Trailer suspension

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CAPTAINMIDNIGHT

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I have recently bought a 12ft dinghy, which I believe to be a Zef La Prairie. There is a partial manufacturer's plate on the trailer which supports this belief.

The trailer has unconventional suspension which needs some work.

https://photos.app.goo.gl/iQeNmxGDvLTwrztw9 (sorry, not sure the best way to upload a picture here)

The belt in front of the wheel is actual a fan belt, which is obviously not right. The previous owner told me there were rubber belts when he got it but they perished. I am wondering if there should be some sort of car type coilover damped suspension unit, but being in front of the pivot it would have to work under tension instead of compression.

If anyone has seen anything like thus before I would be grateful for advice.
 
CAPTAINMIDNIGHT said:
I have recently bought a 12ft dinghy, which I believe to be a Zef La Prairie. There is a partial manufacturer's plate on the trailer which supports this belief.

The trailer has unconventional suspension which needs some work.

https://photos.app.goo.gl/iQeNmxGDvLTwrztw9 (sorry, not sure the best way to upload a picture here)

The belt in front of the wheel is actual a fan belt, which is obviously not right. The previous owner told me there were rubber belts when he got it but they perished. I am wondering if there should be some sort of car type coilover damped suspension unit, but being in front of the pivot it would have to work under tension instead of compression.

If anyone has seen anything like thus before I would be grateful for advice.
Click to expand...

It all looks very dodgy to me

First observation is that to be "road legal" it should have mudguards

Drive belts such as fan belts and more especially can shaft belts wont have sufficient elasticity. You'll need something much stretchier.

Are you sure the tyres are suitable for 60mph road use? What sort of bearings are there?
 
That type of suspension (and tyres, Vic :o) is quite common on small car box trailers here. I see them often and the belts must be available as they look to be in good condition. Feu Vert (Halfords type place) has the tyres on sale, basicly scooter tyres. The belt does not go tound the bent tube, as in the photo, but just the bar in front of it. The arrangement gives a softer ride than the type used by indespension.

To add: the rubber system is slightly self damping.
 
DownWest said:
That type of suspension (and tyres, Vic :o) is quite common on small car box trailers here. I see them often and the belts must be available as they look to be in good condition. Feu Vert (Halfords type place) has the tyres on sale, basicly scooter tyres. The belt does not go tound the bent tube, as in the photo, but just the bar in front of it. The arrangement gives a softer ride than the type used by indespension.

To add: the rubber system is slightly self damping.
Click to expand...

Yes, I was tempted to say it looks home-made until I found this French photo from the 1960s which shows the same type of trailer, with mudguards.

trailer.jpg
 
DownWest said:
That type of suspension (and tyres, Vic :o) is quite common on small car box trailers here. I see them often and the belts must be available as they look to be in good condition. Feu Vert (Halfords type place) has the tyres on sale, basicly scooter tyres. The belt does not go tound the bent tube, as in the photo, but just the bar in front of it. The arrangement gives a softer ride than the type used by indespension.

To add: the rubber system is slightly self damping.
Click to expand...

Scooter tyres ... Never thought of those but its given me an idea if I ever manage to refurbish my dinghy trailer. Always been a bit wary since one of the well known tyre depots tried to sell me wheel barrow tyres for my camping trailer
 
DownWest said:
That type of suspension (and tyres, Vic :o) is quite common on small car box trailers here. I see them often and the belts must be available as they look to be in good condition. Feu Vert (Halfords type place) has the tyres on sale, basicly scooter tyres. The belt does not go tound the bent tube, as in the photo, but just the bar in front of it. The arrangement gives a softer ride than the type used by indespension.

To add: the rubber system is slightly self damping.
Click to expand...

I've seen a few of those box trailers in the UK, just not recently.
If the tyres are 8 inch, then new ones are widely available, but it's often cheaper to buy a wheel with your tyre!
 
lw395 said:
I've seen a few of those box trailers in the UK, just not recently.
If the tyres are 8 inch, then new ones are widely available, but it's often cheaper to buy a wheel with your tyre!
Click to expand...

Well, yes. But those wheels have the bearings in the hub; Bit like wheel barrow ones. Not a prob here, with 123 roulement.com

Back in my trailer daze, We used 8" tyres up to 1200 lbs. Usually with 6 plys.. don't remember a prob with tyres, just a couple with bearings.
 
How often do you see suspension on launching trollies?

For the OP, I will be passing a friendly trailer specialist in the next couple of days, he will know if spares are available. Got to be easier than trying to find (& fit) coil over shock units. At a guess, the trailer would carry 200kg, if there are different sizes.
Cors' it would help if he filled in his location.....


+ looking at google, the sail will likely have a Z on it. Boats were built in the Charente, not far from here.
 
Last edited:
Thanks. The sail does have the slightly unusually shaped Z on it. That was why I thought the boat is a Zef. It looks pretty much like the boat in pvb's post, complete with the mast stepping on the foredeck. 200kg sounds about right.

I am in south Wales but hopefully these days if someone can put me onto a supplier then the internet will be my friend.
 
Thank, but given that it has suspension, proper bearings, and tyres rated at 81mph (all be it perished and in need of replacement) I think that once it is sorted I will give it a trundle up the street.
 
This kind of suspension is/was common on small light aircraft. Piper cub or Auster. The pivoting is sideways though. They use multiple layers of bungee 10 or 12mm to get the right strength of spring for the load. I am not sure if they use one continuous bungee or spliced loops. You might get some clues from aviation suppliers. Certainly drive belt has as little stretch as possible so no good. ol'will
 
PCUK said:
Still doesn't make it a road trailer. Your choice though as it's your boat!
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A zillion box trailers in France do though.

Have seen many with suspension like these on the French roads and autoroutes, usually at around 130kmh. In good condition they're great. Make sure tyres, tubes and suspension are good.

Incidentally, has the OP seen this: http://sailboatdata.com/viewrecord.asp?class_id=6457
 
William_H said:
This kind of suspension is/was common on small light aircraft. Piper cub or Auster. The pivoting is sideways though. They use multiple layers of bungee 10 or 12mm to get the right strength of spring for the load. I am not sure if they use one continuous bungee or spliced loops. You might get some clues from aviation suppliers. Certainly drive belt has as little stretch as possible so no good. ol'will
Click to expand...

I too was thinking of bungee as used by Piper and Auster. Usually supplied as loops. The problem in using it here would be tieing the ends together securely. It was always a struggle to fit them to the aircraft, so I made a jig with a lever system that was quick and easy.
 
PCUK said:
Still doesn't make it a road trailer. Your choice though as it's your boat!
Click to expand...

I don't think the suspension on this trailer can possibly be much worse for the boat than the rock-hard indespension units used for many lightweight boats.
Basically the tyres do most of the work.
However, I was thinking a potential way out would be to fit an indespension axle beam and suspension units, wheels, mudguards etc.
I sometimes tow longish distances and being able to use common wheels, tyres etc is good for peace of mind.
OTOH, usable trailers don't go for much on ebay etc, alas there is a danger of acquiring another boat with it.

I wondered if any industrial size rubber mount might be made to work for the suspension element.
Or just a very butch o ring?
I've cut'n'shut o rings to size before, not sure I'd trust superglue on e.g. 12mm neoprene cord? Maybe it could be joined with cable grips?
 
Have. to agree with most comments supporting this type of suspension, trailers so equipped always seem to tow so smoothly & stable.Trail sailed many boats for over 30years'' one drascombe I got so hacked off with towing on indepension units banging about behind took the step of removing & fitting a single leaf transverse spring which transformed the smoothness & removed the doubts on corrosion of units that on the starts on inside. till they explode and collapse, carp !
 
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