
Never exceed the maximum cold inflation pressure branded on the tire's sidewall. Its shown as a letter after your size in the picture.

When tire inflation reaches its maximum allowed then tire load capacity is reduced as speed increases. The speed rating or speed index is represented by a letter and associated with the tyres maximum speed capability when operating at its maximum load. The next year, Cheech, as the sole employee of Orient Speed, introduced the tire into the US market with Orient Speed being the exclusive distributor. The speed rating of your tyre can be found on the on the outside of the sidewall. Start with tire pressure recommended for normal driving conditions, and as speed increases, initially so does the tire inflation. Choose from Firestone Complete Auto Cares selection of 225/40R19 tires and get an online quote or visit your nearby store. To accommodate higher speeds you need to make adjustments to the tire pressure recommended by the vehicle manufacturer and to the tire's maximum load capacity branded on the tire sidewall. When driving at high speeds, tires are subjected to tremendous stress as tire revolutions per second increase significantly with faster speed.

Recommended High Speed Tire Pressure and Tire Load Capacity Adjustments It is common for a jet airplane tire to carry loads as heavy as 60,000 pounds while operating at ground speeds up to 235 miles per hour.
