[Farmall] newbie questions

[szabelsk at gdls.com]

If we were able to post a sketch or drawing to the site, I could show why 
a wide front would be more stable then a narrow front end.  Suffice it to 
say that given a center of gravity, the further away the front wheels are 
from that center of gravity, the further you have to lift one of the front 
wheels off of the ground in order to get the center of gravity to pass 
over the other front wheel. Once the center of gravity passes over the 
other front wheel, the tractor will roll.  This also would apply if you 
start to lift one of the rear wheels. As soon as the center of gravity 
passes over the other rear wheel, the tractor will roll. The question 
becomes how much wider apart are the front wheels than the rear wheels, 
and which is leaving the ground first, front or back, and by how much. 

Basically if you could spread the front wheels apart so that they were 20 
feet apart and spread the rear wheels apart so that they were 20 feet 
apart, you'd have a pretty stable tractor and would have to really get one 
of the tires pretty high off of the ground before you'd roll the tractor.

You can also do the same analysis going from front to rear and rear to 
front. It's all a matter of getting the center of gravity to pass over the 
center of the tire on the opposite end of the wheel that's being lifted. 
When you drive on an incline you've basically already raised your tires 
off of the ground, since the center of the tire is higher than it would be 
on level ground. That's why you have to be careful of the incline angle. 
The steeper the incline the less it takes to overcome the center of 
gravity.

As an example, I regularly cut the grass in the ditch in front of our 
house with our Cub. I've  done this for years and never had any problem 
with an indication of the Cub wanting to roll.  I always drive such that 
the engine is towards the road and away form the ditch, this keeps the 
center of gravity towards the road due to the offset engine. The weight of 
the mowing deck also lowers the total center of gravity of the Cub. Well 
this spring I took the snow blade off of the Cub to put the mowing deck 
on, but decided to do some minor adjustment on the carb and governor. 
After I did, I took the Cub for a ride down the road for a test run. On 
the way back I decided to pick up the mail and pulled over to the side of 
the road and had the front left wheel into the ditch, angled into the 
road. A large gravel hauler was coming down the road and I pulled forward 
a little to give him plenty of room. That's when I rolled the Cub into the 
ditch. I had the engine on the ditch side, and didn't have the weight of 
the mowing deck on the Cub. Therefore my center of gravity was closer to 
the front left wheel and further into the ditch, as well as the center of 
gravity being higher off of the ground since I didn't have the mowing deck 
mounted. Same ditch I'd driven plenty of times without any problems. Just 
facing the opposite direction with nothing that helped lower the center of 
gravity.  Since then I've mowed the same ditch all this summer, driving 
with the engine towards the road side and with the mowing deck mounted. 
Again, no indication the Cub wanted to roll. 

Carl Szabelski



This is an e-mail from General Dynamics Land Systems. It is for the intended recipient only and may contain confidential and privileged information.  No one else may read, print, store, copy, forward or act in reliance on it or its attachments.  If you are not the intended recipient, please return this message to the sender and delete the message and any attachments from your computer. Your cooperation is appreciated.