Tow ball weight

[winston]

My brother just bought a 4.75m platey with 90 yamaha 2 stroke (yes I know, I would have gone fourstroke or high tech 2 stroke) anyway we went fishing in two boats the other day and he was 20 min. behind.Seems as though he could not lift the trailer onto the tow ball,I checked and neither could I.Since we were 300 Km from the dealer we decided to adjust it ourselves ,we moved the axle about 20 cm forward but the question is how much weight should be on the towball.Yes a new boat should be set up better than this.

[The_Walrus]

I beleive that the norm is to have the tow ball carry 10% of the weight of your outfit.

Luc

[Coke]

Have a look in Boating under "Land Rover Discoverys" thread.

[Coke]

Sorry I meant "4WD-Off Road" - it is not exactly on your point but might help.

[phewy]

Yep 10 - 15%, rather see about 15% on a smallish boat. Do you know the total weight? You dont want it so light that one person could lift a boat that size with ease. Of course, check your download capacity weight of vehicles towbar.

[bidkev]

10 to 15%?????? I think there may be variations in tow ball weight depending on braking system?

I'm not sure on this 10% "standardisation" but I know of 2 boat dealers who have stated categorically that they set their rigs to 7%

cheers

kev

[phewy]

Kev. At least 10%. 10 - 15% recommended by most. Read up some info. Do brakes have anything to do with towball weight?, I assumed either you need them or you don't according to total weight?

Just some advice I found in 5min searching, no one mentions 7%. Caravans, trailers, boats - no difference in towing.
http://www.haymanreese.com.au/consumer/advice/index.htm
http://www.caravanqld.com.au/download/hints/Towing_Guide.pdf (page 15)
http://www.4wdlinks.com.au/4wheelingSA/4WheelingSAautumn2005%20pages%2045-55.pdf (page10)
http://www.caravansplus.com.au/product_info.php?products_id=164&osCsid=820911fef95ff613be64d63cad161d79
http://www.cyberhorse.net.au/safetowing/float.htm

[finding_time]

7% especially on small boats does seem very very light and this results in the trailer fishtailing over the road i'd go 10% min and a bit maybe 15% more on small less than 1000kg outfits. I think duel wheel trailers with larger boats sometimes run a little less than 10% but not much.
Ian

[Lucky_Phill]

We covered this a little while ago, and in depth.

so, or I'll say, is make it a " grunt " lift. that is a good indication that the wieght is right.

Phill

[phewy]

Sounds like in depth was not deep enough. For what size boat exactly....12' tinny or 6m glass??? If you can "grunt" lift a 6m glass something is seriously wrong.
So you're telling me that after all these years of setting up customers caravans/vehicles using professional scales to weigh ball weight, I could have just used the "grunt" lift method instead???? :-? :-/
Sorry Phil, but for something so important as towing weights and safety, would rather see it done right. But its just my opinion.

[Morlers]

Hey Phewy

I have a glass boat with b/m/t weight say 1300-1400kg. It has a tendency to sway a little at highway speeds of 95-100. To ball weight measured by bathroom scales is 45kg. So it appears to be a little light on buy the 10% rule. Would a drawbar weight of say 140kg (10%) eliminate the tendency to sway? I have a 1600kg hayman Reece towbar with a ball weight of up to 160kg. How can I achieve a little more weight on the tow ball? Should I try and place the axle a little further toward the rear? Any suggestions?

:) :)

Morlers

[phewy]

Sounds dangerous Graeme...45kgs??? We had a 17-18' CruiseCraft on a single axle and it needed 2 people to lift it on the ball. Towed magnificently too. Sure you done it right with the bathroom scales? 100% sure that if you added more weight, by moving the axle back, it would help in the towing.

:) :)

[Bosunsmate]

Have 3.6m f/glass with 25/2st on redco trailer and have 45kg at ball...not sure of overall weight but with jockey wheel down I can push it up the driveway and around the yard with a bit of gruntin 'n' groanin.

[Morlers]

Yep Phewy, I can lift it without a 'grunt' and I double checked it on the scales at 45kg. The boat is a Haines Hunter Breeze 5.1m glasss. I was concerned when it tended to sway on the highway. The first time I thought the tyres were wrong pressure or the loading of stuff on the boat was wrong but it did it on two separate trips. This is the way the b/m/t came from the dealer when new. The tyres were 30psi when new but I pumped them up to 50psi but lowered them to 45pdi on advice from a tyre dealer. I have been careful with weight distriubution in the boat. The only thing left I can think of is get more weight on the drawbar and to do this I will need to take the axles back a bit. This shouldn't be too hard to achieve. Any one know of any problems I may encounter? Thanks for the replys. I am not trying to hijack the original post but hopefully add to it.

:) :)

Morlers

[FNQCairns]

Tow ball weight?...... would guess at about 3/4 of a kilo ;D ;D :P

[phewy]

Good one FNQ, is that for a 2" shank or a 3"? :)
Sounds all wrong Graeme. Go to your nearest caravan dealer/workshop and see if they have a set of ballweight scales (they should have if they set up vans/vehicles). Ask if you could borrow them (we lend them out at our workshop, tho you may have to leave a deposit). Or take the rig to a public weighbridge, they can calculate the ball weight for you. Get the exact weight to start off with. Never moved axles on a boat before, but have moved ones forward and back on caravans before....much much harder. Being all bolted it shouldn't be too hard. Little bit at a time, so would be best to try and get those ballweight scales for a weekend. #;)

[seabug]

Used to have a 15ft glass boat on single axle trailer and it fishtailed
something terrible.
Moved the axle back and it was OK.
Do not know what the weight was.

Now have a 1.4 ton single axle van and the builder loaded the coupling 13%, approx 180KG ,and it tows perfectly and has never fishtailed.
We use H/D Hayman-Rheese bars to level tow vehicle.

Sure would hate to tow a glass boat with only 45KG loading.
Regards
Seabug

[bidkev]

10 to 15% is a helluva lot of "room for manoeuvre", especially if it's a big rig. !0% of 3 ton is 300 kilo, 15% is 450. What should it be? 300 or 450, and if an extra 150 either way means little, then why doesn't 7% come into the equation as it's only 30 kilos less than 10% quoted and what are the factors governing that decision (the tow ball weight)?

The way it has been explained to me several times in the past, and I have always understood it, is that the vehicle's suspension and the type of trailer are also considered. ie A tandem trailer tends to "track straight" and not "swing" at the rear or "bob" at the hitch as much as a single axle trailer. This therefore allows that as there is less swing at the rear more weight can be carried there and as there is not as much "bobbing" or "seesawing" at the hitch either more or less weight can be carried there.

Some of the big trailerable cruisers must weigh over 4 ton (some going 5) and I've seen these being pulled by Nissans and Cruisers down the highway. At 10 or 15% hitch weight these vehicles shouldn't stand a chance (400kg/600kg). See how the margin widens the heavier the rig? There is now 200kg discrepancy! The market for these kind of rigs as trailerable boats would fast diminish if a truck was needed to pull them, surely?

I'm not arguing a point here, just brainstorming in the hope that we can get conclusive evidence as to what is safe and correct. As I say above, there are plenty of *very* big trailerable rigs on the road being pulled by domestic vehicles so are they unsafe or is there a way to set up vehicles or trailers to allow for more or less at the hitch than what seems "standard thinking" of 10 to 15%?

In conclusion, I would say that I think that everyone would rather arrive at a definitive answer of either 10 or 15 (or 7 or 20 or whatever) because as I have explained, in a big rig that is a huge amount of kilos difference between the two.

cheers

kev

[bidkev]

<snip>

Any one know of any problems I may encounter?
Morlers

Have you got side lights? Moved the axle on my last rig. It had side lights and the dealership hadn't left any spare wiring. When I moved the axle, it ripped the wiring off the side lights.

cheers

kev

[seabug]

"and what are the factors governing that decision (the tow ball weight)? "

Hi Kingtin,

Legal requirement is to have towball weight at no more than 10% of the weight that the vehicle can tow.

The further behind centre of balance that you can have the axle and still come under 10% of towable weight ,the better it will tow

Early vans were made so that you could lift the front to manouvre them by hand,as there were no jockey wheels available to the public.

Those same vans were a nightmare on our roads ,they would sway at the slightest wind or steering mistake and many crashed.

I know I am talking vans on a boat site ,but the same thing applies to any thing that is towed.

Thus ,if a 2000kg boat was towed by a vehicle with a 2000kg drawbar then the towball weight would be 200kg=10%

If the same boat was towed by a vehicle with a 3500kg towing capacity
the towball weight would be 350kg.
While that would be 17.5% of weight on the towball ,it would still be legal ,and would be more stable .
Regards
Seabug

[seabug]

"Some of the big trailerable cruisers must weigh over 4 ton (some going 5) and I've seen these being pulled by Nissans and Cruisers down the highway. At 10 or 15% hitch weight these vehicles shouldn't stand a chance (400kg/600kg). See how the margin widens the heavier the rig? There is now 200kg discrepancy! The market for these kind of rigs as trailerable boats would fast diminish if #a truck was needed to pull them, surely? "

Toyota Lancruisers and Nissan Patrols are both limited to 3500kg towing limit

Any towing more than that are illegal and a danger to other motorists.
Regards
Seabug

[Mantaray]

Wow isn't this towbar/towball weight thing misunderstood! And as for the "grunt" factor now I had thought that one had been buried deep where bad and lacking infomation would stay bad and lacking but some probably should read it again to know the difference between safe and not safe

http://www.ausfish.com.au/cgi-ausfish/yabb2/YaBB.cgi?num=1123592194/0

But you you can't pull a trailer due to towball capacity exceeded, max towball down weight limits, not being able to meet safe down weight limits then there are 2 ways to fix this 1) Get a bigger truck 2) Get a smaller boat

[Morlers]

Hey phewy

The ball weight scales sounds a good idea. I will check out the local van dealer when I get back from holidays. Thanks.

:) :)

Morlers

[Morlers]

Hi Kev

No side lights to take care of. Only about 8 bolts to loosen and slide the axle/spring assembly back a little. Thanks for the warning.

:) :)

Morlers

[Morlers]

Wow isn't this towbar/towball weight thing misunderstood! And as for the "grunt" factor now I had thought that one had been buried deep where bad and lacking infomation would stay bad and lacking but some probably should read it again to know the difference between safe and not safe

Just a little tongue in cheek with my reference to the 'grunt' factor. ;) Thanks.

:) :)

Morlers

[phewy]

Hey Graeme, one important thing that you will most probably know anway. When you do get around to moving it back, make sure you move both sides exactly the same. Tyre wear and tracking problems if not. Double check by measuring from the towball adjusting bolt on front of coupling to front spring hanger and same to other side making sure the tape measure is running straight and not twisted. We always aim to be within a few mm, no more than 5. (if no adj bolt, mark the centre of the front of coupling). Good luck! #;)

And Kev - Know what you mean about nothing in fine print. But there are certainly alot of vans going around with more than 300kgs on the ball. All perfectly OK with the right vehicle and equipment. Reese weight distribution hitches are available in 550lb, 750lb and even 1000lb (approx 250, 350 and 450kg's) ball weight kits, although I have never fitted the big suckers in my lifetime. Don't think you can buy them off the shelf here, would have to specially order them I imagine.

[Mr__Bean]

G'Day guys,

Interesting topic.

I actually had to move my axles forward a couple of months ago to reduce the weight on the towball.

I tow with a landcruiser and the heavy load on the towball made the headlights shine too high to be safe for other drivers.

I moved forward about 120mm and reduced the towball load to around 130kg (about 5%), it was about double this before the move.

Still tows the same, maybe a bit better if anything as bumps don't transfer back to the tow vehicle as much, no sway present.

I tend to agree with Kev, the 10% figure seems to be rule of thumb, then all other influences need to be considered. Sure more weight on the ball helps reduce sway, but as you get up in the high figures it also lifts weight off the front wheels of the tow vehicle and starts to affect tow vehicle braking efficiency.

To me, lighter trailers can run up to about 15%, mid range about 10%, heavy buggers 5%.

Yes, I know, just another opinion.

- Darren

P.S. # #Graeme, when you have moved the axles back make sure they will have full and free movement throughout their operating range, check they will clear the trailer cross members and that they will not fowl on the bottom of the roller brackets etc, and remember they will move backward about 40 mm under full load as the leaf strightens out.

[Morlers]

Hey Phewy

Had the measuring in mind as had to do it to my box trailer a little while ago due to scrubbing out one tyre. Thanks.

:) :)

Morlers

[Morlers]

Hi Mr Bean

Thanks for your warning re cross member and rollers. I will watch out for obstructions and allow for movement.

Thanks guys...you have been of great help. Once again, Ausfish to the rescue.

:) :)

Morlers

[Mantaray]

Wow isn't this towbar/towball weight thing misunderstood! And as for the "grunt" factor now I had thought that one had been buried deep where bad and lacking infomation would stay bad and lacking but some probably should read it again to know the difference between safe and not safe

Just a little tongue in cheek with my reference to the 'grunt' factor. ;) #Thanks.

:) :)

Morlers

Just as well it wasn't a "jerk" factor?

[noluck]

far as i know it is nothing to do with 10% 15% or 5% .
if compline plate say 250kg that is u can do #if it say 150kg that is #and GTW limit to folow . If u putt to much load on tow ball fron of the car will go in air and you wil not have braking 100% your brake will work only 60 to 75 % or steering#. so u just have to stick no numbers given #by car maker.
cheers no_luck

[phewy]

Thats why they produced weight distribution hitches cheers. To put the load back onto the front wheels. Some cars are very soft in the rear, especially newer Falcons. If the back end drops to far then fit the hitch kit, boat adaptors are available to suit single rail a-frames. The vehicle plates state max weights allowed on the ball. You dont go over it of course, we all know that (read should know).