Surely this is such a bad way to build especially for car transporters and bike trailers, and some trailer builders even add cool 17 inch wheels with no give in the tyres at all. I know people say the car/bike has suspension so no need for springs but that is only adding strain on the tie downs, besides if your carrying race cars/bike would you not be adding wear to the expensive suspension and shocks!
v8_mopar,
Aug 30, 8:21am
More than one reason but for me its hight
richardmayes,
Aug 30, 8:37am
x1
When you stack a car (with one suspension stiffness) on top of a trailer that has a different suspension stiffness, all sorts of dangerous and unpredictable floating behaviour can result. Bitter experience has shown it's better to have the trailer solid - then there is only one suspension working, and no possibility of interference oscillations being set up.
bash,
Aug 30, 9:06am
if trailer is loaded properly and the car is tied down right there is no problem with springs on trailer ,I have done thousands of ks and never had a problem
sr2,
Aug 30, 9:59am
Where on earth did that idea come from!
mrfxit,
Aug 30, 10:57am
Been there done that. Agree
mrfxit,
Aug 30, 7:31pm
IF this was any real sort of a problem, then ALL car transporting companys would be in deep shite. ALL their trailers use spring or air suspension or combo's. NONE use solid axles.
intrade,
Aug 30, 7:38pm
car transport trailer dont need springs the car on top has springs so the springs are there when a car is on it .
dunwoody,
Aug 30, 8:17pm
There is a maximum speed limit for an unsprung vehicle. I think about 25ks
richardmayes,
Aug 30, 9:27pm
you are correct the problem largely disappears when you have 4 or 5 1.4-ish tonne sprung masses (cars) riding on top of one big heavy trailer that itself weighs what, 6 or 8 tonnes. The influence that each little car has on the behaviour of the trailer on its own springs is going to be limited.
(Or even one car riding on the back of a 3 tonne tow truck - but then, ever noticed how hard those are at the back!)
However, when you have one 1.4-ish tonne car riding on a 0.4-tonne trailer, the weight and spring rates of the car are obviously going to dominate the behaviour of the whole system. Wasn't that the original question!
sr2,
Aug 30, 9:34pm
??? I've spent many years towing race cars up and down the country and have never experienced problems with the difference in spring rates between the trailer and the vehicle that it was carrying. As mrfxit pointed out.
???IF this was any real sort of a problem, then ALL car transporting companies would be in deep shite???
richardmayes,
Aug 30, 9:43pm
Beats me then, I'm not in the industry.
(Though I imagine your race car has much harder suspension than, say, a big soft floaty V8 Rover or something.)
Maybe all the people who build and use the unsprung ones are idiots!
mrfxit,
Aug 30, 11:04pm
Probably closer to the truth then you realise. I would suspect that any "bounce" problems are in fact related to a softly sprung trailer with lots of float available in the springs movement up & down.
Much in the same way with the pre war & early post war trailers with 1.5" springs pulled straight out of an EG: Austin 10, & put unaltered on to a trailer chassis. Caravans tend to suffer badly as well but thats in a large part to height verses weight verses no shock absorber suspension system.
mrfxit,
Aug 30, 11:30pm
LOL yea thats part of it with caravans My point there is more to do with sharp turns/ speed wobbles & general swaying etc, of which a lot could be easily managed better by fitting shockys . Oh wait a minute, there is a compromise system to fit on tow bar/draw bars that goes part way to solving THAT issue.
WIth unsprung trailers, the road bump transmits forces to the tyre casing , then to the trailer chassis , then to the loaded car springs. That like . >> . >>>>>>. >>>>>>> in degree's of force
WIth sprung trailers, the road bump transmits forces to the tyre casing ,then to the springs, then to the trailer chassis , then to the loaded car springs. Thats like . >> .>>>> . >>>. >>> in degree's of force
smac,
Aug 30, 11:35pm
Mate that really doesn't follow/make sense.
There are perfectly good unsprung trailers built fit for purpose. There are crap ones. There are good sprung trailers, and there are crap ones. Nothing in this thread is going to get anywhere near "one answer fits all" for whether or not unsprung is a good idea or not. There is no one answer.
So to answer the original question, "why do people build unsprung trailers!": some will be because of cost, some will be because it's the best solution for the purpose at hand.
myrns,
Aug 31, 6:04am
Check this out, seller claims trailers like this cannot be built with solid axles anymore! 402703842
h.e,
Aug 31, 6:21am
the only problem with solid axle trailers is idiots who dont know the correct way to tie a car down.
lookoutas,
Aug 31, 6:25am
It's horses for courses. How much empty towing will the trailer do! Might need springs then!
frytime,
Aug 31, 6:29am
car transport trailers have no springs to lower them, makes them a pain in the bum and back when towed empty. sprung trailers make for nicer tow but are higher, harder to get lowered cars on.
since when can't you make a trailer with no springs!
rob_man,
Aug 31, 6:48am
My old RIB inflatable trailer was unsprung but it had oversize tyres running low pressure. Towed great.
unclejake,
Aug 31, 6:58am
I had an unsprung trailer for the race car for years. It was excellent loaded and horrible empty.
IMHO a trailered car should be tried down by the wheels or some other unsprung component.
chris241,
Aug 31, 7:30am
ive made a couple of motor bike trailers with no springs and there sweet as. They do bounce a bit when you have nothing on them but are fine with a little weight . You can let the tyres down a bit so there not so hard. I dont know why people some use springs and some dont i just did it cause it was cheaper to make!
richynuts,
Aug 31, 7:50am
x1
Totally disagree I bought a motorbike trailer with 14" with 195/60tyres had to run them at 10 psi to stop the thing from bouncing even loaded, changed the wheels to 13" with 175/70and made a difference but not enough so sold it and bought a trailer with springs and 13" wheels and what a HUGE difference and dont cringe every time I go over railway tracks etc, I would never ever buy a trailer again without springs and the height difference is bugger all as I can use the same ramp.
richynuts,
Aug 31, 7:53am
Nice trailer. bad design
mrfxit,
Aug 31, 8:07am
LOL. .OH my mmmmmm I wonder what was acting as springs
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