Thread: 6x6 Truck vs 6x4 Truck - school me

I'm looking at options for a new Cone Penetration Testing rig for work. (CPT = think drill rig but static push rather than rotary drilling)
I'll need to get 4 hydraulic rams fitted to level the whole vehicle and get the wheels off the ground. That's an engineering and cert problem then can be fixed by throwing money at it.


Best case I'd get a 6x6 truck and stick the pushing gear on the back. Would look something like this:




HOWEVER...
In NZ 6x6 trucks are between expensive and stupidly expensive.
Most testing is green fields (paddock) or places a building has been. Would be able to drive a 4x4 ute there kind of thing.


If I went down the option of a 6x4 truck what do I need to look for/avoid?

6x6 not my area of expertise, and I don't know how much weight is in your CPT unit, but about a Iveco Daily 4x4 https://www.iveco.co.nz/Product/daily-4-x-4

Or its big brother https://www.iveco.com.au/whatson/bla...-eurocargo-4x4

What ever you get, can I have a go in it?

@norsk

@Joe_90
A 6x4 would be fine but make sure it has full cross locks and Fit a good Central Tyre Inflation (CTI) system, like the logging trucks use, dropping tyre pressure makes a huge difference
A lot will depend on how you need to mount your CPT. Too much weight over the front axel will be a pain in the arse

Originally Posted by hotbarrels

6x6 not my area of expertise, and I don't know how much weight is in your CPT unit, but about a Iveco Daily 4x4 https://www.iveco.co.nz/Product/daily-4-x-4

Originally Posted by hotbarrels

Or its big brother https://www.iveco.com.au/whatson/bla...-eurocargo-4x4

The pushing gear I want to use for around here will come to about 9 ton. Might be a bit much for the poor wee iveco daily

Originally Posted by Harryg

@Joe_90
A 6x4 would be fine but make sure it has full cross locks and Fit a good Central Tyre Inflation (CTI) system, like the logging trucks use, dropping tyre pressure makes a huge difference
A lot will depend on how you need to mount your CPT. Too much weight over the front axel will be a pain in the arse

I can mount the gear on the deck where ever really. It's effectively a power pack driving 2 big rams to drive a cone to 20m depth. Yes, I'll need a hole in the deck clear of cross members and drive shaft...

I don't think the front axel would get loaded any more than a concrete truck. Good thought with the tyre pressure system. Will do some more research into that.

@Joe_90
This is what I have fitted in a 4x4 Merc Zetros. 5 pressure settings 20 psi up to 60psi. 20 psi has got me out of most spots

I know nothing about those trucks but I am still impressed by the knowledge of some forum members come with to help their fellow mate in such unusual fields.
I guess a small truck like that must cost a little mortgage ? How mush do you charge for your drilling to recover the cost and make a living?

@Harryg, that looks quite good, thank you!
@Friwi, It'll take a couple of years to pay off. The last estimate I sent out today was around $16k. That's 20 test holes to ~20m, for geotech testing it's really good value for money.

Most of the 6X6 stuff is for pulling non driven trailers off road.I don't think you would need it for what you are doing.

You are going to have about the same axel weights with 6x6 and 4x6 anyhow.6X6 isn't less "sinky" it's just 30% more traction.

If you want a 6x6 offroad, Kamaz?

My thoughts exactly,

But for his terrain profile I think it would be a bit of overkill

MAN and others are doing a 6x4 with a PTO hydraulic assist drive on the front axial for a temporary low speed 6x6. I'm sure it's not cheep down here.
Other wise look at what the power companies do for there offroad trucks.

For the money as stated above a set of super singles on the front to reduce sinking and a CTI system and full diff locks on both rear axles like the forestry trucks plus front and rear winches.
Z
https://www.youtube.com/watch?v=EEVjN251a1Y

6x4 works IF you are talking both back axels drive....the absolute pits on any sort of uneven ground is a 6x2 eg lazy rear axel...you can literally get stuck going over a curb.....
the big advantage of fronts driving is steerage in any thing less than ideal-muddy as shit.
a longer truck thats 6x4 will keep going really well in full difflock but wont steer.... if you can lock between dif and cross lock rear you have to spin 3 to be stuck...pretty good at that...ultimate is full difflock so all 4 turn together.
9ton payload....most two axel fert sowers have payload of 6 ton....chuck that 3rd axel in and you be good to go...ISUZUs are cheap..but hard riding and rather tall,lots of ground clearance...difflocks not standard....
scania costs a bomb but are plurry nice trucks all around. super singles on front axel make softer ride and arguably less sinky...but choose tyre rim size wisely or you will be stuck with retreads or bus tyres which are piss poor steerage wise in anything greasy.