Savage direct drive tranny.
 

Has anyone tried this? Looks like a good setup. http://204.186.93.64/Savage-DirectDrive.htm

I have not seen a review on the V2 yet, but the v1 seemed to have some issues. The idea is sound, not sure if the design and materials will take a real hard bashing...

I had him make me something similar to this a few years back, wasn't impressed with the build quality and materials used though. It's a good idea but the use of plastic spacers and the lack of tapped holes just shows a lack of quality IMO.

But hey, he has stepped his game up since back then, he's using some form of CNC now, looks like a waterjet, so it could be better than I remembered.

I have the V2 tranny in my X conversion. Overall I would not recommend it.

Pros:
1. Very smooth and very quiet.
2. Wide gears seem to handle the abuse.
3. Motor is centered in between TVP's.

Cons:
1. Cheap construction.
2. Gears are open to dirt and rocks.
3. Sits too low in chassis for a skid plate.
4. Only held in by 4 screws on one side.
5. Minimal clearance for larger motors.
6. Outdrive cups will not stay on the shafts.

I almost finished with my 1717 upgrade so I'll see if it withstands the punishment. I had to have it post machined to fit the larger motor. The smallest pinion gear that will fit is a 22T. Anything smaller and the motor can hits the idler gear.
It handled the CC 1518 with no major issues.

What is the theoretical top-speed with the 22t pinion then?

Thomas G

I would love to know but KD doesn't list the final drive ratio on his website. He only offers suggested pinion and spur gears for specific motors.

If anybody knows the final radio please let me know. That would be great.

What are the tooth counts of the internal gears rc-nut? With that info it would be easy to figure out the ratio. Loos like a steel pinion and a plastic spur in the picture (inside the 2 bulkheads)

And let us know what spur you plan to use, and if you are using savage or revo spurs.

And fixing the outdrive cups falling off should be pretty easy. Mark where the set screws contact with the output shaft, then drill small dimples for the set screws to engage. Use red loctite and let it dry overnight before use.

"I would love to know but KD doesn't list the final drive ratio on his website. He only offers suggested pinion and spur gears for specific motors."

So one has to remember every motors pinion value, instead of just one ratio. Smart.

TG

He has the KD unit in his savage. Counting the teeth on the 2 internal gears will give all the info we need.

Oh cool.:yes:

motor pinion: 22T
Savage spur: 49T

Internal pinion: 18T
Internal spur: 45T

Flux F+R diffs

Thanks guys.:yipi:

I'll have to give that a shot. I've tried smoothing the flat spot with a dremel as well as blue and green thread lock. I was affraid of the red loctite once I needed to remove it. I have really cranked the 2.5mm set screws too. It's amazing how fast they slip off. I wanted to try drilling a thru hole on the shaft and using an HPI set screw pin but I was affraid of weakening the shaft.

Thanks for the tip.

2.5 internal ratio for the KD unit.

So with that info, and looking at your pics you appear to have some 40 series road hawgs, which are around 6" in diameter. I did not factor any tire ballooning into this, but here is about what you should be doing.

Differential Ratio: 3.3076923076923075
Transmission Ratio: 2.5
Other Ratio: 1
Spur Tooth Count: 49
Pinion Tooth Count: 22
Total Voltage: 22.2
Motor KV: 1580
Tire Diameter (inches): 6
Tire Ballooning (inches): 0
Motor Current Draw: 0
Motor Coil Resistance: 0
Spur/Pinion Ratio: 2.23 : 1
Total Ratio: 18.41783 : 1
Tire Circumference (inches): 18.85 inches (478.78 mm)
Rollout: 1.02:1
Total Motor Speed: 35076 RPM
Vehicle Speed: 33.99 mph (54.61 km/h)
Effective KV Value: 1580

34 mph is a bit slow... The std gearing in the flux tranny is a bit higher at 2.2:1, and that would give you around 40mph. Still not loading that 1717 at all. Plus the flux tranny is sealed, allowing the use of oil for lubrication, and it must be stronger due to all metal gears. The std flux mount will not fit the 1717 but a simple angle mount would, or have a clamp style made up, and clearance the tvp.

I did not have this issue as the 1717 fit my TDR mount in the lst just fine. Just another reason the lst is king...

The hpi set screw with the pin is not really a good idea, IMO... Make a dimple and use red loctite, you can always get the screws back out with some heat from a lighter, heat gun, etc.

I think GCM is working on some FLUX tranny...should be worth waiting ;)

Thanks for running those calculations. I also picked up a 25T pinion just in case so I'll try both.

Who knows maybe I'll try the 1717 in the Muggy and put the 1518 back in the savage.:yes: