A few 2nd-hand caravans currently for sale have an extended draw bar.
Apparently this makes it easier to reverse park, but I wonder if it makes it somewhat less stable to tow. I have read articles that say the further the weight is from the centre of mass, the more prone it is to swaying.
What are the arguments for and against having an extended draw bar?
Thanks.
Woody n Sue said
08:36 PM Sep 8, 2016
Hi Rex I am not that familiar with extended draw bars as I have a 5th wheeler and not sure about your Center of mass comment but I will offer this .
The longer the pull ( with in reason ) from the axel the better a it will be to tow and yes defiantly easier to back, (I have had both long and short semi trailers ) although i can not point you to scientific evidence of this only my experiance in life as a farmer and truck driver.
As for stability I can't see the length of the pull having to much influence on that the height of the weight above the chassis, will however have a profound effect on stability, always keep your weight as low as possible
Woody
macka17 said
08:55 PM Sep 8, 2016
Hey.
It ALL depends on length of original drawbar. Some. are built very short No room for gas bottle s etc and very reactive when reversing.
Some are what you'd call std length. Well balanced plenty of roof for bottles etc. and pretty easy to reverse.
It basically depends on owners individual mind set on which is what. We all different.
Me. on a 5 to 6ish mtrvan. a 5ish ft is about right. 5 ft 6in ok too but not much longer. it weakens it, unless built up in strength. which has a good chance of increasing drawbar weight. which can start affecting towing weights and balance. and putting inside wheels over curb on corners. till you have a bit of practice.
Like driving a short wheelbase truck in morn and going out in long wheelbase after lunch. The first corner or so you often climb the curb.
Swings and roundabouts. you have to see each one.
Just remember. the decent van and trailer MFG's HAVE put a lot of design and trial into getting THEIRS right. Be careful.
Onlly time I've used/built, extended bars, in on my beach fishing boat trlr's.
Either internal pull out. or swing round and lockpin.
for launching on sand. With rope to car kept on hard.
-- Edited by macka17 on Thursday 8th of September 2016 08:59:19 PM
Dhutime said
09:46 PM Sep 8, 2016
Hello Rex, we have an extended draw bar on our Kedron caravan . Very happy with it , we have a plastic tub sitting on the mesh bottom ,housing light bits and pieces , also room for firewood and the outboard motor . Have never had an issue with swaying we don't even use weight distribution bars . Backing the van is very easy with the extra length . I am concious of the possible extra weight on the tow hitch so keep it within the legal limit .
If i had the option again I would go for it
Dhutime
Weedpharma said
09:44 AM Sep 9, 2016
We have a new 19'6" Starcraft with 300mm extension. Dragged it across from Perth to Canberra without any problems.
I don't feel any difference in the backing and never had a problem any way. But my problem was that with a landcruiser and its rear mounted tyer and water can supports, I needed a bit more turning room.
All fixes with the mod and no probs any longer.
Sarge9 said
04:25 PM Sep 9, 2016
easy comparison to make and judge yourself.... 6 x 4 trailer... tray backing that quickly or just try backing one.... then get anything that is longer between the tow ball and the axle and try backing that....
What Woody said is right.... within reason the longer draw bar will always tow and back easier.
(weight and ground clearance eventually become an issue and over 32 metres you probably need a semi licence....)
Aus-Kiwi said
04:56 PM Sep 9, 2016
If strength hasn't been changed it'll be better towing and more stable given correct weight loading ., it's a little like a wheelbarrow with long hands compared to cheap one with short handles ., you have more leverage .. Less tow ball weight .,
erad said
05:16 PM Sep 9, 2016
We have a 16.5 ft Jayco poptop van. When I ordered it, I told them that we were tight on space in our shed and could they give us a van with a shorter chassis - say 6" shorter. Sorry - we cannot do that, but we can give you 200 mm shorter. OK - that will do.... We got it and the gas bottle was mounted on the drawbar. I hooked up my Range Rover to take the van home, did a U turn in the yard and Clang! - the Rangie's bumper hit the gas bottle. Got it home and made up a saddle and the gas bottle now sits in the centre of the drawbar - no problems.
The biggest problem with the shorter drawbar is that Jayco did not allow for this in the manufacture of the van. We have an airconditioner and the condenser unit is mounted in the front corner of the van. There is a front kitchen. The thing is awfully heavy on the towball already and Jayco didn't change their standard design to compensate for all these changes. It is so heavy that I cannot even start to lift the towball by myself.
Having such a short towbar does have 2 advantages.
1 It is heavy and the van is very stable when towing. I recently towed an empty 7 ft builder's trailer and it wagged my Pajero around at times. The van has never done this.
2 By accident, the short towbar seems to have affected the aerodynamics of the whole rig. When I am driving and it starts to rain, the rear window of my Pajero stays totally dry until I stop. There is no road spray comes up from the wet road and even in very heavy rain the rear window does not get wet. This indicates to me that the air behind the car is virtually static. I have tried to analyse this, and have concluded that the air pushed out by the Pajero doesn't get a chance to wrap back behind the car and the van then pushes the air even further out. The roof of the van is only about 100 mm higer than the Pajero roof, so again there is little disturbance to airflow. End result is that the effective frontal area of the rig is that of the caravan only. With a regular rig you have the car pushing air and then the van tends to push the air as well.This had led to very good economy when towing. Flat country, no winds, towing at 93 to 95 km/h (true speed as per GPS, not the car's speedo) I get 12.2 L/100 km. My car is a diesel, but this is excellent economy. On my last trip I averaged 12.8 L/100 km, but I pushed it a little faster and we had some fierce headwinds at times.
Overall, I doubt there is enough justification to go out and shorten your drawbar, but it has worked for me.
Izabarack said
06:02 PM Sep 9, 2016
It is generally accepted that the distance between the hitch to the first spring hanger is a major determinant of stability. The problem I see with extended drawbars is that the space encourages people to put lots of things there.
Iza
Dhutime said
07:29 PM Sep 9, 2016
Rex,
I would like to think that if the van comes out of the factory it should be ok
dogbox said
07:45 PM Sep 9, 2016
Sarge9 wrote:
easy comparison to make and judge yourself.... 6 x 4 trailer... tray backing that quickly or just try backing one.... then get anything that is longer between the tow ball and the axle and try backing that....
What Woody said is right.... within reason the longer draw bar will always tow and back easier.
(weight and ground clearance eventually become an issue and over 32 metres you probably need a semi licence....)
if its over 32meters you'll need more than a semi licence
rexboggs5 said
10:55 AM Sep 10, 2016
Thanks for the wise words, everyone.
colinoldncranky said
07:18 PM Sep 10, 2016
(Ignoring the legalities)
Actually, the longer the distance from the hitch to the wheels the less likely it is to steer your car, certerus parabus ("all things beign equal"). This is because it reduces the torque that the caravan chassis may try and apply to the vehicles tongue under circumstances that can give rise to said steering by the caravan.
However in adding the draw bar all things are NOT equal. Some weight will be tranferred from the axle/s to the tongue on your car which is NOT such a good thing if it reduces the cars ability to resist that torque. So you may need to address by packing ore to the rear of the van. Or maybe add a spare tyre and a tool box on the back of your van, all to reduce that downforce on the tongue.
It's basically just physics.
I still woudn't do it though. It may make it less responsive to careless moves but it will also reduce your ability to get around in tight places. Whereas reversing "easier" is just making it less responsive to a given turn of the wheel but, for the safety of all of us, I would like to think that anyone towing an extra two or three tons has the basic skills to back all trailers of wildly varied geometry.
-- Edited by colinoldncranky on Saturday 10th of September 2016 10:59:28 PM
A few 2nd-hand caravans currently for sale have an extended draw bar.
Apparently this makes it easier to reverse park, but I wonder if it makes it somewhat less stable to tow. I have read articles that say the further the weight is from the centre of mass, the more prone it is to swaying.
What are the arguments for and against having an extended draw bar?
Thanks.
The longer the pull ( with in reason ) from the axel the better a it will be to tow and yes defiantly easier to back, (I have had both long and short semi trailers ) although i can not point you to scientific evidence of this only my experiance in life as a farmer and truck driver.
As for stability I can't see the length of the pull having to much influence on that the height of the weight above the chassis, will however have a profound effect on stability, always keep your weight as low as possible
Woody
Hey.
It ALL depends on length of original drawbar.
Some. are built very short
No room for gas bottle s etc and very reactive when reversing.
Some are what you'd call std length.
Well balanced plenty of roof for bottles etc. and pretty easy to reverse.
It basically depends on owners individual mind set on which is what.
We all different.
Me. on a 5 to 6ish mtrvan.
a 5ish ft is about right. 5 ft 6in ok too but not much longer.
it weakens it, unless built up in strength.
which has a good chance of increasing drawbar weight.
which can start affecting towing weights and balance.
and putting inside wheels over curb on corners.
till you have a bit of practice.
Like driving a short wheelbase truck in morn and going out in long wheelbase after lunch.
The first corner or so you often climb the curb.
Swings and roundabouts.
you have to see each one.
Just remember. the decent van and trailer MFG's
HAVE put a lot of design and trial into getting THEIRS right.
Be careful.
Onlly time I've used/built, extended bars, in on my beach fishing boat trlr's.
Either internal pull out. or swing round and lockpin.
for launching on sand. With rope to car kept on hard.
-- Edited by macka17 on Thursday 8th of September 2016 08:59:19 PM
If i had the option again I would go for it
Dhutime
Weedpharma
Hi rexboggs5. I extended mine 300mm.
I don't feel any difference in the backing and never had a problem any way. But my problem was that with a landcruiser and its rear mounted tyer and water can supports, I needed a bit more turning room.
All fixes with the mod and no probs any longer.
What Woody said is right.... within reason the longer draw bar will always tow and back easier.
(weight and ground clearance eventually become an issue and over 32 metres you probably need a semi licence....)
The biggest problem with the shorter drawbar is that Jayco did not allow for this in the manufacture of the van. We have an airconditioner and the condenser unit is mounted in the front corner of the van. There is a front kitchen. The thing is awfully heavy on the towball already and Jayco didn't change their standard design to compensate for all these changes. It is so heavy that I cannot even start to lift the towball by myself.
Having such a short towbar does have 2 advantages.
1 It is heavy and the van is very stable when towing. I recently towed an empty 7 ft builder's trailer and it wagged my Pajero around at times. The van has never done this.
2 By accident, the short towbar seems to have affected the aerodynamics of the whole rig. When I am driving and it starts to rain, the rear window of my Pajero stays totally dry until I stop. There is no road spray comes up from the wet road and even in very heavy rain the rear window does not get wet. This indicates to me that the air behind the car is virtually static. I have tried to analyse this, and have concluded that the air pushed out by the Pajero doesn't get a chance to wrap back behind the car and the van then pushes the air even further out. The roof of the van is only about 100 mm higer than the Pajero roof, so again there is little disturbance to airflow. End result is that the effective frontal area of the rig is that of the caravan only. With a regular rig you have the car pushing air and then the van tends to push the air as well.This had led to very good economy when towing. Flat country, no winds, towing at 93 to 95 km/h (true speed as per GPS, not the car's speedo) I get 12.2 L/100 km. My car is a diesel, but this is excellent economy. On my last trip I averaged 12.8 L/100 km, but I pushed it a little faster and we had some fierce headwinds at times.
Overall, I doubt there is enough justification to go out and shorten your drawbar, but it has worked for me.
Iza
I would like to think that if the van comes out of the factory it should be ok
if its over 32meters you'll need more than a semi licence
(Ignoring the legalities)
Actually, the longer the distance from the hitch to the wheels the less likely it is to steer your car, certerus parabus ("all things beign equal"). This is because it reduces the torque that the caravan chassis may try and apply to the vehicles tongue under circumstances that can give rise to said steering by the caravan.
However in adding the draw bar all things are NOT equal. Some weight will be tranferred from the axle/s to the tongue on your car which is NOT such a good thing if it reduces the cars ability to resist that torque. So you may need to address by packing ore to the rear of the van. Or maybe add a spare tyre and a tool box on the back of your van, all to reduce that downforce on the tongue.
It's basically just physics.
I still woudn't do it though. It may make it less responsive to careless moves but it will also reduce your ability to get around in tight places. Whereas reversing "easier" is just making it less responsive to a given turn of the wheel but, for the safety of all of us, I would like to think that anyone towing an extra two or three tons has the basic skills to back all trailers of wildly varied geometry.
-- Edited by colinoldncranky on Saturday 10th of September 2016 10:59:28 PM