large diameter spur gears

[DumpsterRC]

I am wondering where to get some large spur gears. The largest I can find (32p) are 72t. I see some of you are getting 84t somewhere. The pitch dosen't matter 32 or 48, but I need about 2.5" pitch diameter.

Thanks

[dezfan]

http://www2.towerhobbies.com/cgi-bin...?&I=LXD250&P=7

[DumpsterRC]

Thanks,
Do you know if the pitch diameter on that gear is 2.5" or close to it. I think a 32p 84t is about the right diameter, which made me think (no real calculations) that a 48p gear would have to be around 100t.

What I am attempting to do (tell me if it's stupid) is to use a Maxx diff (locked) as a transfer case. The diff's pinion would point up with a spur gear mounted on it. There would be a mounting plate above the diff that would clamp on to the diff where the collar usually goes. The motor would hang vertically from the plate.

l-----l-----l-l-l gears
l--------l------l---l mounting plate/chassis
[diff] [m ] differential/motor
[ o ] [ ] "o" = output shaft

I need a gear about 2.5" to clear the diff far enough so it is possible to drive it. Also for the added gear reduction. The motor wouldn't be directly beside the diff but tucked up next to one of the output shafts.

I suppose it could be turned on it's side with the motor above or below. And maybe its been done and proved worthless.
I don't think my drawing turned out. The "l"s on the top two lines are supposed to be the motor/diff shafts and the edges of gears/chassis.

[tkruger]

If you get it to work post som pics. I was thinking of attempting something simular. Only I was going to put a standard tranny up front and run a shaft to the diff in the center. If the gearing is to high you can try adding a GD600. This would also allow the motor to be moved to the side a little more if there is not clearance directly behind the motor plate (had the clearance issue with a battery mount on one of my trucks and the GD600 moved it just enough to the right to clear.)