D-Drive ? Do you guys like them?
- Thread starter Mnt.Tamer
- Start date
This is interesting theory. If engine is running backwards and driveaxle and track foreward - would their rotating masses neutralize each other? Very interesting idea.
On the other hand if you put 3 gears in a row the direction doesn't change. And the secondary would be higher off the ground.
Like said above, its the secondary. The Problem is the DD width which pushes the clutch further out than normal. So in order to make the DD work AC had to build a secondary to work. The Team and older KK clutches, I think where better designed for the application. When team built there new tied clutches for every sled but the DD I called and asked why not the DD. They told me they looked at it for 5 min. and said screw that. I think in short time you will see AC go to a chain case without a jack shaft for more room allowing better clutching. From what I've been told the newer snow pro chassis has a chain case so I can't see why if the DD is so great it wouldn't have one to. I think supreme tool makes one for the M sleds that may allow team clutching??? I was thinking of trying something of that sorts but don't have the time to do all the tuning required, the sleds I ride against I have came out on top(except turbos) so it will work for now.
You cant run th motor backwards for long periods of time, the cylinder will break
The engine would need a complete redesign to run backwards for an extended period of time. As would the clutches and remainder of the drive system.
RMI Drive
The RMI drive doesn't run gear-to-gear with only two gears. It has 4 gears, two of which are idlers so the motor doesn't need to run backwards. It is a Pete Jackson drive design. I don't think he has a patent.
http://www.petejacksongeardrives.net/
I hillcross raced an RMI sled with this setup one season 10 years ago and it was amazing how conected the track was to the throttle lever. I think the DD has a similar feel but not quite the same. I was running a polaris primary and a cat torsional secondary. It probably helped that the sled weighed 420lbs with an 800 PSI motor.
The problem with this type of drive was that everytime you wanted to run different gears it required a hole new case. Maybe they have a solution figured out now, I haven't talked to them in years.
Out of 4 M7s in my group, not one has had DD issues. Probably about 10K miles between us. One guy has 2K miles and has never changed the oil. I keep telling him it needs to be done.
I think it is harder to find an all around clutching setup with the DD. If you want good back shift you loose track speed. You have to clutch it more for specific conditions.
The RMI drive doesn't run gear-to-gear with only two gears. It has 4 gears, two of which are idlers so the motor doesn't need to run backwards. It is a Pete Jackson drive design. I don't think he has a patent.
http://www.petejacksongeardrives.net/
I hillcross raced an RMI sled with this setup one season 10 years ago and it was amazing how conected the track was to the throttle lever. I think the DD has a similar feel but not quite the same. I was running a polaris primary and a cat torsional secondary. It probably helped that the sled weighed 420lbs with an 800 PSI motor.
The problem with this type of drive was that everytime you wanted to run different gears it required a hole new case. Maybe they have a solution figured out now, I haven't talked to them in years.
Out of 4 M7s in my group, not one has had DD issues. Probably about 10K miles between us. One guy has 2K miles and has never changed the oil. I keep telling him it needs to be done.
I think it is harder to find an all around clutching setup with the DD. If you want good back shift you loose track speed. You have to clutch it more for specific conditions.
???
Is it the way it's cast? The metal parts cant tell one direction from another.
Besides, FAST used a 2 gear case on their Blade's. Just turned the engine around, no biggy.
And on the whole DD drive thing, only big benefit I see is brake on driveshaft.
Ok, maybe the physical space freed up by no jackshaft.
The two gears you swap to change gearing are more than a match in weight for chain-case gears. The planetary gear should match or exceed the weight of a chain and a couple extra bearings + the solid casting needed to keep that short secondary stub from flexing should have it down to what??
Couple ounces?
RS
The DD shifting cure
Just take the DD off of the sled. This will save you a lot of weight, also you would not have to worry about the shifting anymore.......at all.
Just take the DD off of the sled. This will save you a lot of weight, also you would not have to worry about the shifting anymore.......at all.
you don't need dd to have the brake on the drive shaft the skidoo xp has the brake on the drive shaft and a jackshaft.
