bounce... could it be bad tug shocks?

[Scott S.]

I seem to feel every bounce my Surfside makes when I tow. is it possible that the shocks on my Pontiac Montana are week or even shot? I tried more weight in the front of the trailer as well as more in the van and it was slightly better. on good roads I hardly notice it but I live in Manitoba so there's not too many really smooth sections or road out there.

[Kevin K]

Test your car without the trailer hooked up, by trying to bounce the car up and down on the back, now let go, and see if the car still bounces up and down, if it does the shocks are shot.

[Casita Greg]

Have you balanced the tires? Most trailer manufacturers, and even tire stores, don't usually balance trailer tires unless you specifically request balancing. Just a thought, but worth checking. If they're not balanced, it could cause the bouncing problems you've described. If they aren't balanced, it will also cause your shock absorbers to die a premature death from excessive cycling (bouncing).
Greg

[Scott S.]

it does about bounce and a half after... I have to take it in anyway so I'll get them checked while it's there. I thought about the tire balance issue as well but all it good there.
I was also thinking it may also be the fact that it's the shortest Montana made.

[Cam A]

I feel for you re: Manitoba roads. Worn cement is the worst, ie TransCanada. I replaced the struts in my Forester (shorter than your Montana) and noticed a great improvement.

[Bill MacDermod]

Do you use a WDH????? I tow a 17' with an Ody and have no bounce at all

[CD Smith]

Some questions.

Have you measured the height from the ground to the top of the inside of the wheel wells: all four wheels, loaded and not loaded, and with and without the RV connected? You may need to add air bags or air shocks to the rear axle to level out the TV before hitching the RV.

Are you overloading the Montana? Look at the placard on the driver's side door. Look for 'Maximum load of passengers and cargo'. Add up driver's weight, passenger's weight, weight of stuff loaded in TV, and hitch weight. Allow about 10% margin.

Are you adverse to using a WDH? If not make sure the TV is level before hitching and re-level TV with WDH after hitching.

Just thought I would ask?

[Roger H]

You may be a victim of a worn out axle on the Surfside if the Surfside has a torsion axle. A trailer flying through the air and slamming down on it's axle without working suspension will definitely make itself felt in the tow vehicle. Something to check, anyway. If it's leaf spring suspension without shocks, shocks may improve it.

Roger

[Doug Mager]

......ALMOST sounds to me like a simple case of too much weight on the front end of the trailer. Weight (IF not reduced) needs to be more evenly spread throughout the trailer.

[Scott S.]

OK, lots to check on... the TV ride fairly level and is not overweight. I thought about a WDH and that may be an issue. the comment Roger made about the worn torsion bar axle on the trailer makes sense too. As a test, I'm going to have a friend tow it with his vehicle and see if the bounce is still there. if not, then I can look at my Montana shocks as they would be 5 years old now and suspect. I haven't owned since new so I'm not positive.

thanx for all the input. help to ask ppl that really know.

[Shelley]

I'd consider the suggestion about too much weight in the front of the trailer too...I wouldn't necessarily describe it as bounce but it sometimes feels a bit like my Explorer Sport and Surfside aren't in synch on bumps. When I think about it, a lot of my heavier stuff is under the front bench....I think I may redistribute some stuff...

[Roger H]

OK, lots to check on... the comment Roger made about the worn torsion bar axle on the trailer makes sense too. As a test, I'm going to have a friend tow it with his vehicle and see if the bounce is still there.

Scott, there are some other tell-tale signs of a rubber torsion axle that has failed. First is, most of your "stuff" inside the trailer shouldn't shift when you tow it down the road normally. If, after a normal trip with regular roads you find your cupboard doors have opened, or "stuff" has shifted significantly on the floor or otherwise moved around, it's probably the axle.

There should normally, in most FGRVs, be about a fist's worth of "bump room" between the top of the tire and the top of the wheel well. If there is significantly less room than you can comfortably put your fist into, or there are rub marks on the top of the wheel well, the axle is likely shot.

The last thing you can do is the "bounce test". Have someone who has some mass (I won't say some of the alternative adjectives... ) stand in the doorway, and bounce up and down. You stand outside and see if the trailer is moving up and down in comparison to the tire sidewall. If the trailer isn't moving, but all you see is sidewall flex, then the odds are pretty good that your axle is shot.

The design life of a rubber torsion axle is about twenty years. Some make it to twenty-five. Practically none make it to thirty. Your Surfside is now thirty-one years old... if it has a rubber torsion axle, and hasn't had an axle transplant it's definitely over-due.

A sway control WDH will help the ride, and make your trailer/tow vehicle combination feel much more solid. It is an excellent idea anyway, provided that it's done with the right load bars so you don't over-stress your trailer's frame and suspension. A WDH will not compensate for an axle that has no suspension.

Roger

[james kent]

Check also the type of tires on the trailer. Automotive tires will bounce more than true trailer tires which have stronger side walls.

[Roy in TO]

There should normally, in most FGRVs, be about a fist's worth of "bump room" between the top of the tire and the top of the wheel well. If there is significantly less room than you can comfortably put your fist into, or there are rub marks on the top of the wheel well, the axle is likely shot.

If you have a [b]torsion axle:

Check out the specs and details on an axle site such as Dexter. A good axle has a certain range of motion based on the original start angle. In an older axle the rubber is stiffer and the range will be less.

If you jack up the trailer so it is off it's wheels, you can measure the start angle and length of the arm. Then you measure the center or top of the spindle to a point on your frame or body.
Set the trailer back down under normal load and get a second measurement from the same 2 points. That will give you 1/2 the info you need.

Now measure from the top of the wheel to a point on the body or top of the wheel well. Get someone to bounce the trailer and find the shortest distance from the same point. Subtract one from the other and you've got the other 1/2 of the info you need.

Add the 2 distances from above and you got the vertical range of motion from "no load" to "shock load" and compare that to the published specs for an axle with a similar start angle and arm length. (Hint, you are looking for the tables with start angles and distances both vertical and horizontal)

If your range is much less, chances are you need a new axle.

Torsion axles with larger start angles either up or down will have greater horizontal (front to back) movement with less vertical (up and down). The opposite applies to torsion axles near the horizontal.

[Benny K]

Depending where you are driving on Manitoba roads, that may be a major part of your problem.....my `74 has the original axle and and have about 3" free space between the wheels and wheel housings..... I run about 15% tongue weight or more and on decent highways the trailer rides like silk,(sometimes forget it`s even there), and I run on auto tires on about 36-38 Lbs pressure with no problems....and this is on a leading axle......if I`m on a concrete section that has the repetative pavement breaks, it`s just terrible once it sets up the bounce rythum.....stuff on the trailer floor will shift somewhat toward the front of the trailer under most conditions just as truck loads tend to shift forward on transfer truck floors .....because of the braking forces I suppose! ...Benny

[Scott S.]

thanks Benny, that's exactly what I'm finding... the bounce rythm on concrete poured in sections (ie: our lovely Perimeter hwy). I did get the shocks checked on the Montana though and they are on their last legs and will be replaced before spring.

I'll be doing some bounce tests this weekend (I qualify weight wise I'm sorry to say). the axle seems to have nice flex/travel but I'll know soon enough using the suggested tests (thanx). whatever my baby needs though... I'll fix her up with the best I can get.

thanx for all the input folks, this is an amazing community.