The Tamiya M06 - Build log, and chassis review. Uh... I understand why people don't race them.

This is sitting on my bench right now.

The M08 was released about 10 days ago.  But.. I have a project to get to before the M08.  I have a M06 to build.  Just so.. we can have a benchmark to compare with.  And since it's about to be irrelevant, lets build the M06.

It always bugged me,why do you still see M05's but not M06's at TCS races.  It turns out.. there's a good number of reasonable reasons, we'll get into those as we build this car. 

First impressions, are that this is a off road buggy that's got a serious case of dwarfism.  That's not bad, as lots of people have converted buggies into very competent road cars.

In an effort to "build it once, and enjoy the car" I bought a bunch of hop up parts to put on the car.  Turns out... remarkably little actually fits.  There's a bearing set, the carbon reinforced arm set, heavy duty drivetrain parts, a swaybar set, and a set of shocks.

So... buying parts before the car didn't work out so well.  The upgrade gears, are the same as the M06 comes with.  It turns out, that the M06 upper links are already threaded rod, so the M05 set was un-necessary.  And the chassis doesn't support the droop screws with the carbon arms.

Because I don't actually plan on racing this car, the choice of motor got to be interesting.  This is a 13.5.  Go big or go home, right?

Here's how you set pinion depth on a Mini.  This cup shaped thing is used to define where the gear teeth go.

So how about the first page of the build part of the manual.

Betty rode shotgun for this, but I had to wait for her to be ready.  So... I did some of the cranky and annoying jobs while waiting for her.

I built the control links.

They're the soft cups, which... comes in handy later. 

And here they are, built, and ready to install.  These end up being a point of.. concern, later in the build.  

Betty was ready, so we got into the nitty-gritty of this build. 

The gear set is the same as the M05. But it's arranged a little differently.  And... not in a good way.  But first, comes the diff.  I've built a few of these, it's the same as the one in the DT-02, DT-03, M05, and M03.  And, I believe a few other tamiya cars.  This is their "universal cheap differential".

Just like the M05, the diff builds quickly.

Grease the output bevel gear, and the bushing it rides on.

Lube the gear spider.

Get the spider gears on there.

Drop them in.

Don't forget to lube the spider gears.

And now we have a diff.  Sadly, no matter how I adjusted it, the diff wasn't running smooth.  I think this is going to need some breaking in.  And while I'm ok with that... getting back to the diff I am NOT ok with.

Ok, now we start shoving the gears into the car.  The biggest complaints I have with this car, relate to this section of the car.

So, bearings go in carriers.

The carriers get stuffed into the gearbox outputs.  And the first side plate gets bolted on.

Evidently I lost a few photos  Here are both side plates installed.  And the cross braces.  So this puts us 3 layers deep to get the diff now.  This is where Tamiya let out a great tip.  For the screws that go into the cross braces, they recommend greasing the screws.  I ended up using a little grease on all of the fasteners on this car.

Grease on the self tapping screws makes them feel "mostly" like running them into pre-tapped plastic.  That's a very good thing.  If you're not going to buy the titanium or aluminum screw sets, this is the thing to do.

Half of the gears hang off the right side of the transmission.

And the primary drive gear sits under this cover.

That cover blocks access to screws that hold the transmission together.  So.. getting in here "later" is not simple.  If that stiff differential doesn't work itself out, I'm in for a solid half hour of fiddling to get back in to it.

The manual says to do it later, but I shoved everything into the transmission, so it's ready to just drop in.

I never actually want to get back into that transmission.  I hope I don't need to.  I suspect I will.  

Moving on, we get to start the chassis build.  I bought the carbon reinforced arms for the M05.  For them to fit, you need to trim off the droop screw holes.  

They otherwise, fit well.  Since they're carbon, the pivot screw pins are a little harder to drive in.  Grease on the threads makes it quite a bit easier.

Betty turned the page this time.  

Once the arms are on, you can slip on the transmission.  The setup here, requires that you bend some parts and "snap" the powertrain on.  This has some relation to the M08, where the chassis halves slide together.  

So that's the back half.  Third maybe?  this is also where you adjust the length of the chassis. That series of holes there lets you configure the chassis for 210, 225, and 239mm lengths.  (I always feel like there's a math error there... and there's some rounding coming out in those numbers.)

We're building the long chassis here.  Betty asked why, and well.. most importantly because this needs to fit the Miata body I think is most proper for this car.  The Minis are also smaller, so will rotate a bit faster than their larger cousins.  A longer wheelbase will help keep rotation under control.  And it opens up moving the battery as a tuning choice.

Moving the battery gives us a bigger range of CG to play with.  More forward for more front grip, more rearward for the reverse.

There are two sets of "bridge" peices to join the front and rear.  This is the wide spacer, with the long chassis rail extensions.

I haven't really talked about it yet, but I think we should cover it now.  Tamiya has lots of plastic they will commonly use.  ABS, nylon, fiberglass reinforced nylon, carbon inpregnated nylon.  And in this case, polycarbonate.  Polycarbonate is a very rigid plastic, and leads to quite the stiff end product.  For how poorly I'm viewing this build already, polycarbonate is a checkmark in the "good" side of the review.

At the back of the chassis, before the motor, you can see the bridge peices that link the front tub with the rear tub.  They're affixed by eight screws.  ... and they're totally not coming off.

Grabbing the tub and twisting, clearly shows how stiff this thing is.  More so than the M05.  Before I put this thing up for sale, I'll definitely be testing it's empirical stiffness.  .... But that's an article for another time.

Now things get weird.  The upper links, mount to the back of the shock tower, between the motor pod and the main chassis.  This "valley" leaves no room for adjusting much of anything.

So the outboard parts are exactly like a M05.  Which also means, no adjustment.  There are some aftermarket towers that allow roll center adjustment.  That... might have saved this models racing career.  Now, I went into this assuming the suspension geometry was going to be the same as the M05.  And.. as I discovered when i tried to make the adjustable suspension links, it's not.  It's better than the M05, but by how much?  I don't know.

Here's the back end, all joined up. The shock tower is quite floppy.  Lessons from the DT-02 and.. really, every Tamiya car says "carbon here is good".  But here we are.  Skinny plastic.  

The front end, is a stack up of parts that would make the TRF-201 proud.  Heck, it even looks similar.  Here's the suspension arm mounting block, with the suspension and steering mount.  These get stacked up on the nose of the front tub.

and with the bumper mount, all get attached with six screws. This ends up being quite solid, but it's hard not to be with that much plastic up front. 

The brass balls are the upper link mounts for the front of the car.  Again, netting us "better" geometry.  But this time, we get some roll center adjustment, as you can shim under those.

Next up is the steering rack.  It's identical to the M05.  Being happy "something" was the same, Betty asked why I wasn't really happy about it.

The steering rack on the M05 is probally it's weakest point.  it's got slop everywhere, and really no matter what you do, there's not a lot to solve the mess that it is.  On my M05, I ended up stacking a bunch of shims, and o-rings to preload and drive out the slop in the arrangement.

Annoyingly, even if you upgrade to all of the aluminum bits and peices, it's still sloppy.

So the front knuckles are mostly the same.  But the M06 gets a good dose of extra baggage.  The M06 knuckles get an additional plate on them, so you can fit swaybars later, and extensions for the steering link balls.  It's... definitely different.

Next page!

I built these bits to tamiya's spec.  Yet I have a bunch of positive camber.  I had to spend a lot of time shortening these down until the car looked even reasonably right.

Then the nose join peice, and front shock tower bolts on, hiding all of those bits.

You need to attach the steering servo link before you put that front deck on.  You really do.  and I had to undo the five screws to get back in there when I didn't.

And now things get awful.  Tamiya has you build and attach the shocks last.  Which is typical... but due to the rear tub geometry, you can't reach the lower screws for the rear shocks unless the tops are un-bolted, and even then, you need a long screwdriver to get clearance to install the screws.  Given the bottom screws are the ones you want to get to the most.. this is not an ideal situation.  Maybe relieving the chassis back there would give clearance, but that is a "should have been molded in" thing, not a "I need to address it now" thing.

The front shock mounts are tight.  But less so than the rear.  There are carbon shock towers available, that provide some shock position adjustment.  I think they're probably worth the investment if you're going to try to race a M06.

This is before I installed the swaybars.  Which didn't go very well... truth be told.

The servo mount, doesn't address shorty servos well, so in spite of having a nice, short, servo, it's mounted a good 5mm off the deck.

Getting down to brass tacks, I can't say i'm thrilled with this chassis.  Differential access is awful.  The amount of "layers" makes getting to things quite difficult, for example, the rear lower shock mounts, or the inner camber link mounts front or rear, or the front end of the servo pushrod.  And you can't touch the rear inner pivot pins without stripping the car down.

Then there's the lack of built in adjustment, and that the car doesn't support (and now never will) droop adjustment.

The car DID come with some interesting parts in the end.  It came with shorter shock shafts, in case you upgraded using the m-class shock set from Tamiya.  It also came with shock springs, to address this cars massive weight diffeerential front to rear.  And finally, if I had bought a complete kit, the cars also came with S grip tires for the back, and normal grip tires for the front.

The variety of "front and back" parts that the car comes with, seems to indicate a poor chassis from the get-go.  Given tamiya won't ship you "other parts" beyond their 5 or 7 turn silver springs unless a car is completely useless without new springs.  It makes me wonder....

I mentioned at the outset, that the car screamed "buggy" to me.  I dug the DT-02 off the shelf, and lets take a look.



Well, we have a vaguely delta shaped chassis.  Same with the M06.  The motor is out back.  The battery is down the middle.  Shocks are in front of the rear arms.  The front end is a several layer stack of parts to get the shock tower, inner pivots, and even the bumper mounts are similar.

Short arms and legs on a normal size body.  Totally dwarfism.  Hah.

So... in the end, I totally understand why, even with the cars ability to put down power earlier, why it's not a popular race car. I would not want to go racing with this platform.  As I built it, I kept finding kludges and things that just weren't ok.  "Well we could do better on..."  Oh yeah, the M08.

The M08 is better.  How much?  We'll find out in a week or so.  

And a hint to some other things I've been up to.  This.. is a velodrome.  With r/c cars on it.

Seeya next time.