Shock Absorbers revisited

[GOTTOYS]

Did some maintenance last week and noted a couple of my shocks were bent. Between the way they are mounted and the probable low quality of these Chinese made components it looks doubtful that there is any benefit in even having them. I know they can be replaced with American made quality components and the mountings can be modified to be more effective. My question is, with the limited suspension travel on our stock suspension would I even notice the difference if I just took these off and tossed them? The way they are bent they don't look like they can move anyway. Maybe in the future I can weld up some new mounts. Have any of you just removed them and if so did you notice any difference?..Don

 

[Ray LeTourneau]

Our original suspension on our 07 3400RL was without shocks. It had the Mor Ryde center shear spring (rubber equalizer mount) but that's all. No Shocks!
When I had MorRyde install the IS it came with shocks mounted in an almost vertical position.
There's been much discussion about shocks and I think the consensus is either mount better or toss them out. There was a recent post where an owner made new brackets for both upper and lower shock mounts and they looked great. Maybe a search would turn up that post. I'll see what I can find.

On Edit, here is the thread I was mentioning.

 

[GOTTOYS]

Thanks Ray. Interesting reading. I'd really like to go with a Mor-Ryde IS but the desire to eat has limited my budget for that at this time. Not 100% sure if this is the rig I plan to keep for several years. Would most likely install it on the next go around for sure. It would be nice if it was available as an option from Heartland but I can understand the logistics during manufacturing would limit that. Just seems a a shame to cast off all the new suspension components when getting the Mor-Ryde installed. Don

 

[boatdoc]

My bent shocks went to the scrapper long ago. No replacement either. Everything gets to where we are going just as before.

 

[TeJay]

I also refitted our NT with shocks. Built the brackets top and bottom. It's was about a $150 dollar upgrade if you have access to a metal shop and can weld. Here's my take on why I did it. Any suspension: coil, leaf or torsion bar move when they hit a bump or dip. The suspension will continue to oscillate until the movement either stops or is dampened by a shock. These oscillations are continuous any time we travel. The oscillations are transmitted into the rig, and the TV. The tires are also affected. Over many miles the tires is subjected to continuous load no load, load no load. As it bounces without the dampening effect of a shock it can and will cause tire wear. The sidewall of the tire is also being subjected to this continuous flexing as the tire bounces. Also when the tire hits a bump and is not dampened when it is in the no load situation the tread is not making good contact with the surface of the road increasing the potential for sliding or slipping especially in wet conditions. It is always to our advantage to keep the tread in good contact with the road surface. I'm making my decision based on facts and a good understanding on how suspensions work. If I can do it all of my Campers will have shocks.

TeJay

 

[RoadJunkie]

So, why do the shafts on the shocks bend? Please don't tell me they're mounted wrong, at the wrong angle, or whatever. I inspected mine about 3 weeks ago and, although they are 2 1/2 years old, they are in great shape and no sign of bending. The springs are not flattening, as well. So is there a weight influence, type of roads traveled, balance of weight between front and rear axle? I find it hard to believe the folks at Lippert don't have and engineer who designed the placement and angle of these shocks.

 

[TeJay]

RoadJunkie,
I replied to your post last night but I guess it did not get posted. I'll try again. I'm not an engineer but it is obvious that engineers do make mistakes or it's a combination of the bean counters saving a buck and the engineers never having pulled a TT. Also why are a lot of campers having tire problems if engineers get it right. I may not have a degree in mechanical engineering but I have a lot of common sense. You will never convince me that a suspension system does not need a shock absorber. I understand enough about suspension systems to realize these facts. I don't care if it's coil, leaf, or torsion when a suspension system encounters road bumps and dips they begin to oscillate. That energy of motion has to be converted into another form of energy or continue its oscillation until it stops. If it is allowed to continue the tire is loosing contact with the surface of the road on the up swing and causing extra sidewall flexing of the tire and extra tread pressure on the downward motion. On all other vehicles on the highways our engineers have determined that we need to dampen those oscillations with shocks and convert that energy into heat energy. This smooths and improves the ride, preserves the camper, increases tire and tread life and reduces the campers rock and roll motion effect on the TV. Why would we not want to achieve these improvements????

Why do shock shafts bend??? You bend something by hitting a stationary object or at least one not moving at the same speed or on the same plane (curb). Or by overloading it. If it's not caused by hitting something then it's overloaded. I'd bet a paycheck on this theory. I'm retired so my checks are not very big. If your shocks are OK one month then bent the next month this is what probably happened. If a spring is overloaded or compressed FURTHER than normal, and the shock is compressed beyond its fully compressed position either before you hit a bump or after a bump further compresses the shock something has to give or bend. Think about it for a moment or two. We do not know exactly how much weight is placed on each wheel of our campers. It is very possible to overload from trip to trip. Also consider the fact that maybe just maybe the camper suspension systems are no build with a lot of margin for error as perhaps our cars and trucks are. I have also seen a few pics showing the flat angle that some of these shocks are mounted and that will contribute to the problem especially when a spring is overloaded. The absolute best location for a shock is to be positioned so that its travel is parallel to the suspensions travel. Any position less than that is a compromised location and it will reduce the shocks ability to perform at its best.
I'm interested in your comments. I will never pull a camper that does not have some sort of shocks. If they don't have them then I will add them and they will work.

TeJay

 

[GOTTOYS]

I'm afraid I have to disagree with the overloaded theory Tejay. I had my rig weighed in Goshen when it was fully loaded. I have one bent shock on the rear axle on the curb side and one bent shock on the front axle on the street side. My combined axle weights are under 9,000# fully loaded. I have a total of 12,000# of axle capacity. I am not even close to being overloaded on any of my wheels. I think the severe angle the shocks are mounted at plays a part in why they are bent. The shocks should by design have enough travel to not bend as the axle moves up and down and should in no way limit the travel of the axle. Their only purpose is dampen any movement. My next move is to remove them as they are probably limiting any axle movement anyway. I might remount some new ones..might not. Don

 

[TedS]

On my trailer the shock shafts connected to the plate at the spring are bent. The angle of the mounting tab on the plate does not match the angle of the shock. I believe the bend is the result of forcing the shock installation to mounting points that do not match the shock angle. I worry about it, but have not done anything about it, yet. At the very shallow angle, the shocks cannot be very effective.

 

[TeJay]

Gottoys,
I respect your perspective on the issue. Diagnosis from afar can be difficult. If you are loaded correctly then you are dealing with angles and cheap china stuff. Depending on the unit it is probably a combination of errors. Not enough margin of error built into the suspension system. Incorrect angle of the shocks and of course cheap stuff. I'll stand by my opinion of having working shocks. They can only improve everything in regards to the suspension, and the life of all components connected with it. Boat trailers in general don't have integral brakes, shocks and some don't have leaf spring suspensions. Larger/heavier boats probably do. It has always been my opinion that the TT industry followed the boat trailer industry and continue making their smaller units with minimal suspension, non-self-adjusting brakes and no shock absorber trailer frames. It is my understanding that Dexter has been using self-adjusting drum brakes for several years but Lippert does not. We all know that disc brakes are by design self-adjusting but most TT's don't come with disc brakes.

We had a TT that was 7,000 max weight and it came with 2-3-K axles. That's 1-K under the max. Tell me that engineers and some companies are building safe units with a good margin of error??? We complained and within 1-week we had 2-3,500 LB axles delivered and installed.

TedS,
The bad angle still allows the shocks to work and they may be effective but the low angle increases the stress and when it is over stressed things bend. I had a British car and because of the low profile and limited travel space they used a shock with a lever extended from the shock top. I may try to locate some of those units and see if I can adapt them to my trailer. When I designed the system for our NT I consulted with Monroe and told them the full compressed and extended information, the weight expected and they recommended a shock. We have probably put 6,000 miles on it and everything has worked perfectly. We have reduced trailer movement and sway and dampening of the unit when hitting bumps. That's what is supposed to happen or not happen.

TeJay

 

[Ray LeTourneau]

Another reason the shocks bend is due to the severe twisting our tires and suspension incurs when backing into a tight spot. Take a peek at your tires next time you cut the rig at a fairly sharp angle while backing in. You'll see your front and rear tires all cattywomped out of line. I can imagine this may also have an effect on the tire plies?

 

[TedS]

Ray, then in my opinion as a reitred product design engineer, it is a poor design if expected use is not accounted for and parts are allowed to permanently bend when they should not. Flex I understand; flexed parts, like airplane wings, come back to 'normal' when loads return to normal.

TeJay, the rod end is bolted tight to the mounting plate. The rod between the plate is bent so that the other end of the shock could be attached to the frame mounting. This as the unit sits static, not the result of suspension movement or overload. I imagine that with the frame upside down when the suspension is attached, the shock end closest to the assembler is attached and tightened first. Then the upper end is forced to fit the frame mounting point bending the rod end previously attached to the spring plate.

 

[TeJay]

Ray,
I'm sure the squirming of the tire when making those tight turns has some effect on the suspension. My tire guy who has 45 years dealing with tires, said that the ST tires are designed for that extra stress and in my way of thinking the suspension and all related components should also. I've said it before but maybe it should be repeated until all parties accept the facts. Camper frames are not designed with much safety margin in mind or longevity either. They are modeled after boat/utility trailers and they are slow to make adjustments. Most companies are cutting where they can to improve the bottom line. When you begin with a structure that is marginal to begin with and begin shaving where you can you are asking for early failures. I've read to much on this forum and others about those early +failures.
I know don't complain unless you want to pay a lot more for a safer product. Trying to not sound like I'm complaining but just stating facts and concerns regarding the margin of safety designed into these units. What is it that ford says concerning how many of their trucks are still on the road??? You've heard the add.
TeJay

 

[lwmcguir]

Ray,
I'm sure the squirming of the tire when making those tight turns has some effect on the suspension. My tire guy who has 45 years dealing with tires, said that the ST tires are designed for that extra stress and in my way of thinking the suspension and all related components should also. I've said it before but maybe it should be repeated until all parties accept the facts. Camper frames are not designed with much safety margin in mind or longevity either. They are modeled after boat/utility trailers and they are slow to make adjustments. Most companies are cutting where they can to improve the bottom line. When you begin with a structure that is marginal to begin with and begin shaving where you can you are asking for early failures. I've read to much on this forum and others about those early +failures.
I know don't complain unless you want to pay a lot more for a safer product. Trying to not sound like I'm complaining but just stating facts and concerns regarding the margin of safety designed into these units. What is it that ford says concerning how many of their trucks are still on the road??? You've heard the add.
TeJay

Very well stated and certainly very factual. It is about money on both ends.

 

[RoadJunkie]

I'm wondering if the axle load rating, or overload rating as the case may be, is based on the static load applied to the axle. The dynamic load as the vehicle moves and bounces down the road can, of course, be considerably more. This would speak to the theory of "overload" and thus bending of the shock shaft as the springs move past the in-line limits of shock. Therefore, if you load toward the high end of the axle rating, you will likely bend the shock shaft, assuming the factory mounting position of the shock. Of course the leaf-springs may be under designed and allow way too much movement as compared to the specified RV ratings, considering the dynamic loads. I believe if you want to avoid bent shafts, without modifications of shock mountings, you must reduce the rolling weight. Good discussion.

 

[Sandpirate69]

Very good topic. My rig does not have shocks and i've been contemplating installing them. I have been considering the issue of angle. I have not looked at an RV with shocks to see how they been angled or not. I would assume that they are straight up/down. I couldn't see them angled, as there only movement is up or down. I can see them angled if they were an independant suspension. My the axle on my dually does have them angled, but one faces back & the other faces forward. We sure need an engineer to explain this to a better degree. It would probably help us with better tire wear & less blow-outs.

 

[westxsrt10]

Ever get a chance to watch how much a solid axle twists under hard braking, this can easily bend the lower shock in many cases.

 

[Ray LeTourneau]

Ever get a chance to watch how much a solid axle twists under hard braking, this can easily bend the lower shock in many cases.

I agree and also think maybe the mounting bolts may be too tight not allowing the shock to flex in the bracket. I still feel the angle is too severe to have much of a damping effect.

 

[TedS]

I went out to look again at the shocks on my trailer and see that they are attached with threaded ends and nuts on both ends. Neither end can swivel as the shock moves. Both ends must bend or flex in the mounting plate holes cushioned only by rubber on either side of the mounting surface. I thought that shocks had one or two eye ends with through bolts so they can pivot around the through bolt as they follow the axle.
Doesn't seem right to not have at least one end pivot.

 

[GOTTOYS]

Ummm..can't be from braking. Mine barely worked if they worked at all, with all the grease they had pumped in them. I was working on them when I found the bent shocks. I never greased the hubs so It had to have been that way since new. I'll go with the severe mounting angle theory. I have around 13,000 miles on my rig. Didn't notice that they were bent last year when I was under it. Don