Ground speed PTO in former days

[eppie]

Hi guys,

I was cutting some bush with the Deutz D50 today. My eye fell on the pto lever. The D50 has a ground speed PTO, just like our 5245 and 6718 Zetors, the Ferguson 35 we had, and more.

In older tractor books, they say the ground speed PTO was used in the fifties to pull wagons in heavy conditions, and over hills. I think this gives quite some strain on the tractor, and it must be hard to operate when the combination has to turn on the headland

Not every tractor has/had a ground speed PTO. Are there any other common use of this feature ? I know of one contractor who uses it on his 160 hp ursus to drive the axle of a 15 ton silage wagon, but i think the use of the ground speed PTO in common has become rare.

[Laapa]

Renze, in the old days it was fairly common around here to build trailers of tandem-axle trucks (replace cab, engine, frontaxle etc with a hitch). Sometimes the driveshaft was kept and could be connected to a ground-speed pto to provide power to the trailers wheels when driving in fields.

I do know of some people who nowadays hook it up to a non-groundspeed pto, put the tractor in neutral and let the wheels of the trailer push. They can reach pretty high speeds on the road this way.

Of course it is stupid, dangerous and illegal. Kids, don't try this at home.

[eppie]

That could give some nice crashes !!
think what could happen if they cant get it out of gear soon enough, and only the tractor is braking? the trailer will push along till the tractors nose will head back toward the trailer.

How fast do they go??
With use of the ground speed, could they get the proper gear ratio ? That contractor i spoke about installed a Merc truck tranny to achieve the right ratio.

But, what law will forbid such practice?? We dont have laws about the method of movement...


By the way, i am thinking of buying an old Zetor, mount the portal axle upwards instead of downwards (making it about 50 cm lower) and install some real big tires. That must be a method to get some racing tractor with an extremely low center of gravity, and 80km/h. I am not sure about how to mount the sprung front axle to the lowered frame, but i wont flip over with it.

Maybe i'll install a Tatra V8 408 hp, if my axles wont snap when i hook on a trailer....

[Laapa]

Hey Renzetor!
If a proper ground-speet-pto-gear was available the trailer would aid providing traction in the field quite nicely.
As far as using the trailer for "pushing", the sky is the limit for top speed i suppose...
I suppose as soon as you make a not-too-sharp-turn they would start to behave weirdly.
I can imagine the hitches on the tractor are not buildt for that kind of treatment either, and I bet there would be plenty of laws against the practice (peedlimit etc.)

Hmmm, if you lower the axle 50 cm you will need quite big wheels on that thing to avoid ground contact.
Big diameter tyres, when rotating fast have an inboard
"force" that makes them hard to manouvre. This is the reason all racevehicles that run on tracks with turns (NOT dragracing and tractorpulling) have small diameter wheels.
(OK, my english is not good enought to accurately explain this phenomenon of the laws of high-school-physics. It is the same principal that works on a motorcycle that kkeps going after the driver falls of. A rotating object strives to keep its angle beacuse a body in motion wasnts to stay in motion etc.) None of what I just wrote made any sense, did it?

[eppie]

Laapa, it did make some sense.

That principle is used by the circus acrobat, balancing a turning dish on a stick.

[Andrew S]

My experiences of Ground Speed PTO relate to Massey tractors, & it's use to provide 'Powered Axle' systems on trailed Lime Spreaders in the U.K.

The arrangment consists of a tractor with the Ground Speed PTO, coupled to the trailed spreader, through a transfer box, to the spreader's driven axle. These sytems were an early way of achieving 4WD, hence more traction & stability on sloping land. I have also seen similar arrangments on gravel trailers, used by land drainage contractors

Several U.K. manufacturers designed such spreaders, the most popular probably being LandDrive from Cannonbie in Cumbria. Systems are also offered by Transpread, who are from New Zealand but have there designs manufactured under liecence in several countries.

The early systems used donor parts from military & commercial trucks. Many were based on Bedford (GM) parts, whilst others used Leyland/Albion truck axles. It is critical that the tractor & spreader wheels rotate together to achieve an identical forward speed. This is achieved by selecting suitable gear ratios, within the transfer box & axle, & tyres of the correct rolling circumference. If this is done correctly, it is possible to leave the drive engaged when turning, given that there will be some wheelslip under field conditions. The system should not be engaged on the road, as the lack of wheelslip leads to 'wind-up' eventually resulting in the failure of some part of the system (often the striping off of gear teeth either within the spreader axle or the back end of the tractor).

My father still operates a 3.5 tonne capacity LandDrive spreader which he bought second hand in the early 1970's. In that time we have had a Massey 65, 185, 290 & currebtly a 390T to pull the spreader. The 290 was fitted with a Duncan cab, we had it Turbocharged & it eventually reached in excess of 11,000 hours before we traded it for the 390T. This tractor is 4WD, hence the outfit together is 6WD.

We have found the system unbeatable in it's ability to provide additional traction & stability when working on the considerable slopes found in some areas of our part of Devon. The system also seams to reduce compaction & rutting when working on cultivated land.

I am sadend by last weeks news that AGCO plans to close the Banner Lane factory in Coventry (incedentally the original home of the Ferguson TE20 range), & wonder whether this spells the end of Ground Speed PTO on Massey tractors?

As far as I am aware Ground Speed is currently offered by Valtra, Lambourgini (& Same), Styre (& hence some Case) & maybe Fendt. Does anybody know of any others?

[HPP]

I should think most manufacturers do offer ground speed PTO. I know Fendt do.
To me ground speed PTO always has been connected to potatoharvesters, planters and stuff like that. We even had ground speed PTO as standard equipment on the Fendt Farmer300:s for some years.