nutsster
Member
I thought that I would share some thoughts and experiences about operating the C-4 differential in my Thiokol 1402 and my OC-12 in DMC 1200 snow cats over the last couple years. I hope others will add their experience too.
A couple of weeks ago, we received about three to four feet of "Utah" powder on top of about a 18" base. I couldn't wait to operate my DMC 1200 on it after the extensive restoration that I made to it over the last summer. When I made it up to our cabin the following day, I drove it on many of our roads in untouched powder. It was unbelievable, the steering was light and responsive, and the cat ran flawlessly. I must have covered 30 miles that first night.
Over the next two weeks, the temps fell to maybe single digits in the day and -20 to -30 at night. The snow was very light and grainy. It compacted very nicely on the roads from all the traffic. Almost too nicely!
With the snowmobile and snowcat traffic plus sub zero temps, the roads set up like cement. However, the compacted snow still allowed the grousers to penetrate deep into it for traction. The cold conditions and very hard snow (where compacted) made the steering much more difficult. ( My DMC 1200 has the very agressive 4" grouser that the later Thiokols and LMC snow cats used. ) The extreme traction would require much more steering pressure to complete turns and would also drive the differential temps up dramatically. Some steering became so difficult that the drive sprockets would skip too. However, driving thought fresh uncompacted snow would instantly return the cat to the light steering pressures of the week before (in the fresh powder).
On the hard and grippy snow, it was much easier to make several quick shallow turns then attempt a medium or large turn. It is also very noticable to me that as the differential temp climb, that steering performance drops off dramatically, especially when the oil gets near 170 to 180 degrees. The manual warns ab out exceeding the 180 degrees limit! The C-4 differential doesn't normally have a temp guage or a lot of oil for cooling like the OC-12. I am considering installing one to be able to monitor the oil condition on my smaller cat.
I don't have a lot of experience driving hydro-static cats, but have been told that it is the same for them too. My one friend grooms for Deer Valley, and informed me that under some conditions they get the sprockets to skip in turns too.
During this same week I broke the left axle on my Imp 1402 driving on the "hard & grippy" snow. I'm glad it happened near my place instead of 20 miles back in.
That axle was a four lug axle, which I found out was much weaker than the five lug. The flange was also slightly bent from previous abuse that I'm confident had stressed it. The other axle on my cat has the five lug axle already installed.
Please feel free to add your experiences from operating in changing snow conditions!
A couple of weeks ago, we received about three to four feet of "Utah" powder on top of about a 18" base. I couldn't wait to operate my DMC 1200 on it after the extensive restoration that I made to it over the last summer. When I made it up to our cabin the following day, I drove it on many of our roads in untouched powder. It was unbelievable, the steering was light and responsive, and the cat ran flawlessly. I must have covered 30 miles that first night.
Over the next two weeks, the temps fell to maybe single digits in the day and -20 to -30 at night. The snow was very light and grainy. It compacted very nicely on the roads from all the traffic. Almost too nicely!
With the snowmobile and snowcat traffic plus sub zero temps, the roads set up like cement. However, the compacted snow still allowed the grousers to penetrate deep into it for traction. The cold conditions and very hard snow (where compacted) made the steering much more difficult. ( My DMC 1200 has the very agressive 4" grouser that the later Thiokols and LMC snow cats used. ) The extreme traction would require much more steering pressure to complete turns and would also drive the differential temps up dramatically. Some steering became so difficult that the drive sprockets would skip too. However, driving thought fresh uncompacted snow would instantly return the cat to the light steering pressures of the week before (in the fresh powder).
On the hard and grippy snow, it was much easier to make several quick shallow turns then attempt a medium or large turn. It is also very noticable to me that as the differential temp climb, that steering performance drops off dramatically, especially when the oil gets near 170 to 180 degrees. The manual warns ab out exceeding the 180 degrees limit! The C-4 differential doesn't normally have a temp guage or a lot of oil for cooling like the OC-12. I am considering installing one to be able to monitor the oil condition on my smaller cat.
I don't have a lot of experience driving hydro-static cats, but have been told that it is the same for them too. My one friend grooms for Deer Valley, and informed me that under some conditions they get the sprockets to skip in turns too.
During this same week I broke the left axle on my Imp 1402 driving on the "hard & grippy" snow. I'm glad it happened near my place instead of 20 miles back in.
That axle was a four lug axle, which I found out was much weaker than the five lug. The flange was also slightly bent from previous abuse that I'm confident had stressed it. The other axle on my cat has the five lug axle already installed.
Please feel free to add your experiences from operating in changing snow conditions!
