nubs

iTrader: (2)

Not good for rally. You would need to create a shroud to protect the spur and pinion. Wouldn't suggest running mod in this thing.

rccartips

iTrader: (3)

Hey guys does anyone remember the smallest spur + biggest pinion combo that can fit with a dremeled motor mount? Thanks.

Tom1977

I think a 53/72 64dp combo was the way to go.

minidriver

iTrader: (2)

Is there any way to get down to a 3.0 final drive in TB-04 that is TCS legal?? Lowest 64P option can come up with is 72/53 for a 3.39 final drive (53T is the max pinion that will fit without hitting motor screw holes, and I don't see any available 64P spurs that fit lower than 72T). Guys running 21.5 fixed timing motors are gearing 2.9 to 3.2 final ratio at our track, which may exclude any TB-04 entry. Anyone know the lowest final drive ratio obtainable with 48P gears and TCS legal?

zxcvb1t

I believe this is the maximum whith exotek adapter. otherwise you may have to modify the motor mount.

rccartips

iTrader: (3)

Might need to start replacing the crown gears to lower the IR.

Dyingslow

iTrader: (1)

You can fit a 54 tooth pinion in both the Tamiya High Gear (54601) and the Exotek mount as long as you remove the threads from the middle of the motor screws. I tried to attach a picture from my phone (sorry if it comes out weird). Once you shave the threads then you will have about 0.25mm clearance from the screws. I ran my TB04 with a 54 tooth pinion and 73 tooth spur when I was playing with gearing. I think you can get a slightly smaller spur in there but if I remember correctly I was pretty close to the end of the motor mount adjustment slots.

Sadly, I need to make space in my pit bag so I just put my TB04 up on ebay. I will try to mount up a motor today to see how much motor slot is left with a 73/54 combination.

Dyingslow

iTrader: (1)

The 73/54 combination leaves only about 0.5mm of play left in the motor adjustment slot. I threw some long set screws in the motor and held it by hand in the picture below so accuracy wise it is not so good but qualitatively a 72 tooth spur is likely the smallest you could fit in. To get closer to the ratios your are talking about then you would need to get some evo4 gears and shave the tops of the drive gear so that you can get the e-clip on the shafts and use ring gears from a TB03 (takes transmission ration to 39/17, if I remember correctly). I ran that set up for a while I really liked it but I eventually put everything back to stock for TCS since the mod goes against the spirit of the TCS rules.

rccartips

iTrader: (3)

Die hard shaft driver. Reviving an old TB04r to race in our 21.5 class. Low cg mods to lighten, lower cg and allow low hood bodies.

DaSilva3525

Nice! Btw I enjoy your videos sir, always entertaining

rccartips

iTrader: (3)

Re-engineered the old TB04 with lower cg (no front shock towers), wiring under the shaft, flex, lighter weight and inboard rear shocks. First shakedown run it beat our championship winning Xray T4 2018 by 0.2s/lap in the modified class using 5.5T motors. For those who love this chassis, it is still really fast

Techno Duck

iTrader: (5)

I finished up this TB04R to run in Tamiya Super GT, a popular class here in San Diego for Tamiya tub chassis cars. I ran a FF03 all last year, it became really difficult to keep up in the A-Main in a field of 4WD cars like the TT02 SRX, TB03, TA05..etc. I probably would have saved alot of money just getting a new TT02 SRX, but i had a lot of fun hunting for parts and building the FF03. Plus learning all the quirks of some of these older Tamiya chassis. This TB04R was no different.

Here are a few pictures from the build. Ill share the FF03 and recent TB05 builds i did also in the near future.

Arrived in great condition. This is the 2nd time i had a good experience buying an old Tamiya chassis from a member here on RCTech.



Fully disassembled.



I replaced all the gears for the angle drive and diffs. I spent quite a while getting all the shimming perfect. The spur gear shaft took almost 1.5mm worth of shims to get all the play out! The only change i made was using the aluminum diff housing from the TB05.





For gearing, i settled at 74/52 which puts me at 3.55FDR. A 53t will fit without any grinding, but requires a narrow pinion otherwise it will rub on the countersunk screws. I bought a Arrowmax composite which ill try out one day. Changing the gearing is a bit of a chore, so ill probably never adjust this again. We run fixed timing 21.5, so 3.55 should be enough.



All ready to close up.



The only major issue with this build was the chassis tweak. I saw this is a common issue with this chassis with the right rear twisting upwards. On droop blocks, i can could probably fit a 1.5mm feeler gauge under one side of the droop block. I have two new spare chassis, one carbon and standard that have the same issue. After a few hours of thinking about this, i was able to get nearly all the of tweak out. For the rear chassis braces, i drilled the holes out slightly larger. I then placed the chassis on a tweak plate with the rear on top of a ride height gauge. So when i press on the shock towers, it twists the chassis in the opposite direction. Then tighten the rear braces. The chassis now sits perfectly flat on the droop blocks.



I completed the final setup last night. As expected, the electronics side is 60g heavier than the battery side. I see Tamiya included 50g of brass lipo weights with this kit, but unfortunately this car didn't come with them. I added some brass to the receiver box opening to even things out a little. I currently have a 6k stick pack in, so i could go up to a 8.2k pack which is 25g heavier. Still, it would need a 20-25g lipo weight to even out. The NSX body i am using is 142g, so race weight would probably be pushing 1500g!
Right now i am considering moving the ESC over to the battery side and running a 6k shorty pack. After moving things around i think i can get it down to a race weight of 1430g. The main thing keeping me from doing this is the electronics layout doesn't look as clean .

bertrandsv87

iTrader: (2)

Wow...The minimum weight for this class should be pretty high then...The body is really the issue at 142g. Find the lightest possible body for the class first, then the lightest shorty lipo(170g or less), and then light electronics/motor,etc, before adding the rest of the weight under the battery with those 50g thin plates....

rccartips

iTrader: (3)

You can try running the wires under the shaft by drilling a small hole in the chassis.

https://youtu.be/1PD_QqpUwWU?si=w0N4t_6t3EvCGGTB

bertrandsv87

iTrader: (2)

Great advice rccartips....Those high wires move around alot, messing up the cg....My radio wires are always messy...lol....