Tyre pressues, calculating ??

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H

Hirsty's

Guest
Some time ago on one of the NG I saw a set of postings about pressures and
how to calculate them for a particular set up.
Anybody know of this ?
I would like to calculate the correct pressures for my 110 CSW on alloys
with 235's. I cannotget a definitive answer from anywhere including Lode
Lane !!

--


" ..... it is the provenence of knowledge to speak, and it is the privelage
of wisdom to listen"


 
On or around Sun, 05 Sep 2004 13:36:09 GMT, "Hirsty's"
<[email protected]> enlightened us thusly:

>Some time ago on one of the NG I saw a set of postings about pressures and
>how to calculate them for a particular set up.
> Anybody know of this ?
>I would like to calculate the correct pressures for my 110 CSW on alloys
>with 235's. I cannotget a definitive answer from anywhere including Lode
>Lane !!

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.



"Austin Shackles" <[email protected]> wrote in message
news:[email protected]...
> On or around Sun, 05 Sep 2004 13:36:09 GMT, "Hirsty's"
> <[email protected]> enlightened us thusly:
>
> >Some time ago on one of the NG I saw a set of postings about pressures
and
> >how to calculate them for a particular set up.
> > Anybody know of this ?
> >I would like to calculate the correct pressures for my 110 CSW on alloys
> >with 235's. I cannotget a definitive answer from anywhere including Lode
> >Lane !!
>
> 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.


 
Hirsty's wrote:

> Some time ago on one of the NG I saw a set of postings about pressures and
> how to calculate them for a particular set up.

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

> I would like to calculate the correct pressures for my 110 CSW on alloys
> with 235's. I cannotget a definitive answer from anywhere including Lode
> Lane !!

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


--
EMB
change two to number to reply
 
In article <[email protected]>, Austin Shackles
<[email protected]> writes
>On or around Sun, 05 Sep 2004 13:36:09 GMT, "Hirsty's"
><[email protected]> enlightened us thusly:
>
>>Some time ago on one of the NG I saw a set of postings about pressures and
>>how to calculate them for a particular set up.
>> Anybody know of this ?
>>I would like to calculate the correct pressures for my 110 CSW on alloys
>>with 235's. I cannotget a definitive answer from anywhere including Lode
>>Lane !!
>
>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.
>
LR - London Rubber?

--
Frank Erskine
 
On Sun, 05 Sep 2004 13:36:09 GMT, "Hirsty's" <[email protected]>
wrote:

>Some time ago on one of the NG I saw a set of postings about pressures and
>how to calculate them for a particular set up.
> Anybody know of this ?
>I would like to calculate the correct pressures for my 110 CSW on alloys
>with 235's. I cannotget a definitive answer from anywhere including Lode
>Lane !!


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.

 
On Sun, 05 Sep 2004 13:36:09 GMT, "Hirsty's" <[email protected]>
wrote:

>Some time ago on one of the NG I saw a set of postings about pressures and
>how to calculate them for a particular set up.
> Anybody know of this ?
>I would like to calculate the correct pressures for my 110 CSW on alloys
>with 235's. I cannotget a definitive answer from anywhere including Lode
>Lane !!

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
 
Austin Shackles wrote:

> On or around Sun, 05 Sep 2004 13:36:09 GMT, "Hirsty's"
> <[email protected]> enlightened us thusly:
>
>>Some time ago on one of the NG I saw a set of postings about pressures and
>>how to calculate them for a particular set up.
>> Anybody know of this ?
>>I would like to calculate the correct pressures for my 110 CSW on alloys
>>with 235's. I cannotget a definitive answer from anywhere including Lode
>>Lane !!
>
> 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.

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
<[email protected]> enlightened us thusly:

>In article <[email protected]>, Austin Shackles
><[email protected]> writes
>>On or around Sun, 05 Sep 2004 13:36:09 GMT, "Hirsty's"
>><[email protected]> enlightened us thusly:
>>
>>>Some time ago on one of the NG I saw a set of postings about pressures and
>>>how to calculate them for a particular set up.
>>> Anybody know of this ?
>>>I would like to calculate the correct pressures for my 110 CSW on alloys
>>>with 235's. I cannotget a definitive answer from anywhere including Lode
>>>Lane !!
>>
>>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.
>>
>LR - London Rubber?

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


 
On or around Mon, 06 Sep 2004 09:47:18 +1000, JD <[email protected]>
enlightened us thusly:

>4: Pressure to ensure even tyre wear - less critical with radials.

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.



"Austin Shackles" <[email protected]> wrote in message
news:[email protected]...
> On or around Mon, 06 Sep 2004 09:47:18 +1000, JD <[email protected]>
> enlightened us thusly:
>
> >4: Pressure to ensure even tyre wear - less critical with radials.
>
> 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.
>


 
On or around Mon, 06 Sep 2004 08:53:31 GMT, "Hirsty's"
<[email protected]> enlightened us thusly:

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

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 <[email protected]>, Austin Shackles
<[email protected]> writes
>On or around Sun, 5 Sep 2004 22:04:09 +0000 (UTC), Frank Erskine
><[email protected]> enlightened us thusly:
>
>>In article <[email protected]>, Austin Shackles
>><[email protected]> writes
>>>On or around Sun, 05 Sep 2004 13:36:09 GMT, "Hirsty's"
>>><[email protected]> enlightened us thusly:
>>>
>>>>Some time ago on one of the NG I saw a set of postings about pressures and
>>>>how to calculate them for a particular set up.
>>>> Anybody know of this ?
>>>>I would like to calculate the correct pressures for my 110 CSW on alloys
>>>>with 235's. I cannotget a definitive answer from anywhere including Lode
>>>>Lane !!
>>>
>>>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.
>>>
>>LR - London Rubber?
>
>wot you doin' in the lard rover froup, Frank?
>
I drive a Discovery at jbex.

--
Frank Erskine
 
On Mon, 06 Sep 2004 18:25:46 +0100, Austin Shackles
<[email protected]> wrote:

>On or around Mon, 06 Sep 2004 08:53:31 GMT, "Hirsty's"
><[email protected]> enlightened us thusly:
>
>>I got 50k out of my standard fit goodrich 235. Most on road and round town,
>>is that reasonable, seems like even wear.
>
>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.

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...

--

Tim Hobbs

'58 Series 2 88" aka "Stig"
'77 101FC Ambulance aka "Burrt"
'03 Volvo V70

My Landies? http://www.seriesii.co.uk
Barcoding? http://www.bartec-systems.com
Tony Luckwill web archive at http://www.luckwill.com
 
On or around Mon, 06 Sep 2004 23:47:09 +0100, Tim Hobbs
<[email protected]> enlightened us thusly:

>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.

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.
 
On Tue, 07 Sep 2004 07:42:38 +0100, Austin Shackles
<[email protected]> wrote:

>On or around Mon, 06 Sep 2004 23:47:09 +0100, Tim Hobbs
><[email protected]> enlightened us thusly:
>
>>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.
>
>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.
--

Tim Hobbs

'58 Series 2 88" aka "Stig"
'77 101FC Ambulance aka "Burrt"
'03 Volvo V70

My Landies? http://www.seriesii.co.uk
Barcoding? http://www.bartec-systems.com
Tony Luckwill web archive at http://www.luckwill.com
 
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