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:
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!
-Nero
