Draw Bar Flexing

Submitted: Thursday, Nov 19, 2009 at 02:36

ThreadID: 126214 Views:4358 Replies:7 FollowUps:1

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Eric & Gail

Hi All

I have a mate who recently took delivery of a new Franklin 19ft 6inch Van, he is on the road with no computer so I am trying to help out, he is having problems with ride comfort in his 1991, 80 series Landcruiser station Wagon, whilst towing on any road surface other than dead smooth, fitted with WDH, new rear shocks and Poly air bags. The Van seems to be hobby horsing which transmits to the tow vehicle and creates an uncormfortable ride, being a retired motor mechanic he has investigated and found that the draw bar is flexing, he rested front of draw bar on a jack stand and stood on draw bar and bounced his weight up and down and found there was considerable movement, the draw bar is 150mm x 50mm and 3mm wall thickness, but reduces down to 100mm x 50mm approx 800cm from front of van for the rest of the length of van. Do you think uncomfortable ride in the vehicle is caused by the flexing? if so what is the suggested fix? I have 150 x 50mm on my BT but it does extend the full lenght of van and I don't have those problems
Regards
Eric

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Reply By: Silver and Tinks - Thursday, Nov 19, 2009 at 06:15

Thursday, Nov 19, 2009 at 06:15

Hi Eric

You do not say if he has chine bars under the draw bar the same as your BT
If he does not they will probably fix the flex.

Scott

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AnswerID: 579384

Reply By: Andy1 - Thursday, Nov 19, 2009 at 16:53

Thursday, Nov 19, 2009 at 16:53

First thing is to check the ball weight. Some adjustment in the van loading may ameliorate the problem.

Andy

AnswerID: 579385

Follow Up By:- Thursday, Nov 19, 2009 at 18:22

Thursday, Nov 19, 2009 at 18:22

+1
Not enough ball weight will have that effect and if so needs to be rectified pronto.....safety issue here.

FollowupID: 852045

Reply By: Eric & Gail - Thursday, Nov 19, 2009 at 23:41

Thursday, Nov 19, 2009 at 23:41

Thanks All
He is welding some chine bars on as we speak, hopefully solves problem, ball weight I think will be ok as he has put an alluminium box on A frame for Generator etc, he has yet to put rig across a weigh bridge but that is on the agenda as soon as he can find one, guess that will throw some more light on the issue.
Regards
Eric

AnswerID: 579386

Reply By: SMICK - Friday, Nov 20, 2009 at 03:14

Friday, Nov 20, 2009 at 03:14

Watch out for electrical wiring running through the A frame!!!!!!

AROUND AUSTRALIA AT 80 KAYS.
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Michael Mnew
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AnswerID: 579387

Reply By: Deleted User - Saturday, Nov 21, 2009 at 18:54

Saturday, Nov 21, 2009 at 18:54

Hi Eric

1. Over the years we have owned several trailer sailers (7.8 to 8.3 metres) with trailable weights of between 2000 & 2500 kg & the trailers have had some flex in the drawbars. These boats were towed by a Ford Falcon, LC 80 & LC 100. With around 200kg towball weight I have never experienced any towing problems despite a larger overhang than our BT19 plus the weight aft of an outboard & fuel on the transom.

2. Other than lack of appropriate towball weight, perhaps he should check how the van is loaded as too much weight aft may adversely affect towing comfort & safety. Some vans also appear to be built with too much overhang & sway bars may also need to be fitted to assist the WDH system.

3. Most important ! ! !
Suggest he also check what weight his vehicle can legally tow . I once owned a 1991 80 series which was only rated to tow 2500 kg after being certified by letter from Toyota Australia to do so. Check the towbar compliance plate for details.

Happy & safe travels
Regards
Greg

AnswerID: 579388

Reply By: Eric & Gail - Sunday, Nov 22, 2009 at 04:34

Sunday, Nov 22, 2009 at 04:34

Chine bars have solved the problem by about 75% weigh bridge next to see what ball weight and total loaded weight of van is. Rob has had the towing capacity of his 1991 cruiser increased to 3500kg by fitting the larger brakes that came on the late 1992 model and had approved by an Automotive engineer who supplied a new compliance plate.
thanks again for all your posts
Regards
Eric

AnswerID: 579389