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-   -   Trailer Shock Absorbers (http://www.fiberglassrv.com/forums/f51/trailer-shock-absorbers-37396.html)

Steve Dunkel 04-14-2009 07:38 PM

I've noticed that some trailers independent of length or size have shock absorbers while others do not. The Oliver can be ordered with up to two on each side. I also recall seeing them on the latest Airstreams. Bigfoot has them on their most recent models beginning with at least their 21'. The 2005 Bigfoot 21RB that I just bought does not. I'm curious, what benefit do shock absorbers provide on a travel trailer? Is the handling performance enhanced in any way?

curtis c 04-14-2009 08:13 PM

shocks are great for dirt roads with washboard. helps the trailer from wandering back and forth as much. when i change the axle in my lite house ill be adding a set of shocks.

Frederick L. Simson 04-14-2009 08:20 PM

A long time ago (pre-hack, which would have been before November of 2005), Pete Dumbleton posted a comparison chart that <strike>Dexter</strike> Al-Ko made up on this subject. It was to illustrate how the ride response was far superior for the rubber torsion axle found on most Fiberglass trailers, such as Boler, Scamp, and Casita. As I can attest, a regular leaf spring suspension gives the trailer a harsh ride. My Fiber Stream is quite bouncy going down the road. Adding Shock absorbers to a leaf spring suspension dampened and smoothed the ride somewhat. <strike>Dexter's</strike> Al-Ko's comparison chart showed that their rubber torsion system was even smoother than putting shocks on a leaf spring. There were posts here pre-hack where some people modified their torsion systems to add shocks for an even smoother ride.

I sure wish I had shocks.

Pete Dumbleton 04-14-2009 09:52 PM

It wasn't a Dexter chart, it was from Al-Ko. I looked for it the other day, but the RV site it was on seems to be gone and I don't see it on the Al-Ko site.

Some folks have added shocks to their Scamp 5W trailers and report an even better result than just the torsion axle.

JenPB 04-14-2009 11:25 PM

On the pre-hack issue, does the site have current info backed up for recovery in case this happens again? There sure is a lot of wonderful, helpful information here. I've been very grateful to find help with all my FG questions here!

BobB 04-15-2009 07:19 AM

Shocks were added to the Bigfoot trailer we have by the original owner. Shocks make the trailer less bouncy and reduce damage to the trailer and its contents. They are omitted from trailers to reduce cost. I would recommend them even if you don't usually go on "rough roads". Some of our paved roads can really give the suspension a test. Monroe makes shocks that can be added to trailers. Unfortunately, welding is required.

Donna D. 04-15-2009 07:24 AM

Quote:

On the pre-hack issue, does the site have current info backed up for recovery in case this happens again?
You BETCHA! We never, ever, ever want to go through that again. There were some stressful long hours put in to get back what we could. Thank goodness the albums, home page pictures, document center, helpful links and all the stuff in the left nav bar wasn't touched.

Gene Layton, webmaster at CasitaForum has a great writeup with pictures and a template for putting shock absorbers on a Casita. This is the link, you have to be a member of CasitaForum to view: Shock Absorber Mod

In this link of Merle Lilly's tandem axle Scamp 5th wheel, you can see a shock absorber setup. http://www.fiberglassrv.com/files/TandemAxleSetup.pdf

ronsmith100 04-15-2009 09:26 AM

Quote:

A long time ago (pre-hack, which would have been before November of 2005), Pete Dumbleton posted a comparison chart that <strike>Dexter</strike> Al-Ko made up on this subject. It was to illustrate how the ride response was far superior for the rubber torsion axle found on most Fiberglass trailers, such as Boler, Scamp, and Casita. As I can attest, a regular leaf spring suspension gives the trailer a harsh ride. My Fiber Stream is quite bouncy going down the road. Adding Shock absorbers to a leaf spring suspension dampened and smoothed the ride somewhat. <strike>Dexter's</strike> Al-Ko's comparison chart showed that their rubber torsion system was even smoother than putting shocks on a leaf spring. There were posts here pre-hack where some people modified their torsion systems to add shocks for an even smoother ride.

I sure wish I had shocks.
I wish I would have had a look at that data before I built my own shocks for the castia.
http://www.kanabco.com/casita/mods/shocks/shocks.html

I had arranged to have an ex-student run a solids model through his pro-engineer station where he worked but I could not give him the physical properties of the rubber.
I had many personal phone calls with "engineers" at Dexter and they could not give me a modulus of elasticity or any other physical property data for their axle (another example of "engineers" in name only).

Anyway, I built them and put them on my Casita and five others I know of have followed my blueprint. 'They" say they can tell a difference but I am too much of a skeptic so I don't want to say they work or don't work -- although I did some tests as shown on the site.

Good luck Steve

Ron

Pete Dumbleton 04-15-2009 10:09 PM

It wasn't data, per se, merely two graphs showing dampening differences between a leaf spring and a torsion axle. Apparently Americana dropped the torsion info because they have gone to air springs:

"Why did you decide to change your AL-KO torsion ride suspension? Why is air ride suspension better?

For many years the only available suspension on the market was (and still is) standard elliptical spring and shackle type. This type of suspension has been used for hundreds of years in applications from carriages, wagons and automobiles among other things. Torsion suspension came along and dampened (softened) the ride to another level. Air Ride Suspension is the ultimate system in today's world. Air ride cushions the ride and absorbs the impact from the road resulting in a longer lasting 5th wheel. The handling aspects of air ride are terrific--it tames the "Tiger into a Kitten" and glides down the roadway. Other advantages are (optional) on board 12 V compressor w/90 LB. reservoir tank for emergency tire inflation. Dump valves and gauges for leveling the coach side to side eliminate (in most cases) the use of boards under tires. Absolute load leveling if you were to load the 5th wheel to heavy on one side or the other."


Last time I checked, Scamp uses Dexter for the 13' trailers and Al-Ko for the 16'/19' models.

BTW, Al-Ko does their axle with a triangular inner bar on the rubber, while Dexter uses a square inner bar as you can see from this cutaway view of the Al-Ko:

http://www.al-kousa.com/prod_rubsus.htm

I dunno if that makes any difference.

Good news -- I looked through my downloaded stuf and I have an Al-Ko PDF from Americana RV with the graph in it.

Bad news -- I have no idea how to post the PDF to the group, not having a web site.

I have uploaded the PDF to the Yahoo Scampers group, in the Files section, but the Files and Links are only accessible by members -- Since Yahoo membership is free, I would advise joining the group to access the info that's been gathered as Links or Files in the group.

http://groups.yahoo.com/group/scampers/fil...s%20-%20Chains/

I also uploaded it to a friend's site created for this kind of thing, but I dunno if you have to be logged in to access it -- Click on "Axles....pdf" to download it:

http://www.neon-john.com/Files/index.php?dir=

Donna, perhaps you can download it from the Yahoo group and put it into Documents so we have it here in our archives.

Donna D. 04-16-2009 05:49 AM

Quote:

Bad news -- I have no idea how to post the PDF to the group, not having a web site.

Donna, perhaps you can download it from the Yahoo group and put it into Documents so we have it here in our archives.
Pete, post it here just like a picture. Same process.

I'll snag it from the topic and get it into the Document Center.... give me a couple of weeks.

Pete Dumbleton 04-16-2009 10:03 PM

Donna, that didn't work -- It was bigger than the photo size limit (2.4 MB).


Donna D. 04-17-2009 05:41 AM

Quote:

Donna, that didn't work -- It was bigger than the photo size limit (2.4 MB).
PM sent.

ddayton 04-17-2009 04:16 PM

1 Attachment(s)

Attachment 19453

Here is a link to my mod of putting shocks on a 2005 Scamp 19' 5vr. Could tell from the reduction of 'things' thrown about the cabin that they did reduce the shock (pun intended) of the trailer being towed even on interstate!

http://tinyurl.com/3c7gtw

<span style="font-size:10pt;line-height:100%">Don</span>

ronsmith100 04-17-2009 04:46 PM

Quote:

Attachment 19453

Here is a link to my mod of putting shocks on a 2005 Scamp 19' 5vr. Could tell from the reduction of 'things' thrown about the cabin that they did reduce the shock (pun intended) of the trailer being towed even on interstate!

http://tinyurl.com/3c7gtw

<span style="font-size:10pt;line-height:100%">Don</span>
Thanks for your link

It's interesting seeing these other axles. I had no idea there was such a variety of lifts (angles) within the torflex group.
My casita is a "high lift" dexter which under no load puts the dog bone exactly parallel to the frame. Yours appears to be something like 20 degrees down at no load. Monroe made the kit for your axle but not for mine (and not for many others from what I gather) so many of us had to mess to make things fit. This tells me that the preponderance of dexter torflex are made for some kind of standard that casitia didn't chose to follow (since Monroe only made one kit when I bought mine). What do you think?
I had to look it up once but I think the stock casita axle (not high lift) has something like a 10 degree [b]up angle... weird.


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