Do trailers with coil springs and shock absorbers sway at higher speeds?

Trailer, not glider, but...

Last week my wife and I were towing our utility trailer with two 17'
kayaks on the interstate. I've also been carrying 3 5-gallon cans of
water up front in the trailer as ballast. Last week one of the cans
developed a leak and suddenly, at 75 mph, the trailer began to sway
violently left to right. Slowing down to 60 mph would make the swaying
stop, but that's dangerous out west. So - first exit we got off and
loaded a bunch of rocks in the front of the trailer. Problem solved!

Dan Marotta

On 6/7/2014 7:39 PM, wrote:
Been towing gliders for some time.
Tongue weight is number one. You want significant forward CG in trailer.
Stiff sidewall tires is number two. Get trailer tires. Not car tires.
Keep it under 80mph.

There are three Avionics owned by members of my club. They all have the torsion type axle and tow quite nicely. Mine (a 2004) was not quite as good as the other ones though until I put 175 size tires on it in place on the 165's it came with. The newer ones came with 175's from the factory.

Shocks certainly wouldn't hurt but the suggestions about increasing the tongue weight are worth following. It may make a significant improvement and would be easy and inexpensive to try.

Trailer stability is weird though. The Pfeister trailer my club has for a Twin Astir has almost no tongue weight when loaded but towed nicely behind my old Nissan pickup. Once, when taking it through the Rockies it had been loaded the "proper" way by the club expert - he put ballast right up front so it had about 100 pounds tongue weight. Loaded like that it tried to throw me off the road at anything above 75 KMH towed by the same truck. Go figure.

On Wednesday, June 11, 2014 4:53:40 AM UTC-4, wrote:
There are three Avionics owned by members of my club. They all have the torsion type axle and tow quite nicely. Mine (a 2004) was not quite as good as the other ones though until I put 175 size tires on it in place on the 165's it came with. The newer ones came with 175's from the factory.



Shocks certainly wouldn't hurt but the suggestions about increasing the tongue weight are worth following. It may make a significant improvement and would be easy and inexpensive to try.



Trailer stability is weird though. The Pfeister trailer my club has for a Twin Astir has almost no tongue weight when loaded but towed nicely behind my old Nissan pickup. Once, when taking it through the Rockies it had been loaded the "proper" way by the club expert - he put ballast right up front so it had about 100 pounds tongue weight. Loaded like that it tried to throw me off the road at anything above 75 KMH towed by the same truck. Go figure.

A very significant factor, mentioned by Bob above, is the vehicle and the quality of suspension and tires on the vehicle.
Generally said, a vehicle that handles very well, with good tires properly inflated, should be a decent tow machine.
It is important to not have the trailer tail heavy, but over loading the tongue on a bad vehicle- trailer combination won't solve much and can make a poor combination worse. Old tires and suspension, with low air pressures, and maybe some extra overhang on the tow hitch,and a really heavy tongue, will make a very uncomfortable situation.
Moving some heavy crap out of the trailer and into the tow vehicle, between the axles can make startling improvement in some cases.
Jaguar XJ6 towing Cobra trailer, is the best combination I ever used. Solid, comfortable, and safe at any speed you would want to drive the car. But not a desert rig. Never had more than 75 lb on the tongue.
UH

My 2001 Cobra trailer arrived from the previous owner with lead weights and dumbbells at the front to increase tongue weight. I removed them and found still plenty of tongue weight and no towing instability behind a Toyota 4Runner at speeds up to 85 mph (Arizona highway speed!) I replaced the tires last year with recommended trailer tires and have absolutely no problems except in very strong gusty side-winds, when I slow to 70 mph.

I suspect the geometry and suspension of the tow vehicle are an important part of the equation - I have always used robust, heavy four-wheel drive vehicles designed for towing and have never experienced severe instability problems.

Mike

On Wednesday, June 11, 2014 8:33:32 AM UTC-4, wrote:
On Wednesday, June 11, 2014 4:53:40 AM UTC-4, wrote:

A very significant factor, mentioned by Bob above, is the vehicle and the quality of suspension and tires on the vehicle.

Generally said, a vehicle that handles very well, with good tires properly inflated, should be a decent tow machine.

It is important to not have the trailer tail heavy, but over loading the tongue on a bad vehicle- trailer combination won't solve much and can make a poor combination worse. Old tires and suspension, with low air pressures, and maybe some extra overhang on the tow hitch,and a really heavy tongue, will make a very uncomfortable situation.

Moving some heavy crap out of the trailer and into the tow vehicle, between the axles can make startling improvement in some cases.

Jaguar XJ6 towing Cobra trailer, is the best combination I ever used. Solid, comfortable, and safe at any speed you would want to drive the car. But not a desert rig. Never had more than 75 lb on the tongue.

UH

Quick and timely corroboration of the above. I sold my LS8 with 1990 Komet Euro Light trailer last week. Incredibly well behaved rig behind anything that's towed it over the last 14 years (Sprinter Van, Honda Odyssey, VW Sportwagen TDI). New buyer got only a few miles down the road on Interstate 95 before calling to ask about significant sway at highway speeds. What changed: 1) the tow vehicle 2) I took out a bunch of crap from the front of the trailer.

New buyer was towing with a Toyota Tacoma. The first/easiest thing to do was to up the tire pressure in the rear of the Tacoma to max recommended pressure. Calls back one hour later to report that everything is great. A simple fix with positive results.

FWIW, I've always towed with the rear tires at their max recommended pressure in the tow vehicle. Has worked well for me over the years.

I'll talk about a homebuilt trailer with leaf springs. Towed OK but I got pretty good sway when a semi passed, oddly most noticeably when it passed in the same directly.

After doing all of the assorted things mentioned above by others (which did help some) I ended up installing a sway bar kit which significantly corrected the situation. Your mileage may vary.

See http://www.etrailer.com/Weight-Distr...ies/83660.html

- John

a friction stabilizer works wonders, and it is very common in Europe.
http://www.al-ko.com/322.htm

aldo cernezzi
www.voloavela.it

Aldo is correct- a friction anti-sway device is very effective. There are a couple of things to consider, though.

The Al-KO clamping hitch is an excellent piece of gear, BUT WILL ONLY WORK WITH A 50 MM BALL! Normal 1 7/8 or 2 inch balls are too small or too large for the clamp to handle. I have installed a few of these on Cobra trailers and the results are excellent. Note that the ball MUST be welded or otherwise fixed to the receiver extension to keep the clamp from loosening the nut on the ball shank. I machine a "flat" on the base of the ball and weld a piece of bar stock to the hitch to keep things from moving.

This is a rather expensive solution, and the AL-KO hitch is not available in the US, so I bought some from a supplier in the UK. Note that this design is the only one I have seen that will work with the usual European surge brake coupler.

For a tongue without a surge brake, there are several designs that are inexpensive and very effective. Most will require some welding and proper alignment is necessary, so a pro should be consulted. Here is a link to sway control devices from etrailer.com: http://accessories.etrailer.com/search?w=sway%20control

Mark Mocho
MM Fabrication

I tow an Avionic behind a BMW 325 with a 2 inch ball- no problems.

On Thursday, June 12, 2014 9:34:18 AM UTC-4, wrote:
I tow an Avionic behind a BMW 325 with a 2 inch ball- no problems.

Lots of good ideas shared here. Thanks.

My goal is to achieve 70 mph stable towing for East Coast towing and 80 mph for western states towing.

From comments made here, it appears to be possible to achieve these numbers with the Avionic torsion bar suspension with a moderate sized vehicle like Volvo XC70.

Things to try:

1)Increase tongue weight which is a measure of how much the CG is forward of the axle.

2)Increase cargo mass close to the tow ball in both the trailer and the tow vehicle.

3)Trailer tires- use trailer type tires, use max pressure to increase sidewall stiffness. Avionic specific, increase tire size to 175 from 165.

4)Tow vehicle- increase cargo mass near tow ball, verify/upgrade suspension stiffness, increase rear tire pressure for sidewall stiffness. Possibly upgrade rear tires for side movement stiffness.

5)Check that the axle is perpendicular with the longitudinal axis of the trailer. Correct misalignment if possible.

My glider is assembled in a hangar, so I'll experiment to get the best performance with the empty trailer and expect things to change a bit with the glider. I'll replicate the best tongue weight when I put the glider back in and go from there. The trailer CG is close to neutral with the glider and nothing else in the front of the trailer. One of the best trailer sales/maintenance meccas in the region is within an hour's drive of the airport and I will get their help if I still have problems.