Tires build up heat as they turn, mostly from the flex of the contact patch
when rotating, and also, separately, from heat generated by the brakes
under braking. As the tire material degrades over time (and hardens too),
it can not withstand the flex/brakes heat cycle as well and this compounds
the decay...hence problems in the moment of crisis when you "load" up the
tire's sidewalls. I get a shutter when I see obviously old tires with
cracking, dry-rotted sidewalls mounted to classic cars...your safety margin
is very small at that point. For TR6s, tubed-tires create even more
internal heat than non-tube, as the tube rubs against the inner tire during
the contact patch flex (and, in a nutshell, is why tubed performance radial
tires were very short-lived in the marketplace) .
I also understand that this is a big problem with RVs that sit for long
periods of time...the tires degrade tremendously and blow out with very low
actual driven miles.
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Date: Mon, 15 Oct 2001 09:05:32 +0100
From: Will <tr6@mac.com>
Subject: Re: Tires - Let's be safe!
> The accident was blamed on the failure of his old tires.
>Please, everyone, if you have old, original tires that you want to use for
>show purposes, only use them for that purpose. Keep another set of tires
>and wheels with modern tires for running at highway speeds or normal
>driving. Me - I run on 2 year old 205/70x15s and keep an old tube-type
>Michelin redline as my spare.
>
>Rex Townsend
I'd like to second this one.
Last year we set out across France on two new tyres, one almost new
tyre & one 'old' tyre, which nonetheless had plenty of tread & no
sign of damage. We reached the centre of France by Autoroute without
incident, however the return journey began with a wooden palette
lifting off a trailer I was following, and crashing into the road in
front of me. The hard steering needed to avoid this must have
weakened the old tyre: just minutes after joining the autoroute it
burst, & the car ended up a write off.
A new body & chassis later & its back on the road, but I won't be
caught on old tyres again....
- --
William Davies
1975 TR6 PI
CR6157-O
William Whitmoyer
69 TR6
90 BMW iX
91 CRX Si
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