[Neweller]

RecNo DateCreated TimeCreated DateModified Name Email Subject Message QA
58 8/14/2000 12:19:56 PM 11/7/2003 Newell staff engineering@newellcoach.com Proper Tire Inflation SUMMER SEASON TIRE CARE

The simple rule: proper inflation for Michelin 315/80 R 22.5 front tires on a Newell motor coach is 130 p.s.i. cold for 65 m.p.h. speed rating and 140 p.s.i. cold for 75 m.p.h. rating. Running at lower pressure decreases the load carrying capacity and speed rating of the tire and can result in a blowout. This is particularly critical running freeway speed in the heat of summer.

The majority of the weight supported by a tire is actually being carried by the air contained within the tire body rather than the rubber tire carcass. A tireÕs sidewalls are designed to contain air, not to support the weight of the vehicle. However, decreasing air pressure reduces the weight that the air can support, and causes the tire sidewalls to flex as the vehicle is driven. Excessive sidewall stress causes heat buildup, especially running in the heat of the summer.

When heat buildup reaches a critical stage, the rubber actually begins to liquify, the bond between the tire casing and tread will begin to degrade, particularly with higher centrifugal forces at high speed, and the tread can suddenly delaminate from the casing. This typically happens at freeway speeds without warning.

Running at 130 or 140 p.s.i., versus lower inflation pressures, reduces sidewall flex and heat buildup, contributing to reliable, safe tire performance.