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

My Avionic trailer has leaf springs and no shocks and the rhythmic ass end sway that develops at higher speeds encourages me to keep the top speed at 60-65 mph. That speed is just fine with me except when interstate traffic if flying by at 80 mph. In that case I feel that I'm something of a hazard, especially if I'm trying to merge or change lanes.

I'm thinking that shocks might dampen out the rhythmic sway that seems to be self-reinforcing. Tow vehicle is 2004 Volvo XC70. Single seat glass glider.

On Friday, June 6, 2014 6:44:32 PM UTC-4, son_of_flubber wrote:
My Avionic trailer has leaf springs and no shocks and the rhythmic ass end sway that develops at higher speeds encourages me to keep the top speed at 60-65 mph. That speed is just fine with me except when interstate traffic if flying by at 80 mph. In that case I feel that I'm something of a hazard, especially if I'm trying to merge or change lanes.



I'm thinking that shocks might dampen out the rhythmic sway that seems to be self-reinforcing. Tow vehicle is 2004 Volvo XC70. Single seat glass glider.

If you see rolling associated with the motion,damping might help. I doubt that to be the case.
This topic has come up several times.
Easy improvements a
Get any weight you can out of the back of the trailer.
Check your tires to see that they are properly inflated. Stiffer side walls that result from somewhat higher pressure sometimes helps.
One guy I know put "trip strips" on the leading edge of the dog house on his Avionic trailer and claimed it made a big difference. Color me skeptical but it may work.
UH

On Friday, June 6, 2014 3:44:32 PM UTC-7, son_of_flubber wrote:
Tow vehicle is 2004 Volvo XC70. Single seat glass glider.

Every time I've had the problem you describe, the solution has been one of the following:

* Fix the suspension of the tow car. New shock absorbers, and replacement of any worn or crumbling suspension bushings. And, trust me, the AWD versions of the Volvo P2 chassis cars have plenty of opportunities for those. My next snow car is definitely gonna be a Subaru; I'll take a head gasket change over that clusterfutzery any day.

* Lengthen the trailer tongue. Glider trailer tongues are way too often too short; sometimes an extra 4" or so will make a huge difference in stability.

Thanks, Bob K.

On Friday, June 6, 2014 6:44:32 PM UTC-4, son_of_flubber wrote:
My Avionic trailer has leaf springs and no shocks and the rhythmic ass end sway that develops at higher speeds encourages me to keep the top speed at 60-65 mph. That speed is just fine with me except when interstate traffic if flying by at 80 mph. In that case I feel that I'm something of a hazard, especially if I'm trying to merge or change lanes.



I'm thinking that shocks might dampen out the rhythmic sway that seems to be self-reinforcing. Tow vehicle is 2004 Volvo XC70. Single seat glass glider.

My Komet swayed at highway speeds after weight was taken out of the front of it and items were also moved to the rear of the trailer. Shifted items back to the front and added about 25 pounds of weight to the front and swaying stopped at highway speeds. Previous owner had similar observations.

Trailer weight is too far aft. Our Komet trailer with LS4 tows fine at highway speeds behind my old Ford Ranger and my newer Toyo Tundra Gen2.
We had that problem towing an empty Cobra Grob 103 trailer until we put a couple of tool boxes and spare tires in the front. Towed just fine with a 103 inside.
Factory Grob 103 trailer towed really bad with a glider inside. It took a lot of weight at the front end of the trailer to settle down.

BillT

Its always a good idea to fit Shock Absorber, if you have ever follow a
Glider trailer without shocks you can see the way trailers dance and move
about on any surface that’s less than perfect.
Proper loading of the trailer is very important as been said before,
another issue is crabbing, the trailer should run straight, check to see
that axle and tow hitch is true.

Vernon.


At 04:50 07 June 2014, Bill T wrote:
Trailer weight is too far aft. Our Komet trailer with LS4 tows fine at
highway speeds behind my old Ford Ranger and my newer Toyo Tundra Gen2.
We had that problem towing an empty Cobra Grob 103 trailer until we put a
couple of tool boxes and spare tires in the front. Towed just fine with a
103 inside.
Factory Grob 103 trailer towed really bad with a glider inside. It took a
lot of weight at the front end of the trailer to settle down.

BillT

Longer wheelbase tow vehicle

On Friday, June 6, 2014 6:44:32 PM UTC-4, son_of_flubber wrote:
My Avionic trailer has leaf springs and no shocks and the rhythmic ass end sway that develops at higher speeds encourages me to keep the top speed at 60-65 mph.

When I got my Avionic trailer in 2009, I got the shocks as a 110Euro option - it is very well-behaved at speed - no sway. I tow with a Jetta TDI (7 l/100km - 32 mpUSg at 65 mph). Well worth the money. I'd check with windpath to see if they can be retrofit. Small price considering what's in the trailer.

2D

Trailers are funny beasts, especially long trailers.
Shocks are important items as is using real trailer tires if your having problems; Trailer tires have stiffer sidewalls to help with the sway.
Make sure they are at max pressure.
The trailer C.G. is also very important; the C.G. must be well ahead of the axle, this where tongue weight comes into play. The tongue has to be heavy; how heavy? heavy enough to minimize the sway effect.
If you cannot picture this CG thing draw a picture of a trailer and move the CG ball aft of the axle and think about the CG being back there...When it starts moving back and forth it wants to go divergent, not good.
My Cobra trailer came with two large sandbags in the front of it and I cram all I can into the front storage space, self rigger, tow out gear etc and bungee it all down.
Flub, try and find a old school trailer man in your area, I bet he could look and your rig and have a solution.

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.