Sprung trailer

[Bobobolinsky]

I'm building a sprung trailer at the minute capable of handling five tonnes of boat 10metres long. I'm having difficulty sourcing spring equalisers in the UK.
I contacted Jones springs, but they didn't even know what I was talking about.
It seems that most trailer builders in the UK build on rubber nowadays and independent spring suspension non-existent.

So anyone know of a UK manufacturer?

 

[Avocet]

That's quite a lot of boat! Is this a road trailer, and what would you plan to tow it with? Anyway, leaving that aside, the typical rubber-sprung suspension units ARE independent. They're popular because they're cheap, compact, and you get free damping (of sorts!) thrown in, because of the rubber's natural properties. Three, 2 tonne units ( if you can get them that big) should do it. The problem is that typical rubber-sprung trailers stop at about 3.5 tonnes. Your other option would be to build from first of principles, using axles from the larger "Transit-sized" vans, but it won't be easy.

 

[Avocet]

A bigger problem will be brakes, if it's a road trailer. You're unlikely to find anything "off the shelf" that will meet the legal requirements.

 

[Daydream believer]

Considering that there are a lot of 5 tonne road trailers about i would have thought it not worth making.
On the SBS trailer they use leaf springs in such a way that the close coupled wheels act like a swinging axle bogie ( for want of a better description) & distribute load evenly over bumps. This deals with the equalisation you are referring to. I suggest you look at one. It also allows the tow hitch to be raised & lowered without putting extra weight on one pair of wheels as with rubbers. If you are towing 5 tonnes with rubber units the towing vehicle could effectively be lifted off the ground because of the way the 4 wheels are fitted
Furthermore with independent rubbers are that if you hit a bump under one wheel you will overload it & i suspect you have sussed this hence the request for spring equalisers
Springs can be obtained ( or could - i have moved) from Brambler springs in Grays essex
Brakes can be easily fitted by making hydraulic units. The overrun fitting can be fitted to the same brake type cylinder fitted to a car. The actuator or brake lever would push back & push the piston on the cylinder this would the actuate the 4 units on the wheels. I have seen this but do not recall precise details
My 5 tonne trailer had rod & wire operated brakes. I could officially tow 3.5 tonnes on conventional brakes behind my Disco or 4.5 tonnes with hydraulic activated brakes so one would assume you will be using a commercial HGV towing vehicle or an agricultural tractor to tow with
In reality i often had nearly 6 tonnes on normal braked 5 tonne trailer to tow wood chips 2 miles from my joinery works to the local stable . Never got stopped but the local hill could be agro going down!!!

 

[Lakesailor]

I take it the OP has an HGV to tow with. These people have all the stuff you can shake as stick at. http://www.chieftaintrailers.com/en...ailer-spare-parts/92-trailer-suspension-parts

Or in this catalogue http://www.ttcparts.com/Catalogues/ (choose the suspension /trailers section)

 

[ffiill]

Autow the online public face of Peak Trailers-as well as what you see rated up to 3.5 tons they can source heavy duty stuff from Peak Trailers.
As I mentioned on another trailer thread in US and OZ leaf springs are still popular and very cheap-just check out eBay.com
Hydraulic overrun brakes although rare over here are the usual fittment in nz where trailers have to have annual warranty of fitness tests(mot)
Also worth remembering that you can tow a trailer without suspension on the public highway as agricultural trailer/logging trailer subject as I recall to a 20 mph speed limit.