[AT] OT truck tires/driveshaft?

[Ron Cook]

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
>>
>>