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Trailer question: Why don't trailers use shocks?
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Hi everyone -
My name is Dave Williams. I am the owner, designer, and builder PikesPeakTrailers.com. I saw references to our site from this website when looking at our web logs and decided to check it out.
The trailer being referenced is one that we built and was used as a giveaway. I am writing to address the use of shocks on trailers. My comments are specifically directed about the trailers we build which are designed to be taken off the highway. Our design characteristics and components we use have been tested over 10s of thousands of hwy miles and hundreds of trail miles. This include a variety of off conditions: rockcrawling, beach, fireroad, etc.
So, with this as a background, here is what I can tell you - for certain conditions the correct dampening system (shock) can make a tremendous difference in how a trailer behaves. Below are tested and observed facts, again specifically to our trailers.
-If the trailer is oversprung and does not flex, as many trailers are, shocks will not matter.
-Even when properly sprung to flex some when empty and more when loaded, hwy based travel does not benefit much from shocks as the bumps in the road are insignificant enough to cause much tracking disturbance or hop.
-By far, the biggest benefit we have seen to adding shocks is off road. The trailers are light enough so that, when used without shocks, hitting a large obstacle with a tire on one side can cause a severe pogo effect as the kinetic energy in the compressed spring fires back violently. This can cause the trailer, especially one side, to rebound and for the tire to get air. Proper dampening dramatically mitigates this.
-On washboard or other small tight terrain the effect is similar those understated. We have many hrs of video footage from a following vehicle observing how the trailers react on real trails.
-Re: the shock setup and the notion that nothing will wear out other than the bushing, this is primarily an optical illusion due to the angle of the shocks. Because the shock are not mounted perfectly vertical travel is a factor of the axle travel. But, since our suspension actually flexes and is tuned for the weight of the trailer and since the axle slightly moved backwards when compressed, we get about 3/4 shock travel to axle travel. In other words, if the suspension is compressed 1 inch, the shock moves 3/4 inches. Plus, the shocks are pre-loaded allowing dampening even if a tire is off the ground.
-I spent quite a bit of money researching different shock manufacturers to get find the shock best tuned to the trailers. The red shocks in the Jeep giveaway have actually been replaced with a new set that we use. I contacted each major shock company describing our goal, weight, travel, etc. and we now use a shock that runs about $30.
-For those that have stated that our use of shocks is an advertising or aesthetic ploy, I can promise you they are not. Our trailers are each hand built after a one-on-one design process, using CAD, with our clients. If you have researched the off road trailer market you will know that our prices are near are on the low end while our components are on the high end. There is nothing on our trailers that is not primarily pragmatic and I would not spend the fab time, the cost of the shocks and mounting hardware if I was not positive it would improve our product.
Our trailers are tested in very harsh conditions. Last weekend we took an older prototype (without shocks) and ran Chinaman Gulch in Buena Vista, CO. This is considered a difficult trail (at least for non buggies) and we dragged the trailer across the entire trail. There are many videos on our side showing the obstacles we cross and how the the trailer fared. Also, our production trailers are significantly stronger and more heavily built than the proto in the videos.
Finally, we love Utah, got married there two years ago and I love visiting the state. For anyone in the CO Springs area, we let people "rent" one of trailers for free to test it out. If you wish to go camping and want to try out one of our trailers, shoot us a note. There is no cost.
Take Care and please let me know if you have any further questions.
Dave.
Here is a shot of our most recent design. Also not the bumpstop.
For lots of videos, check out our site.
I live in Woodland Park and operate an asphalt paving company, and I have a cargo trailer which holds a lot of my equipment. I do my best to strap everything down but hitting a large pothole (Colorado is known for them) or even taking it down some of the dirt roads in Divide (some are so bad it could constitute offroad) can result in equipment bouncing around or propane bottles ending up on the other side of the trailer or cracking regulator glass, etc. I'd be very interested to know if a cargo trailer can be modified with shocks. I'm in the Springs often.