Speedy's TB04 PRO Build Thread

[speedy_w_beans 4272]

Top view of chassis with the front and rear pretty much complete.

Center gearbox cover, chassis motor brace, and antenna holder installed.

Outer bearings, cross pins, wheel hexes, dummy wheels/tires, and locknuts installed.

Front bumper, front body mounts, and rear body mounts installed.

And that pretty much wraps it up. I need to go through my toy box and see if I have a good brushless system and servo to install. As far as a body is concerned, it will have to wait until the weather is warmer for painting. I don't have a good idea for one yet.

Now that I have a complete chassis in my hand I have a few feelings about it:

- On one hand this has been one of the more touchy kits I've built. Dealing with a warped chassis tub, fixing leaky diffs, shimming all the gears and suspension parts carefully, etc. requires patience -- it's not a kit to be slapped together without care. Upgrading the diff O-rings, providing some diff sealing tips, and instructing how to shim the gears would help people who haven't built a TB03 or TB04 before. Even including a little black RTV and some packs of shims along with the O-rings would make the experience easier, and it doesn't cost much to include these items.

- On the other hand I was really jazzed about this release a year and a half ago, and I wanted to do as high quality a job on it as possible. I've been a TB03 fan for a long time and was looking at everything very closely as the build went together.

- The short TRF dampers and ball bearing steering are very nice.

- The drivetrain feels fine, but I can't assess it well until it's broken in some. I need to run a pack or two through it to loosen things up a little.

- The motor mount limits the gearing choices somewhat; this might be an issue for someone trying to run one in 17.5T classes. For fooling around in the street, it doesn't matter.

[Butler 338]

What are your thoughts on all the shimming? I am about to build my 4th FF03 and thinking about building it shimmed to remove as much slop as possible, although on this model I don't think the gearbox needs it. The rest of the car could be tightened up though. Is it worth it?

[Cplus 94]

F you are racing, getting rid of slop is always worth it. Just make sure there is no binding across the whole motion range.

It won't make you faster in an absolute sense typically, but it can mean that extra bit of consistency which leads to those lost tenths.

If you're bashing, unless it is so bad it causes binding itself, well, it will make you feel better having done it.

[speedy_w_beans 4272]

On straight gears I wouldn't worry about shimming unless there's a chance the gear will rub against the gearbox. I doubt that's likely on the FF03. On the TB04 I was keen on shimming because almost all the gears are bevel gears; under load they are constantly trying to push away from each other; this can impact how they wear.

Like Cplus says, suspension/steering/damper shimming is more about consistency than anything.

[speedy_w_beans 4272]

There are no self-tapping screws included with the TB04 PRO kit except for two supplied for the servo horn.

In the first release of the TB04 PRO (84339) the majority of screws are Philips (JIS) head machine screws; there are a few hex cap screws for the differentials and the center gearbox.

In the TB04 PRO II (84382) the majority of the screws are hex machine screws. This is similar to the TA06R; it comes with hex machine screws as well.

[Butler 338]

The car is only used on a track, whether purpose built or temporary. I was considering going for a better steering servo than the Acoms ones I have been using for years. Then thought whether it therefore I should tighten the car up to suit.

[JeepnMike 150]

Looks awesome Paul! All of the blue Tamiya bliss on that chassis really makes it a stunner to look at. I hope you chime back in after you have had a chance to drive it a bit and of course please add photos when you have a painted body!

Side note, I was asked to be on a team doing a 6 hour enduro race designed to mimic a LeMans race (info here). I have never raced a touring car... never even driven on carpet! This should be interesting!

[speedy_w_beans 4272]

The car is only used on a track, whether purpose built or temporary. I was considering going for a better steering servo than the Acoms ones I have been using for years. Then thought whether it therefore I should tighten the car up to suit.

Since you're using it on the track then shimming is worthwhile. It will help eliminate some small variables while working on bigger setup issues. You don't want to overdo it; everything should still move freely, but here are some areas to evaluate:

- Suspension arms near the suspension mount blocks

- Uprights and C-hubs at the ends of the suspension arms

- Steering knuckles to eliminate up/down undamped movement

- Damper pistons to eliminate undamped movement

- Axles to eliminate in/out wheel movement

- Differential to set mesh position and eliminate side-to-side movement

- Diff internals to minimize wear and maintain consistent motion

If you're running the IFS setup then shimming the bearings in the IFS rocker arms is a big improvement as they tend to move a good amount on the posts -- this represents motion that doesn't get transmitted to the dampers. I'm also a big believer in replacing the IFS bushings with 850 ball bearings to reduce stiction/friction; it made a huge difference in one of my TB03s.

I'm also a big fan of using ball bearings in the steering bellcranks and steering bridge; the bushings and flange tubes are not as precise. So definitely use ball bearings in the steering setup and in the IFS rockers if you're running those.

[speedy_w_beans 4272]

Looks awesome Paul! All of the blue Tamiya bliss on that chassis really makes it a stunner to look at. I hope you chime back in after you have had a chance to drive it a bit and of course please add photos when you have a painted body!

Side note, I was asked to be on a team doing a 6 hour enduro race designed to mimic a LeMans race (info here). I have never raced a touring car... never even driven on carpet! This should be interesting!

Thanks! I'm not sure I put a lot of value on the blue turnbuckles or the blue ball connectors, but the dampers, damper stays, and steering are nice. I was pleased to see the kit includes low-friction adjusters for all the ball connectors.

This PRO ended up very similar to my main TB03:

- Stock plastics

- Fully shimmed throughout

- Turnbuckles w/ low-friction adjusters

- Full ball bearings including steering

- Better dampers (short dampers vs. TRF415 dampers)

Enjoy the enduro; I'd love to hear your impressions of on-road after driving off-road for so long...

[Butler 338]

Thanks for your help speedy and cplus. I have bearings. Is there a standard shim pack I should start with?

[Cplus 94]

3mm Tamiya one comes with 0.1/0.2/0.3mm and can do the arms and uprights.

You need 5mm on the steering and IFS posts.

Don't bother shimming if you are using plastic spacers and suspension mounts. You'll never get rid of the slop.

[speedy_w_beans 4272]

Other options include 3Racing shim kits -- 3RAC-SW03, 3RAC-SW03/V2, 3RAC-SW05, 3RAC-SW05/V2.

The non-V2 kits are 0.1/0.2/0.3mm shims; the V2 kits are 0.1/0.15/0.2/0.25/0.3mm shims. I just went with the non-V2 kits because they were a little cheaper; the extra 0.05mm steps didn't seem worth it to me.

[speedy_w_beans 4272]

Short update -- I did finish this chassis with electronics and put a HPI BMW M3 shell on it.  No other mods or upgrades have been made to date.

[TwistedxSlayer 1290]

OMG that is a good looking chassis, loved reading this thread, I'm very impressed with it. Looks great with that body and wheels

[Room335 738]

Great thread @speedy_w_beans, thank you. I'm looking at a TB-04 standard kit. Just finished building a pair of TT02's, and wanted something that was a little more challenging. I have a couple of questions for you (or any other TB-04 gurus):

1. You mentioned the unsealed center gearbox. Is there any way to remedy this? I will be running in parking lots. Is this a recipe for disaster?
2. Anything you recommend as critical upgrades (keeping in mind this a standard TB-04 kit)?
3. Is the shimming necessary for casual use?

Thank you!!

 

 

 

 

 

[speedy_w_beans 4272]

@Room335, some thoughts:

1.  These plastic tub cars tend to collect microscopic pebbles in them from driving in parking lots/asphalt. Collect enough of them and a few are bound to slip under the motor and get to the spur.  I'd say get yourself some aluminum tape and just cover over any gaps you find around the center gearbox and tub (there aren't too many) and you'll probably be fine.  I complained a little when I did the build because I had previously built some TB03s, and all gears are enclosed on those chassis.  Likewise, the TB05 PRO gears are protected as well.

2.  Referring to the base TB-04 manual here (https://www.tamiya.com/english/rc/rcmanual/tb04_t.pdf), some parts I would consider upgrading or addressing include:

Step 4:

• Replace the BA25 O-rings with TRF orange O-rings to avoid oil leaks between the diff cases and the out drives.
• Coat the mating diff surfaces (where the gasket goes) with a thin coat of silicone RTV or Associated green slime to avoid oil leaks between the diff cases.
• If you're going to run a hot motor and bash the car hard, I'd consider metal cross pins and diff gears for added durability.

Step 5 and 6:

• Again, if you're going to run the car with a hot motor then consider replacing the 20T miter gears with metal gears from the DB02 center gearbox.
• Because the spur gear mounting screws are so thin, be sure to have some decent JIS screwdrivers (not Philips) for the best locking action between the driver tip and the fastener.

Steps 7 and 8:

• You might assess how much play there is between the bevel gears and shim them a little.  It seems like I had to shim a fair amount in my build, but it might be better with later production parts.

Step 9:

• Turnbuckles can be a pain to build; it's helpful if you have a better turnbuckle wrench, adjuster holder, and calipers to take measurements.

Step 12:

• Note that M3 needs to be filed slightly so the steering doesn't interfere with it later.

Step 14:

• Recommend upgrading the 630 metal bushings with 630 ball bearings for the steering.

Step 16:

• Recommend upgrading the 850 metal bushings with 850 ball bearings for the IFS rocker arms.  This makes a noticeable difference in suspension friction; I've witnessed it directly on my TB03.

Step 22:

• For casual use the kit CVA dampers are fine; I just think the kit oil (yellow, 400 cst) is a little thin for them.  I'd get a bottle of 500 cst from any brand and use that instead.

Step 25:

• Recommend upgrading to a steel pinion to replace the kit aluminum pinion.
• If you can find the upgrade, look into replacing the kit T5/T7 motor spacers with aluminum parts from Tamiya or Exotek.  Both brought parts to market that allow slightly larger pinions to be installed if you run a slower speed motor.  The flexibility is nice to have.

Step 31:

• Recommend upgrading the A4 plastic wheel hexes to some aluminum clamping hexes (5mm thick).  I think you can find a set from Yeah Racing for about $7.  It's just really nice to remove a wheel and not have the cross pin fall out of the axle because the hex shifted.

For casual fun, that's about it.  I wouldn't worry about lots of blue aluminum bling.  Most of the suggestions are minor improvements or ways of adding durability for higher power levels.

3.  You don't have to be as careful about shimming as I was.  The front and rear gearboxes are pretty good; just pay a little closer attention to the center gearbox.

I hope you enjoy the kit!

[Room335 738]

Amazing reply @speedy_w_beans, thanks so much! Really looking forward to the challenge of this build, and decal set:

[DeadMeat666 1675]

Very organized build thread, which makes it a joy to follow. It's very interesting to see the differences between your TB04 Pro and my TB04R. Interestingly, your motor plate are blue aluminum while mine are BLACK aluminum! I'm not sure why Tamiya did this to be honest. Maybe they were going for a more 'stealth' look for the R? 

My bodyset will be quite different though, but yours will be tough to beat!  

Keep up the good work!