Monday, November 13, 2017

Weighty subjects. FF03 parts.

To make this post make sense, we need to talk about USGT racing.  Lets start here:  The important bit of that PDF is the following quote:

Weight Specification: 4wd Minimum 1380g in race-ready trim Fwd no minimum weight

No.  Minimum.  Weight.  

Oh boy!  new parts.  A big pile of carbon reinforced parts.

So the FF03 chassis is soft, and flexy.  The springs are to hard.  And really, I was very displeased with my FF03 as it came out of the box.  $40 later, I had ordered all of the carbon or at least "hard" parts.  Most of them Tamiya claimed they were lighter.  I... well, mostly they weren't.   

Here's the evidence.

First, starting weight: 

The gearbox bridge:  3.5g  No savings.

Front suspension bridge: 2.2g savings

Main chassis: 5g savings

Moto brace: Gain .1g

Front bumper mount: 0.2 gram gain

Shock Pivot Top: 0.2g loss

Rear suspension pad: 0.6 gram gain

Rear suspension brace: 0.7g loss (times two..)

Rear suspension tower: 0.2 gram gain

Rear shock tower: 0.3 gram gain

And in the end, we have this:

Something like a 9 gram weight savings.  That... was not worth the effort.  For weight savings, at least.  The car is ~massively~ more stiff, so there is that. 

PS: as a side note, the suspension on the FF03 is mostly TB03/TRF418 stuff.  The knuckles, suspension arms, driveshafts and such, are all from the TRF crowd.  

Friday, November 10, 2017

Racing the Tamiya Team Hahn Euro Truck on CRC Black Carpet

First of all.  Here's Tamiya's rules: 2017 TCS Rules  Go to page 12 for the stuff on the trucks in specific.

Here we are, before my first race with my Euro Truck.  We're racing at Windy City RC. 

The Euro Trucks handle asphalt really well, as stock.  Things get all sorts of weird once you introduce high traction carpet, that's doped with traction compound.  So I thought I'd share what I've seen what makes these trucks work on Black CRC Carpet.


I've seen use of both the inside, and outside shock holes.  The fastest guys use completely oppisite setups, so I believe this may just be a "driving style" thing.  The fastest lap was turned by a truck with both springs "in" and the guy who won the main, had his out.  There's not enough data to draw conclusions on that. Yet.

Both people had "some goop" on the shocks.  I believe million weight diff oil.  Others are using Lucas Marine Grease.

The steering links can also be a little tight, and cause some binding and somewhat inconsistent steering.  It's to your advantage to waller them out a bit with a drill so that at the extends of steering and suspension travel you don't have any binding.


The fastest lap time was turned by a truck with no weights on it.  The next fastest guy, who was running 20-30g, just enough to balance out the chassis left-right, and move the CG back a bit.


Almost everyone is doing "something" under the bodys to suck up the space between the body and the bumper.  Nothing seems consistent.  I don't believe this has any real effect on handling.


Everyone has "something" in the front diff.  Rear diffs are nearly, or completely open.  I was told to go with 1,000,000 weight up front, 10k in back, and that seems to have helped corner entry.  Keep in mind that the diffs are not sealed, and whatever you put in, will leak out eventually.


This is where the answers are pretty consistent.  Everyone is running a whole lot of glue.  While it's typical to glue the outside of a tire, everyone is gluing both sides.  People who aren't tipping over, glue from rim to tread on the outside fronts, as a minimum.  I think I ended up with three layers of glue on my tires.  Everyone was running at least glue up tot the part line on the inside of the front tires.  In the rear, everyone was running something on the outside, usually to the part line, some to the tread.


First, the steering servo arm boss is long enough to hit some servo bodies.  It needs trimming.  Do that or else your truck will have inconsistent left and right turning behavior.

Now, the radios, it's key to keep your steering to "just enough" so you don't tip over.  This can be difficult to set at first, as the trucks behavior changes somewhat between tiptoeing around the track, and a full speed run.  Going fast means having your steering limited to 60-80% of your full steering travel.  That percentage seems to change as traction some up, or goes down during the day.  This is a "travel", EPA, or DualRate, not expo or speed.


The long and short of it is, 4 wheels on the ground, and commit.  These things tend to corner on three wheels, so before you punch the throttle again, get the rear wheel back on the ground, then go.  Getting on the gas before you have all 4 wheels down leads to some squirrely behavior.  (Swapping ends, fishtailing...)

Race to Race Prep:

Between races, the front tires get cleaned between rounds.  With a paper towel, and the usual r/c safe motor spray type stuff.  (Duratrax Magnum II at the local track...) The rear tires get some traction compound.

So that's what I've seen, and what I've learned.

Monday, October 16, 2017

A hint at my FF-03

USGT has a interesting rule hole.  It's intentionally placed there, to encourage FWD cars.  They have zero weight limit on FWD cars. 

...So I bought a FF03

How light can this thing be?

It's so hard to read that.  

861 grams without wheels.

What about with the stock wheels on it?

971.2 grams with everything, the stock motor, and a cheap brushed ESC. 

In our next installment, we'll talk about the carbon reinforced parts.  

Thursday, October 5, 2017

Torque the ripper - TT02b gear destruction.

I got together with a buddy of mine this weekend, and the name of the game that day was "lets landscape his backyard".  Erm, we did laps, and laps, and laps of his back yard.  Many pounds of dirt were moved, grass or no grass. 

Suffice it to say, we had fun.  My car was doing some odd things.  We'll cover the electronics woes in a later article, but in this case, there was a clicking noise.  Sometimes.  Well my TT02b has eaten two, maybe three, diffs over the months I've owned it.  I figured I ate another diff.  I was already figuring I had not shimmed the diffs properly. 

Turns out, I was wrong.

There is something quite therapeutic about the after run cleaning.  The shocks are fine, the swingarms all drop smoothly.  Everything is fine.  ... Including the differentials.  Huh?  The diffs are fine?  ... what the?

Well... here's what was causing the clicking.

It seems my pinion moved on the motor shaft.  Then lodged itself in there.  Motor torque was enough to cause it to get pinned on the motor shaft, in spite of the loose setscrew.  What we're also seeing here, is just how tough the Tamiya fiber impregnated gears are.  There's nearly no wear on that spur gear, and that pinion is T O A S T. 

Well.. now i'm running a 25 tooth pinion.... and I swapped spurs because I had a few spares. 

If you look closely, on the right, you can see my friends "hey lets never have the shock towers get loose again" mod.  I've mentioned it before.  It turns out there's enough meat on the diff covers that you can through drill, and through bolt the shock towers.  I highly recommend doing this. 

Now... what will we break next?

The f104w transformed. A f104 pro?

The F104, and F104w are "related" cars.  And they can be converted.  the F104 front end is a lot more sophisticated than the sliding knuckles on the F104w.

I bought the wrong tires for my F104w, and the wrong body.  Between the two, I figured I was most of the way to converting the car over.

Well, here's the result:

Looks good doesn't it?  It's a f104 pro body and wing set.  I trimmed the "pro" refrences off, because i'm that sort of retentive.  

I am going to re-wire the guts of this thing.  The damping plate fouls a bit on the motor wires and battery wires.

For those who want to convert their F104w into a F104, here's what I needed:

F Parts: 42289 TRF102 / F104
Stainless Shaft: 58431 - 3x33.4mm F104
4mm Ball Connector: 44002 (Gold Color, 5pcs)
4mm Adjuster: 44002 - 6pcs
5mm Aluminum Ball Nut - Blue 10pcs
E-Clip 2.5 x 6 x 0.4 - 10pcs RM01 / F103 / FGX
Double Metal Shield Bearing 5 x 10 x 4 mm (2 pcs) - F104 Front Axle Bearing
M3x6 Flathead Screw (20pcs)
TurnBuckle 3x35mm(2pcs)
30mm m4 flathead screws.  (2pcs)

M4 nut (2pcs)

The conversion costs around $30.  To make the 3mm turnbuckles work with the 4mm adjusters, you need to drill them out quite a bit.

It looks a lot better.  It drives about the same.  I don't know if it was worth the effort.  But, it does mean that I can run in the local F1 r/c races.

Friday, September 22, 2017

The TT02b MS - Answering the question, again, of what happens when you turn a touring car into a buggy.

Mistakes.  They have been made.  In spades.  This time, it was some purchasing agents wanting to dispose of extra stock of some Tamiya buggys.  

Here we have, a TT02b MS.  
(Thanks RCMart)
Amusingly, TT02b based buggys are available for around $160.  They’re pretty complete, and include things like a nice ESC, and a motor.  However, this, is not that.  “MS” is Tamiya speak for “special edition.”  Something much better than stock, but much less than the “R” chassis.  R is for race, and come with a complete set of upgrade parts.

The TT02 is not a 4wd buggy, it’s a touring car.  Yet, here we are, staring at a 4wd buggy.  But it all starts back with that TT part of the name.  TT is Tamiyas new generation of touring car chassis.  The “b” part, is buggy.   This is not the first time this has happened.
Where the car came from
In 1992, Tamiya released the TA01 cars, and with it, started what was the parking lot racing boom.  Those cars had their roots in basher level 4wd buggies.  But very quickly they became their own unique chassis.  As soon as they got popular, everyone in the industry started making touring cars.

That eventually lead to the current state of affairs in on road racing, where the popular classes are mostly based on 4wd touring car chassis.  The bleeding edge of development, is mostly with on road cars, leading to the strange situation, where the 4wd tech from a road car, might just make for a better buggy.  


Touring cars, the have made the trip back to 4wd buggy have surfaced before. Most famously, In 2005, J Concepts released the BJ4, a conversion kit for the Team Associated TC4.  

And that’s how the TT02b came around.  Tamiya took their TT02 touring car chassis, and threw some long suspension arms on it.  I think I like what came of it.  

What is the TT02b

The TT02 chassis, is in it’s basic form, a very cheap tub chassis.  The sort of thing that comes with spring dampers, plastic drive shafts, and bushings everywhere.  I’m still mystified on how Tamiya manages the plastic drive shafts, and drive cups.  

It also comes with pre-molded steering and suspension links, meaning you can’t set it up wrong.  Typical of Tamiya, the motor mount has preset motor positions, so you can’t screw up the pinion mesh.

The car is a great measure of “enough”.  It’s stiff enough that the drivetrain doesn’t tie itself in knots.  It’s got enough suspension travel to be useful.  It’s complex enough to be an challenging build.  It’s simple enough to be cheap.  It’s price point is right where it’s an easy decision to buy.  

What about the TT02b MS

Well, “enough” isn’t exactly enough for what I want to do.  I want something cheap, but I also don’t want to pogo stick dampers, control linkages that can’t be adjusted, and I can buy my own motor and speed controller, thankyouverymuch.

But first, let’s take a good look at the platform in general.

The high points:

  • Sealed Gearboxes
  • Bellcrank Steering
  • 4 wheel independant suspension
  • A durable tub chassis
  • Integrated gearbox and chassis
  • Most TT02 parts fit
  • Radio protection box
  • Includes a Motor
  • Includes a Brushless Capable ESC
  • Wide range of gearing options

The low points:
  • The suspension arms are soft.
  • The tub chassis is flexible.
  • Lots of steering slop.
  • Questionable motor cooling.
  • Requires two sizes of bearing.
  • No caster.  
  • Plastic differentials.
  • Plastic differential drives.
  • Plastic driveshafts.
  • Plastic shock towers.

That’s where the TT02b MS comes in.  The MS comes with most of the basic bits you would want to turn the super basic chassis into something nice to drive.  Those are, a metal drive shaft, metal dogbones, metal outdrives, and metal rear hubs.  Along with that, you get composite shock towers, a full set of turnbuckles, Tamiya's oil filled shocks, and very little else.  

While the typical TT02 comes with an ESC, motor and tires, you don’t get any of that with the MS.  Which means my friend and I had to seek our own.  This is where mistakes start to rear their head again.  We bought 13.5 turn Brushless motor setups.  

The choice was driven by the local RC track specing 13.5 blinky as the motor setup of choice for their weeknight racing program.  

The whole drivetrain is supported by plastic.  In some ways that make me a little nervous.  As is typical, the main spur gear is plastic, and that doesn’t faze me at all.  However, the bevel pinion gears that drive the differentials, are also plastic, and I fear that under the full force of an angry 13.5 brushless they might give up the ghost.  

But that’s not all that has me uneasy, the differentials are completely plastic.  That includes the little metal spider that’s in the center of most tamiya diffs, and all of the gears.  I have a sneaking suspicion that the front and rear gearboxes are going to be the weak point on this car.  Time will tell on that one though.  

The Build

Building the TT02b is remarkably simple.  Everything builds up, or down, from the chassis pan.  The chassis pan is exactly the same as the one from the TT02 touring car.  This leads to the need to use some adapters.  

The swingarms use typical tamiya bent wire hinge pins.  The TT02 road car, uses large diameter plastic nubs on the swingarms to handle the hinge duties.  To take up the slack, there are plugs to take up the slack on the rear of the chassis, and some rather fiddly slip in adapters in the front.  

Both the front and rear suspensions hang off of the diff covers.  This means you’re just 4 screws away from having access to the diffs.  The build manual says to use a little bit of AW grease in the diffs.  It makes them a little stiffer, but nowhere near enough to make the car handle as well as it should.  If you can get your hands on it, I recommend some 200k weight grease packed into the front diff.  

Speaking of which, you can install the diffs upside down.  I’d say make sure you get that right, but it’s a good idea to assume that’s the problem instead of assuming you’ve hooked your motor up backwards. Not that I’d know about doing that sort of thing.  

The kit doesn’t come with tires, so you’ll need to provide your own.  We went with J-Concepts Bar Codes, and haven’t been disappointed.  Those tires come with “standard” foam liners, and while you can stuff the whole thing in the tire, I do not recommend that.  Trim the foam liners to match the width of the tire.  

Painting the body is a little, off putting, as tamiya builds go.  Tamiya recommends applying the stickers before painting, which means the overspray film is more or less useless.  You’re to apply the stickers, because there’s no other good way to determine where to do the paint lines.  I’m saying “be careful”  or put tape on the outside of the body once you’ve applied the big stickers.  

On a pleasant note, unlike many tamiya sticker sets, the MS sticker set, is friendly to different paint patterns.  My friend painted his car blue and grey, and mine is white and grey.  They look very good.

What needs fixing: AKA Living with the TT02b

The MS models are somewhat modified from the factory, and along those lines, I also bought a bunch of parts to install before I took the car out for the first time.  During the initial assembly, we installed the TT02 hard chassis, some TRF dampers, a 19 tooth pinion, metal motor mounts, and metal bearing supported bellcanks.  

These address a few things right off the bat.  First, the chassis is … soft.   The hard chassis has glass fiber injected in it, and is remarkably rigid.  With the airtime that a 13.5 powered buggy can get, plastic shock bodies just won’t have a good time, the TRF dampers have metal bodies, and can stop those from blowing out.  Running a car hard, can cause plastic to soften, so the aluminum motor mounts were called for.  The metal steering bits were to overcome the typical tamiya steering slop.  

I also cut small slices of fuel tubing to put on the steering and front suspension balls. This removed nearly all of the steering and camber slop.  Generally this isn't needed, but the car was wandering fairly badly. The arms still drop freely, but now there's a whole lot less wiggle room.
My goodness, there’s something magical about that first time you peg the throttle on a 4wd buggy.  They’re really quick.  Especially when you’ve got some reasonably sticky rubber on them.  Unlike a touring car, a buggy is sprung softly, and between the weight transfer, big contact patches from the 2.2” wheels, and that 13.5 turn motor, things would get going rather quickly.  

After a few months, a few things have popped up.  So far, I’ve stripped one differential drive gear, and one pinion.  I’m told that shimming the diffs to improve gear engagement fixes the issue.  For now, I have .3mm of shims on each differential.  And I have some GPM metal ring gears to replace the stockers if they strip again.

The fiberglass shock towers like to wiggle loose.  And the screws holding them to the diff covers aren’t exactly confidence inspiring.  Thankfully, where the shock towers mount, are in clear plastic, so you can drill through.  Once you’ve drilled through, you can then through bolt them.  Once through bolted, they do not come loose.  

The lack of front end kickup, makes hitting jumps, and landings a bit challenging.  This is a legacy of the touring car chassis, so I don’t know what can be done about that.  I just drive better.

I’m still deep on the tuning adventure with the car, right now I'm running 200k diff oil in my front gearbox, and the rear is essentially open.  My friend has 500k in his rear diff, but his car has never seen the track…   On the bright side, a complete replacement diff set is $7.  They’re cheap enough that you could buy a few, and with the quick access to the diffs, swapping them out for testing isn’t really a chore.  

So I've broken mine. My friend has broken his. On a bad landing, I caught a rear swingarm, and stopped the buggy dead. That landing ripped the pivot pin out of the rear of the car, swung the swingarm back, and tore the hard plastic chassis. I suspect a normal ABS chassis would have been fine after that crash, excepting the whole rip the swingarm out thing. But.. we'll never know on that one. In another crash, I broke the ears off a steering servo. The servo mounts are a bit soft, so I think that figured into that bit of damage. Oddly, it seems that the front shock tower is a bit of a weak point. If you're industrious, it might be worth copying it in carbon, as replacement FRP ones aren't exactly cheap. Finally, the car has a habit of dropping front dogbones. When that happens the steering locks to the side. I think some CVD's would fix the issue. But it doesn't happen often enough that i'm really worried about it. And CVD's aren't exactly cheap.

How can I buy a TT02b, whats the best to buy?

The TT02b is available in three flavors.  The Neo Scorcher, the Plasma Edge II, and the Dual Ridge.  The TT02b MS is built off the Dual Ridge.  
  • Neo Scorcher - 58568
  • Neo Scorcher Bright Pink Metallic - 84387
  • Dual Ridge - 58596
  • Plasma Edge II - 58630
  • Neo Scorcher Blue Metallic - 47346
  • Dual Ridge Black Metallic - 47355
  • TT-02b MS - 84418

The TT02b MS is definitely the one to get right now.  (as of September 2017) For $160 you get the car, and a bunch of upgrade parts that really do make the car better to own.  So that's where I'd go.  What you don't get, is a motor or ESC.  A stock tamiya motor is about $10, but who'd do that in this day and age of crazy brushless setups.

Thanks for reading.  I'm sure there will be updates in the future!