RS Stage 2 motors in an AWD car

[Team AMG]

OK, I think i already know the answer to this one but I have to ask anyway.
On an XMOD car, when you install the Radio Shack Stage 2 motors you get a set of replacement bevel gears that go with each motor. That bevel gear goes on the drive shaft and connects the power to the diff, the rear end, etc...
On an AWD car, when you repace that back bevel gear, do you/should you also replace the front bevel gear with the same color gear to avoid an overdriven/underdriven situation? I have both the Stage 1 and Stage 2 motors so I do have 2 of each gear to do just that if needed. But since it was more of a technical problem I figured I'd ask the experts here first.

[viperdout]

Leave the front gear alone. The only diference with the different color bevels is the gear that touches the pinion. The cone part must always keep the same number of gears to mesh correctly with the diff. BTW, if you lose the front cone, you can machine down a bevel to fit.

[Team AMG]

Wow...looks like I stumped everyone with this one.

Here's the answer;

If I were to use the Stage 2, 8 tooth motor (white) I wouldn't have to change the front gear, the ratio is the same, front to back. Any other gearing change would require the front gear to be identical to the bevel gear in the rear. Here in lies the problem: The front bevel gear is more than a rear gear with the toothed motor drive ring removed, it has the width of that drive ring machined down to allow the tie rod to move back and forth below it....sounds like something Dean needs to stock in his store for us AWD guys running hot motors (hint, hint).

The overdrive difference changed with each motor, the 6:1 Drift gear ratio is stock AWD, the 5.11:1 would mean an overdrive of 12.87%, and it goes up from there. That means your front wheels would be traveling at a different speed than the rear wheels unless you change out the gears.

How I'm going to do it is I'm gluing my gear to my old driveshaft using silicone, this will be easily removed once the machining is done. Once dry I'll chuck the drive shaft into my lathe and carefully begin milling away that drive ring until I get to the reinforced part where the drive shaft goes in. Low speed + light pressure should do it, I don't want to break the gear or strip the slot for the drive shaft, so I'll do my white gear first since that's the stock gear already in the car. I'll let you guys all know how it works out.

[viperdout]

Originally Posted by Team AMG

Wow...looks like I stumped everyone with this one.

Here's the answer;

If I were to use the Stage 2, 8 tooth motor (white) I wouldn't have to change the front gear, the ratio is the same, front to back. Any other gearing change would require the front gear to be identical to the bevel gear in the rear. Here in lies the problem: The front bevel gear is more than a rear gear with the toothed motor drive ring removed, it has the width of that drive ring machined down to allow the tie rod to move back and forth below it....sounds like something Dean needs to stock in his store for us AWD guys running hot motors (hint, hint).

The overdrive difference changed with each motor, the 6:1 Drift gear ratio is stock AWD, the 5.11:1 would mean an overdrive of 12.87%, and it goes up from there. That means your front wheels would be traveling at a different speed than the rear wheels unless you change out the gears.

How I'm going to do it is I'm gluing my gear to my old driveshaft using silicone, this will be easily removed once the machining is done. Once dry I'll chuck the drive shaft into my lathe and carefully begin milling away that drive ring until I get to the reinforced part where the drive shaft goes in. Low speed + light pressure should do it, I don't want to break the gear or strip the slot for the drive shaft, so I'll do my white gear first since that's the stock gear already in the car. I'll let you guys all know how it works out.

But that ratio is on the pinion-to-bevel gears, not on the cone part of the bevel-to-diff. I know, I counted.

[Brickmodder]

He's right. The bevel part of the gear has the same number of teeth on the fornt gear as it does on the back gear. That means your safe... Ride on with your AWD with no worries mate...

[Team AMG]

DOH!!! I just looked, yup, yer right. Now I got a gear glued to my old LWB drive shaft...until the morning.