Light trailer performance

blogzy, Aug 21, 3:59pm
I'm in the market for a small trailer. (8x5 or thereabouts)
What are the design / tyre size that increase the likelihood of this size trailer fitting the
" tows well" category. I borrowed my brother's 7x 4 trailer today and at most speeds over 40klm it created a sort of jerking action transfered through to my vehicle. To me it felt like trailer suspension was too stiff, creating an annoying bounce. With a 250k load it was still there but not as bad as empty.

nzmax, Aug 21, 4:04pm
Odd question. do you have a removable tongue/towball as part of your towbar? I found the same thing happened with most trailers when the car I had used a removable one, due to the movement in the fitting. Fixed towbar, was much better.

toyboy3, Aug 21, 4:10pm
Increase the loading on the drawbar, or get a trailer with the axle rearward of halfway of the tray

msigg, Aug 21, 5:05pm
Yes, above is correct. Axle further back makes backing easier too.

tweake, Aug 21, 5:50pm
the common problem is often spring related.
they are simply so light the springs don't work properly and that many manufactures put heavier springs in because kiwis overload the hell out of trailers. heavier springs make it worse when empty.
the other major cause is lack of shock absorbers. for small single axle trailers its very easy to do and these days they are available off the shelf.
i have followed a car towing a small trailer and the trailer was going airborne when it hit tiny bumps in the road @ 50-60 kmh.

what doesn't help is if the tow ball height is quite low (ie using a car instead of a ute) which pitches the trailer nose down and means the spring actions has a small forward and back motion to it.
trailer should ride level.

wind.turbine, Aug 21, 8:53pm
I think to be fair most trailers, unless its one of ours which is 1ton empty, bounce around like hell when empty just down to them being so light weight.

softer springs will only take up so much, then you have the problem where you find it starts farting around when it hits potholes when loaded up due to the softer springs.

Towing is not made to be comfortable, although trying to have a bit of weight on will always help.

perhaps consider a boat, then there will always be weight on the trailer when towing :)

mrfxit, Aug 21, 9:06pm
Yep had the same many times before.
Oddly enough all my trailers that I have rebuilt springs for, tow well empty & of course better full.

Just going from memory . .
All have from around 800gk to 1.8T capacity's (weight bridge checks) from 6x4 / 7x4 & 7x5 decks.
Pretty sure it's not the weight of the trailer or capacity of the springs, but more to do with how short the spring is or how deep the spring curve is thats the problem.
Recently town a single axle furniture float & it was a bouncy butt wrenching pig of a bouncy ball, empty or full.
It's also got fairly short springs on it.

All my trailers have had spring s of around 800mm to 1m long & 4 /5 leaves & all springs are centered 2" back from deck center
The big trailer has around 1m springs & 4 x 6mm x 2" springs & tows very smoothly even empty.

Most modern springs are only about 600mm & have a very deep curve

blogzy, Aug 21, 10:27pm
Yes, now I think about it I have experienced this with other trailers. Come to think of it, I have towed a few tandems and can't recall any having this bounce tendency. Maybe I should consider tandem.
Unless like previous poster suggests, a different (longer) leaf spring is an option also.
Anyone know a manufacturer who builds a better riding small trailer (single axle) ?

pauldw, Aug 21, 11:01pm
I have a removable with the socket drilled and tapped to hold a bolt that tightens on the removable tongue. That stops the rattle.

serf407, Aug 21, 11:52pm
Just depends where the prospective trailer purchaser's budget is at.
Asian made with NZ assembly.
https://www.tufftrailers.co.nz/faq Timbren have been promoting the Silent ride trailer suspension set up. (Trailparts - nz supplier) https://youtu.be/gVAyMrYRKDc (silent ride 8K)
The silent ride 2K = 2000pounds rating single axle suspension etc (lots of variations)
http://www.timbren.com.au/wp-content/uploads/2015/06/SILENT-RIDE-Parts-Rev052115.pdf To get a custom build , probably be one of the trailer builders like Prescott.
https://www.prescotttrailers.co.nz/our-trailers/domestic-trailers
There are various trailer builders in Aus and NZ who use Airbags to alter the loading height and suspension characteristics etc.
trailing arm, airbag, flexible strap and shock absorber
https://airbagtrailer.com.au/enclosed-bike-airbagged-trailer/

Trailer drawbar length is another key characterists. Can use water ballast in 20 litre containers when running the trailer empty and empty out when the load is on the trailer.

mrfxit, Aug 22, 10:51am
Would only consider the hassle of carting 20ltr bottles if they were filled with Bourbon

tweake, Aug 22, 11:20am
i don't know why they run such short springs. maybe it helps locates the axle better ie stops it from moving side to side so it tracks better.
plus none have load springs, tho the lack of travel may have something to do with that.
and of course no bump stops.

if the furniture float is a hired one its more than likely got over sized springs. people abuse the equipment so they oversize it so it doesn't break. which means the suspension doesn't do anything unless its at max weight or more. the tires are doing all the suspension work.
same trick is done with the brakes, detune the override coupling so the brakes only work when its under very heavy braking.

mrfxit, Aug 22, 8:58pm
It's almost as a cheat sheet trick to get lots of suspension travel with minimal weight & spring steel used

blogzy, Aug 23, 11:27am
You guys have nailed the problem. Hi volume trailer production, not too much attention paid to trailer ride. Primary focus on load capacity and cost of springs. Are longer (800 - 1m) leaf springs for light trailers available ?

tweake, Aug 23, 12:09pm
longest i can recall is trojen and CM long series which is 770mm i think.
otherwise what guys have done is used ute springs which are common enough aftermarket for higher rated ones (just don't use the flat type a few utes have).

however i have used a light trailer (200kg if i remember right) and had no issues (mind you i'm towing with a ute not a car).
it also used the really small diameter tires (its a flat deck) which has the big advantage if being light weight. heavy tires on a light vehicle/trailer makes it handle badly.
stock standard trailer springs, nothing fancy and no shocks.

s_nz, Aug 23, 4:21pm
What do you think of this suspension setup? I'm sure one of the NZ trailer builders would custom build a trailer with it.

http://airbagtrailer.com.au/diy-trailer-swingarm-complete-kit/

Independent suspension with shock absorbents. Airbag's allow you to set the pressure for the correct ride height to suit your typical load. If you are ever going to carry an abnormally heavy load you can pump the pressure up a bit to restore normal ride height. Conversely if you are going a long distance empty, the bags could be aired down for a softer ride.

Also can dump the air out to decrease the height of the trailer if you are ever loading heavy, difficult stuff.

xs1100, Aug 23, 4:57pm
gibbons in the waikato build a nice trailer, heaps of good trailer builders around. But yes sounds more like a spring issue than anything. It did have the right coupling for your towball also just a thought wasnt a 50mm coupling on a 1 7/8 ball. Theres a lot of those around these days and yes they do jump off ask your local hire centre

tweake, Aug 23, 5:22pm
good setup. quite a few different ones around of that type.
typically used with offroad trailers/campers.
downside is you need air compressor.
that particular one is a budget version more suitable for roads. the higher end ones have better air bags and more shock absorbers.
tho i really dislike the dual axle version of those as there is usually no equalising. tho that can be done with a connection tube on the air bags but i have not seen one yet that equalises the shocks.

tweake, Dec 2, 4:08pm
gibbons is usually pretty good.
one thing i like with theirs is they get the side boards hinges the right way around. 90% of ute deck and trailer manufactures put them on the wrong way.