[AT] OT truck tires/driveshaft?

charlie hill charliehill at embarqmail.com
Thu May 15 08:35:20 PDT 2014


Ron,  the first time I ever heard the idea of running max pressure in tires
was when Firestone was trying to weasel out of responsibility for their
tires that were blowing out on Ford Explorers.  I'm not saying their tires 
were
bad.  I'm just saying that is the first time I heard this idea that tires 
MUST be inflated
to max pressure.

Charlie

-----Original Message----- 
From: Ron Cook
Sent: Thursday, May 15, 2014 10:40 AM
To: Antique tractor email discussion group
Subject: Re: [AT] OT truck tires/driveshaft?

My long time, now retired, favorite tire dealer once told me when I was
asking what pressure to run in some tires on a trailer......they need to
be round with the tread flat on the surface.  Now I admit this was long
ago enough that we were talking bias ply tires.  It did, however work good.

Charlie has it right.

Ron Cook
Salix, IA
On 5/15/2014 7:15 AM, Stephen Offiler wrote:
> I completely agree with Charlie.  Including his apologies to Jeff.  We
> *respectfully* disagree.
>
> I've lost track of the vehicle in question but I think maybe it's an old
> F-600.  I'd be surprised to find a tag inside the driver's door listing
> recommended pressures, but I suppose it's possible.
>
> Ah, but then... even if you do have those recommendations, are they right?
>
> I've got a '97 F-250HD with 8600lb GVWR and a 6500-lb rear axle.  Tires 
> are
> rated max 3250lb at max 80 psi. (I've always thought it is more than
> coincidence that two 3250lb tires add up to exactly the 6500lb axle 
> rating,
> but I digress).   The sticker inside the door says 55psi in front, 80psi 
> in
> back.  Hmmm.  With 80psi in back I am good to load the axle right up to 
> its
> maximum, and the truck right up to its maximum.  But it weighs 5400lb
> empty, meaning I've got 3200lb to play with.  If I am running empty, or
> running light such a trip to the transfer station with household trash,
> 80psi in back is just ridiculously high.  I typically run about 50 psi
> front and rear when empty.
>
> As I read thru Charlie's note, I kept thinking to myself "but Charlie,
> temperature plays a big role" and I was really happy to reach his 
> paragraph
> about the infrared thermometer.  They are readily available and pretty
> inexpensive these days.  In terms of light-duty vehicles (which we aren't
> actually talking about) sidewall temperature is an interesting measurement
> in addition to scanning across the whole face of the tread.  There are 
> some
> rules of thumb regarding how much you want the sidewalls to warm up.
>
> SO
>
>
>
>
>
> On Thu, May 15, 2014 at 6:49 AM, charlie hill 
> <charliehill at embarqmail.com>wrote:
>
>> Jeff I know you mean well by posting that and since I don't
>> remember seeing you post here before I don't want to discourage
>> you with a negative reply but I just can't agree with that.
>>
>> Generally speaking your tires should be inflated to the pressure that
>> creates maximum
>> contact with the pavement.   Put a set of load range  E  tires on a 
>> pickup
>> truck and inflate
>> them to their max and try to drive on wet pavement.  You'll be lucky to
>> keep
>> the
>> vehicle under control.   I nearly wrecked my truck once when I bought a 
>> set
>> of tires
>> out of town at a chain tire store who did just that.  My vehicle
>> recommended
>> 36 psi.
>> The store set them at 50 psi.  I noticed they were very squirrely feeling
>> on
>> the way
>> home but didn't think much about it until I hit some rain and nearly
>> wrecked.  Those tires
>> weren't Load range E, they were just good quality load C tires with a 
>> high
>> max pressure
>> rating.
>>
>> I drove a tractor trailer for many years and we always adjust tire 
>> pressure
>> to load.  Most of the
>> time we were running heavy loads and when we were dead heading somewhere
>> and
>> it started
>> to rain we had to be very careful.   Tire pressure is often adjusted down
>> for running off road on
>> soft surfaces as well.  In fact, some tractor trailers now come with a 
>> rig
>> that allows them to adjust
>> tire pressure from the cab of the truck.
>>
>> Running too much pressure (just because the tire says you can) will cause
>> premature wear in the
>> center of the tire as well as making the vehicle hard to handle.   If you
>> really want to know how to
>> precisely set your tire pressure get yourself an infrared thermometer,
>> drive
>> the vehicle until the
>> tires are warmed up good by going around some curves.  Then stop and have
>> someone take
>> temperature readings across the face of the tire.  If the temps are about
>> the same on all of the
>> treads you have them right.  That is how race teams set up their cars for
>> racing assuring they
>> have maximum tire contact.
>>
>> Others might have different opinions but I know what has worked for me 
>> for
>> a
>> few million miles
>> in all sorts of vehicles.
>>
>> Charlie
>>
>>

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