Bit of an odd request but I’m looking for advice on ground clearance on tractor units. Had a crazy idea to convert a cheap tractor unit to take our artic trailers into the field for loading. It’s a summer requirement, so don’t need full on 4 wheel drive as I’d put flotation tyres on it (plus the diff lock) and just use it to haul to the road side before switching trailers with a volvo unit for the road work but … biggest issue I can see is ground clearance I’ve looked at our volvo FH12 and whist the air suspension lifts the rear of the chassis the axles stay super close to the ground. Are there any units out that there that have better ground clearance? I know that Mercedes & Man for example make a 4x4 or 6x6 but they are going to be mega money i was just looking for a way to get some of the utility of a fastrac but on the cheap 
I also wondered if the ground clearance on a rigid / dawbar chassis (ex concrete lorry for example) might be better?? … any ideas welcome!!
Diggerlot:
Bit of an odd request but I’m looking for advice on ground clearance on tractor units. Had a crazy idea to convert a cheap tractor unit to take our artic trailers into the field for loading. It’s a summer requirement, so don’t need full on 4 wheel drive as I’d put flotation tyres on it (plus the diff lock) and just use it to haul to the road side before switching trailers with a volvo unit for the road work but … biggest issue I can see is ground clearance I’ve looked at our volvo FH12 and whist the air suspension lifts the rear of the chassis the axles stay super close to the ground. Are there any units out that there that have better ground clearance? I know that Mercedes & Man for example make a 4x4 or 6x6 but they are going to be mega money i was just looking for a way to get some of the utility of a fastrac but on the cheap
What is it ya loading? Been in and out of fields with standard artics picking up hay and straw for years with no major issues from a Scania 112 Upto 144 2 and 3 axles and everything thing in between and also the mighty magnum, damp conditions may be an issue but a hefty tractor or loader always gets them out.
in good ground conditions as weeto says just about any unit will do the job but in damp / wet typical UK weather your going to need something better designed for the job . Look around for an old 200hp agricultural tractor with air brakes and a fifth wheel dolly .
In good conditions the tractor can help tow the lorries in and out of the fields .
in moderate conditions it can use the fifth wheel dolly to tow the trailers round the field .
in poor conditions it can get stuck and you still have your lorries on the roadside lol
the idea - but this is brand new shiny expensive kit .
The only way to raise the diff and front cross member is to put bigger tyres on, might be worth considering an ex military tractor unit, often coming in 6x4 guise, usually running 1200/1400 x 20 tyres and chassis/diffs designed to cope with rough terrain impacts, but probably more expensive to buy than you have in mind, heavy too.
If never going on the road, then a normal artic tractor with a few sizes larger tyres and the fifth wheel back as far as possible would do the job.
Seen some farmers using the rear chassis only of a tractor unit hitched behind a decent sized normal farm tractor to pull artic trailers about, if you buy a complete tractor unit consider using the engine and gearbox already mounted in the front chassis for a stand alone PTO drive unit, one place i used to load regularly had a massive sucker blower (not many tractors would have coped with the thing) attached to a 250 ■■■■■■■ driving the blower through a David Brown gearbox, but could be used for all sorts of jobs requiring drive taht doesn’t stall out.
weeto:
Diggerlot:
Bit of an odd request but I’m looking for advice on ground clearance on tractor units. Had a crazy idea to convert a cheap tractor unit to take our artic trailers into the field for loading. It’s a summer requirement, so don’t need full on 4 wheel drive as I’d put flotation tyres on it (plus the diff lock) and just use it to haul to the road side before switching trailers with a volvo unit for the road work but … biggest issue I can see is ground clearance I’ve looked at our volvo FH12 and whist the air suspension lifts the rear of the chassis the axles stay super close to the ground. Are there any units out that there that have better ground clearance? I know that Mercedes & Man for example make a 4x4 or 6x6 but they are going to be mega money i was just looking for a way to get some of the utility of a fastrac but on the cheapWhat is it ya loading? Been in and out of fields with standard artics picking up hay and straw for years with no major issues from a Scania 112 Upto 144 2 and 3 axles and everything thing in between and also the mighty magnum, damp conditions may be an issue but a hefty tractor or loader always gets them out.
Basically looking to make a poor man’s agro truck by changing it onto flotation tyres. Hauling hay, straw, baled silage, gravel & construction materials. Yes I could go & buy a 200 hp tractor but that is £25-30k minimum plus the cost of the dolly probably another £5k so it’s £30-35k… when you can buy a 2nd hand tractor unit for what £7 - 10k and change the tyres for another £3-4K … ■■
If your loading in the field and possibly going out on the road delivering with it, I would go for a standard unit with good drive axle tyres, if ya do get stuck in the field the loader should get ya out, carry a chain just in case, top tip, in corn fields stick to the tram lines.
I’ve only ever got seriously stuck in a field 3 times in 15 years of field work, most farmers are more than willing to help ya get out.
An old 6x2 tag unit that’s been on the logs will probably have half decent ground clearance, at least compared to some of the on road stuff I see. (Anything that hangs down will have been ripped off long ago).
Tag has good traction empty, but not as good as double drive when loaded. You can “doctor” the tag to stay up even when loaded, or you could stick a “Robson” drive on it, get the best of both worlds.
Old John:
An old 6x2 tag unit that’s been on the logs will probably have half decent ground clearance, at least compared to some of the on road stuff I see. (Anything that hangs down will have been ripped off long ago).
Tag has good traction empty, but not as good as double drive when loaded. You can “doctor” the tag to stay up even when loaded, or you could stick a “Robson” drive on it, get the best of both worlds.
I’d never heard of a Robson drive until you mentioned it… looks an interesting idea … are they expensive?
Diggerlot:
Old John:
An old 6x2 tag unit that’s been on the logs will probably have half decent ground clearance, at least compared to some of the on road stuff I see. (Anything that hangs down will have been ripped off long ago).
Tag has good traction empty, but not as good as double drive when loaded. You can “doctor” the tag to stay up even when loaded, or you could stick a “Robson” drive on it, get the best of both worlds.I’d never heard of a Robson drive until you mentioned it… looks an interesting idea … are they expensive?
No idea of cost I’m afraid, nor any idea where you would get one.
Not seen one on a UK vehicle for a long time.
Last one I saw was on an old Danish Scania that was up here on Wind turbine haulage a few years ago.
Reckon it would be worth some research for your job though.
You need a unit with a portal axle/hub reduction that gets rid of the low diff casing. You can find usually older on road units with it fairly cheap Example at link
Own Account Driver:
You need a unit with a portal axle/hub reduction that gets rid of the low diff casing. You can find usually older on road units with it fairly cheap Example at link
Fair point re hub red drive axle.
Portal axle, however, is a very different yoke. I’ve seen them on tractors and extreme LandRovers, but never on a tractor unit. ( Not saying they don’t exist)
This is just me thinking lazy but if your working alongside a hefty enough tractor/ telehandler/ loader. Just use a standard tractor unit but make sure you’ve got a decent set of chains or strap to tug you off if need be? Especially if working in dry conditions.
Failing that an ex waste unit should be good if it used to be used on Landfill type work.
Have been taking to a bloke that has a 2007 Renault Kerax 6x4 manual for sale, it’s a 44t train weight & has been a mixer unit but only done 150,000 km. Kerax’s are built as construction wagons so have a much higher ground clearance (385 mm according to the brochure) was thinking on adding a fifth wheel & some flotation tyres … in principle it would be perfect??
Diggerlot:
Have been taking to a bloke that has a 2007 Renault Kerax 6x4 manual for sale, it’s a 44t train weight & has been a mixer unit but only done 150,000 km. Kerax’s are built as construction wagons so have a much higher ground clearance (385 mm according to the brochure) was thinking on adding a fifth wheel & some flotation tyres … in principle it would be perfect??
Unless this is a project you’re pursuing with a bit of a hobby element it’s a lot of work and not really a cheap option.
If you’re going to throw time and money into building a one off truck I’d always tend towards a make with a reputation for longevity as parts are always easier to come by. With Renault there’s obviously Volvo overlap but it’s not 100%.
Own Account Driver:
Diggerlot:
Have been taking to a bloke that has a 2007 Renault Kerax 6x4 manual for sale, it’s a 44t train weight & has been a mixer unit but only done 150,000 km. Kerax’s are built as construction wagons so have a much higher ground clearance (385 mm according to the brochure) was thinking on adding a fifth wheel & some flotation tyres … in principle it would be perfect??Unless this is a project you’re pursuing with a bit of a hobby element it’s a lot of work and not really a cheap option.
If you’re going to throw time and money into building a one off truck I’d always tend towards a make with a reputation for longevity as parts are always easier to come by. With Renault there’s obviously Volvo overlap but it’s not 100%.
I hear you but we are in Normandy France, so Renault parts & service here is really good. We already have had two older Renault Premium rigids flatbeds (03 & 05 both 270 hp) that have done us great service the last couple of years, they were both bought from UK for a song (it was cheaper to fly over buy a truck and drive home loaded with some farm kit we’d bought, than to hire a haulier to do it for us) and I sold them last week for export for virtually the same money I paid for them 5 years ago & neither one has had a spanner on it in that time save for servicing filters etc. They are leaving for Africa on Saturday.
So flushed with my new found wealth (& before the wife got any ideas about new kitchen units 
) I put my brave pants on & bought the Kerax today for £6k & a set of 700x50 x26.5 wheels & tyres for another £3k. I’m planning to strip the mixer kit off the chassis & hitch it to 70 hp perkins that we’ve just liberated from our JCB 535 to create a batching plant for concrete on the farm. Then hopefully for less than £10k will make a poor mans Agrotruck from the Renault … sounds simple … in theory!!
Buy an old Renault 6x4 tipper double drive load of ground clearance put a 5th wheel on, job done