Damping "jounce"

[Gwenne & Len]

With two trips under our belt with the same tv but with 2 different TM's, the first an 05 2720, and the second an 09 3124, I'm trying to sort out what the best combination of towing system ingredients is. We are pulling with a 2012 awd Highlander. Due to the press of scheduled trips the only readout on weight has been measuring the extent to which the hitch lowered when the trailer tongue was attached. Curiously the depression from the 2720 was 3 3/4 inches and the longer, heavier 3124 less at 2 3/8 inches with less than 1/4 inch rise in front.
The 2720 had Carlisle tires inflated to 50#s and the 3124 Good Year Marathons inflated to 65#s.
Both units towed without sway. The ride with the 2720 was quite smooth with a couple major jounces but little suspension excitation from uneven road surfaces. The 3124 didn't undergo major jounce excursions but seemed more sensitive to uneven road surfaces - much like coil springs perpetuate same frequency jounce when compared to shock and air lift/shock dampened leaf sprung suspensions.
Has anyone added shocks or air damping to their TM's?
It seems adding damping to the TM suspension would improve cargo abuse as well as undesirable effects communicated to the vehicle. Air Streams using the same Dexter Torflex axles use shock absorbers.
I also read the Toyota warning about equalizers not being adviseable for unibodies. The Highlander uses a rear McPherson strut shock-in-coil system that isn't amenable to air shock installation.
And then there's the issue of mileage. We did get between 18 and 20 mpg with the 3124 with the 65 psi Marathon tires. Do the Marathons inflated to 65# tend to introduce roughness?
I would appreciate any suggestions on strategies to improve ride smoothness.

[Gwenne & Len]

With two trips under our belt with the same tv but with 2 different TM's, the first an 05 2720, and the second an 09 3124, I'm trying to sort out what the best combination of towing system ingredients is. We are pulling with a 2012 awd Highlander. Due to the press of scheduled trips the only readout on weight has been measuring the extent to which the hitch lowered when the trailer tongue was attached. Curiously the depression from the 2720 was 3 3/4 inches and the longer, heavier 3124 less at 2 3/8 inches with less than 1/4 inch rise in front.
The 2720 had Carlisle tires inflated to 50#s and the 3124 Good Year Marathons inflated to 65#s.
Both units towed without sway. The ride with the 2720 was quite smooth with a couple major jounces but little suspension excitation from uneven road surfaces. The 3124 didn't undergo major jounce excursions but seemed more sensitive to uneven road surfaces - much like coil springs perpetuate same frequency jounce when compared to shock and air lift/shock dampened leaf sprung suspensions.
Has anyone added shocks or air damping to their TM's?
It seems adding damping to the TM suspension would improve cargo abuse as well as undesirable effects communicated to the vehicle. Air Streams using the same Dexter Torflex axles use shock absorbers.
I also read the Toyota warning about equalizers not being adviseable for unibodies. The Highlander uses a rear McPherson strut shock-in-coil system that isn't amenable to air shock installation.
And then there's the issue of mileage. We did get between 18 and 20 mpg with the 3124 with the 65 psi Marathon tires. Do the Marathons inflated to 65# tend to introduce roughness?
I would appreciate any suggestions on strategies to improve ride smoothness.

[BrucePerens]

Monroe had one that was discontinued, it appears. Lippert has one but it doesn't look like it would fit.

Padgett would know better, he's an engineering motorhead, but I think that rubber axles as used in the Trailmanor provide some frictional damping not unlike that in a conventional shock absorber. And shocks make the ride more comfortable by damping oscillation rather than reducing the impulse. There is also the problem that shocks need a lot of clearance that we might not have.

[Gwenne & Len]

Originally Posted by BrucePerens

Monroe had one that was discontinued, it appears. Lippert has one but it doesn't look like it would fit.

Padgett would know better, he's an engineering motorhead, but I think that rubber axles as used in the Trailmanor provide some frictional damping not unlike that in a conventional shock absorber. And shocks make the ride more comfortable by damping oscillation rather than reducing the impulse. There is also the problem that shocks need a lot of clearance that we might not have.

Thanks Bruce! No reply from Padget. Reran the trap lines with Dexter and Airstream. Airstream uses the same Torflex axles as TM. Dexter welds a shock mounting stud to the backside of AS's torque arms. AS obtains a special shock from Gabrial only made and sold for them. So it seems the engineering is done and ordering a couple from an AS dealer and fabing a couple mounts will give us an airstream ride. AS switched to Torflex axles on all products long ago so examining one on the lot will reveal the correct engineered geometry.

[flipflop]

SumoSprings is a high quality well-known manufacturer for 'cushioning' the ride on TV's that have additional loads.

I didn't know the Highlander has the McPherson struts on the rear, so no airbags, but SumoSprings makes a 'helper' for them, seems to have good reviews. https://www.etrailer.com/Vehicle-Sus...cc-onlyreviews

[Gwenne & Len]

Originally Posted by flipflop

SumoSprings is a high quality well-known manufacturer for 'cushioning' the ride on TV's that have additional loads.

I didn't know the Highlander has the McPherson struts on the rear, so no airbags, but SumoSprings makes a 'helper' for them, seems to have good reviews. https://www.etrailer.com/Vehicle-Sus...cc-onlyreviews

Thanks Flipflop! Ran similar trap lines on Highlander suspension aids and purchased the SumoSpring sleeve inserts. Haven't installed them yet but they should provide some resistance to vehicle tail drop from tongue weight as well as cushioning under towing conditions.
Beyond that, my sense about unwanted disturbances is to locate damping as close to the source of unwanted reactions to road surface aberrations as possible - to improve both smoothness of the trailer ride (and it's contents) while communicating as little disturbance forward to the vehicle.
I am investigating adding shock absorbers as Airstream uses with the same Dexter axle as TM's.
Wonder if any other Trail Manner owners have performed such a retrofit?

[rickst29]

Originally Posted by Gwenne & Len

.....Do the Marathons inflated to 65# tend to introduce roughness?
I would appreciate any suggestions on strategies to improve ride smoothness.

Marathons at 65 Cold PSI can definitely shaking your TM on rough roads. Goodyear published a table for reducing the pressure in Marathon tires, according to the load on the tires. My best post on the subject was made long ago, in 2006. Here: http://www.trailmanorowners.com/foru...56&postcount=2
It contains a link to the Goodyear document. In that post I discuss a 3024, but your 3124 is fairly similar. Measure your loaded TM axle weight at any truck scale, it doesn't cost much. Being chicken about low PSI, I wouldn't go all the way down to the PSI which Goodyear recommends - but if you round up to nearest 5 PSI above the Goodyear figure, you'll probably end up at 55 PSI (rather than 65). From there, you'll want to push it back up a bit if you're driving at high speed on smooth freeways.

[rickst29]

Booster Springs (in the Toyota) would create the appearance of level loading on the Toyota axles, but it's not really there. The compressed Springs raise the body over the rear axle by applying equal force Upwards (against the Unibody frame) and Downwards - (into the rear axle and tires tires).

They DO NOT really restore the loading on front versus rear axles of the Toyota, to the same proportions which the Toyota had before the Trailer was attached. They help to protect the hitch and bumpers from getting scraped, but they do not help to keep more weight on the front axle - where you need it for proper steering control and braking.

My recommendation is to get a WDH First, and pull it the chains to put at least some of the Trailer Hitch weight forward (to the front axle).

[Gwenne & Len]

Rickst29 - Appreciate your reference to Marathon inflation per load specs. Will weigh the trailer. On the subject of WDH's I am respectful of Toyota's warning about not using them with the Highlander's frameless unibody. When we towed the 3124 home after purchase it behaved well. Tire pressures were 55. It was not a long trip and we didn't encounter a wide variety of road surfaces but the ride was definitely better. Will play with pressure increments over a local stretch of road encountered on our second outing that excited the TM with 65# inflation. Other than this issue the Highlander seemed to handle the 3124 quite well.
Am still intrigued by the potential of adding shocks to the TM and will check out an Airstream shock installation on an identical Dexter Torflex axle at a local dealer next week.

[flipflop]

Originally Posted by Gwenne & Len

Rickst29 - Appreciate your reference to Marathon inflation per load specs. Will weigh the trailer. On the subject of WDH's I am respectful of Toyota's warning about not using them with the Highlander's frameless unibody. When we towed the 3124 home after purchase it behaved well. Tire pressures were 55. It was not a long trip and we didn't encounter a wide variety of road surfaces but the ride was definitely better. Will play with pressure increments over a local stretch of road encountered on our second outing that excited the TM with 65# inflation. Other than this issue the Highlander seemed to handle the 3124 quite well.
Am still intrigued by the potential of adding shocks to the TM and will check out an Airstream shock installation on an identical Dexter Torflex axle at a local dealer next week.

Shocks on the trailer would be helpful. One thing I did was grease the axles. Took 15 pumps from a mini grease gun each side, required a full tube.