On Fri, 1 Jun 2018 22:29:56 +0100, Steve Walker
wrote:

snip

but did get a couple of tyres and rims from the wreckers

Dangerous and stupid thing to do.

Nope, just because the body of the car was
a write off says nothing useful about the tires

Exactly, it says *nothing* about the tyres.

And equally you know nothing about the tyres on any second-hand car that
you buy

Not entirely true. You know that they currently work and aren't
showing any signs of issue in use. You may know the PO (family?) and
so have a good idea of their likely treatment. Not the same for a
vehicle where the last time the wheels went round is when they were
winched up the back of the recovery vehicle after a crash, being
stolen and joy ridden or some accidental off-road experience.

- or do you immediately replace all the tyres no matter how much
tread is on them?

Yes, it's not unknown for me to fit all new tyres to a vehicle new to
us (irrespective of the tread etc) because:

1) They are rarely a complete set of the same brand / model.

(We have got second hand cars with 4 different makes / models of tyre
fitted or one car that tyre of a different size! Another (a van) had
two brand new tyres on the front that may have had sufficient load
rating for the front but not if they got moved to the back when they
could have been overloaded. So we changed the set).

2) They are rarely the tyres I would fit given the choice.

3) They have often been 'getting old', even if they appeared ok from
the outside (especially on trailers and motorbikes) and so I will
often change them 'anyway'. I noticed (during a long trip pre check)
the tyres on the back of the Meriva were the originals (same date code
as the reg) and I wanted to change the fronts anyway. So, I changed
the set (so they were all the same model).

4) As we generally keep any vehicles till their end, we might as well
have something known / good from the getgo (or once we have determined
it's a keeper etc).

Tyres are your only contact with the road and in the event of a
catastrophic failure can end up costing *way* more than a set of
tyres.

So, I have *never* bought a second hand tyre, *especially* from a
breakers and yes, often replace what look like fairly good tyres on
any second hand vehicle we get, *because* I value lives (convenience /
licence) more than I want to gamble with a complete unknown or
something with a question mark on it (age or suitability etc).

YMMV etc. ;-)

Cheers, T i m

p.s. I bought a new to me motorbike and whilst the tyres were (looked)
fine, they were quite old so I mentioned to the local motorcycle shop
that I needed some new ones and because I'd previously helped them out
with IT stuff (for nothing), they gave me the new tyres at cost. I
didn't get round to fitting them and now they are probably 7 years old
(still unfitted) so I'll probably throw them away. The last thing I
need is to fit tyres that may have hardened because they haven't been
used or may have some other issue (*especially* on a motorbike).

I recently gave away a 14' dinghy for a neighbour because I wanted the
trailer it sat on. I only needed to take it about 5 miles but because
the tyres were old, had been left under inflated and were showing
slight signs of cracking on the sidewalls, I replaced them both (with
brand new complete wheels).

1) I didn't want to be stuck with a failed tyre anywhere on the trip.
2) I didn't want to risk 6 points on my licence.
3) I hoped to be using the trailer after getting rid of the boat.