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Tyre pressures

Posted: Fri Aug 18, 2006 10:04 am
by sansom
Hi all,

I've been lurking the forum for advice on replacement tyres (still can't decide whether to get Camac and save some money or splash out on the Bridgestones!)

However, looking through the forum I was interested to read what tyre pressures folks are using.

My MM owners manual says to use 22 front & rear for normal use and 24 at the rear when loaded but several people on the forum seem to be using much higher pressures.

Is there a specific reason for higher pressures? Do modern tyres need higher pressures?

Discuss. ;-)

cheers,
[dave]

pressures

Posted: Fri Aug 18, 2006 10:55 am
by Willie
Radial ply tyres transform the Minor in every way except that they tend to
make the steering slightly heavier. The popular pressures for Radials centre
around 24psi front and 26psi rear. I have been using 25psi all round for some
time on Firestone 145X14" but notice that the centre of the front treads is
wearing less than the sides so have increased my pressures to 27psi all round. I would suggest you start with 25psi and watch the wear on the treads. The wear fate on the sides applies to BOTH sides of each tyre, if the
wear is on one side only then the tracking is out!

Posted: Fri Aug 18, 2006 11:17 am
by sansom
Hi Willie,

Thanks for the sound advice, I think I'll pop for a new set of Bridgestones and try them at 25psi all-round as you suggest.

We don't do a lot of milage in Millie (which incidently looks like a twin of your lovely convertible) so it might take a while to see the wear. What sort of "shelf-life" should I expect from a tyre?

I hear that old tyres tend to go hard with age and with low milage I don't expect to wear them out very quickly.

cheers,
[dave]

Posted: Fri Aug 18, 2006 11:34 am
by alex_holden
I had to replace a couple of the radial retread tyres on my Land Rover after about 7 years because the rubber was starting to crack and split in a few places. Not sure how typical that experience is.

PS. I'm still waiting for my Bridgestones from mytyres.co.uk over a week after ordering them.

Posted: Fri Aug 18, 2006 12:16 pm
by sansom
Another question on tyres...

I see the Bridgestones are called a "Summer" tyre. What does that actually mean?

[dave]

Posted: Fri Aug 18, 2006 12:24 pm
by paulk
I think that means not a winter tyre ie studded. I've used Mytyres and the Bridgestone Ecopia 145/80 sr 14 looks like a perfectly normal tyre.

Posted: Fri Aug 18, 2006 2:19 pm
by Kevin
radial retread tyres on my Land Rover after about 7 years because the rubber was starting to crack and split in a few places.
Ah but how old was the carcase that the retread had been put on, you will never know..........

Posted: Fri Aug 18, 2006 2:53 pm
by alex_holden
That shouldn't matter - it was the new rubber that split, not the carcass.

Posted: Fri Aug 18, 2006 6:57 pm
by minor_hickup
Sansom, are you fitting 145's or 155's? 155's require a few more psi and from watching tyre wear wreckon 29/30psi front and 28/29psi rear is best.

Posted: Fri Aug 18, 2006 8:36 pm
by Kevin
That shouldn't matter - it was the new rubber that split, not the carcass.
I have no direct knowledge about this subject apart from logic tells me that the much older carcase would be harder through age and this would reduce the flexibility of the outer casing, in some cases it has been known for the retread part to come of the original casing which is why I personally keep clear of retreads but each to their own and I was just offering a possible cause to the issue.

tyre life

Posted: Fri Aug 18, 2006 8:37 pm
by Willie
Dave, as you see from the various posts you are more likely to have to change a radial due to deterioration of the sidewall rubber than due to a worn out tread if you do a low annual mileage. 145X14 radials are the correct
size for standard Minor wheels and these are actually wider than the widest
tyres ever fitted by the factory even on the later, wider, van wheels.

Posted: Sat Aug 19, 2006 8:29 pm
by bmcecosse
Sidewalls will take a hammering if run at low pressure. My 155 s are run at 30 psi all round.

Posted: Sat Aug 19, 2006 10:28 pm
by bigginger
Kevin wrote: I have no direct knowledge about this subject apart from logic tells me that the much older carcase would be harder through age and this would reduce the flexibility of the outer casing, in some cases it has been known for the retread part to come of the original casing which is why I personally keep clear of retreads but each to their own and I was just offering a possible cause to the issue.
As one who has had the tread separate entirely from the tyre at motorway speed (not a Minor, a VW van) I will NEVER drive on remoulds again, however skint I am...

Posted: Tue Aug 22, 2006 12:10 pm
by sansom
minor_hickup wrote:Sansom, are you fitting 145's or 155's? 155's require a few more psi and from watching tyre wear wreckon 29/30psi front and 28/29psi rear is best.
I'm fitting (and have fitted) 145's. I'm guessing from what's been said then, that the lower pressures quoted in the owner's manual relate to the older narrower tyres.

cheers,
[dave]

Posted: Tue Aug 22, 2006 12:21 pm
by Kevin
Dave I think its mainly because they were crossplies just start with Willies suggeastions and see how they wear, I wouldnt go with the suggestion of rear tyre pressures being lower than the fronts as that is the opposite of all reccomendations especially when loaded.