Tamiya F104 Pro!
#1876

This is likely not a diff issue but a rear axle issue. When you tighten the set screw on the non-diff side hub you want a slight amount of play in the axle. Typically in pan cars we slip a piece of paper between the spacer/shim and the bearing when tightening down the hub then remove it after. This gives you the right amount of play in the rear axle. Because the diff is on one side of the rear axle bearings if the axle is too tight it will cause the diff to give uneven amounts of power to the left and right wheel.
Thanks!
#1877

From the looks of things, everyone's set-up is different. My opinion along with my set-up is the opposite. I use no shim, along with no play (slack) in the rear of my 104. I personally have no issues. As I mentioned before a few pages ago, that nut that you tighten berfore the final hub piece on the diff side, should be tightened all the way- then back that nut off a bit. If it's grindy still- back it off some more. You should have a smooth roll yet a tight feel. If you set you 104 down and it doesn't move then obviously re-tighten that very nut a bit more. Not to mention I haven't used that trick were you sand down those diff rings yet either, and I still have no issues. That's my humble opinion.
#1879
Tech Initiate

vonjet- I noticed the same thing when I built my car last week and I was a bit put off by it, but apparently that's just the way it is. If I had to guess I would say that maybe Tamiya made a change to the tire width after they finished the molds for the wheels. Perhaps they found that the handling balance of the car needed changing.
#1880
#1882

Never mind, I just took a closer look @ the bottom of the side pontoon mold and saw it clear as day.



#1885


#1889
#1890