Trailer: single or twin axle

Tim M · 15 January 2007, 15:17

Which is preferable for a boat of about 7m, assuming both are rated for the same weight. Is a twin going to be more stable whilst towing? Is a single going to be easier to tow?

Comments please.....

codprawn · 15 January 2007, 15:22

Extra security wins every time. A single axle trailer is easier to man handle around in tight spots but if you are towing any sort of distance it's no contest.

For me the extra security of a triple axle will be the way to go - the stability is awesome but maybe overkill even for my 9m!!!

Tim M · 15 January 2007, 15:31

Will the twin be more stable though (ie less likley to snake/wobble around). Presumably it will bounce less than a single?

I would also assume a twin axle (if set up right) will be kinder on the car. Ie if u go over a bump presumably there is quite a loss of force being applied to your towbar. Does a second axle help to balance the trailer in such a case and counteract that somewhat (leading perhaps to a more comfortable journey for the people in the car?).

I have very limited experiance of twin axle trailers, but on the few occastions I have towed them (normally flatbeds) they have seemed a lot less bouncy then ones with a single axle....

Nick Hearne · 15 January 2007, 15:33

Have to agree with Codders, having just changed from a single to a twin axle!
I could wheel around the single no problem on a hard level surface, but now it is a hell of a job to maneuver by hand with the twin!
If I should have a blow out then I have anther wheel B4 it all goes pair shape!

codprawn · 15 January 2007, 15:44

Quote:

Originally Posted by Tim M

Will the twin be more stable though (ie less likley to snake/wobble around). Presumably it will bounce less than a single?

I would also assume a twin axle (if set up right) will be kinder on the car. Ie if u go over a bump presumably there is quite a loss of force being applied to your towbar. Does a second axle help to balance the trailer in such a case and counteract that somewhat (leading perhaps to a more comfortable journey for the people in the car?).

I have very limited experiance of twin axle trailers, but on the few occastions I have towed them (normally flatbeds) they have seemed a lot less bouncy then ones with a single axle....

Technically the bounce has nothing to do with the number of axles - it's down to the weight and suspension setup.

You should get more stability with a twin and also better braking. The 3 axle trailer I used would stop my Discovery a treat - once I had started the breaking acion the trailer would do most of the work.

You are right about the the forces being less on the towbar but that is also down to balance. The more axles you have the less you need to worry.

Pete7 · 15 January 2007, 15:56

Quote:

Originally Posted by Tim M

Is a twin going to be more stable whilst towing? Is a single going to be easier to tow? Comments please.....

Yes, Yes, never mind that, what have you bought now ?

Pete

Nasher · 15 January 2007, 15:57

Tim

Having changed my trailer from single to twin axles I believe there is no contest. Twin axles all the way, far more stable under way, and I've not noticed much differance manouvering in tight spots.

However, I never move the boat around by hand when its on its trailer which would be more difficult.

Nasher.

Tim M · 15 January 2007, 16:12

Quote:

Originally Posted by Pete7

Yes, Yes, never mind that, what have you bought now ?

Pete

Nothing (yet)

Sounds like a twin would be better then.

Jono · 15 January 2007, 16:23

Looks like I’m in a minority of one then

I much prefer towing with a well set up single axle trailer.

Safety argument - Safer if a tyre blows out ? Ok.. if it’s well maintained what are the odds of a modern tyre blowing out ? The odds are just as great as blowing out one of the tyres on the steering axle of your towing vehicle and how many people worry about that?

A lot of the stability problems are down to poor weight distribution. With a multi-axle trailer you have to be lot more careful about not only nose weight, but also the height of your tow hitch.

Towing the 7m Humber on a single axle trailer was a breeze. It was well set up, used a suitable tow vehicle and was properly looked after and manoeuvring it in tight spaces was far less stressful on the tyres and nerves……

MikeCC · 15 January 2007, 16:25

For 7m I'd look at a twin unless you will regularly be moving it by hand into a tight spot. (Even then you can make life easier by putting a bit more air into the tyres)

Mine's a twin and I managed to drive it a few miles on 3 wheels without any drama after one of the suspension units failed.

With 4 wheels sharing the load obviously less wear and tear on each bearing.

Jono · 15 January 2007, 16:31

Quote:

Originally Posted by MikeCC

For 7m I'd look at a twin unless you will regularly be moving it by hand into a tight spot. (Even then you can make life easier by putting a bit more air into the tyres)

Mine's a twin and I managed to drive it a few miles on 3 wheels without any drama after one of the suspension units failed.

With 4 wheels sharing the load obviously less wear and tear on each bearing.

So how come one of the suspension units failed?....

A trailer with twin axles will have suspension/hub/tyres that are (in simplistic terms) rated for 1/4 of the carrying capacity of the trailer, whilst on a single axle its 1/2.....

jwalker · 15 January 2007, 16:39

Tim, twins take more charge of the car, tripples more so again. They are more akin to a vehicle in their own right which you are towing, whereas a single is more like an extension of the car. The nose weight varies more over undulating surfaces with the twin or tripple rig. With my tripple set up, I can get a situation where there is almost no nose weight if the road is a small brow, eg. the car is on the level and the trailer is on the hill.

Hand manoeuvring a twin is very difficult and a tripple is impossible. It follows that there must be increased side loads on the draw bar when turning and that there is tyre scrub, also wheel fatigue and hub fatigue can be an issue and these loads are also transferred to the trailer so it too must be fully sound.

However, twins and tripples are far superior at riding poor road surfaces, consequently they give the boat a nicer ride. They may be essential for a large boat simply because you will not get a single axle which can carry the load.

Dirk Diggler · 15 January 2007, 16:40

No contest, on a little rib like yours it would have to be a single!

codprawn · 15 January 2007, 16:47

Quote:

Originally Posted by jwalker

Tim, twins take more charge of the car, tripples more so again. They are more akin to a vehicle in their own right which you are towing, whereas a single is more like an extension of the car. The nose weight varies more over undulating surfaces with the twin or tripple rig. With my tripple set up, I can get a situation where there is almost no nose weight if the road is a small brow, eg. the car is on the level and the trailer is on the hill.

Hand manoeuvring a twin is very difficult and a tripple is impossible. It follows that there must be increased side loads on the draw bar when turning and that there is tyre scrub, also wheel fatigue and hub fatigue can be an issue and these loads are also transferred to the trailer so it too must be fully sound.

However, twins and tripples are far superior at riding poor road surfaces, consequently they give the boat a nicer ride. They may be essential for a large boat simply because you will not get a single axle which can carry the load.

It is not impossible with a triple - just bloody difficult. My brother and I managed to swing our rig through 90 degrees and push it along a corridor until it was parked nicely - wouldn't like to repeat it though!!! It did help it was a very smooth sealed concrete floor.

Good point about the trailer taking control - hadn't thought about it quite like that but spot on about the changing weights at the back etc. There is a good saying amongst railway men - "the engine pulls the train but it's the train that stops the engine".

MikeCC · 15 January 2007, 17:06

Quote:

Originally Posted by jwalker

so it too must be fully sound.

Quote:

Originally Posted by Jono

So how come one of the suspension units failed?....

Errr . . .not quite sound enough!

Box section on one of the suspension units corroded out underneath and one corner too many pushed the bar through. Anyone else with those units I'd suggest close inspection of the underside as you can't really see this from a quick look. Give it a good poke with a screwdriver to be sure.

. . . so twin axle is no reason to be complacent

jwalker · 15 January 2007, 17:39

Galvanised suspension units can be purchased.....

simmons0 · 15 January 2007, 18:44

Double the number of bearings to rust up and need changing and double the number of brakes to stick on when you don't want them too.

Yep. Ours is going nowhere right now. Most or all of the brakes are stuck on and couldn't move it an inch even with the car in low box giving it some.

Didn't use the handbrake either so we didn't expect that.

Harry

Biggles · 15 January 2007, 18:46

Quote:

Originally Posted by simmons0

Double the number of bearings to rust up and need changing and double the number of brakes to stick on when you don't want them too.

Yep. Ours is going nowhere right now. Most or all of the brakes are stuck on and couldn't move it an inch even with the car in low box giving it some.

Didn't use the handbrake either so we didn't expect that.

Harry

Hit the drums really hard with a Hammer. If you already knew that just ignore me.

BogMonster · 15 January 2007, 19:22

Twin for me on the rough roads here and also it means that if a wheel bearing jacks in and spits a wheel off then you don't end up with a road full of bits of boat cos there is still one left

I have watched a single axle trailer going down the gravel road to the slipway where I launch mine and it was bouncing and leaping all over the place. My trailer runs on 4 x 7.50R16 Land Rover tyres and hardly notices on the same bit of road

Aidan · 15 January 2007, 19:44

Whats wrong with carrying spare wheel with Tyre bolted to trailer along with two sets of Bearings and Bearing Pullers and finally an Inflate spray.

Add all of the to two wheel trailer and presto.

I also agree with previous writer which mentions 4 wheels is double the trouble for Hubs and Brakes etc.

Never a dull moment to take a few hours extra before getting launched.

And as for Trailer side crawling, just slow it down...