A few questions re: towing

[Treads]

Instead of hijacking this thread: http://www.aulro.com/afvb/technical-chatter/58340-towing-manual-v-auto.html I thought I'd ask some related questions here instead.
I'm towing our double horse float approx 2500Kms in a couple of weeks. It's about 18 months old, has electric Al-Ko brakes fitted to the front axle and controlled by a Tekonsha Prodigy EBC. It came with 195/75 14's on solid holden rims, which I recently changed to 205/65 15's on 6JJ ventilated holden rims (off a VT). The 15's have a slightly higher load rating as well as feeling more stable with their greater contact patch. I currently have them at 40Psi as we usually only have one horse aboard and for short trips of less than 20mins.
The float weighs 800Kg and we estimate the horses to weigh 600Kg and 500Kg respectively. The heavier horse rides on the RHS of the float, however the LHS has extra tool boxes, jerries etc mounted over the mudguard (40Kg's?)
I normally run 38Psi all round on my disco with Bridgestone 694LT 245/75 16's, which I bump up to 42Psi when I'm loaded up in the back (and will be plenty loaded for this trip!)

So after all that:
1) Where should I start with cold pressures for the truck?
2) Any recommendations for cold pressures on the float?
3) Should I compensate with different pressures for road camber or weight difference between the 2 sides of the float?
4) How much rise is too much on any tyre? I've got 5Psi in my head, but can't work out where I heard that :unsure:
5)should I compensate between the braked front axle and the unbraked rear axle in regards to pressures?

I have an onboard compressor and a long airline if I need to make changes on the run :cool:

Also is it more economical to try to get into 5th gear as much as possible, or just leave it in 4th at higher revs? Haven't had the disco long enough to work out whether they get better mileage at slightly too high revs, or slightly labouring :huh:

Cheers for any help :)

[RonMcGr]

Cold pressures in the tow vehicle, use maximum recommended by vehicle specs.

Horse float, if it has light truck tyres, 45 to 50 psi.
If they are radials maximum recommended on the tyre.

Don't worry about sides and axles, just keep the pressures even.

If the float moves from side to side you have the pressure to low. If you can feel the horse float hitting every bump in the road, though the towing vehicle, back of the pressure by 5 psi.

The idea is to have the tyres tight enough to stop sway on both units.

Cheers,
Ron

[xrayxray]

Tow in 4th gear as 5th gear is to weak to tow with.
Your combined weight in the float will be approx 1900 kilo's,this only leaves you 100 kilo's left for gear and stuff before you are over 2 tons at which point you need Breakaway Trailer Brakes.

[Treads]

Tow in 4th gear as 5th gear is to weak to tow with.
Your combined weight in the float will be approx 1900 kilo's,this only leaves you 100 kilo's left for gear and stuff before you are over 2 tons at which point you need Breakaway Trailer Brakes.


I think we are over-estimating our horses weights, but certainly don't plan on putting too much more gear on the float anyway. We've got a weighbridge not far from us which I plan on using before we go, just to see what the whole lot totals :eek:

[JDNSW]

I think we are over-estimating our horses weights, but certainly don't plan on putting too much more gear on the float anyway. We've got a weighbridge not far from us which I plan on using before we go, just to see what the whole lot totals :eek:

It would be interesting if you posted the comparison between your estimate and what it actually weighs!

John

[Treads]

It would be interesting if you posted the comparison between your estimate and what it actually weighs!

John

I'm shocking with these things. I can look at a steer and guess to within 50kgs or so, but horses! :confused: Might get a chance to pop the horses on later this week and take it over.

[Redback]

I will echo what Ron has said, also i see your tow mule is a D1, if they are the same as the D2 in regards to tyre pressures, then i would go 46psi in the rear and 28 too 34 in the front.

46psi is what LR recommend when fully loaded in the rear, this is what i run when loaded and towing the camper with my D2 and it is very stable with this pressure, i'm about 400kg shy of what your towing, try it at least, do a few short trips and see what pressures work best.

As for towing in 5th, for me i use 5th all the time, as long as your not holding 5th for long periods up long grades and labouring the car i can't see a problem, you will feel the car starting to slow and this is when you decide when to go back too 4th, do it well before it's starts too struggle, just keep the car in the max torque zone and it should be fine.

The way i do it is if your in 5th and you put your foot down and it doesn't respond or excellerate, that's when i go to 4th, in some situations, when you put your foot down, the car will actually get slower, so changing back early rather than later is better.

Baz.

[Treads]

It would be interesting if you posted the comparison between your estimate and what it actually weighs!

John

Well I took the rig over to a transport place who has a weighbridge today. Unfortunately I could only get over the bridge with either the rig or the trailer, so no combined weights.

My estimates were:
D1 = 2200kg
Float = 800kg + 2x horses 1100kg
Total = 4100kg

With the float on, the back of the truck 1/2 loaded and 2/3 of a tank of fuel:
D1 = 2500kg! :eek:
Float = 700kg
Total = 3200kg
The float placard says it weighs 800Kg, so would I be correct in saying that it has a 100Kg download on the towball when empty?

I went back and put the ponies on:
D1 = 2550kg
Float = 1750kg
Total = 4300kg! :o Poor little 2.5! No wonder it's a slug with the float loaded! :(

So it looks like the float must be pretty well weighted, only a 50kg increase in weight on the Disco with the horses on. And I was spot on the money with the horses weights! :cool: 1100kgs between them.

https://www.aulro.com/afvb/images/imported/2008/06/211.jpg

It sits pretty flat considering there's 1 & 3/4 ton hanging off it's bum!

https://www.aulro.com/afvb/images/imported/2008/06/212.jpg

None of the jerries or toolboxes on the float are full.

https://www.aulro.com/afvb/images/imported/2008/06/213.jpg

The first culprit (Ridden by the main suspect in all this caper :angel: )

https://www.aulro.com/afvb/images/imported/2008/06/214.jpg

The second one, and that dodgy person on the right again :D

[slug_burner]

It is not recommended to tow in 5th.

Drive goes straight through the gearbox in 4th and is the recommended gear for towing. All other gears need to put the drive through the lay gear and it is a common problem to have the input gear and the matching gear on the lay gear chew each other up as a result of towing in 5th. When I was getting my box fixed for this problem, the shop (non LR specialist but a Gbox specialist) had another R380 GBox in with the same problem.

[Lotz-A-Landies]

... 100 kilo's left for gear and stuff before you are over 2 tons at which point you need Breakaway Trailer Brakes.

Breakaway brakes on both axles!


I will echo what Ron has said, also i see your tow mule is a D1, if they are the same as the D2 in regards to tyre pressures, then i would go 46psi in the rear and 28 too 34 in the front.

46psi is what LR recommend when fully loaded in the rear, this is what i run when loaded and towing the camper with my D2 and it is very stable with this pressure, i'm about 400kg shy of what your towing, try it at least, do a few short trips and see what pressures work best. ...

... Baz.
Back when I was a member of the Range Rover Club in Richard Asquith's Presidency days they used to say that on long trips with a load it was better to disregard tyre pressures and adjust the rolling radius to be equal on all four wheels with the tyres hot. (50 K or so into the trip) The fronts generally remained the same but you sometimes had to adjust the rears to different pressures to get the height correct.

This accounts for different loadings from side to side and the differentials are not compensating for the various wheel speeds.

Does anyone else do this?

Diana

[Treads]

Breakaway brakes on both axles!

And that isn't cheap! I am in the process of getting land rover pattern electric hubs made up for it ($370pr). I might as well get 2 sets while I'm at it. By the time we fill the jerries on the RHS, load up the toolboxes on the LHS, put another tool box on the drawbar (planned) and an awning on the LHS, we'll be pushing 2t :eek:

[Col.Coleman]

This is why it is now a waste of time to hire a car trailer to tow a car. If you look carefully you will notice all hire car carriers are maximum 2 tonne atm with over ride brakes. Think how much one weighs and put your landy on top, or even a mid sized sedan. Totally illegal and no insurance if you stack it. They don't mind taking your money though.

How many people didn't know that?

CC

[Lotz-A-Landies]

And that isn't cheap! ...
... :eek:
You'll be glad you did, in spite of the cost. My car float (for 80" Land Rover) is only rated to 2,000Kg but I have put 10" AlKo electrics on all four wheels. The braking is very efficient and noticeably better than when only braking on one axle. You feel confident of being able to stop whatever emergency pops out at you.

Diana