LONGER TIRE WEAR. LOWER OPERATING COSTS.
Today’s commercial tires are better than ever, constructed to deliver longer original tread life, designed with durable casings and built to withstand more retreads. Despite these on-going product improvements there are still things that you can do to get the most out of your tires.
Getting the most out of your vehicle should be simple?all that is required is that your tires roll smoothly through an optimized footprint. Unfortunately the tiniest of imperfections in one of hundreds of mechanisms involved will make your vehicle operate less efficiently. Vigilant inspection, regular service, and prudent operation are paramount to ensuring that your CPM stays as low as possible.
There are three primary types of factors that prevent optimum performance from being achieved with otherwise mechanically sound vehicles:
- Incorrect air pressure
- Improper alignment
- Operational inefficiencies
In general, tires perform best when inflated to match vehicle and axle loads. Steer tires often require maximum inflation pressure to carry the steer axle load, while trailer tires should be set at pressure corresponding to actual tire loading. Included in this guide are the current load/inflation pressure tables for all Yokohama products, only. There are three recommended ways to correctly determine and set operational inflation pressures:
- Yokohama tire load/inflation charts
- Actual vehicle weight
- Yokohama Tire Inflation Pressure Calculator -
Proper Air Pressure
How a tire wears depends on the forces that act upon the contact patch of that tire as it meets the road. Therefore, it is important to maintain proper inflation pressure. If a tire’s load is equal on all ribs or elements, it tends to have a square footprint shape.
An overinflated tire tends to have a short shoulder rib contact area (shorter than the center rib). As the tire rotates, the footprint center maintains close contact, but the shoulder area does not. This causes scrubbing action and uneven wearing of the shoulder rib while placing more strain on the contact area.
An underinflated tire can’t maintain its shape and becomes flatter than intended while in contact with the road. This causes over-deflection, internal heat buildup, increased rolling resistance and reduced fuel economy. Under-inflation flexing and heat buildup within the tire components, which deteriorate tires and reduces casing life and retreadability.
- 20% underinflation can reduce tire life 30%
- 30% underinflation can reduce tire life 40%
- 40% underinflation can reduce tire life 50%
YOKOHAMA TIRE INFLATION RECOMMENDATIONS
Actual Vehicle Weight
1. Determine actual tire loads.
- Weigh several tractor/trailer vehicle combinations that best represent actual maximum load conditions for these vehicles while in operation.
- Determine average weights per axle of these weights and divide that value by the number of tires on that axle to determine actual tire loading.
2.Determine minimum cold inflation pressures for each tire per axle.
- Use the actual load per tire (per axle) to determine the cold inflation pressures for the tires by size, ply, and type.
- The actual tire load should be compared to the tire load limits on the chart for the particular tire size and ply rating.
- The corresponding recommended cold inflation pressure is indicated for the load in the chart heading.
- If the actual tire loads are heavier than the ply rating of the applied tire, it may be necessary to install a tire with a higher ply rating.
3.Use the determined inflation pressures as minimum inflation values to set up the vehicle for improved handling.
- In all cases, the determined inflation pressures based on actual load conditions should be considered minimum pressures.
- Operational air pressures can be set higher, but under no circumstances should they be set lower.
Air Pressure Calculator
These recommendations as outlined should be adopted and used for all Yokohama truck/bus tires when the tires are new and first installed on the vehicle. Correcting inflation pressure after irregular wear has begun will not correct the wear pattern.
The pressures will only be effective in preventing wear if used from the point of the original mounting. For specific recommendations, please refer to the Yokohama Tire Inflation Pressure Calculator HERE.