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Timbren Silent Ride tandem axle suspension, lifted!


John E Davies
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So I was thinking that:

 

1 - Oliver will not sell me a factory lifted suspension.

 

2 - The Dexter EZ-Flex, while a great (and stronger) upgrade, still has LOTS of moving parts that require frequent lubrication.

 

3 - The stock leaf springs are prone to breakage when used off pavement.

 

4 - Leaf springs are 18th Century technology and inappropriate for a 21st Century RV.

 

I may go this route:

 

The stock axles simply bolt to the new arms.

 

It has three moving parts, the rubber springs have a ten year warranty, and they make the trailer ride very smoothly. The springs are progressive in action, soft getting gradually stiffer as they compress. The springs are initially stiff in cold weather but as they warm up they regain their normal action. (I suspect that the Dexter rubber equalizers have the same behavior.) They are self dampening, so no shocks are required!

 

Video: ... 

 

Home Page: ... http://timbren.com/silent-ride/

 

Here are the available systems:

 

http://timbren.wpengine.netdna-cdn.com/wp-content/uploads/2015/06/SILENT-RIDE-Parts-Rev052115.pdf

 

Unfortunately, they are apparently only offered as standard - I have emailed them asking if there is a lifted kit, or if it is practical and safe to simply weld in a 2 inch x 4 inch tall steel spacer on to the existing suspension subframe. Or to move the axle perch from the top of the arms to the bottom... Regardless, with a lift I think one should install a beefy crossmember to handle extra twisting forces.

 

The final assembly should be much lighter than the original - leaf springs are HEAVY. I don't know how much weight would be added by brackets and extra crossmember.

 

Pricing? I haven't found any, but have asked Timbren. eTrailers shows their 14,000 pound kit for $1264: ... https://www.etrailer.com/Trailer-Suspension/Timbren/TSR14KT01.html .... I suspect the lighter duty units are a little cheaper since they require less steel. Since I would not need to buy the EZ-Flex upgrade, that would save $270, and I can sell the take-off shock absorbers and springs locally for a couple of hundred $, perhaps.

 

I would give my left testicle for this as a factory installed system.

 

More to come. Comments are welcomed and encouraged.

 

John Davies

 

Spokane WA

 

 

  • Thanks 1

"Mouse":  2017 Legacy Elite II NARV (Not An RV) Two Beds, Hull Number 218, See my HOW TO threads: https://olivertraveltrailers.com/topic/john-e-davies-how-to-threads-and-tech-articles-links/

Tow Vehicle: 2013 Land Cruiser 200, 33" LT tires, airbags, Safari snorkel.

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Update:

 

MSRP for the "Tandem with 3" round axle seat" in different load ratings:

 

7K : $1113

 

10K: $1265

 

14K: $1471

 

I suspect that the 7K kit would give a softer ride for a lightly loaded Ollie, but the 10K would be superior for nasty pot-holed ranch roads and a really heavy trailer. I listed the 14K one just to show the eTrailer's street price - it is about $205 less (14%). A similar discount would put the 7K kit at about $958.

 

I did get some info from their tech/ sales rep Jeff Scott:

 

The system is robust and easily field serviceable using no special tools. It would perhaps take a couple of hours to change all four rubber springs by a competent mechanic.

 

It rides very well and should work well in this application (an Ollie).

 

There is no individual parts/ price list - "I think I have only ever sent out one set of replacement springs for this suspension. It never needs parts."

 

As far as lift goes: "Perhaps you should take some measurements of your existing suspension and compare them to the dimensions of our tandem and you may find that you have already gained some height. Aside from that, blocking up the suspension for additional height is simply the process of welding on a riser of your choice between the existing frame and the new suspension."

 

As per their drawings, the distance from bottom of frame to axle centerline (unladen) is about 6.5 inches. I have no clue what the standard suspension dimension is. The 10K rubber spring would obviously ride a little higher than the 7K one..

 

It doesn't sound too terribly difficult or expensive. Who wants to do this first and post instructions? It would make a great project for a sunny weekend.....

 

As a footnote, I once bought a new 27 ft SeaRay powerboat that came with an undersized trailer and it was a disaster. I made the store take the trailer back and substitute one with a proper (higher) GVWR. They half heartedly admitted their mistake, but were very unhappy to eat the cost of buying back a "used" trailer. I will never go with inadequate suspension, when in doubt go heavier. (This is why Oliver upgrades the axle tubes and hubs.)

 

JD

 

Spokane WA

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"Mouse":  2017 Legacy Elite II NARV (Not An RV) Two Beds, Hull Number 218, See my HOW TO threads: https://olivertraveltrailers.com/topic/john-e-davies-how-to-threads-and-tech-articles-links/

Tow Vehicle: 2013 Land Cruiser 200, 33" LT tires, airbags, Safari snorkel.

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  • 3 weeks later...

It's a very nice looking design and I like getting away from the 19th century leaf springs and linkage.    But adapting it to an Ollie will require taking some responsibility for the outcome without knowing how it will play out in the long run.

 

The standard leaf spring system carries the load of the trailer in three places on each side for a total of six points distributed along the steel subframe.  The subframe is somewhat flexible and bolted directly to the aluminum frame which is bolted to the fiberglass body.  As a whole, there is a lot of strength there, the load is distributed well, but the system still flexes.   Just jacking the trailer to level I can hear it flexing as the body creaks a bit.

 

So now you apply all the load to two points with the Timbren system and the subframe is unfairly loaded and transferring that load to the trailer disproportionately.  On top of that the twisting load all goes to those two points as you turn sharply, so the trailer has more of that load localized as well.  Ollie's were not designed to deal with those two changes.

 

The fix is a stiffener under the subframe that spreads the load fore and aft and a cross member, or X member, that makes the two sides share the twisting load.   This will lift the trailer by the size of the stiffener, but offset that lift by the difference between the leaf spring design height and the Timbren design height.

 

It might be interesting to find out how much the Timbren system settles at a 5,500 lb load, for instance, and decide if the 10K or the 7K system is best.

 

The other thing is, if someone was going to change to this, I would go ahead and put in a set of 5,200 lb axles because they have the larger brakes.  Those bigger brakes are much more powerful than the 3,500 lb brakes.  My Ollie, unfortunately, has the 3,500 lb brakes.  So that issue alone could decide the model of the Timbrens used.

 

It would be nice to never worry about a broken leaf spring or those lousy nylon bushings wearing out.  I'm planning to upgrade mine with the Dexter E-Z Flex kit to at least get rid of the cheap bushings.

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John


"I only exaggerate enough to compensate for being taken with a grain of salt."


LE2 #92 (sold),   Black Series HQ19   

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It’s a very nice looking design and I like getting away from the 19th century leaf springs and linkage. But adapting it to an Ollie will require taking some responsibility for the outcome without knowing how it will play out in the long run.

Thanks for your great post, you brought up a few things that I had in the back of my mind, but have not really studied yet.

 

I would never install this system without also installing a long, strong steel longitudinal mount that ties into all the existing suspension bracket bolts. It would indeed be foolish to concentrate all the twisting forces on just the small area of the Timbren bracket. I would incorporate a small lift while I was at it using spacers, plus side to side reinforcing bars of some sort.

 

Their Axle-Less suspension for smaller trailers has a built-in receptacle so you can slide in a rectangular steel crossbar for strength. The tandem version omits this, but does provide a pair of heavy inside brackets for the same purpose. Timbren seems to understand that this bracing is necessary.

 

It would be risky to do this mod locally .... however, a factory R&D effort would work out the kinks in design and specifications, without the worry of us owners screwing up our trailers.....

 

Aluminum frames are very cool, but they are NOT so good off pavement because they do not like to flex the way steel does. The metal will eventually fatigue and crack if abused for too long. I am not aware of any offroad trailers in Australia that use aluminum frames, correct me if I am wrong. Steel just holds up to constant hammering from horrible roads way, way better than aluminum.

 

This is why I want to upgrade the suspension, to reduce as much as possible the forces on the frame.

 

Maybe a Hover Suspension would be worthwhile. ;)

 

John Davies

 

Spokane WA

"Mouse":  2017 Legacy Elite II NARV (Not An RV) Two Beds, Hull Number 218, See my HOW TO threads: https://olivertraveltrailers.com/topic/john-e-davies-how-to-threads-and-tech-articles-links/

Tow Vehicle: 2013 Land Cruiser 200, 33" LT tires, airbags, Safari snorkel.

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It is interesting how the Ollie frame system is designed.  The front section ahead of the body, that becomes the tongue, is amazingly strong looking with gusseting and a number of for and aft members all welded nicely together.  The main section under the body is more of a unibody with stiffeners design, I guess. It clearly relies on the stiffness of the body, in conjunction with the frame.  The frame in that area seems more like a way to connect the tongue to the suspension subframe, but not as a way to support the trailer at points, like on a traditional trailer or truck.

 

One of the reasons I got rid of my toy hauler, which was about the same size as my Elite ll, was the affect dirt roads had on it.  The poor thing was just beating itself to death.  It had the identical suspension design as the Ollie, but everything inside was coming apart or getting jostled around.   I'm hoping that the Ollie can deal with rough roads better because of it's much better design and construction, plus softer springs.  I'm also a big fan of tandem axles because of the way they track and how they step over bumps.  The other thing was the water tank location and general weight distribution.  The batteries sat on the tongue and the 100 gallon water tank in the very front put 1/3 of it's weight on the hitch.  This jarred the truck and increased the need for a load leveling hitch.  Oliver  carries it's weight with better distribution and it really shows while towing.

 

In looking around, I've seen a couple of variations on the walking beam, equalizer concept of the typical tandem axle suspension.  A sort of hybrid between the Timbren system and the stock system, with rubber and links to smooth out the shock loads.  Maybe we can do an upgrade sometime that won't require a re-design.

John


"I only exaggerate enough to compensate for being taken with a grain of salt."


LE2 #92 (sold),   Black Series HQ19   

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