How to make a Van Handle (reasonably) well

[Fatboy]

Hi Everyone,

Browsing of Youtube the other night turned up a few videos of the A-Team Van - particularly the 5th Gear A-Team vs VW Van, and I was most amused by the comedy suspension bouncing, but also dead certain that I need an A-Team Van, but preferably one the doesn't handle like a pig on a pogo stick.

Now I know that simply stiffening up the suspension would help, (as would non-knackered dampers ), but I was wondering what could be done to improve the handling while retaining the ability to carry a fair amount of stuff, without turning it into a 'shake out your fillings' ride?

I was wondering about airbag suspension (as used on P38 Rangies and a lot of 10 ton and upwards wagons), as well as just remote adjustable dampers and re-work the suspension to take different springs, but does anyone else have any good ideas?

All suggestions, no matter how ridiculous, are welcome

Fabricating new suspension mounts/systems and radical alterations to the chassis are perfectly OK, as long as it still looks like the A-Team Van, and can still carry a fair amount of stuff.

[Stu R]

Coilover suspension, lower it, get the geometry done and cornerweight it, some nice sticky tyres, anti roll bars, polybushes.
Roll cage inside, perhaps some underbody bracing.


Then watch it tip onto it's side as soon as you overcook a corner

[Fatboy]

Stu R said:

Coilover suspension, lower it, get the geometry done and cornerweight it, some nice sticky tyres, anti roll bars, polybushes.
Roll cage inside, perhaps some underbody bracing.


Then watch it tip onto it's side as soon as you overcook a corner

So relatively straightforward then?

I was thinking some form of adjustable rear to allow for different loads, and I was also thinking falling over would be quite likely - so lowering it is probably a good idea

Cheers

[HiRich]

The big problem with van suspension is the huge variation in rear axle load (and that it's not matched at the front). For even reasonable ride, you need the rear primary ride frequency to remain about 10% higher than that at the front. That frequency is a function of spring stiffness/sprung mass. With single rate springs, that means a really stiff spring when lightly laden.

So air springs potentially offer a really interesting way to match stiffness to load, but without having a huge ride height difference between laden & unladen. LDV tried this on the rear some years back - whilst badly implemented, the principle is very strong.
Another option would be to choose a van with a lower plated weight - if you only need 2.3t GVW, don't use a suspension and spring designed for 2.8t.
On the front, I would look for independent suspension (on which you could fit a rising rate spring), or indeed airsprings there as well.
A lot more effort could go into tuning bump stops to act as spring assisters more than damage preventers. More conical shapes to smooth their introduction - the slap of the standard boxy units upsets the transition.

If you choose an RWD van, unsprung mass is very unhelpful. I would look towards a chassis-mounted diff (Jaguar?), driveshafts and independent suspension (wishbones or trailing arm). If you decided not to go down the airspring route, I would consider a transverse leaf for its roll stiffness properties (which I'll come back to).

If you stick with a solid beam axle (live or dead) I would locate it better in all axes - be it Watts linkage or trailing reaction arms.

I would definitely look at stiffening the chassis. Strength versus weight will have dominated the design process over stiffness. So we're looking at the equivalent of strut braces. If it has a ladder frame, I'd look a attaching a sheet to the bottom of this to box section it. But be aware that stiffening may increase the loads at some critical spots - top & bottom of the A-post, and side door aperture corners.

If you get serious and start playing with geometry, you would want to look at ride height (something air suspension would help with enormously), roll centres & roll stiffness. This is more difficult than cars, as you need to allow for wider variation of the CoG height with different loads and load types (think gold bullion vs. a wardrobe). I'd look to significantly increase inherent roll stiffness, using the (rising rate) springs & bump stops, and minimising the requirement for anti-roll bars (with such big loads, the weight and stiffness necessary on the standard layout is enough to impact noticeably on ride and the reaction to bumps & dips).

In general terms, I would be looking as much at building suppleness into the suspension. Vans already run very stiff springs. As such performance problems - braking and accelerating as much as cornering - are often more as a result of the wheel failing to maintain decent contact/load against the ground than they are to do with body roll and camber & toe changes. Look to put stiffness into the chassis and take it out of the suspension.

[Fatboy]

That's brilliant - thanks very much

Glad to see I'm not the only person thinking airsprings are a good route forward... They also appeal to my geeky nature - more toys to play with.

Not that I've even got as far as buying a van More of a theoretical exercise, but I'm thinking a project like this is best properly planned before running out and buying bits and pieces I may not need. I already have a garage full of stuff bought that way

[Incorrigible]

I wouldn't concern yourself with chassis stiffness or corner weighting in the first instance (if ever) because of their construction vans are pretty stiff anyway (obviously if the windscreen starts popping out every time you go round a roundabout you may want to reconsider )

Also you can get 7.5 ton trucks with air (Merc definitly do them) and it would be a great experiment, there are plenty of Range Rovers in the scrappys to get the compressors and actuators from

OTOH you can get springs in loads of differnt rates, much simpler but less fun

[Fatboy]

You can buy air suspension kits for motorhomes, which might work, but as you say a P38 rangie or 7.5 tonner in a scrappy would be a cheaper (and probably more robust, being designed for more weight and abuse) way of doing it - MAN also do them with air suspension (or did 6 years ago anyway).

Another great excuse to go hunting at the scrappys

[OJ]

Incorrigible said:

I wouldn't concern yourself with chassis stiffness or corner weighting in the first instance (if ever) because of their construction vans are pretty stiff anyway (obviously if the windscreen starts popping out every time you go round a roundabout you may want to reconsider )

You could always try lowering the centre of gravity by removing the roof eh mate

[DrDeAtH]

sod all that lark... strap a pallet loaded with about 10 bags of sand in the back, that will hold the rear end down and stop it from tipping(a bit). then drive it with no fear.... on 8 ply tyres

edited for poor spelign

Edited by DrDeAtH on Friday 2nd January 20:12

[Fatboy]

Uprated version of a bag of cement in the back of a capri

[mat205125]

I assume that they are on a live axle. You can always do a 4/5 link job like people do with rally escorts. Coil overs and 5 link works very well compared to normal leafs and live axle .... lots of chopping and fabricating though

[Fatboy]

mat205125 said:

I assume that they are on a live axle. You can always do a 4/5 link job like people do with rally escorts. Coil overs and 5 link works very well compared to normal leafs and live axle .... lots of chopping and fabricating though

I'm guessing that the old tinworm will ensure a 1983 GMC van requires plenty of chopping and fabricating anyway

[DrDeAtH]

you will probably end up with a full tube chassis with the remains of the van body slung over the top.... still would make an interesting drag van....