Tyre pressues, calculating ??

On or around Sun, 05 Sep 2004 13:36:09 GMT, "Hirsty's" enlightened us thusly:

about 36 all round unless you're carrying heavy weight in the rear, in which case you want the rears up to about 40 or maybe 42.

from my experience. LR say 28 in the front which look, feel and wear as though they're too soft, especially with modern radial tyres.

They also tend to say about 42 in the rear which is too hard if running light, IME.

36 all round is what I'm running the discos on as well. Got some of those cute valve caps with mini-pressure-gauges built into 'em. dead neat, and they come with a freelocknut kit to make 'em more difficult to pinch. About 14 quid per vehicle.

at the moment I run 28/35 but often wondered if it was correct. Tried upping the pressure with full load but it really changes the character of the vehicle.

IMHO that set of calculations were quite badly flawed - nice logic but absolutely useless.

What seems to work is 34-36 all round, add up to 10 more in the rear if heavily loaded.

In article , Austin Shackles writes

LR - London Rubber?

Dont know if it would translate but a "generally" accepted method in Aus is to set the pressure cold, then after a decent run (to get tyres warm) check the pressure again if it has increased by more than 4 psi then the initial pressure was too low, if there has been no or only

1-2 psi then the initial pressure was too high.

Don't know if this would work on crossplies (if anybody is still running them) or whether the generally much cooler road temps in the UK would negate this method.

I'd say about 34-36 all round for normal use, rears up to 40-45 if fully laden. Somewhere around those figures will do you.

Alex

Interestingly the Australian supplement to the owner's manual for my 110 ups the pressure by around 5-10 psi over the UK figures. Recommended pressures vary from 35/35 unloaded at speeds below 120kp to 50/65 fully loaded at speeds above 140kph.

In practice I use 35/35 unloaded (nowhere I drive has a speed limit above

110) and up to 45/50 fully loaded.

There are several conflicting factors in deciding tyre pressures. The usual overriding one is enough pressure to prevent excessive heat build up. This depends on whether the tyre has a tube or not, type of tyre construction and tread, ambient temperature, speed and trip length. Other considerations are

1: handling, which is particularly sensitive to front/back pressure ratios and loading - remembering that on both lwb and swb landrovers most of the difference between loaded and unloaded is on the rear wheels. 2: Ride - generally the lower the better 3: Ground pressure - on sand or soft ground the lower the better 4: Pressure to ensure even tyre wear - less critical with radials.

So as you can see, there is no single, simple, answer - it depends on how your particular circumstances make one or other factor more important.

JD

On or around Sun, 5 Sep 2004 22:04:09 +0000 (UTC), Frank Erskine enlightened us thusly:

wot you doin' in the lard rover froup, Frank?

On or around Mon, 06 Sep 2004 09:47:18 +1000, JD enlightened us thusly:

but much less easy to spot, too. Radials in LR-style sizes can be 10lb down on optimum pressure, and look virtually normal, but they'll still wear wrong. The set on the one disco here had a couple of tyres with a habit of going soft, and, not being checked enough, they wore unacceptably on th outer edges, to the extent that at least 1mm of tread was wasted on the centre part due to the tyres becoming illegal due to edge wear.

you may have different tyre wear rules, of course. In the UK, the minimum tread depth is 1.6mm which must be present across the middle 3/4 of the tyre width. The remaining part of the tyre can have less than 1.6mm tread but must have some visible tread. So an 8" tyre, for example, where 1" at the edge has no tread left is illegal, even if it has new tread the other side, and similarly, if the tread 1" in from the edge of the tyre is under 1.6mm it's also illegal. bearing in mind the fines for illegal tyres, it's not worth taking the risk, so managing the tyre wear is quite important.

I got 50k out of my standard fit goodrich 235. Most on road and round town, is that reasonable, seems like even wear.

On or around Mon, 06 Sep 2004 08:53:31 GMT, "Hirsty's" enlightened us thusly:

BF Goodrich are noted for being long-wearing, mind, I didn't like 'em on wet tarmac, meself - too twitchy feeling, due no doubt to the hard compound.

dunno if the MT ones cope so well with tarmac use, but the ATs, Trac Edges and the more road-going ones like Long Trail are reckoned to last forever. They also cost more, of course. Just had 4 pirellis fitted and balanced for a tad over 300 notes.

In article , Austin Shackles writes

I drive a Discovery at jbex.

Paid about £80 per corner for BFG Long Trails on the Discovery about

40000 miles ago. Martyn will probably get almost the same again if he wants to run them to the legal limit.

I didn't notice significant loss of performance against the Michelin XPC's that I took off. The Long Trails are also pretty decent in the gloop for what they are. Only got stuck at Billing once last year, and that's because I stupidly obeyed the marshall and tried to go through Defender depth ruts...

On or around Mon, 06 Sep 2004 23:47:09 +0100, Tim Hobbs enlightened us thusly:

good price, I suspect. I haven't asked the local supplier (who's very cometitive) but the online types are listing AT-KOs at around 100 each.

There's two types, BTW with different speed ratings, with a £20 difference. I should also add that I bought 5 Long Trails and 5 Trac Edge, plus wheels at the same time, so a decent deal was struck with Nene Valley (top blokes, BTW).

As I remember it the cheaper rating (which I bought) was a bit borderline (an 'S' rating if I remember right). I think it was OK for the diesel but a little under for the V8, but I could be wrong. As I rarely get top-side of 85mph it didn't seem to be a big deal.