Suspensions/Foundations Fivers - RV-Dreams Community Forum

HSsweethearts · RV-Dreams Community Member

Suspensions/Foundations Fivers

Howard · Host

Hey Brian,

There are several trailer suspensions out there that are better than the standard leaf spring suspension. In my opinion, the Mor/ryde IS is the best trailer suspension out there, but it's not a complete runaway. Lippert and Dexter have very good suspensions, but the IS allows a little better "travel" when you hit a bump or pothole and the independent aspect eliminates side-to-side sway. Having had both the Mor/ryde RE suspension (with leaf springs, axles, and shackles) and then changing to the Mor/ryde IS without axles, there is a world of difference. And because Linda follows, she has a long-term visible reference for the improvement in the shifting and bouncing of the fifth wheel. The IS suspension, especially on heavier fifth wheels, certainly will reduce stress on the frame over traditional suspensions.

So, is it a deal breaker if a trailer doesn't have Mor/ryde IS? Absolutely not. However, especially on trailers over 16,000 lbs (random number from me) for full-time use that we hope will last as long as possible, it's the option I would choose every time. If I were buying new, I would choose it as an option if available. If not available, I would add it later. If I were buying a used unit that didn't have Mor/ryde IS, I would immediately start saving money to install the IS (along with disc brakes).

The IS is not "crucial" or a "necessary" upgrade. But us full-timers are better off in the long run if we make sure we have good quality tires, wheels, and suspensions. We tend to load our RVs heavy, so any "foundation" safety margin will keep us from repeat service trips and make our rigs last longer by reducing stress on the frame.

Just my opinion based on our personal experience and our experience weighing RVs and seeing what can happen with suspensions, axles, and tires on heavy trailers (even if they aren't technically overloaded). :)

Jack Mayer · RV-Dreams Family Member

I totally agree with Howard. I have had IS on 5 high heavy 5ers now - ranging in weight from 16,500 lbs to 23, 800 lbs. OUr new trailer will be in the 25K lb range.

The last 3 trailers have been custom built and I could have any suspension package on it that is available in the industry. I chose Mor/Ryde IS.

Bill and Linda · RV-Dreams Family Member

X3. On our last trailer we upgraded from springs, with the equalizer system, to the MOR/ryde IS so we were able to do an “apples for apples” comparison. The difference is pretty dramatic because each wheel is totally independent so when a wheel hits a bump the shock isn’t transferred to the other 3 (or 5) wheels causing even more shock. The IS also has more vertical travel range, along with a recoil dampening shock absorber, thus reducing the possibility of “bottoming out.”

We have some 100,000 miles of towing travel experience with springs and with the IS. Quite a bit of that is over unpaved roads in Canada that are far worse than most anything you will experience in the states in normal travel. There is no question – and we just had to deal with this decision – if we were to purchase a trailer without an IS we would take it directly to MOR/ryde and have the IS installed and aligned. Unlike a spring suspension you can align the IS just like a car - toe, camber and caster.

BTW, if your trailer isn’t running level with the truck MOR/ryde can do a proper lift and make it run level with your truck. Very easy process actually. This is a very important as to tire wear and safety. They can also upgrade the brakes to disc and tires to “H” at the same time. Highly recommended for any rig but especially, as Howard mentioned, for rigs at 16,000 and up.

HSsweethearts · RV-Dreams Community Member

Thanks for the input. Still looking for some dissenters that have found comparable suspensions/foundations. Are you out there?

Thanks again,

Brian

HSsweethearts · RV-Dreams Community Member

Forgot to ask: Disc brakes are a must (is this the electronic brake that can be activated/adjusted from the cab of the tow vehicle?) Is this called a surge brake?

I'm confused about 7,000 lb vs 8,000 lb axles, when the independent suspension has no axles? Are 8,000 lb axles a must or at what point (weight) are they a must have?

Also, "G" or "H" rated tires, are "G" tires 16" & "H" tires 17.5"? Again, are "H" rated or 17.5" tires a must or at what point (weight) do they become necessary?

You guys said there are no dumb questions. However, somehow I feel the need to apologize for my naiveté.

Brian

Bill and Linda · RV-Dreams Family Member

HSsweethearts wrote:
Forgot to ask: Disc brakes are a must (is this the electronic brake that can be activated/adjusted from the cab of the tow vehicle?) Is this called a surge brake?
I'm confused about 7,000 lb vs 8,000 lb axles, when the independent suspension has no axles? Are 8,000 lb axles a must or at what point (weight) are they a must have?
Also, "G" or "H" rated tires, are "G" tires 16" & "H" tires 17.5"? Again, are "H" rated or 17.5" tires a must or at what point (weight) do they become necessary?
You guys said there are no dumb questions. However, somehow I feel the need to apologize for my naiveté.
Brian

Great questions:

Are disc brakes a must? IMO, yes they are unless you seldom move the trailer. Certainly if you travel a lot it is a huge safety issue.

Are they like a surge brake? Not really. But they are hydraulic and are actually controlled from a 12 volt controller in the truck. Not as complicated as it might sound.

Can you adjust the braking from the cab of the truck (to properly balance trailer braking with the truck?) Yes.

Are 8K axles a must? Not to be smart, if the 7K are overloaded, yes 8K’s are a must. It depends on the trailer but if you have to guess, get 8K’s. If you are going fulltime most likely the rig will need 8K once all your “stuff” is in the trailer. It is easy to add 2,000+ lbs to a trailer with no trouble at all. At least the big 5ers we're discussing in this thread.

“Also, "G" or "H" rated tires, are "G" tires 16" & "H" tires 17.5"? Again, are "H" rated or 17.5" tires a must or at what point (weight) do they become necessary?”

G114 “H” tires are 17.5” tires and require wheels (rims) specific to that type of tire. The “H” G114 tires are commercial grade, expensive and worth it IMO. It isn’t as much a weight issue as a dependability issue for lesser tires.

IMO, I would have “H” tires on any rig approaching 16K and up. Overkill, probably to some – but they won’t blow out like “G” and “E” tires do and can really tear up a trailer when they blow out.

Don’t be confused about the 7K and 8K IS suspension that actually has no axle tube running under the trailer. 7K and 8K means the same with an IS, independent suspension, as 7K or 8K “spring” axles. It is the total weight rating of the individual suspension system is rated to carry.

Terry and Jo · RV-Dreams Family Member

HSsweethearts wrote:
Thanks for the input. Still looking for some dissenters that have found comparable suspensions/foundations. Are you out there?
Thanks again,
Brian

I'm not really a dissenter as the IS system is a very good one. If one doesn't necessarily feel the need for that system, an air ride system is also good. On our Mobile Suites, it is equipped with the Trail-Air air ride suspension as well as the Trail-Air air ride pin box. That Trail-Air pin box also has what is called "Tri-Glide" which is a way of reducing (or eliminating) the "chucking" one feels on rough roads.

While we've not be extensive travelers (we are full-timers but stay in one place for some time), the times we have pulled our Mobile Suites have been smooth and trouble-free. And, that includes towing on some pretty rough Oklahoma roads.

Going slightly beyond your question about suspensions, there are also air ride fifth wheel hitches out there to be had. They are more expensive than the normal fifth wheel hitch, but they do a lot to cushion the ride as well. Our fifth wheel hitch is not an air ride, but with the Trail-Air system, I've not felt the need to spend the extra money for an air ride hitch.

Terry

kb0zke · RV-Dreams Family Member

I'm a bit odd, but I really would like the axles to be able to carry the entire load of the trailer. I realize that some will be on the hitch, but I like a large safety margin. There are roads that, if taken at the right speed, will have the hitch "floating" on a rebound while the whole weight of the trailer is slamming down on the axles. Maybe the axles are rated for that, but I'd rather be safe than sorry. Just my opinion.

Bill and Linda · RV-Dreams Family Member

kb0zke wrote:
I'm a bit odd, but I really would like the axles to be able to carry the entire load of the trailer. I realize that some will be on the hitch, but I like a large safety margin. There are roads that, if taken at the right speed, will have the hitch "floating" on a rebound while the whole weight of the trailer is slamming down on the axles. Maybe the axles are rated for that, but I'd rather be safe than sorry. Just my opinion.

Actually David I agree to a point and that is one reason the MOR/ryde IS is superior to spring based systems. It has more vertical travel and hence is less likely to bottom out if he rig bounces as you indicated. And it will bounce no matter how good a driver you may be and that’s one of the ways springs are broken. Seen that a lot including some RV-Dreamer's recently before they had the IS installed. Happened to them twice.

A lot of the newer 5ers from big name manufactures are running right at the limit of the axles. The carrying capacity of the trailer is pretty small once all the options are added. I know of one manufacture going to 2 - 9K axles and they are still getting close. But from a practical stand point so many of the rigs in the 36’– 37’ and up class need three axles of 7K – some three 8K. Remember as well that weight is not going to be evenly distributed between the two (or three) axles. The front axle is almost always taking more of the load and the driver’s side front tire the most of all 4 (or 6) wheels. (Because most of the load from the kitchen is on that side.) Even on an 8 K axle it is easy to get up close to 4K on one side which is the actual limitation. 8K total, but only 4K a side and that assumes the tires are rated for a 4K load. (Another reason for “H” range tires.)