Here is my TBO3D overdrive mod using STR067 counter drift unit stage 2 (rear) from active-hobby. the unit is supposedly for yokomo but some they have done it on TB03. to the moderators, it's fine with me if you consider putting this in a new thread.

The tools i used in this mod are:

a small file set
hex screwdriver
caliper
hack saw
O-ring

Now we start,

here is the comparison of the gears, on the left the STR067, on the right is the tamiya solid spool assembly. the ring( large) gear is almost identical in size and it will fit snugly tight on the tamiya solid spool. even the screw holes are similar so you will have no difficulty in putting it in.







the STR067 is much more thicker than tamiya. the STR067 has 43t (ring gear) and 13t ( bevel gear )



The shaving part..
you need to enlarge the top end hole of the small gear so it will fit on the propeller joint. is use a round needle file for this. do it really slow and careful not to exceed.




The measurement..
the tamiya small bevel gear is 8mm length. i use a hack saw to shave a few mm on the small gear - do it slowly!
after cutting it i used a flat file to make it smooth. file the top end lightly for the circular clip (E-clip)


I thought its done but the small gear can't pass the through the propeller joint due to it was meant for yokomo. you have to file the inner part of the small gear - shave off the guide/lock for yokomo propeller joint. i file it with angle and i just roll it back and forth on a carpet like this..

i used a semi round file for control. I'm not confident in using a drill or dremel.

again when filing some things do it really careful and slow!

after few trials the shaft will pass through. and now try putting the e-clip

almost done but not yet.

Remember that the tamiya small bevel gear has small shaft in order for it to turn. mark the bevel gear while it's on the propeller joint .make sure that you mark it exactly. once you marked it, use a small flat file and round edge file for filing/ rounding it.



Put the entire assembly again with the shaft on. prepare a large pen ( i use a fountain pen ) and put an 0-ring - (this will act as lock for the shaft). make sure that the pen you gonna use is large enough to make the small gear fit inside. when ready put inside the small gear and slowly slide the O-Ring down until it transfers the small gear and the shaft. so it will look like this.



Now its done!




Didn't try running it as of now. about the gear meshing issues ,well i just have to put shims the the screw of large ring gear for any adjustments. I'll give the updates since my work is still on progress.
hope this one answers the query of TB03 users regarding on overdriving.

nice work man i looks perfect

But correct me if im wrong, you place those gears at the rear that means your rear will turn slower than the front?

because those bevel gear is much smaller than the standard tamiya bevel.

great detailed build tutorial sir!

all props to you!!!

great work on your OD mod


but i think jon has a point, it is installed in the rear so the rear will turn slower.

i got a FCD unit stage 2 for the rear and the bevel gear is larger than the ring gear.

TN Racing has a similar product to this and they call it TN Front Counter Gear... meant to reduce the front gear ratio so it will spin slower.

oh my god! really? but the kit says "for rear" i'll have to run it first for me to see. i still got the stage 1 which should be on the front. let me see guys..i'll do it when i'm free. Thanks once again!

goodluck on your endevour! lol!

Very good modifications! I just hope the gears mesh just fine. Or will be after some shims. From the pics, I can see that they're not properly meshed.

I admire your patience and perseverance. Modifying gears as not as easy finding pulleys.
Hats-off to you.

Btw, I also think that the replacement gears are supposed to make the rear rotate faster.
Anyway, the front and rear differentials of TB-03s are reversible (I think - as I haven't built one yet) so you can swap it with the front.


Thanks for the detailed Tut..

Great job mc drift!!,... cant waith to see it doing CS drifting...im also looking for those gears for my Yokomo kit.PM me for more details.thanks bro.