BigDogRacing

iTrader: (12)

Cobra- thak you and thanks for teh very intelligent description of the problem.

Atomix- you are right about the other cars being 3 piece shafts, but wrong about what the problem is... you say the solid shaft car keeps the drivetrain running true but that's where you are wrong. In fact, the reason Tamiya purposly incorporateld "float" into the pinion bearings in the front and rear transmissions is because there will always be some runout in the shaft and therefore something must give to keep from binding. This "floating bearing" is THE NUMBER ONE REASON for the teeth stripping on the ring gears and pinions. The next worst (excuse poor grammar) problem is the fact that the shaft does NOT fully engage the FRONT pinion (bevel) gear and even if it did, the horrendously long bevel on the front of the shaft allows the pinion to kick sideways (deflect is the technical term) and bind up. Both of these faults cause the lash between the pinion and ring gear to open up under any strain and we all know that the less the teeth engage each other the more chance there is of breaking them.

You can take the car to any good engineer or machinist and explain the problem and they will tell you that I'm correct. We thought the shaft was coming forward at first like you do, but found that isn't the problem. If you do the simple and cheap fix like I showed along with using a decent backing plate for the oneway gear (the third problem on the list of faults) then you won't have any more problems and you can shim your drivetrain correctly to be free and fast. Or you can keep replacing gears and take a chance on it costing you the state race in 19 turn sedan becasue your good friend got turned sideways in the first turn and you hit him square which cocked your pinion gear into a bind in the transmission and your car was so slow with the binded gear and chewed up ring gear that it wouldn't pull a greasy string out of a cat's butt... Of course that's just a theoretical situation...