Originally Posted by
Farmer_John
I've found a source for 13t, mod1 bells that fit the Associated three shoe clutch. What size spur and is there a way to isolate the spur from the dif? That way an adapter can span from the spur to one side of the dif. I would think then the size of the ball dif could be built no larger or heavier than need be. I would also think that dif rings, balls and ball disc (as it would no longer be a spur) would be easier to build and maintain.
I think a 13 tooth bell is really marginal. Back in the day, with way weaker and lower revving engines, we were running 11/60 or so which is 5.45. It would be very difficult to get to 5:1 with a 13 tooth. It would take a 65 tooth spur and that would be very close to the same diameter as the tires. You would probably have to specify the gear ratio for everybody.
A spur gear in the area of 60 tooth would be close, using an 11/12/13 bell but with so few teeth there are big jumps. I don't know how the motors would like being over geared that much....60 tooth is about 2.5" dia. so you have to watch the tire wear. I think going to the belt reduction may have had something to do with getting the gear dia. down as well as other advantaages. Might be able to go to a 32pitch gear and maybe a smaller motor like a OS .18, since the car will be so lite, but that opens up another can or two of worns...
Right now I don't know what the spur would look like. I can only assume it would be similar to the Associated. Depending on the gear and hub, mods may have to be made to accommodate and a seperate diff unit may work. The biggest problem I see is the the Associated type ball diff is very narrow, there really is not much space to make it wider. Remember the gear and the brake have to be connected. That's why that type of diff is so good.
Drilling 8 holes in a plastic gear isn't to hard....
How do we press/connect the diff washer drive plate in minimal thickness on a hardened axle, so it never moves?
Keep the ideas coming!!!