# What causes weaving?



## ThePrisoner

Have just travelled to Cornwall whilst towing our car. On the way there we noticed our van was weaving/wobbling whilst driving along. We were going about 60 mph, so not speeding. We pulled over at the services to check all was ok, and it was. Continued with the rest of the journey without incident.

Whilst travelling back today the same thing happened a couple of times. The weaving this time was quite scary so we slowed right down until the van stabilised. 

This has happened even when we have not been towing and always on motorways. Any ideas? 

Could it be the road surface?


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## alexblack13

Yes that is possible. Many main roads are badly rutted by the hgv's constant use.

It might be an idea to check the nose weight of the loaded trailer (if using one). 

If the car is on an A frame, then I suspect it probably is the road surface if your checks have revealed everything is correctly fitted etc.

AB13CHB


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## jwinder

you say that this has happened when not towing if you are overweight on your rear axle this could lead to a light steering feel like you describe
just a thought hope you get it sorted soon
frank


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## hampsterracing

My van does this if the tyres are over inflated.

if they are at the 78psi listed on the door pillar it is terrible to drive and becomes almost uncontrollable if you hit "tramlines" on a worn bit of road.

at 52psi front and 60psi rear it is all fine 

Roger


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## Mrplodd

If this was on a motorway then almost certainly due to rutting (no not THAT sort :roll: ) of lane one. 

The wheel track of an HGV is slightly wider than that of a motorhome. What happens is that the wheels on one side of your MH drop into one of the ruts. The wheels on the other side are then sat on the "rim" or edge of the other rut, those wheels will then drop into their rut, this moves your MH slightly sideways pulling the other side up onto the rim of "it's" rut. It's not something you can really control so if you Repeat this action you get weaving!

The only way to counteract it is to ensure you drive in a position so that neither wheels is near a rut, in other words you need to "straddle" one of the ruts with your two wheels.

If it happens again try moving into another lane, if you no longer get weaving you have your answer.

It is a common issue on many motorways. That's why HGV's pay so much road tax, they are the ones who bu**er the roads! not cars. An HGV can legally transfer 8 tonnes to the road surface via each axle!!


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## philoaks

Not sure if it applies with your Hymer but we've noticed that the problem is far worse since having a MH based on the Fiat Motorhome chassis where the track width of the front wheels is narrower than that of the rear.

As Mr P says the wheels move around within the rut but because of the differing widths it seems to amplify the problem.


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## Mrplodd

The other possible reasons could be side winds (unlikely as we have had good weather lately) or, if using a trailer, the trailer nose weight was much to high, this would result in the front axle weight being greatly reduced


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## padraigpost

Agree with Mrplodd, wheel ruts in nearside lane are almost certainly the problem caused as he says by constant HGV traffic in that lane, has the effect that you have been caught in "hidden tramlines"
Don


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## rugbyken

Whilst I agree with everyone about the rutting in the road I spent a couple of years thinking that was my problem , checked tyres constantly good tread equal pressure etc, then one day I was rotating front to back etc and got a shock to see the tyre that had been on the rear was round like a motorbike tyre and standing almost 2" taller than the one on the front tread was perfect but nylon interior had broken down , a third of the wheel at the top was covered by the valance and not viewable in situ after buying a new tyre and it was like driving a new van. 
It had almost reached the stage of giving up the van as I couldn't handle crosswinds without slowing right down and thought it was my driving at fault.
If your convinced in your own mind that it's a little more than normal!! 
Deviation check the individual tyres carefully,


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## ThePrisoner

Thanks for that everyone. It helps to know that it has not just happened to me.

I think the worst thing about it was whilst driving in the dark down the M6 through the road works with lorries not obeying the fifty mile per hour limit and scaring the holy shut out of me.

Thanks rugbyken, I will get my tyres checked too just to be on the safe side.


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## melfay

you may want to check your track rods and ball joints as this can give the same effect


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## ThePrisoner

The van is only a year old. Would this be a problem on such a new van?


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## melfay

would depend on what sort of ground you have been driving over and the mileage you have covered or even a good pot hole can give damage


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## wug

You were towing a car, so it sounds like what caravanners call snaking. You could try googling for info from the caravan clubs etc. Here's some info: Towing


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## Wizzo

I would be quite concerned with what you have described, particularly as you say it happens whether towing or not. My initial thought was that it could be the trailer being incorrectly loaded that caused it, you need to check that the nose weight is to recommended limits otherwise you could be in for a serious accident. Anyone who has experienced the effect of the 'tail wagging the dog' when towing knows that it is seriously scary.

I would also want to make sure that the axle weights are within limits and contact the tyre manufacturers for the correct inflation pressures.

If those actions do not cure it and you are able to rule out the road surface then it only leaves a mechanical fault as far as I can see.

JohnW


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## DABurleigh

I would visually inspect ALL the tread, sidewalls and tyre pressures, check axle loadings on a weighbridge, and then only worry about it if it happens OTHER than on lane 1 of a motorway.

Dave


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## Pudsey_Bear

I run at 65psi front and 70psi rear, this seems to give good MPG, and it's not crashing over potholes, but we are normally up to 3.5t in holiday trim.


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## Wizzo

> I run at 65psi front and 70psi rear, this seems to give good MPG, and it's not crashing over potholes, but we are normally up to 3.5t in holiday trim.


But, with respect, this does not relate to the OP's van or tyre size. There is only one sure way and that's to ask the manufacturer, giving them axle weights.

JohnW


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## Pudsey_Bear

Yes, I agree john, but I've been driving vans of this size for almost 30 years, always had good tyre wear, and MPG, so I must be doing something right, you get an eye for the way your tyres look and feel.

You ride a bike where tyre pressure make a huge difference, when did you last ring the tyre manufacturer, you put the recommended pressure in then adjust it for personal preference, how it feels and handles, which is how I arrived at the figures for my van and how I drive.


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## Sprinta

another thing to consider when towing - 60 is a limit and not a target


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## Glandwr

DABurleigh said:


> I would visually inspect ALL the tread, sidewalls and tyre pressures, check axle loadings on a weighbridge, and then only worry about it if it happens OTHER than on lane 1 of a motorway.
> 
> Dave


Nice van Dave. When did you get that?

Dick


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## nipperdin

*What causes weaving*

I find that our van can get a little unstable if the water tank is about half full.
It sloshes (is that a word?) around.
Best to drive with only a low level of water in the tank- and the grey water tank empty.
A full tank is okay but you then have to watch your weight limits.
Our van does have a long rear overhang

I have heard tales of vans being stopped at road checks, found to be overweight, and told to drive around the block and come back with an empty tank.
Not sure if that is apocryphal.


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## ThePrisoner

Thank you all once again. Definitely some food for thought here.

Dave......I have noticed it does not happen outside of the first lane, so am now beginning to think it could be the rutting problem. But, I will get things checked out just to be on the safe side.

And Wizzo......I have assurances that the a frame and car are within acceptable levels for my van. But I will also get this checked and confirmed.


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## ThePrisoner

*Re: What causes weaving*



nipperdin said:


> I find that our van can get a little unstable if the water tank is about half full.
> It sloshes (is that a word?) around.
> Best to drive with only a low level of water in the tank- and the grey water tank empty.
> A full tank is okay but you then have to watch your weight limits.
> Our van does have a long rear overhang
> 
> I have heard tales of vans being stopped at road checks, found to be overweight, and told to drive around the block and come back with an empty tank.
> Not sure if that is apocryphal.


Thanks for that. We do try not to drive around with tanks full as they are at the back of the van so don't like to put extra pressure on whilst travelling.


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## DABurleigh

Day trip to Germany last Monday, Dick, and did the deed. There is a facelifted one on display at Dusseldorf in 4 weeks, so there are good dealer deals with the £ also much better against the euro.

Dave


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