Ag Tire Inflation Advice - Bias vs. Radial

Posted by Jim Enyart on Jul 24, 2019 9:48:05 AM

Radial and bias Ag tires are different in many ways, including how you determine the correct air pressure. This latest CEAT blog post explains so you can get optimum performance from both types.

First, let's start with the overall objective as outlined in my previous blog post -- inflate to the air pressure appropriate for your most demanding application for each tire. This critical information is contained in the tire manufacturer’s data book. The load and inflation tables show the speed range, the inflation range and the load range for each tire.

Bias vs radial inflation pressures

Inflation pressures for bias tires are quite often higher than for equivalent radial sizes.

Bias tires are really designed to carry loads and transport them over distances. Radial-designed tires carry the load and transport that load, but also provide increased traction, improved flotation, reduced compaction and a longer service life. 

The higher the inflation pressure, the more load you can carry. This generality is due to the design differences, as well as the performance features of both types of tires.

When flotation, foot prints and traction are not of primary concern, it is much IMPLEMENT 404 - 135 Angleeasier to alter designs to carry increased loads via bias design tires. Bias tires, such as the CEAT Farm Implement 404 (pictured to the right), are more tolerant of overloads than radials.

The casing design of bias tires is suited to carry the heaviest of loads utilizing higher inflation pressures as well as higher ply ratings to achieve these results. When you need more load-carrying capacity with a bias tire, you can increase the ply ratings as well as beef up the bead package, increase your maximum inflation pressures and carry increased loads to a point.

CEAT FARMAX R85-2Radials, such as the popular CEAT FARMAX R85 (pictured to the left) can carry heavy loads as well, but are less tolerant of overloads because the radial design delivers sidewall deflection that provides the advantage of longer, flatter footprints, increased flotation and traction. While load-carrying capacity is important, the primary benefit of a radial tire is to provide minimal compaction as well as traction. These features are primary and altering belt strength without maintaining flexibility will reduce performance of the radial tires.

Again, consult the tire manufacturer’s data book. The load and inflation tables show the speed range, the inflation range and the load range for each tire.

A Cold One

Air pressures should be taken when the tires have not been running and are FARMAX R85 squareconsidered to be at a “cold” temperature. Checking first thing in the morning is best due to the tires sitting overnight.

Air pressures taken after the tire has been running will be higher then the “cold” air pressures and can be misleading. If you reduce your pressure after taking a warm inflation pressure you likely will end up in an under-inflation situation. Under inflation of any tire can result in sidewall deflection that extends beyond the deflection parameters of the sidewall, resulting in tire damage.

Over inflation can also be damaging. Maximum “cold” inflation pressures should be adhered to very diligently. The air chamber determines the load each tire can carry! The larger the air chamber the larger the load it can carry.  When you have too small of an air chamber to carry the required load it is sometimes tempting to over inflate the tire. Increased air pressures can carry more load but exceeding the manufacturers maximum inflation pressure is not endorsed by any manufacturer!

Tires are expensive, down time is critical and tires do not repair themselves!

Inflation pressure for Agricultural tires is very simple. You just need to inflate to the most demanding application. The hard part is determining exactly the most demanding application and asking enough questions to get the best information. Inflating tires to their maximum recommended air pressures is one approach but it not the best way to deliver the maximum performance and benefits from your tires.

Look for future blog posts on additional advice on inflation pressures for implement tires and other Ag tire categories.

If you have questions, please leave a comment below and I will get back to you. Or click on the banner below to be contacted about CEAT Ag tires.

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Topics: Ag tire maintenance