photohiker wrote: tyre failure increases with age as they get harder and more brittle.
Giddy_up wrote:photohiker wrote: tyre failure increases with age as they get harder and more brittle.
Interesting photohiker, my experience is exactly the opposite for the same reason you list. When I had my farms we would buy sets of tyres for all our equipment and vehicles and we would hang them in a dry, dark shed for storage so the rubber could harden in the tyres. We found they lasted longer and we achieve superior mileage from hardened tyres as apposed to fresh soft rubber straight from the tyre fitter. We use to do plenty of miles as well, we lived 140km from the nearest grocery store to give you some idea.
How old is too old?
This is a subject of much debate within the tyre industry and no tyre expert can tell exactly how long a tyre will last. However, on the results of experience many tyre companies, including Bridgestone, warrant their tyres against manufacturing and material defects for five years from the date of manufacture. Based on their understanding a number of vehicle manufacturers are now advising against the use of tyres that are more than six years old due to the effects of ageing.
Tyre Ageing Mechanism
There are three main mechanisms of tyre ageing. The first involves rubber becoming more brittle. Sulphur is used to link rubber molecules together during vulcanisation with the application of heat and pressure, giving the rubber its useful elastic properties and strength. As the tyre absorbs energy in the form of light, heat or movement the tyre continues to vulcanise. This ongoing vulcanisation causes the rubber to become stiffer and more brittle.
The second mechanism of tyre ageing is oxidation involving oxygen and ozone from the air compromising the strength and elasticity of the rubber and the integrity of the rubber to steel bond. Basically heat and oxygen cause cross linking between polymer chains (causing the rubber to harden) and scission of polymer chains (leading to reduced elasticity).
Thirdly, breakdown of the rubber to steel-belt bond will occur due to water permeating through a tyre and bonding with the brass plate coating on steel belts. This causes the steel to rubber bond to weaken leading to reduced tyre strength and reduced heat resistance. If compressed air used for inflation is not completely dry, tyre strength will be affected over time. Even unused tyres will become more brittle, weaker and less elastic with exposure to water, air, heat and sunlight.
Warning signs
Regardless of their age tyres should be replaced if they show significant crazing or cracking in the tread grooves or sidewall (Figure 3&4) and or bulging of the tread face or sidewall. All tyres, especially unused spare tyres, should be inspected periodically to determine their suitability for service. If there is any question about a tyre's suitability please consult your local Bridgestone Tyre Centre expert.
Strider wrote:You won't regret it. Coopers are the worst tyre I've ever had the displeasure of using. So bad they literally chipped themselves apart until they eventually just leaked all over the tread surface!
johnnymacfnq wrote:Good to hear, I've been looking at getting a RTV and due to the wider track tyres are a real PITA. If you're not already a member check out http://www.fordforums.com.au/, good info, good people.
Users browsing this forum: No registered users and 16 guests