Flat Plate & Flotation

by | Jun 28, 2016 | Featured, Flotation | 0 comments

What is a flat plate measurement and how does it affect flotation, traction, and yield?


Flat Plate describes the contact patch or footprint in square inches of AG Tire, as shown below:

Flat Plate with Arrow

As discussed in “Better Yield” post, larger flat plate is important as increased flotation and larger contact patch enables more full weight disbursement, thus reducing compaction. Click Better Yield Basics Post link if you need review.

Best use of Flat Plate Measurement is by comparing sizes among manufacturers. Reason:  there is no standardized methodology or air pressure to measure flat plate. As a result, measurement varies between manufacturers; however, they are consistent within each individual manufacturer.

Michelin Row Crop Sprayer Tire Example
VF380/90R46 173D Michelin Spraybib:  Flat Plate = 267 square inches
380/90R46 157B Michelin AgriBib:  Flat Plate = 224 square inches
In short, VF rated 173 D tire has 16% larger flat plate.

It is also important to note that higher load speed index will also contribute to less air pressure required to carry load.

In short, if you are looking to increase flat plate on a particular size:

  1. Use VF Technology
  2. Choose highest Load Speed Index available.

All information is provided in this blog solely to provoke thought. All deductions made from information on this site must be confirmed by Certified Ag Tire Dealer before use. Ag Tire Talk does not recommend anyone conduct tire service work with exception of Certified Ag Tire Dealer Professionals.