Towbars and motorcycle carriers

[irondoc]

Hi guys

Getting my D4 in 3 weeks !!!!!!! (After lurking on this forum for about 2 years...) Looking for something to carry my motorbike around. Don't want to get a trailer - nowhere to put it, rego, etc. Was thinking about one of these:

http://www.newlite.com.au/images/bh2010-small_01.JPG

Has a standard tongue attachment that goes into a 50mm hitch. The bike weighs around 130kg, towbar carrier weighs around 25kg, so total a bit over 150kg.

For people that have used the D4 hitch, I would be interested in whether you think the standard hitch is up to the job, given its unique design.

Cheers
Lucas
100 series convert.....

[MC D4]

Hi Lucas,

Prior to buying my d4 last December I was very close to getting a bike carrier myself but was worried about it being on the back of my then VE GTS. In the end I opted for a D4 and made a bike carrier that bolted to the draw bar of my camper trailer.

The D4 tow bar set up appears to be a very good piece of engineering and i cannot see an issue with putting a bike carrier on the back. We now have a 2.5 ton jayco base station and the 220kg plus tow ball weight is no issue so your 155kg bike and carrier would be safe as houses.

There was a post about the tow bar attachment falling out on an RRS which was a bit of a worry however it would seem that this may have been as a result of other contributing factors. I know that I take care to make sure mine clicks in well and it works!

You are going to love the D4!! :D

[richard4u2]

i would check with the police to see if its legal

[irondoc]

I haven't looked it up, but they are made in Australia and have lights and number plate brackets, so I assume they are legal....

[mudmouse]

Generally, it can't protrude more than 150mm from the sides, can't obscure the tail lights and can't obscure the number plate (which must be illuminated at night). Have a look at the vehicle standards bit on the RTA website.

I always thought the weight on a tow ball should not exceed 80kg. Can't find a legal reference for that, but I know what it's like trying to hitch a car trailer, and the importance of balancing the load in terms of how the car feels when towing.

Matt.

[rmp]

I haven't looked it up, but they are made in Australia and have lights and number plate brackets, so I assume they are legal....

By no means is everything designed and/or sold in Australia is legal to use in Australia, or in all states. This may well be fine as it does have the extras you mention.

[Wilbur]

Hi Lucas,

The D4 tow bar set up appears to be a very good piece of engineering and i cannot see an issue with putting a bike carrier on the back. We now have a 2.5 ton jayco base station and the 220kg plus tow ball weight is no issue so your 155kg bike and carrier would be safe as houses.

:D

I can't get my head around the maths, but it seems likely that if the centre of gravity of the bike/rack combination is behind the centre of the tow ball, 155kgs may seem like a lot more.

With a trailer, the weight is straight down through the centre of the ball. From the picture posted, it looked as though the centre of gravity would be well behind the ball, effectively adding leverage to the weight.

Anyone skilled in maths able to comment?

[Duck's Guts]

What Wilbur said does need to be carefully considered.

The problem relates to a rotational force (engineering term 'moment').
Basically the further from a pivot point that a force is applied, the less force that is required to achieve the same result. Hence the 'leverage' advantage achieved when using a high lift jack, hydraulic bottle jack, etc.

For those who like the math approach to things, and have the inclination, a good description of the concepts can be found at:
Introduction to Statics: Moments (http://www.engin.brown.edu/courses/en3/notes/Statics/moments/moments.htm).

[blue_mini]

Ive got one of these that i put onto the back of my 4wd bravo ute. Works very well to move it round and take it places (ive got a canopy so cant put it in the tray).

Its got separate lights that plug into your trailer socket and a place to attach your numberplate to, so its all legit.

The tongue goes into the socket approx 200mm, so can spreads the load a bit, but once its all secured in and tied down it doesn't move. But id definitely think twice before going off road with it, it kills your departure angle.

Only other downside to putting one on a 4wd is actually getting the bike up there, there is a ramp to put it on, and itd be possible with one person, but far easier with 2.
Ive got one of these
Motor bike carrier : Wingham Welding Works, Motorbike Stands Built Aussie Tough! (http://winghamweldingworks.com.au/index.php'main_page=product_info&cPath=26&products_id=105)