4X4 Specs and setup

Slidey

Split from the other thread>

Continue discussion on specs and prefered setup for optimum off roading here

Thanks

peasant

The main issue still is that from a design point of view what is good off-road is poor on road and vice versa.

To have a semi decent chance to get anywhere off road you need cart technology ...solid axles, high ground clearance and huge articulation ...all detrimental to good on road behaviour.

My Syncro van for example has a pretty decent road chassis for what it is (a van !). Independent suspension all round with trailing arms and stabilisers. Now when they slapped on the permanent 4x4 drive system they found that they had to add at least one difflock or else it wouldn't have gone further than the first deep-ish pothole as there is next to no articulation in the suspension.

With two difflocks (optional) of course you can hammer a Syncro through pretty much everything, if you're so inclined and have no mechanical sympathy ...but it still isn't a good off-roader, as it simply wasn't designed that way...just a good compromise.

That's what most off-road vehicles are these days ...a compromise. The demand for sheer off road ability is small, most vehicles get driven on road most of the time and on road behaviour is what they get judged on more and more. You wouldn't seriously recommend a Defender to someone who puts up 30.000 or more road miles every year, would you?

So the whole discussion is somewhat academic, as it really very much depends on what you actually need your vehicle for and what you do with it to say if your choice is any good and fit for purpose.

Having said that ...at the end of the day a Toyota 70 series or even a Suzuki Jimny just breaks down less frequently than anything made in Sollihull.

gofaster_s13

peasant wrote: »

The main issue still is that from a design point of view what is good off-road is poor on road and vice versa.

To have a semi decent chance to get anywhere off road you need cart technology ...solid axles, high ground clearance and huge articulation ...all detrimental to good on road behaviour.
.

Independant suspensions are the holy grail of off roading, far better than live axles just very costly to engineer and manufacture, some of the best off road vehicles use independant suspensions ie Tatra

BeardyGit

Hmmmm. I don't see how you can state that and expect much less than a bit of a fishtake, lad. Independent suspension is useful, but it's far, far, far from the holy grail.

Can you actually explain WHY you think that? Or are you just regurgitating some tripe you've read online or heard down the pub?

gofaster_s13

Why then are vehicles that are designed as off road vehicles first and on highway vehicles second equipped where possible with independant suspensions ie GM humvee(original version), Tatra trucks, General dynamics Mowags, Timoney technologies airport fire tenders, Moxy dump trucks etc.
Live axles were originally fitted as a low cost method of fitting a vehicle with with all wheel drive on vehicles that were marketed as low cost utility vehicles.

thethedev

gofaster_s13 wrote: »

Why then are vehicles that are designed as off road vehicles first and on highway vehicles second equipped where possible with independant suspensions ie GM humvee(original version), Tatra trucks, General dynamics Mowags, Timoney technologies airport fire tenders, Moxy dump trucks etc.
Live axles were originally fitted as a low cost method of fitting a vehicle with with all wheel drive on vehicles that were marketed as low cost utility vehicles.

Independant suspension is great if all you want to do is drive rough roads. But for proper balls out offroading it has to many parts.
The applications you have mentioned above are fine as they would be expected to maintain a high speed and/or stability over reasonably rough ground. But if your going to be winching your way up a mountain or flooring it up through mud independant suspenion lacks clearance and strenght.
Almost every proper offroader will either attempt to buy a vehicle with
solid axles front and rear or convert when they sick of breaking driveshafts and getting hung up on stumps!!

gofaster_s13

It doesnt get more balls out off roading than this,
http://www.youtube.com/watch?v=xoG2Inl5PEg
Independant suspension in proper off road applications(not the compromise efforts offered by most manufacturers) is by far the best solution for off roading.

101sean

The British Army's new fleet of Supacat Jackals and Coyotes are all independantly sprung and are expected to operate in extreme off road conditions. They are large vehicles though with variable height air suspension. Pinzgauers, Tatra Kolos, Bucher Duros and the like perform phenomenally well off road with independant suspension. Balls out off roading needs well designed and protected suspension with diff locks or traction control, whether independant or solid axle.

The downfall with independant suspension on simpler smaller vehicles is in ruts and rocky ground, the sump and front diff can ground out. It's how I wrecked the front axle actuators on L200s and Rangers as they were poorly protected by inadquate plastic skid plates. Thy can perform well in these conditions but not as standard. Modern Discoveries and Range Rovers get round this by being well protected and having air suspension and sophisticated traction control.

Challenge type off roaders will use solid axles, often portal type, as this is what's affordable and easily repaired. It's different for the military and Baja type racers as budget and maintenance isn't an issue.

DirtyDiesels

gofaster_s13 wrote: »

It doesnt get more balls out off roading than this,
http://www.youtube.com/watch?v=xoG2Inl5PEg
Independant suspension in proper off road applications(not the compromise efforts offered by most manufacturers) is by far the best solution for off roading.

nice

peasant

gofaster_s13 wrote: »

It doesnt get more balls out off roading than this,
http://www.youtube.com/watch?v=xoG2Inl5PEg
Independant suspension in proper off road applications(not the compromise efforts offered by most manufacturers) is by far the best solution for off roading.

If you put a suspension like that on your Defender / Landcruiser type vehicle, the price would probably double (along with its offroad ability)

gofaster_s13

peasant wrote: »

If you put a suspension like that on your Defender / Landcruiser type vehicle, the price would probably double (along with its offroad ability)

Which is exactly my point, live axles are fitted as a cheap substitute to keep build and retail costs down while still performing adequately off road, but cost being no option, independant suspension is far superior.