Reducing Crosswind Wobbles. Any Ideas?

[Bellini]

Good morning all!

After owning Udo, my 1992 RMB 670 Silver Star, for 18 months now, I've come to the conclusion that he doesn't like crosswinds on motorways very much.

This first came to my attention in February 2014 after driving back home from Dave Newells place in heavy winds. Udo would squirm about scarily in gusts and rock about a bit.

After that scary drive home, I uprated the rear suspension leaves and had Conrad Anderson fit airbags to the rear. Tyres are brand new Firestones with the correct pressures.

Driving home yesterday from a thoroughly enjoyable stay in the New Forest, I was again confronted with gusty crosswinds and those constant 'oh sh*t!' moments that my son kept referring to.

Udo is a little more stable since the rear suspension has been sorted. Slightly more stable since increasing the pressure slightly in the rear left, but still rather sensitive to things in my opinion.

Under gusts, he'll require steering corrections to keep him on-track and he rocks a little. He can be blown off course relatively easily and generally leaves me feeling rather nervous during these gusts.

His water and waste tanks were empty, by the way, on all occasions.

I slow down to around 45-50mph and just concentrate. But I don't enjoy it one bit.

So... is there anything that can be done to improve things? I know motorhomes are large, slab-sided bricks that are more prone to windy gusts than a car, but I see far larger vehicles seemingly at-ease on the road and I do wonder.

Would fitting stiffer dampers be worthwhile?

Would stiffening up the wallowy (but in very good order) front suspension be a good idea?

Any views / opinons / suggestions gratefully accepted.

 

[Judge Mental]

Air bags usually do the trick, maybe problem is the front. Thing being, its a 92 vintage camper, maybe some wear? Addressing front suspension issues more tricky but german company goldsmitth? ( spellin alert ) do front upgrades for most vans, and are a common upgrade fitting these days on A class vans

 

[Snowbird]

I never had that problem with my 410 based RMB but it was always well heavy. I did have the rear suspension uprated, but with a garage full of must have stuff and an extra fuel tank it would have taken something like a hurricane to move that bus. Get it on a weighbridge, as maybe you are running to light.

 

[Jaws]

beat me to it Judgemental !

While changing the dampers for something more suitable and commiserate with the weight of a motorhome will help, ultimately fitting air bags will completely change the way the van behaves in high winds

In theory it should not work and the better option would be to do as you suggest, change those saggy shocks.. But in practice ( and from personal experience ) I would urge you to go down the air bag route !

 

[Sidney]

Travel with the fresh water tanks full. If its blowing a gale you could fill the waste tank too. That's a lot of weight at the bottom of the van which lowers the centre of gravity.

Option B - park up and wait for the weather to improve

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[Sidney]

I hated my old van (Kontiki 600) in the wind. Filling the tanks made it easier but it meant running heavy.

 

[Judge Mental]

Found it: but can't post link from phone

Edit: link works...

www.goldschmitt.de

 

[Bellini]

I asked CA to sort front air bags for Udo last year and their research concluded with their findings that MB don't recommend front air suspension on a 410. Maybe MB didn't mean front air-assist. Regardess, CA couldn't find front 'bags at all anywhere.

I've also looked for a front aftermarket assist system before now and can't find a thing anywhere. Rear air-assist for a 410 was difficult enough, but perseverence paid off as I knew they used to be available. Nothing at all for the front.

Dave, thanks for your reassurance that your old one was stable.

Udo runs with a garage full of 'stuff', including 3 bottle jacks, cleaning stuff, a full case of wine, lemonade and Pimms (Udo's bar is full of single malt...), chairs, table, Cadac and accessories, mascerator pump for his black tank, picnic hamper and a few other 'non-essentials' that one may need. He's stocked with toiletries and non-perishable food inside. I don't think he ever runs light.

From your very helpful replies, it seems like better dampers may be the (partial) ticket. I know he had new front units before I bought him, but maybe he needs better ones?

I'll look into front 'bags again, though. That's my preference.

Sidney: had both those thoughts.

Judgemental, thanks! Their website only goes into the Sprinter and not as far back as the 410, but I'll make contact with them to be sure.

 

[Forestboy]

We had a 36ft Rv with exactly the same problem it was terrifying to drive in any sort of crosswind. Fitted some cheap aftermarket airbags (sorry no idea what make) Hey Presto it was a completely different van noticed the difference within a mile.

 

[DanielFord]

I recently drove home from Newcastle in the high winds we had. I filled both of the tanks with water, as many have said on here, I reckon that gives around 200kg of low down weight. You want the centre of gravity as low as possible in a cross wind.
Despite several HGV's tipping over in front of me, and several "brown trouser" moments, I got the van safely home.

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[DavidG58]

I have just invested a small fortune to try to eliminate similar on our Sprinter based Hymer, we suffered from three effects

1. On rough ground massive sideways rocking, quite violent at very low speeds
2. Rolling at roundabouts
3. Side winds / overtaking issues

I have had removed a basic manual air bag system, now replaced with full rear VS air suspension

Results so far

1. 70% better
2. 70% better
3. 100% better

£4800 poorer !!

We have also now got a rear ride height change option to hopefully stop grounding on small ferries

I need to do a few more journeys before commenting fully, but will be looking at this thread and others for front suspension advice next

 

[DavidG58]

regarding water tanks, we always travel with fresh tank full and usually bring grey and black home as we have our own manhole on drive, but word of caution, our fresh tank base sits on the floor level so maybe not as low level as you might think, in our A class it puts it above wheel height about 3' off the road, black and grey are below floor level

 

[Jaws]

believe me, just fit air bags on the rear.. unless there is something odd going on that will be all you need.
AS supplied my kit.. less than an hour to fit ( actually did it in the street with snow on the ground ! )

 

[Bellini]

Interesting comments about the tanks.

In Udo, the fresh water tank sits in the garage area just behind and a good 300mm above the rear wheels. It is approximately one metre tall by 400mm deep and one metre wide. So, when full, it would hinder stability in my view.

The waste tanks are below floor level amidships. Well, I've not actually looked exactly where there are, but both exit between the left front and rear wheels, so maybe they're on one side? The 125 litre fuel tank sits opposite on the right.

However, I always travel with the waste tanks empty.

DavidG58, that's exactly what Udo does. It's MUCH better since fitting rear air helpers and uprated leaf springs, though, but still a bit too 'rock n' roll' for my liking in gusty weather. Your rocking at low speeds rings very true.

This all leans towards uprating the front suspension. By far the biggest improvement was fitting air bags to the rear, so I'm going to head in that direction. Found the following company who could possibly help...

Broken Link Removed

And I also think uprated dampers, if I can find them.

 

[Larrynwin]

I sort of lean to one side and lift one cheek when the wife is not looking

I had rear air bags fitted early on, helped prevent body roll and reduced movement in cross wind.
The ford chassis is also fitted with a steering damper thingy on the track rod.

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[TheDogMan]

I have an Iveco 3.5m high and I had a distinct improvement when I had AS air fitted on the rear but still in strong gusts I have to be careful, I do fill the 200 litre fresh tank right up if its windy and that does make a difference

 

[jemhorn]

Not sure if this is relevant but sometimes the HGV Tracks along the inside lane are inclined to throw you about. If this is combined with side winds it could be a bit scary.

 

[Sidney]

Interesting comments about the tanks.

In Udo, the fresh water tank sits in the garage area just behind and a good 300mm above the rear wheels. It is approximately one metre tall by 400mm deep and one metre wide. So, when full, it would hinder stability in my view.

The waste tanks are below floor level amidships. Well, I've not actually looked exactly where there are, but both exit between the left front and rear wheels, so maybe they're on one side? The 125 litre fuel tank sits opposite on the right.

However, I always travel with the waste tanks empty.

Something doesn't have to be below the centre of the wheel to add stability. Its about lowering the centre of the mass http://www.schoolphysics.co.uk/age11-14/Mechanics/Statics/text/Stability_/index.html

Equally you could make the axle track wider by modifying the chassis, changing the axle or choosing different wheels with a larger offset or by using spacers. This of course will increase the stress on the axles, bearings etc so you'll be best to consult an expert to see if this is practical.

I must say I often see older MHs on the road that have a really narrow axle track and wonder how they drive in the wind

You do have my sympathy I used to get so stressed in my old van. It wasn't fun and I know exactly what the funsters mean when they talk about brown trouser moments.

£4.8k is a lot of money and it makes you wonder why the manufacturer was happy offering a MH with the standard set-up. But if the MH is perfect for you it is a worthwhile investment.

Simple air bags may help but you may have to bite the bullet and consider changing the MH. It's just about working out what suits your wallet.

 

[mariner]

Had 2 Hymer Starline "Rock and Rollers" did thousands of miles in them and neither ever fell over.
So they roll a bit, my advice is, stop worrying and get used to it.

 

[Sidney]

Had 2 Hymer Starline "Rock and Rollers" did thousands of miles in them and neither ever fell over.
So they roll a bit, my advice is, stop worrying and get used to it.

I don't think this will get you nominated for the Humanitarian Citizen Award

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[Sundowners]

we have had similar issues in the past and fitted gas shocks (dampers) with a great deal of success-------can you get them for your chassis???

All the other things help though----more weight low down/higher rated tyres/higher tyre pressures/stronger springs etc.-------but for the price, we have found gas shocks to be REALLY good (if you can find them for your's)
Nigel & Pamala

 

[Snowbird]

As Bellini knows I used to own the exact same van and after uprating the rear springs I had hardly any roll in winds. I must admit, it did used to roll around a bit on rough ground if I was travelling any faster than walking speed but they are a high van compared with others, I learned to take my time. I always ran heavy, with long range fuel tanks, LPG tank full plus 2 X 13 KG gas bottles in the gas locker, with another 13 kg gas bottle in the garage for the outside oven and BBQ. The RMB has a massive fresh water tank in the garage and if thats full it stops any roll. They are built on the 4.6 ton Merc chassis and do run better the more you load them.

 

[funflair]

As Bellini knows I used to own the exact same van and after uprating the rear springs I had hardly any roll in winds. I must admit, it did used to roll around a bit on rough ground if I was travelling any faster than walking speed but they are a high van compared with others, I learned to take my time. I always ran heavy, with long range fuel tanks, LPG tank full plus 2 X 13 KG gas bottles in the gas locker, with another 13 kg gas bottle in the garage for the outside oven and BBQ. The RMB has a massive fresh water tank in the garage and if thats full it stops any roll. They are built on the 4.6 ton Merc chassis and do run better the more you load them.

@Snowbird

What all up weight was your van 4.6 ton chassis doesn't sound much.

 

[Snowbird]

@Snowbird

What all up weight was your van 4.6 ton chassis doesn't sound much.

The first RMB was a 4.6 ton chassis. The second was a 7.5 ton chassis.

 

[JJ]

This offer is ONLY because you are a Funster.

I will come around and take this troublesome RMB off your hands for you.

There will be be no charge at all.

This generous off of help will enable you to switch to a different motorhome which behaves better.

JJ

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[Minxy]

I wonder if you are running TOO heavy at the rear? This could then be making the front too light and in itself could cause some issues in windy weather as the front may be able to be moved sideways more than the rear ... just a thought.

 

[GWAYGWAY]

Find somewhere to stop, face into wind, and put down jacks wait for spring.