Trailer tires

Gang,

I'm leaving this Friday to pick up a glider that I purchased 1100
miles away. The trailer looks brand new, but is about 12 years old,
as are its tires. The glider and trailer weigh in the vicinity of 950
#. The tire spec from the owner is :
Carlisle Sure Trail ST
ST205/75014 (replaces F78-14ST)
Max Load 1760 lbs @ 50 PSI (actual load will be under 500 lbs)

I plan to buy 2 new tires before the trip, and stop at the first
service station after the pickup and have them mounted. Question is,
what to buy. It does not appear that the trailer has any suspension,
so I think I'd run the tires slightly soft, maybe 25-30 psi. I was
wondering about whether it should be radial or bias ply? Any
particular brands?

Thanks in advance,
Ed

Ed,

My research into this question resulted in me concluding that one
should look at the Duro, Maxxis, Denman (in that order) tire brands.
Goodyear Marathons are variable. Carlisle are not recommended (note
that Carlisle also owns Titan). I chose Duros.

Whatever you choose, make SURE that it is an ST tire - this stands for
Special Trailer. And DO NOT run them at low pressure - run them at
whatever the pressure is that is stamped on the sidewall to get
maximum load carrying ability with minimum heat build up.

As for the radial/bias question, radial tires are *not* recommended
when lateral sway is a problem. However, radials do run cooler, and
they provide a softer ride. I chose radials for my Cobra trailer,
since sway has never been an issue, and there is no suspension.

As for longevity, it's recommended that you replace trailer tires
every 5 years. Although they may look "new", the sun and atmosphere
damage the rubber.

Finally, what kind of glider did you buy?

-John

On Jan 20, 10:14 am, flying_monkey wrote:
Gang,

I'm leaving this Friday to pick up a glider that I purchased 1100
miles away. The trailer looks brand new, but is about 12 years old,
as are its tires. The glider and trailer weigh in the vicinity of 950
#. The tire spec from the owner is :
Carlisle Sure Trail ST
ST205/75014 (replaces F78-14ST)
Max Load 1760 lbs @ 50 PSI (actual load will be under 500 lbs)

I plan to buy 2 new tires before the trip, and stop at the first
service station after the pickup and have them mounted. Question is,
what to buy. It does not appear that the trailer has any suspension,
so I think I'd run the tires slightly soft, maybe 25-30 psi. I was
wondering about whether it should be radial or bias ply? Any
particular brands?

Thanks in advance,
Ed

Get ready for some great advice on this topic. My pennies worth are to
never run tires below reco. pressure unless you want more traction out
of a mud pit or to lower your vehicle to get it below a bridge. Low
pressure will cause more sidewall flex and lead to an overheat
failure. Get Trailer tires only as they will have an extra sidewall
layer needed for trailer sway that will wear on car tires. I learned
from Charlie Spratt that you want 10% min. of the total tow weight on
the ball to help prevent excessive rear end swaying. Finally, Walmart
sells mounted trailer tires, that's tires and rims together, ready to
go in 13", 14", 15" size that have a C rating. $79, not bad. You can
mount them at the pickpoint and be ready to haul.
Next.....

I'd also check the axle bearings. If they haven't been repacked in the
past couple of years, you'll want to repack them before your trip.

-Kevin

On Jan 20, 10:43*am, " wrote:
---snip
Finally, Walmart
sells mounted trailer tires, that's tires and rims together, ready to
go in 13", 14", 15" size that have a C rating. $79, not bad. You can
mount them at the pickpoint and be ready to haul.

Great idea, except that I have no idea what lug spacing is on there,
and there are many possibilities.

At 15:14 20 January 2009, flying_monkey wrote:
Gang,

It does not appear that the trailer has any suspension,
so I think I'd run the tires slightly soft, maybe 25-30 psi.

Hard to imagine a trailer without any kind of suspension. Seems to me it
would bounce like crazy over any kind of rough road, not to mention
beating the glider to pieces.

Jim Beckman

Jim Beckman wrote:
At 15:14 20 January 2009, flying_monkey wrote:
Gang,

It does not appear that the trailer has any suspension,
so I think I'd run the tires slightly soft, maybe 25-30 psi.

Hard to imagine a trailer without any kind of suspension. Seems to me it
would bounce like crazy over any kind of rough road, not to mention
beating the glider to pieces.

Agreed. An axle using torsion arms for sprung suspension may "look"
like it has no springs, i.e. no leaf springs or coil springs, when in
fact it does.

Regards,

-Doug

At 15:27 20 January 2009, jcarlyle wrote:
Ed,

My research into this question resulted in me concluding that one
should look at the Duro, Maxxis, Denman (in that order) tire brands.
Goodyear Marathons are variable. Carlisle are not recommended (note
that Carlisle also owns Titan). I chose Duros.

Whatever you choose, make SURE that it is an ST tire - this stands for
Special Trailer. And DO NOT run them at low pressure - run them at
whatever the pressure is that is stamped on the sidewall to get
maximum load carrying ability with minimum heat build up.

I would Not do this. The pressure marked on the tyre is the maximum
permitted inflation pressure. This would not allow the tyre to flex and
only the central part of the tyre would be in contact with the road. It
would also bounce all over the place on a rough surface. Inflate to the
reccomended pressure for the trailer. If not available try 35-40psi If the
trailer weighs considerably less than the max tyre load heat build up will
not be a problem.

Nigel

In article f8aea33b-9947-4af8-9f65-092874f2dbb7
@x37g2000yqj.googlegroups.com, says...
Gang,

I'm leaving this Friday to pick up a glider that I purchased 1100
miles away. The trailer looks brand new, but is about 12 years old,
as are its tires. The glider and trailer weigh in the vicinity of 950
#. The tire spec from the owner is :
Carlisle Sure Trail ST
ST205/75014 (replaces F78-14ST)
Max Load 1760 lbs @ 50 PSI (actual load will be under 500 lbs)

I plan to buy 2 new tires before the trip, and stop at the first
service station after the pickup and have them mounted. Question is,
what to buy. It does not appear that the trailer has any suspension,
so I think I'd run the tires slightly soft, maybe 25-30 psi. I was
wondering about whether it should be radial or bias ply? Any
particular brands?

Thanks in advance,

If I were you I'd use LT tires (light truck), and run 'em at their rated
60psi (60-65 is about normal for LT tires (should be written on them,
often is)).

I'd also double-check the suspension, could in "in-axle" type, as is
popular in NZ - a Co. makes 'em here and call 'em Duro-torque (sp?).

--
Duncan

jcarlyle wrote:

Whatever you choose, make SURE that it is an ST tire - this stands for
Special Trailer. And DO NOT run them at low pressure - run them at
whatever the pressure is that is stamped on the sidewall to get
maximum load carrying ability with minimum heat build up.

Be aware ST tires have a 60 mph speed rating at the standard pressures.
You can raise the rating to 70 mph if you inflate to required pressure
for this higher speed.


As for the radial/bias question, radial tires are *not* recommended
when lateral sway is a problem.

Cobra delivers all their trailers with radials. Go to the RV dealers and
look at all travel trailers and 5th wheel trailers, and you will find
out they are all riding on radials. That's because radial tires are far
better tires, even for trailers. The bias ply tire's only advantage is
it's a few dollars cheaper.

If you compare a passenger car radial to a bias ply ST trailer tire, you
might be right.

However, radials do run cooler, and
they provide a softer ride.

And they are more road hazard resistant.

I'm leaving this Friday to pick up a glider that I purchased 1100
miles away. The trailer looks brand new, but is about 12 years old,
as are its tires. The glider and trailer weigh in the vicinity of 950
#.

What is in it? It is worth weighing it if you are at all suspicious
about the claimed weight.

Assuming the 950 pounds is right... Unless you are towing this with a
Volkswagen Beetle, it seems unlikely such a light trailer will cause any
problems, regardless of the tires.

The tire spec from the owner is :
Carlisle Sure Trail ST
ST205/75014 (replaces F78-14ST)
Max Load 1760 lbs @ 50 PSI (actual load will be under 500 lbs)

The ST inflation chart show a load rating of 850 pounds at 15 psi! This
tire is serious overkill for the weight of your trailer. Even the
smaller ST175/R13 has a 670 pound rating at 15 psi.

If it were my trailer, I'd just put on passenger car tires with a speed
rating about 20 mph higher than I planned to tow, and a 1000 or so pound
load rating, then use the correct pressure for a 600-700 pound load.

--
Eric Greenwell - Washington State, USA
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