Del Rawlins

On 05 Dec 2003 08:40 AM, Lon Stowell posted the following:
> At 12/5/03 05:24, mabar bespake thusly:
>
>> Bob:
>>
>> All tires have a maximum tire pressure stamped on them. That is the
>> maximum tire pressure for that tire, not for your vehicle. That tire
>> can be used on many vehicles, some that are MUCH heavier than a
>> Wrangler. If you put 80 lbs in your Wrangler tires, the Jeep would
>> ride like the tires were made out of concrete. The recommended
>> pressure for your vehicle is on a sticker on the drivers door, or
>> door jam.
>
> Unfortunately that pressure is based on using the OEM tire, not
> an aftermarket one, and simply does not apply for either a
> specialty low pressure or high pressure tire.

The Goodyear Wrangler MT/R _IS_ the OEM tire on the Wrangler Rubicon, so
the pressure listed on the door jamb label is correct.

In any case, the MT/R is not a "specialty high or low pressure tire."
It is certainly a specialty tire, but for running on the road you should
use the same pressure as you would any other tire of the same size and
construction on that vehicle. Off-road, you will probably want to air
down for better performance but that isn't really relevant here.

I'm running MT/Rs (aftermarket) on my TJ and I use the door jamb
pressure, but I'm running 30" tires which are a size available from the
factory. Bigger tires will most likely need to run at a slightly lower
pressure, but that doesn't make them a low pressuer tire.

----------------------------------------------------
Del Rawlins- del@_kills_spammers_rawlinsbrothers.org
Remove _kills_spammers_ to reply via email.
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Del Rawlins

On 05 Dec 2003 08:40 AM, Lon Stowell posted the following:
> At 12/5/03 05:24, mabar bespake thusly:
>
>> Bob:
>>
>> All tires have a maximum tire pressure stamped on them. That is the
>> maximum tire pressure for that tire, not for your vehicle. That tire
>> can be used on many vehicles, some that are MUCH heavier than a
>> Wrangler. If you put 80 lbs in your Wrangler tires, the Jeep would
>> ride like the tires were made out of concrete. The recommended
>> pressure for your vehicle is on a sticker on the drivers door, or
>> door jam.
>
> Unfortunately that pressure is based on using the OEM tire, not
> an aftermarket one, and simply does not apply for either a
> specialty low pressure or high pressure tire.

The Goodyear Wrangler MT/R _IS_ the OEM tire on the Wrangler Rubicon, so
the pressure listed on the door jamb label is correct.

In any case, the MT/R is not a "specialty high or low pressure tire."
It is certainly a specialty tire, but for running on the road you should
use the same pressure as you would any other tire of the same size and
construction on that vehicle. Off-road, you will probably want to air
down for better performance but that isn't really relevant here.

I'm running MT/Rs (aftermarket) on my TJ and I use the door jamb
pressure, but I'm running 30" tires which are a size available from the
factory. Bigger tires will most likely need to run at a slightly lower
pressure, but that doesn't make them a low pressuer tire.

----------------------------------------------------
Del Rawlins- del@_kills_spammers_rawlinsbrothers.org
Remove _kills_spammers_ to reply via email.
Unofficial Bearhawk FAQ website:
http://www.rawlinsbrothers.org/bhfaq/

mabar

Bob:

My '02 Wrangler came with 30 x 9.5 x 15 tires. The factor door sticker says
29 lbs.for all 4 tires. I changed to 31 x 10.5 x 15 and now run with 28 lbs.
Seems to be just about right.

Tom

"bob zee" <cam509@linuxmail.org> wrote in message
news:bqq1ic$24jurj$1@ID-177997.news.uni-berlin.de...
>
> "mabar" <mabar@NOSPAMgbronline.com> wrote in message
> news:ZLSdnbQn2KSQGk2i4p2dnA@gbronline.com...
> > Bob:
> >
> >
> > The recommended pressure for your vehicle is on a sticker on the drivers
> > door, or door jam.
> >
> > Tom
> >
>
> i will look at the door jam the next time i see this thing. it is my
wife's
> jeep and to be honest, i feel REALLY stupid for not thinking to look at
the
> door jam.
>
> my original intent with my post was to find out what others were doing and
> maybe somebody might be using their Jeep in a manner similar to my wife.
a
> little extra air pressure would increase the mpg a small percentage.
would
> it be worth it? a sacrifice in ride quality with more air, yes, but would
> it also sacrifice safety?
>
> i know, i know. if i was so worried about mpg, i should've bought a
diesel
> rabbit...
> i did and i run about 40psi in those tires and printed on the sidewall -
> 35psi max
>
>
> --
> bob z.
>
> "people with less brain power than you are doing more difficult things
> everyday"©
>
>

mabar

Bob:

My '02 Wrangler came with 30 x 9.5 x 15 tires. The factor door sticker says
29 lbs.for all 4 tires. I changed to 31 x 10.5 x 15 and now run with 28 lbs.
Seems to be just about right.

Tom

"bob zee" <cam509@linuxmail.org> wrote in message
news:bqq1ic$24jurj$1@ID-177997.news.uni-berlin.de...
>
> "mabar" <mabar@NOSPAMgbronline.com> wrote in message
> news:ZLSdnbQn2KSQGk2i4p2dnA@gbronline.com...
> > Bob:
> >
> >
> > The recommended pressure for your vehicle is on a sticker on the drivers
> > door, or door jam.
> >
> > Tom
> >
>
> i will look at the door jam the next time i see this thing. it is my
wife's
> jeep and to be honest, i feel REALLY stupid for not thinking to look at
the
> door jam.
>
> my original intent with my post was to find out what others were doing and
> maybe somebody might be using their Jeep in a manner similar to my wife.
a
> little extra air pressure would increase the mpg a small percentage.
would
> it be worth it? a sacrifice in ride quality with more air, yes, but would
> it also sacrifice safety?
>
> i know, i know. if i was so worried about mpg, i should've bought a
diesel
> rabbit...
> i did and i run about 40psi in those tires and printed on the sidewall -
> 35psi max
>
>
> --
> bob z.
>
> "people with less brain power than you are doing more difficult things
> everyday"©
>
>

mabar

Bob:

My '02 Wrangler came with 30 x 9.5 x 15 tires. The factor door sticker says
29 lbs.for all 4 tires. I changed to 31 x 10.5 x 15 and now run with 28 lbs.
Seems to be just about right.

Tom

"bob zee" <cam509@linuxmail.org> wrote in message
news:bqq1ic$24jurj$1@ID-177997.news.uni-berlin.de...
>
> "mabar" <mabar@NOSPAMgbronline.com> wrote in message
> news:ZLSdnbQn2KSQGk2i4p2dnA@gbronline.com...
> > Bob:
> >
> >
> > The recommended pressure for your vehicle is on a sticker on the drivers
> > door, or door jam.
> >
> > Tom
> >
>
> i will look at the door jam the next time i see this thing. it is my
wife's
> jeep and to be honest, i feel REALLY stupid for not thinking to look at
the
> door jam.
>
> my original intent with my post was to find out what others were doing and
> maybe somebody might be using their Jeep in a manner similar to my wife.
a
> little extra air pressure would increase the mpg a small percentage.
would
> it be worth it? a sacrifice in ride quality with more air, yes, but would
> it also sacrifice safety?
>
> i know, i know. if i was so worried about mpg, i should've bought a
diesel
> rabbit...
> i did and i run about 40psi in those tires and printed on the sidewall -
> 35psi max
>
>
> --
> bob z.
>
> "people with less brain power than you are doing more difficult things
> everyday"©
>
>

Del Rawlins

On 05 Dec 2003 10:10 AM, Tim Hayes posted the following:
> I agree with this. I have a Sahara with the standard 30x9.5 Goodyear
> GS-A tires still on it.
>
> I used my 6yo daughter's sidewalk chalk. Came up with 30psi as being
> "right" with perhaps a bit more necessary in the front. The sticker
> says 29psi, the tires say 44psi max. Use the chalk to draw a thick
> line across your tires and drive STRAIGHT ahead for 50-100 feet. See
> if the chalk has worn off evenly. Adjust air as necesary and repeat
> until you get it right.

It sounds as though you managed to verify that the Jeep factory got
their recommendations for stock tire pressure right. The difference is
certainly within the margin of error of your gauge.

> You can estimate the minimum pressure 'allowable' on the road by
> looking up the tire manufacturer's max load (at max PSI). You need to
> assume a 50/50 weight split front/rear, which for a wrangler is
> accurate if there isn't a winch on the front, otherwise you need to
> modify this procedure to take the higher of the front/rear loads.
> Both should always be the same pressure on a 4x4 even if it isn't
> necesary for load reasons.

Actually there is nothing special about a 4x4 that requires the front
tires to be the same as the rear. Matter of fact, I used to drive a
pickup truck for work that needed 55psi in the front tires, and 80 in
the rear. Any more than 55 in the front would have led to uneven
treadwear, while any less than 80 in the rear and it wouldn't have
handled the weight.

> Take the max PSI, multiply that by 1/4 of your vehicle weight, and
> divide by the max load for the tire. That is close to the minimum
> pressure that is OK for the road. For *my* TJ Sahara that is about 26
> PSI with my wife, daughter, and a tank of gas (truck stop scale!)

10+ years in the tire business and I have never seen or heard of that
method being recommended, though it seems to make some sense. If you
have any documentation supporting it I would be curious to read it.

----------------------------------------------------
Del Rawlins- del@_kills_spammers_rawlinsbrothers.org
Remove _kills_spammers_ to reply via email.
Unofficial Bearhawk FAQ website:
http://www.rawlinsbrothers.org/bhfaq/

Del Rawlins

On 05 Dec 2003 10:10 AM, Tim Hayes posted the following:
> I agree with this. I have a Sahara with the standard 30x9.5 Goodyear
> GS-A tires still on it.
>
> I used my 6yo daughter's sidewalk chalk. Came up with 30psi as being
> "right" with perhaps a bit more necessary in the front. The sticker
> says 29psi, the tires say 44psi max. Use the chalk to draw a thick
> line across your tires and drive STRAIGHT ahead for 50-100 feet. See
> if the chalk has worn off evenly. Adjust air as necesary and repeat
> until you get it right.

It sounds as though you managed to verify that the Jeep factory got
their recommendations for stock tire pressure right. The difference is
certainly within the margin of error of your gauge.

> You can estimate the minimum pressure 'allowable' on the road by
> looking up the tire manufacturer's max load (at max PSI). You need to
> assume a 50/50 weight split front/rear, which for a wrangler is
> accurate if there isn't a winch on the front, otherwise you need to
> modify this procedure to take the higher of the front/rear loads.
> Both should always be the same pressure on a 4x4 even if it isn't
> necesary for load reasons.

Actually there is nothing special about a 4x4 that requires the front
tires to be the same as the rear. Matter of fact, I used to drive a
pickup truck for work that needed 55psi in the front tires, and 80 in
the rear. Any more than 55 in the front would have led to uneven
treadwear, while any less than 80 in the rear and it wouldn't have
handled the weight.

> Take the max PSI, multiply that by 1/4 of your vehicle weight, and
> divide by the max load for the tire. That is close to the minimum
> pressure that is OK for the road. For *my* TJ Sahara that is about 26
> PSI with my wife, daughter, and a tank of gas (truck stop scale!)

10+ years in the tire business and I have never seen or heard of that
method being recommended, though it seems to make some sense. If you
have any documentation supporting it I would be curious to read it.

----------------------------------------------------
Del Rawlins- del@_kills_spammers_rawlinsbrothers.org
Remove _kills_spammers_ to reply via email.
Unofficial Bearhawk FAQ website:
http://www.rawlinsbrothers.org/bhfaq/

Del Rawlins

On 05 Dec 2003 10:10 AM, Tim Hayes posted the following:
> I agree with this. I have a Sahara with the standard 30x9.5 Goodyear
> GS-A tires still on it.
>
> I used my 6yo daughter's sidewalk chalk. Came up with 30psi as being
> "right" with perhaps a bit more necessary in the front. The sticker
> says 29psi, the tires say 44psi max. Use the chalk to draw a thick
> line across your tires and drive STRAIGHT ahead for 50-100 feet. See
> if the chalk has worn off evenly. Adjust air as necesary and repeat
> until you get it right.

It sounds as though you managed to verify that the Jeep factory got
their recommendations for stock tire pressure right. The difference is
certainly within the margin of error of your gauge.

> You can estimate the minimum pressure 'allowable' on the road by
> looking up the tire manufacturer's max load (at max PSI). You need to
> assume a 50/50 weight split front/rear, which for a wrangler is
> accurate if there isn't a winch on the front, otherwise you need to
> modify this procedure to take the higher of the front/rear loads.
> Both should always be the same pressure on a 4x4 even if it isn't
> necesary for load reasons.

Actually there is nothing special about a 4x4 that requires the front
tires to be the same as the rear. Matter of fact, I used to drive a
pickup truck for work that needed 55psi in the front tires, and 80 in
the rear. Any more than 55 in the front would have led to uneven
treadwear, while any less than 80 in the rear and it wouldn't have
handled the weight.

> Take the max PSI, multiply that by 1/4 of your vehicle weight, and
> divide by the max load for the tire. That is close to the minimum
> pressure that is OK for the road. For *my* TJ Sahara that is about 26
> PSI with my wife, daughter, and a tank of gas (truck stop scale!)

10+ years in the tire business and I have never seen or heard of that
method being recommended, though it seems to make some sense. If you
have any documentation supporting it I would be curious to read it.

----------------------------------------------------
Del Rawlins- del@_kills_spammers_rawlinsbrothers.org
Remove _kills_spammers_ to reply via email.
Unofficial Bearhawk FAQ website:
http://www.rawlinsbrothers.org/bhfaq/

Mike Romain

The chalk method works great for oversized tires.

I used it on my 31x10.5's and 26 psi front and rear worked. They wore
out totally even for tread wear.

Same for my new 33x9.5's, at 35 psi like they came from the tire shop, I
only have 4" of tread touching. Drop them to 26 psi and I am only
missing 1/4" on the edges. This turns out to be too low for the tall
sidewall on the 33's and the edges scuff, so I use 28 psi.

A Jeep CJ or Wrangler has almost a 50/50 weight split on the tires when
not loaded. I believe the Cherokee is close to the same.

They both call for even front to back air pressure.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Del Rawlins wrote:
>
> On 05 Dec 2003 10:10 AM, Tim Hayes posted the following:
> > I agree with this. I have a Sahara with the standard 30x9.5 Goodyear
> > GS-A tires still on it.
> >
> > I used my 6yo daughter's sidewalk chalk. Came up with 30psi as being
> > "right" with perhaps a bit more necessary in the front. The sticker
> > says 29psi, the tires say 44psi max. Use the chalk to draw a thick
> > line across your tires and drive STRAIGHT ahead for 50-100 feet. See
> > if the chalk has worn off evenly. Adjust air as necesary and repeat
> > until you get it right.
>
> It sounds as though you managed to verify that the Jeep factory got
> their recommendations for stock tire pressure right. The difference is
> certainly within the margin of error of your gauge.
>
> > You can estimate the minimum pressure 'allowable' on the road by
> > looking up the tire manufacturer's max load (at max PSI). You need to
> > assume a 50/50 weight split front/rear, which for a wrangler is
> > accurate if there isn't a winch on the front, otherwise you need to
> > modify this procedure to take the higher of the front/rear loads.
> > Both should always be the same pressure on a 4x4 even if it isn't
> > necesary for load reasons.
>
> Actually there is nothing special about a 4x4 that requires the front
> tires to be the same as the rear. Matter of fact, I used to drive a
> pickup truck for work that needed 55psi in the front tires, and 80 in
> the rear. Any more than 55 in the front would have led to uneven
> treadwear, while any less than 80 in the rear and it wouldn't have
> handled the weight.
>
> > Take the max PSI, multiply that by 1/4 of your vehicle weight, and
> > divide by the max load for the tire. That is close to the minimum
> > pressure that is OK for the road. For *my* TJ Sahara that is about 26
> > PSI with my wife, daughter, and a tank of gas (truck stop scale!)
>
> 10+ years in the tire business and I have never seen or heard of that
> method being recommended, though it seems to make some sense. If you
> have any documentation supporting it I would be curious to read it.
>
> ----------------------------------------------------
> Del Rawlins- del@_kills_spammers_rawlinsbrothers.org
> Remove _kills_spammers_ to reply via email.
> Unofficial Bearhawk FAQ website:
> http://www.rawlinsbrothers.org/bhfaq/

Mike Romain

The chalk method works great for oversized tires.

I used it on my 31x10.5's and 26 psi front and rear worked. They wore
out totally even for tread wear.

Same for my new 33x9.5's, at 35 psi like they came from the tire shop, I
only have 4" of tread touching. Drop them to 26 psi and I am only
missing 1/4" on the edges. This turns out to be too low for the tall
sidewall on the 33's and the edges scuff, so I use 28 psi.

A Jeep CJ or Wrangler has almost a 50/50 weight split on the tires when
not loaded. I believe the Cherokee is close to the same.

They both call for even front to back air pressure.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Del Rawlins wrote:
>
> On 05 Dec 2003 10:10 AM, Tim Hayes posted the following:
> > I agree with this. I have a Sahara with the standard 30x9.5 Goodyear
> > GS-A tires still on it.
> >
> > I used my 6yo daughter's sidewalk chalk. Came up with 30psi as being
> > "right" with perhaps a bit more necessary in the front. The sticker
> > says 29psi, the tires say 44psi max. Use the chalk to draw a thick
> > line across your tires and drive STRAIGHT ahead for 50-100 feet. See
> > if the chalk has worn off evenly. Adjust air as necesary and repeat
> > until you get it right.
>
> It sounds as though you managed to verify that the Jeep factory got
> their recommendations for stock tire pressure right. The difference is
> certainly within the margin of error of your gauge.
>
> > You can estimate the minimum pressure 'allowable' on the road by
> > looking up the tire manufacturer's max load (at max PSI). You need to
> > assume a 50/50 weight split front/rear, which for a wrangler is
> > accurate if there isn't a winch on the front, otherwise you need to
> > modify this procedure to take the higher of the front/rear loads.
> > Both should always be the same pressure on a 4x4 even if it isn't
> > necesary for load reasons.
>
> Actually there is nothing special about a 4x4 that requires the front
> tires to be the same as the rear. Matter of fact, I used to drive a
> pickup truck for work that needed 55psi in the front tires, and 80 in
> the rear. Any more than 55 in the front would have led to uneven
> treadwear, while any less than 80 in the rear and it wouldn't have
> handled the weight.
>
> > Take the max PSI, multiply that by 1/4 of your vehicle weight, and
> > divide by the max load for the tire. That is close to the minimum
> > pressure that is OK for the road. For *my* TJ Sahara that is about 26
> > PSI with my wife, daughter, and a tank of gas (truck stop scale!)
>
> 10+ years in the tire business and I have never seen or heard of that
> method being recommended, though it seems to make some sense. If you
> have any documentation supporting it I would be curious to read it.
>
> ----------------------------------------------------
> Del Rawlins- del@_kills_spammers_rawlinsbrothers.org
> Remove _kills_spammers_ to reply via email.
> Unofficial Bearhawk FAQ website:
> http://www.rawlinsbrothers.org/bhfaq/