Tamiya TB Evo 4 2015 edition (Part 1)

With the exciting news of Tamiya eventually releasing the TB04 and now a new TB Evo 6 (Review soon) it also provided existing Evo owners t...

With the exciting news of Tamiya eventually releasing the TB04 and now a new TB Evo 6 (Review soon) it also provided existing Evo owners the option of a few new parts that they can add to their existing cars.

Eric Bresser is one such owner and here is part one of his guide to updating the mighty TB Evo 4.


With the coming of the new TB evo 6 i just got interested again to update my “old” Tamiya evo IV. In this Part I, I will explain how to use the new gears (gear-diff and  bevel gears) from the new TB04 pro and TB Evo 6.


First up, I replaced the suspension components with the TRF418 suspension parts, lighter and better geometry.


At the moment I have just removed the posts to allow the chassis to flex. I also spaced the steering with bearings to make the arms lower for improved geometry. Here you can see how the upper arm from the servo still has to be mounted high to ensure that it does not hit the centre drive shaft.

Drive Train

I bought the TB04 gear diff and some other gear parts and updated my Evo 4. I just took all my parts (spools, gears etc from the TB03, Tb Evo IV and started... and made different combinations to find the best fit. It took some time but now the drivetrain is smooth like butter :)

For the rear: First you have to remove the top and bottom diff covers, the TB04 gear diff has an oil cylinder that is too fat to fit with these installed.  Then you want to get all the TB04 gear parts (gear diff and bevel gear). This is because the bevel gear from the TB Evo 4 it will rub against the gear-diff oil cylinder.
The std TB04 bevel does not fit, it rubs against the TB04 gear diff in the rear
So to fix this you will need to use the TB04 bevel gear.. The gear diff fits perfect but for the bevel-gear I made a little adjustment. The bevel-gear is to close to the gear-diff and won’t fit the shaft perfect.

Here you can see the larger hole reamed into the Bevel gear to make it fit on the shaft
What I did is to make the hole from the bevel gear a little wider. Now the bevel-gear moves further over the shaft and sits further from the gear diff.
Here is the result, a perfect fit
We now have to fir the bevel gear onto the change the screw that
Here is the full assembly
To fit and hold the bevel gear I used some 0.2mm shims to cover the end of the bevel gear and a 2x5mm flat cheese head screw as the Std M2 screw has a fatter head, and this could faintly rub against the oil cylinder on the new gear diff.
Here is the final installation, with space to spare and the gears run smoothly

Front end (Using the TB Evo 4 Spool)

Here using the TB04 gears needed some more adjustment, they were way too tight and it did not spin freely.

For the bevel gear I made the same modification as the rear of the car and that moved the gear down the shaft and stops it binding with the Spool gear.
Front bevel gear assembly all ready to go into the car.
Fitting the TB04 40t gear onto the TB Evo 4 front spool I needed to sand the 40t gear. This is because the back of the gear has way more off set and it makes the spool bind with the front bevel gear. You just need to sand the offset of the gear and its a perfect fit. (NOTE, You do not have to do this now, as Tamiya has since released a TB04 spool / Direct coupling  (Tamiya Part no 54592) which is a perfect fit)
A quick Dremel moment
From Left to right, TB04 gear, TB Evo 4 Gear, Sanded TB04 gear 
This is a quick process, although a different spool (maybe the TB04 one) will probably have a different offset and may just fit in easily with no modifications.

Now its time to fit it into the car.

Here are some more pics

The next wave of modifications will include:
  • Low profile shock towers (For Short TRF shocks)
  • New chassis (Narrow and for Lipo)
  • New Servo Holder
  • New lipo Holder

Now its time to start on the CAD package and get ready for PART 2 (Click here)

Very cool stuff :) Check out Part 2 (Click here)

Words and pictures Eric Bresser

trf 7981549471406785918

Post a Comment

  1. What sort of turnbuckle ends are they?

  2. Hello Clive,
    These are xray turnbuckles.. sorry for the Tamiya-guys. But ik like the way these work, smooth, no binding, and nice black color instead of gray.
    Best regards Eric

  3. Hi there Eric,
    It looks really inspiring :).

    I would like to enhance my good old tb evo 5ms and have some questions.

    You said you have used 418 suspension parts. Did you mean only arms or even uprigths, c-hubs, stab bars, etc? What about axles? and double cardan joints in front drive?

    Regarding diffs, I think it's clear that using TB04 diff and spool with TB04 bevels is the way to go. It should be almost direct fit in my evo 5ms (just by enlarging bevel's hole and shimming acordingly). I'm wondering whether DCJ (#42216) is a direct fit in my evo 5ms. Probably I should change c-hubs also and don't know what else :S.

    By changing original diff and bevel, I would say that internal ratio also changes, unless there is the same number of teeth in the TB04 bevel/diff spur than in TB evos.

    By the way, do you use metal or plastic bevels for the rear diff?

    Thanks in advance for your comments and for your awesome work upgrading the evo 4!

  4. Is there any FRP chassiss for tb evo VI

  5. This comment has been removed by the author.



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