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Structurally they are reasonabley sound, they have to meet a minimum standard. Compounds are played with, a brand is introduced with a hard compound. Word gets around that one bung lung tyres last forever,in the meantime, the compoundhas been altered. By the time the tyres have a bad name, the brand has been changed, start again. these type of tyres are generally bought by people who are looking for the cheapest tyres, not the safest.Quote:
Originally Posted by isuzurover
New rego of a 15 yo Volvo:clap2:Quote:
Originally Posted by DiscoMick
Move to Canberra; it never rains there :p:wasntme:
You can get products like this: AZNU pageQuote:
Originally Posted by DiscoMick
However they are for race/offroad use only, and as Rick said, they may do more harm than good.
It has been stated on another forum that only the outer layer of the tread hardens, so if you can remove that layer (while driving or otherwise) then the tyre will work better.
Ozone deteriorates rubber (see here: [ame=http://en.wikipedia.org/wiki/Ozone_cracking]Ozone cracking - Wikipedia, the free encyclopedia[/ame]) so make sure no "ozone cracking" is visible. This also suggests that tyres which spend most of their time in sydney or melbourne would deteriorate/harden more rapidly than those which are driven mostly in country areas.
I checked the date on my tyres this morning. If I am reading it right, they were manufactured (in the USA) in mid 2002. However they were in storage for 3 years while we lived OS. As they look perfect (defect free), have no issues when aired down as low as 7psi, still grip better in the wet than the original cross plys, I have no issues with still running them (but will of course drive accordingly - in 4WD - in the wet). I might try siping them out of interest though. Or "smoking them up" with the mighty 2.25D :D
I don't buy that at all.Quote:
Originally Posted by isuzurover
Tyres do 'skin', but it scrubs off pretty quickly.
Heat cycles and UV are the real killers, and the tyre engineers I knew reckoned that once the oils leached out the tyre was hard through.
We also proved this when tyre testing different makes/types/compounds for the category.
All tyres went off with heat cycles, some much faster than others and none ever 'recovered' their grip once lost, they only lost it, regardless of how they were scrubbed.
This was borne out when I threw away far too many sets of Dunlop race tyres in the last year I raced.
Often they would only have one meeting under them and two weeks later you would take them out and they would be 2 seconds a lap slower at Eastern Ck :eek:
Not 2/10, but 2 whole seconds.
The car would be sliding all over the place and virtually undriveable.
After twenty laps sideways on every corner you should have worn a bit of rubber off, but they would never come back, and everyone else had the same problem.
Bolt a new set of tyres on and off you'd go again, instant speed.
They couldn't even be used for practice/testing, they were so bad.
Interestingly the Avon tyres used previously and in subsequent years were far more forgiving, dropping little time as they wore out and were far more consistent overall.
Just better compounding and construction.
Aren't the compounds in race tyres very different to road tyres though Rick? I thought race tyres had an incredible short life regardless.....like F1 tyres I thought they were only good for so many laps not races
When you get to F1 there are differing compounds for different tracks, temperatures, weather, driving style/preference/skill, et al; almost day of the week!Quote:
Originally Posted by dullbird
Compound selection is particularly strategic the higher up the classes you consider. Balance lost time per lap/number of laps for given compound/lost time changing tyres.
I suspect the guy in question was running illegally oversized tyres, and/or non adr/dot approved tyres. Which would give the insurance company grounds - if they can show the tyres contributed to the accident.Quote:
Originally Posted by rmp
Missed this previously Rick. When I first bought the tyres (and the IIA was a hardtop), I found 42-44 handled best on-road. I pumped them up to 45/6 coming across the nullarbor, and have kept them there since. It weighs about 1950kg (unladen except for tools, spare, jack, recovery gear).Quote:
Originally Posted by rick130
Btw - I thought some people may not have seen this, which was posted in the poll:
Pre 2000 tyres used a 3 digit code.Quote:
Originally Posted by isuzurover
Quote:
Reading the code. The code is pretty simple. The three-digit code was used for tyres manufactured before 2000. So for example 1 7 6 means it was manufactured in the 17th week of 6th year of the decade. In this case it means 1986. For tyres manufactured in the 90's, the same code holds true but there is a little triangle after the DOT code. So for this example, a tyre manufactured in the 17th week of 1996 would have the code 176triangle
After 2000, the code was switched to a 4-digit code. Same rules apply, so for example 3 0 0 3 means the tyre was manufactured in the 30th week of 2003.
there was a program on TV. some racing team, rather than get there tiers from the supplier at the track they had picked up the same tiers a few month earlier from another dealer. they were only lasting 4-6 laps. turns out they were 2 years old ( old stock) apparently race tiers doint have a shelf life.
Did a quick experiment today. This morning the roads were almost dry. Couldn't get the tyres to break traction.
Most of the day it has been raining on and off lightly. Had to pick up some lab stuff at lunch, so did a small experiment. With the tyres at their usual pressure (44psi) in an unladen IIA ute in 2WD, drove along some back streets - and as per usual the tyres slid a bit when I pushed the IIA hard.
Dropped pressures (rear only) to about 36 psi. Drove the same backstreets at similar speeds. The car slid around MORE, and even chirped the tyres when changing into 2nd - something I have never done ijn the IIA!!!