi above the recommended pressure for the load.
• Do not exceed the maximum pressure for the wheel.
• If the maximum pressure for the wheel prohibits the increase of air pressure, then the maximum speed must be restricted to 65 mph.
• The cold inflation pressure must not exceed 10 psi beyond the inflation specified for the maximum load of the tire.
END QUOTE
Another quote to explain why 65 mph is fine by me:
BEGIN QUOTE
Effects of Higher Speeds
• When traveling at 65 mph vs. 55 mph, tires will experience a 15% tread life penalty (30% at 75 mph)
• Trucking fleets report fuel economy losses of about one mpg for every ten mph over 55 mph (a 15% loss)
• Longer breaking distances (SAFETY ISSUE!)
• Reduced handling ability (SAFETY ISSUE!)
• More fuel stops due to reduced fuel economy
• Tire load-carrying capability decreases as speed increases
END QUOTE
|