Trailer tires

Well, folks, the die is cast. Last night I bought 2 Carlisle ST
205R75 tires. I'll let you know what happens.

Ed

On Jan 21, 10:38*am, kd6veb wrote:
Hi Gang
* There is another important consideration that has not been
thoroughly dealt with in this thread and that is trailer sway with
depends critically on the tires used and their pressures. What is
trailer sway? Well you are tootling down the highway at 50mph and
everything is great and then as you go through 65mph your trailer
begins to swing from side to side much to the consternation of anyone
following you. The only way to reduce this low frequency oscillation
is to slow down fast before the situation can get away from you. So
what are the factors affecting sway? Well the weight of the trailer is
one, the weight of the vehicle hauling, where the trailer wheels are
placed (front, middle or rear) but probably the most critical *factor
is the lateral flex of the sidewalls of the tires, wand of course, the
pressure of the tires. When I received my Cobra trailer from Germany
the tire pressures were low about 25psi and what I described above is
a true story. So I pumped the tires up to 40psi and no sway to 70mph
when towing with a heavy vehicle.
* In researching trailer sway more fully I found the general consensus
was to use tires with very stiff side walls such as 10 ply non radial
tires (truck tires) and to keep tire pressures up close to the
manufacturers maximum pressures especially if you are going to tow
with a small vehicle. I hope this is of some help.
Dave

Some people believe that the lateral stiffness of the towing vehicle
rear suspension and tires (tyres) is more important for sway control
than the stiffness in the trailer.

When observing a sway oscillation of a trailer and tow vehicle do you
see translation or rotation at the trailer axle? If both, which is
dominant?

Andy

On Jan 22, 7:24*am, flying_monkey wrote:
Well, folks, the die is cast. *Last night I bought 2 Carlisle ST
205R75 tires. *I'll let you know what happens.

Ed

Well, the trip's complete, no problems. We stopped at a WalMart about
5 miles from the glider pickup location, and had the tires changed,
setting the pressure at 40psi. Their max pressure was 50, but we
thought that with the load as low as it was, somewhat lower would be
better. With the above described tires, the trailer towed flawlessly
at speeds of 70-75 mph for miles at a time, and probably intermittent
80 mph stretches. The tires and bearings stayed completely cool.

Regarding the suspension, it turns out that there is torsion bar
suspension, which hooks some way into the arm which supports the hub.
This arm a casting about 9 inches long welded onto the end of the
torsion rod. The suspension is totally sacked out, so is just a solid
ride. Even with both wheels off the ground, the suspension just sits
in the maximally compressed position. The tire man said that usually
there is an adjustment bolt somewhere on the axle near the center
which adjusts the ride height, but nothing like that was seen here.
I'm almost thinking that we'll have to grind off the axle and weld on
a new one to solve this problem. Anybody seen this before, or have
any ideas?

I see that NorthernTool has some axles similar to this, but the lowest
capacity is 2000#. If something similar to this was on our trailer,
it might seem as if it was locked up but be just sitting at the
beginning of its travel and there's not enough weight to make it
move. I doubt that, though, because the trailer tire sits within 1/2
inch of contacting the fixed fender, and in the whole trip, there's no
evidence that it ever touched the fender.

TIA,
Ed

On Jan 22, 6:52*am, Andy wrote:
On Jan 21, 10:38*am, kd6veb wrote:





Hi Gang
* There is another important consideration that has not been
thoroughly dealt with in this thread and that is trailer sway with
depends critically on the tires used and their pressures. What is
trailer sway? Well you are tootling down the highway at 50mph and
everything is great and then as you go through 65mph your trailer
begins to swing from side to side much to the consternation of anyone
following you. The only way to reduce this low frequency oscillation
is to slow down fast before the situation can get away from you. So
what are the factors affecting sway? Well the weight of the trailer is
one, the weight of the vehicle hauling, where the trailer wheels are
placed (front, middle or rear) but probably the most critical *factor
is the lateral flex of the sidewalls of the tires, wand of course, the
pressure of the tires. When I received my Cobra trailer from Germany
the tire pressures were low about 25psi and what I described above is
a true story. So I pumped the tires up to 40psi and no sway to 70mph
when towing with a heavy vehicle.
* In researching trailer sway more fully I found the general consensus
was to use tires with very stiff side walls such as 10 ply non radial
tires (truck tires) and to keep tire pressures up close to the
manufacturers maximum pressures especially if you are going to tow
with a small vehicle. I hope this is of some help.
Dave

Some people believe that the lateral stiffness of the towing vehicle
rear suspension and tires (tyres) is more important for sway control
than the stiffness in the trailer.

When observing a sway oscillation of a trailer and tow vehicle do you
see translation or rotation at the trailer axle? If both, which is
dominant?

Andy- Hide quoted text -

- Show quoted text -

I'm a big believer in tow vehicle stiffness as THE solution. I've got
a fair amount of experience hauling long (sometimes heavy) trailers.
You can do all you want to the trailer tires, but you'll get the best
effect by stiffening the tow vehicle. Just adding tires with higher
load rating (stiffer sidewalls) yields a huge improvement in sway
control. The downside is harsher ride for passenger cars.

In article 1af7d33b-3bbe-42a6-bb11-1b8c67ba13e9
@r28g2000vbp.googlegroups.com, says...
On Jan 22, 7:24*am, flying_monkey wrote:
Well, folks, the die is cast. *Last night I bought 2 Carlisle ST
205R75 tires. *I'll let you know what happens.

Ed

Well, the trip's complete, no problems. We stopped at a WalMart about
5 miles from the glider pickup location, and had the tires changed,
setting the pressure at 40psi. Their max pressure was 50, but we
thought that with the load as low as it was, somewhat lower would be
better. With the above described tires, the trailer towed flawlessly
at speeds of 70-75 mph for miles at a time, and probably intermittent
80 mph stretches. The tires and bearings stayed completely cool.

Regarding the suspension, it turns out that there is torsion bar
suspension, which hooks some way into the arm which supports the hub.
This arm a casting about 9 inches long welded onto the end of the
torsion rod. The suspension is totally sacked out, so is just a solid
ride. Even with both wheels off the ground, the suspension just sits
in the maximally compressed position. The tire man said that usually
there is an adjustment bolt somewhere on the axle near the center
which adjusts the ride height, but nothing like that was seen here.
I'm almost thinking that we'll have to grind off the axle and weld on
a new one to solve this problem. Anybody seen this before, or have
any ideas?

Torson bar suspension is typically adjusted quite easily. The end of the
torsion bar should be splined. You should be able to take out the bar
with the trailer "de-loaded" (jack the weight off it), and reset it in -
turned around some - and let the weight back on. Hopefully, you now
have suspension again.

--
Duncan

I never thought of that. Thanks. But what holds the removable part
into the axle? I can't see anything. I don't see any kind of
setscrew anywhere. The outside end is just the end of a square tube,
and the part attached to the wheel is welded to the torsion element.

Ed

Torson bar suspension is typically adjusted quite easily. The end of the
torsion bar should be splined. *You should be able to take out the bar
with the trailer "de-loaded" (jack the weight off it), and reset it in -
turned around some - and let the weight back on. *Hopefully, you now
have suspension again.

--
Duncan

Regarding the suspension, it turns out that there is torsion bar
suspension, which hooks some way into the arm which supports the hub.
This arm a casting about 9 inches long welded onto the end of the
torsion rod. *The suspension is totally sacked out, so is just a solid
ride. *Even with both wheels off the ground, the suspension just sits
in the maximally compressed position. *The tire man said that usually
there is an adjustment bolt somewhere on the axle near the center
which adjusts the ride *height, but nothing like that was seen here.
I'm almost thinking that we'll have to grind off the axle and weld on
a new one to solve this problem. *Anybody seen this before, or have
any ideas?
TIA,
Ed

Ed, buy yourself a new Torflex axle of the correct size/rating (get
one with the electric brake flange on it so you can upgrade
someday...). It's an incredibly easy install, and your trailer will
ride like a dream with it's freshly recharged independent rubber-band
suspension and your ship will thank you for it. The elastomer bands in
these wear out over time (not as bad with newer techniques/
formulas...) and go flat as yours have. If you have elastomer
suspension (as it sounds like you have...) , there's no 'fix', there's
'replace'. The axle is only a couple hundred bucks though, and the
Dexter peeps are mighty helpful in the selection process should you
need to call them.
http://www.dexteraxle.com/torflex_axles I will not admit on this
forum how fast my trailer has been 'stability tested' up to with one
of these axles, so lets just say waaay too fast ;-)

-Paul

OK, mayby I got yer wrong - maybe it's a different "torsion bar" setup,
quite common on trailers in New Zealand - they're called Duro-Torque
(made by Trojan I think) - and work like this...

Two square hollow bars (square tubes), one is smaller and inserted into
the other at a 45 degree offset. And set into the "gaps" - are big
rubber bits.

These are fixed, by way of the way they're contructed. Their downfall
is, that when the turn round to a point, they basically roll round and
fail . The only fix is usually to replace the rubber (and they're damn
hard to seperate the two box pieces, given the rubber jammed in there.

I'd find out who makes them, or who can service them, and see if you can
get 'em reconditioned, or replaced - typically not very expensive.

--
Duncan

In article 3d6a5cbb-6d19-4636-90bf-e56fb1f8a036
@o36g2000yqh.googlegroups.com, says...
I never thought of that. Thanks. But what holds the removable part
into the axle? I can't see anything. I don't see any kind of
setscrew anywhere. The outside end is just the end of a square tube,
and the part attached to the wheel is welded to the torsion element.

Ed

Torson bar suspension is typically adjusted quite easily. The end of the
torsion bar should be splined. *You should be able to take out the bar
with the trailer "de-loaded" (jack the weight off it), and reset it in -
turned around some - and let the weight back on. *Hopefully, you now
have suspension again.

--
Duncan

PS: the link that sisu1a posted...

http://www.dexteraxle.com/torflex_axles

Is exactly what I meant, re Duro-Torque suspension.

And my advice still stands, get 'em serviced (normally replaced as
that's typically the only option) by the maker or agent that can do it.

--
Duncan

In article 3d6a5cbb-6d19-4636-90bf-e56fb1f8a036
@o36g2000yqh.googlegroups.com, says...
I never thought of that. Thanks. But what holds the removable part
into the axle? I can't see anything. I don't see any kind of
setscrew anywhere. The outside end is just the end of a square tube,
and the part attached to the wheel is welded to the torsion element.

Ed

Torson bar suspension is typically adjusted quite easily. The end of the
torsion bar should be splined. *You should be able to take out the bar
with the trailer "de-loaded" (jack the weight off it), and reset it in -
turned around some - and let the weight back on. *Hopefully, you now
have suspension again.

--
Duncan