And a PS on tires and hot road trips - Please CHECK YOUR TIRE
PRESSURES BEFORE you start!!!
Regardless of age, one of the most significant causes of tire
failure is UNDER-INFLATION, particularly AT SPEED on a HOT DAY.
And if you find one tire significantly lower than others LOOK for
the CAUSE and fix problem.
Have a good trip and a successful meet - wish I could be there.
First - tires do age and there can be age related failures. It
is not simply a ploy to sell more tires though that side effect
is not undesirable to tire manufacturers. Like most warning
labels, their primary goal is to avoid liability for failures
and / or to comply with regulations.
And a number of factors in addition to age contribute to tire
aging. These include how they were stored, exposed to sun or
other weather, mounted or not, loaded or not, etc. Further the
choice of rubber compounds may cause Brand C to have more
detrimental aging than Brand A or B in a specified time.
In the US there is not yet a mandated Sell By or Use By date
system for tires, but rather it is left to manufacturers to
determine what they want to do - for example they may choose to
warranty their tires for 5 or 6 years from date of manufacture
(the 4 digit DOT code on sidewall - first 2 digits are week and
last 2 are last 2 digits or year made), or some will cover for 3
or 4 or 5 or 6 years from date of purchase.
Then there is the tire dealer's policy as to whether to set a
limit on age of tires he will sell. Again 3 years and 5 years
seem to be common limits. I purchased some tires off eBay, but
first asked about seller's age policy and I was told they would
not sell tires more than 3 years old, if date code was older
than 3 years they would exchange tires - OK - I bought - tires
came in about 16 months old - which is about same as what I can
get from inventories locally. Depending on size and popularity
newest I can remember is about 6 months.
I think there may be some age limits somewhere or maybe just
proposed - Japan or Europe maybe and it seems like I have heard
8 or 10 year limits - but I have no direct knowledge of such.
Lots of wind but no answer - right? I doubt anyone will tell
you to drive 60 mph on 20 year old tires, but here is what I
would look for on ANY tire.
First, What IS the age? If you still have the 3 digit DOT code
they are probably too old. 5, 6 years maybe even 8-10 may be OK
IF everything else is OK - Do a real visual inspection looking
for any local pattern of cracks. Check for nails and cuts and
any other damage while you are at it.
Second, While inspecting, look for signs of aging in the tread
- brittle rubber and possible chunks missing. I have had both OE
tires on an 250 truck and OE tires on trailer (same brand) show
detrimental aging at 3 to 4 years.
I lost chunks out of 3 of 8 LT235/85R16 trailer tires on hot
day in Arkansas under load (Saw one come off and found others
when I stopped). It cost me an overnight stay in Bentonville and
a trip to Sams Club in the morning for 8 new Goodrich tires (in
stock). Yes these were the Goodrich that were recalled - I later
got a free set of Michelin XPS to replace them but some of the
new XPS were already 4 years old. Months later I found small
chunks gone from 2 of my truck's tires (same brand) - dealer
offered me warranty ONLY if I replaced with same tires (Ha
Ha!!).
Another sign of tread aging is small lines in tread rubber
mostly on shoulder block and mostly parallel to side of tire.
These sometimes occur especially on front tires and may result
from a relatively brittle tread rubber subjected to load while
turning wheels. This is more of a tread compound aging issue
which may indicate hardening of rubber, but it is still an
undesirable aging effect.
Third, How have the tires been stored and maintained - If they
have been stored in dark environment at controlled temperature
and not under load, you should get much more life than something
stored outside in the sun, or even partly in the sun - or in
freezing weather in a puddle of water (ice). And load and
inflation may be significant, especially at high load and/or low
pressure.
Fourth, How long have you been driving on them and do they stay
parked and not driven for long periods with significant load on
tires? Parked cars can develop flat spots that can both cause
local deterioration and result in asymmetric loading when tire
spins up at speed. This is especially true if a tire sits flat
for a long period - Replace it. But even if not flat, look for
little cracks at the buldge around where tire meets floor,
especially if any of tires are or have been low on pressure for
long periods.
SORRY NO REAL ANSWER but some things to think about. If in
doubt I would replace them especially considering your planned
drive.
Edward Mills Antique Tractors 1930-1960
Antique Cars 1960-1985
Sent from my iPhone
Begin forwarded message:
All;
I’m trying to get by on a set
of Coker Classics in my 300F, but want to
drive the car about 250 mi north to the 300
Club meet in Rohnert Park in a couple of
weeks.
The tires seem fine as I tool
around Palm Desert on 20-30 mi runs, often
at 60- 70 mph in stretches.
Lots of tread depth and no side
wall cracks or blisters but here are some
hair line cracks on the side wall running
parallel to the wheel, just outside the
wheel lip.
I’ve been told everything from
‘get new tires immediately to cheap sob’ to
‘if the cracks deepen to 1/8", it’s time to
buy new tires’ to ‘hell, roll ‘em off the
rims, it’s all a scam by the manufacturers
just trying to get you to buy more tires
more often’.
It’s hot weather here now,
90-100 in the daytime and I’ll be rolling up
I5 to San Francisco at 60-65 mph. It’s
likely 7-8 hours with three or four stops
along the way.
Question: ‘get new tires you
cheap sob’ or ‘roll ‘em off the rims’?
Thanks,
Mark
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