Suspension Necessary?

[martini]

Just been trying to fit new wheel bearings on the trailer and managed to destroy the thread on one axle

Also the brake linings fell of while removing the drum, brakes are all seizing up, leaf springs are rotten, tyres need replacing etc etc...

So I'm thinking about just replacing the whole lot but would like to do away with the suspension, less to go wrong and lowers the height a few inches.

Is this going to be problem do you think? My max speed is only 25-30 mph, trailers rated for 4700kg gross, 1400kg unladen which about right, I guess the boat is about 3000kg.

I wonder if no suspension would put extra stress on the tyres when you go over a bump maybe?

[Erin]

Would make for a very harsh ride on our roads I would have thought (the Avenue won't be smooth for long ).

Also a risk of damage from vibration etc even at low speed. I know on a car it makes a major difference to braking distances if the suspension isn't right, so maybe it might affect a trailer to some extent as well. I guess the biggest risk would be the boat juddering/jumping around on the trailer and possibly shifting position if you came accross a big enough pot hole.

[martini]

The hardest part at the moment seems to be finding anything that will take the weight! Twin axle so each axle needs to be rated for 2400kg to be safe. Most axles, wheels and tyres etc I can find go up to 1800kg

[Erin]

I had the name at one point for one of the main UK suppliers of trailer parts. If I can find it I'll let you know. They supply axles to the main trailer makes and I spoke to them when I was looking at purchasing an Admiral trailer, they may be able to help.

[BogMonster]

What do you tow it with, if it weighs 4.7 tons? Most 4x4s are only rated to 3.5.

I think you'd struggle to find axles that strong without going to commercial stuff. Most light Ifor Williams type trailers are using twin axles from about 2 tons upwards and max out at 3500kg to match most vehicles. Even the rear axle on a Defender 130 is only rated at 2200kg.

At that speed you won't need suspension - my old twin axle trailer (on 7.50R16 Land Rover wheels) had no suspension, the ride wasn't great but at 25mph it wasn't a problem unless you hit the sort of pothole you could see about 100 yards away.

[Bigmuz7]

How far do you need to travel with it ? .. The hull will certainly get a slap if you do hit one I'd have thought ?

[ScotSeats]

At that speed if you arn't towing a huge distnace it will not be a problem the thing i would tend to think about more is if you do decide to take further one day or resale value in the future.

[m chappelow]

On uk roads legaly i think you would need suspension,,though a lot of our local fishing boats are on solid no suspension trailers for launching and a very limited distance on roads ,,but the tyre walls are heavy enough to take all the shocks from the road or any bumps , with a solid trailer my fishing boat that weighs in at around 1 ton will pop out the walls of normal tyre walls and shakes the whole boat and it only has to move 100 yds or so .on a smooth surface fine but finds any small holes or stones pebbles or concreate slipways with grip lines in .suppose it depends on the size of the wheels/tyres and the pressure inside ,, bigger and softer they are less they find the bumps but then will the tyre walls stand the flexing ,,,,the boat in the pic uses agricultural type tyres think weighs about 5 tons .

[wavelength]

I don't know but think it unlikely that you can do away with the suspension when using on uk roads. However without suspension you will certainly become an expert in wheel bearing replacement as its gonna knock **** out of them.

[Rogue Wave]

What trailer are you using presently. My Avon 3ton boat is on an ex Navy air braked twin axle trailer it uses indepentdant suspension units that are rated at over 1.5 tonns per wheel and Air brakes. I know wher there is a bogey with two of these axles on (4 wheel) I'll find out who owns it if you wish.

I bought my trailer from Phil you may have seen them there when you bought your boat. My trailer weighs 1.5 tons BTW

http://www.brambertrailers.com/itemdetl.php/itemcode/10

[Nasher]

Not quite sure how to say what I want to.

But with a twin axle suspension trailer, as you go over the apex at the top of a slip or similar, the weight is still spread a little as one axle goes light and the other compresses.
With solid axles all the weight would transfer to one axle for a short time.

The weight transfer could be enough to rip the coupling up off the towball and the boat and trailer would launch itself.

Nasher.

[Erin]

Originally Posted by Nasher

The weight transfer could be enough to rip the coupling up off the towball and the boat and trailer would launch itself.

Nasher.

That sounds like a fun day out. Might go down and watch Martini II being launched if it's suspension less. To give moral support obviously... not just to have a laugh

[martini]

Originally Posted by Erin

That sounds like a fun day out. Might go down and watch Martini II being launched if it's suspension less. To give moral support obviously... not just to have a laugh

Thanks for the offer, you can stand behind me and see me back

Nasher, I think I get what you're saying but the axles are so close together I don't think it would make that much difference to the nose weight. Still raises a good point though, on an uneven surface or apex etc., without suspension theres more chance that 1 axle would be taking much more load than the other and quite easily exceeding its capacity.

Rogue Wave, this trailer is also one of Phils, built by SBS with air brakes and leaf springs. It uses landrover size 7.5R16 wheels with commercial 12 ply tyres.

I know it exceeds the capacity of my rangerover and the only brake on it now is the hand brake but it still seems to stop and drive fairly well. All completely illegal of course but as the weight of the whole rig is probably just over 7.5t I'd need an HGV licence in order to comply

I'm now waiting for SBS to get back to me with a price for complete new axles same as original with leaf springs. Probably the safest route and saves having to modify the trailer to take any different systems.

[Rogue Wave]

Originally Posted by martini

Thanks for the offer, you can stand behind me and see me back

Nasher, I think I get what you're saying but the axles are so close together I don't think it would make that much difference to the nose weight. Still raises a good point though, on an uneven surface or apex etc., without suspension theres more chance that 1 axle would be taking much more load than the other and quite easily exceeding its capacity.

Rogue Wave, this trailer is also one of Phils, built by SBS with air brakes and leaf springs. It uses landrover size 7.5R16 wheels with commercial 12 ply tyres.

I know it exceeds the capacity of my rangerover and the only brake on it now is the hand brake but it still seems to stop and drive fairly well. All completely illegal of course but as the weight of the whole rig is probably just over 7.5t I'd need an HGV licence in order to comply

I'm now waiting for SBS to get back to me with a price for complete new axles same as original with leaf springs. Probably the safest route and saves having to modify the trailer to take any different systems.

yeah thats the trailer I have but without the leaf springs, the bogey I'm talking about comes with leaf springs and is the same wheels axles brakes as yours.

I really like my trailer but I can't get an airbrake unit for my Pajero, so I'm getting a custom built jobbie, hopefully!

You could go legal if you wanted to with one of the kits made by these lovely people.

http://www.erentek.co.uk/conv-kits.htm

I havem't been to the yard where the bogey is for a couple of months but I will have a look tonight

[jyasaki]

Originally Posted by Nasher

With solid axles all the weight would transfer to one axle for a short time.

The weight transfer could be enough to rip the coupling up off the towball and the boat and trailer would launch itself.

That happens, on occasion, even with suspension. Usually at ramps with a an abrupt change from flat to a steep slope. One more reason to make sure your safety chains are up to snuff.

Seems to be more prevalent with triple axle trailers, but has happened to twin axles as well.


Solid-mounted axle, I'd worry more about tires than bearings (though they probably wouldn't last too long either) or boat. Any energy from the trailer bouncing would have to be absorbed by the tires, and it wouldn't take a whole lot of bounce to put them way beyond their load rating.

My $.02US;

jky

[BogMonster]

Originally Posted by jyasaki

That happens, on occasion, even with suspension.

I have some quite rough ground on the approach to the house and my twin axle Ifor Williams trailer regularly has one or other axle off the ground if lightly laden - it doesn't take much. A ton of fuel in it sorts it out though

[Nasher]

Originally Posted by jyasaki

That happens, on occasion, even with suspension. Usually at ramps with a an abrupt change from flat to a steep slope. One more reason to make sure your safety chains are up to snuff.

jky

Hi jky

We don't tend to do safety chains over here, we have breakaway cables that are meant to break and apply the handbrake at the same time.
I've a funny feeling they are not legal here, but am probably wrong.

On the other hand I'm not sure how I feel about having the boat and trailer attached losely by a strong chain whilst I try to slow down from motorway speeds. I'll need to think on that one and let you know.

Nasher.

[Poly]

Originally Posted by Nasher

Hi jky

We don't tend to do safety chains over here, we have breakaway cables that are meant to break and apply the handbrake at the same time.
I've a funny feeling they are not legal here, but am probably wrong.

On the other hand I'm not sure how I feel about having the boat and trailer attached losely by a strong chain whilst I try to slow down from motorway speeds. I'll need to think on that one and let you know.

Nasher.

Nasher chains are only used here on unbraked (i.e. < 750 kg) trailers.

[Nasher]

Originally Posted by Polwart

Nasher chains are only used here on unbraked (i.e. < 750 kg) trailers.

Ta

Nasher

[jyasaki]

Originally Posted by Nasher

Hi jky

We don't tend to do safety chains over here, we have breakaway cables that are meant to break and apply the handbrake at the same time.
I've a funny feeling they are not legal here, but am probably wrong.

On the other hand I'm not sure how I feel about having the boat and trailer attached losely by a strong chain whilst I try to slow down from motorway speeds. I'll need to think on that one and let you know.

Nasher.

Off-topic reply...

I think we've been over this before.

In the US, braked trailers have both a breakaway cable (to actuate the brakes should the trailer get loose) and safety chains (to prevent the former scenario. (Non-braked trailers have just the chains, naturally.)

I've never had it happen, but know a couple of people who have: ideally, should the hitch fail, the trailer tongue drops into the cradle of the chains (they're crossed to run left trailer to right side of tow vehicle and vice versa), keeping the tongue from pole vaulting the trailer ass over teakettle. One guy said he had no problem getting to the side of the road and stopping; the other said he swerved all over, but got stopped safely.

Bottom line: Don't know if it's better or worse, but given the number of non-functional braking systems on trailers over here, I gotta think the safety chains are a good thing.

jky