The Tamiya M08 Concept - Doing a RWD mini right. Lets build it.

I've been itching to do this one for a long time.  In December, we got a model number, on a parts list.  In march, we got the shadow, and in april we got a picture of the actual car. 

..... and then we had to wait.  June 21 the car was released.  I placed my order that night, along with a bunch of hop up parts.

While waiting for the car, I placed some other orders.  A huge bag of screws, and some hop up parts.

June 30, I got this.



It's like a red version of the M07 box.  I approve. 

Carbon shock towers, some tires, and the low friction pivot bushings also showed up.

So why would I want a M08?  I'm hoping that a RWD car will be faster in low traction situations.  My M07 spins the tires for-ev-er.  This should not do that. 

Since the screws having arrived yet... lets dig into the box.

Lets start with the box labels.  In japan, where space is an issue, most shops display the ends of boxes.  So the M08 (like many other cars..) gets a pretty end card.  This one typical Tamiya, showing everything vital, and the name.

And here's what's in the box.  It doens't look like much.  Definitely not as "much" as the M06 seemed to have.  

So.. I got this one upside down, but here's everything bagged.  

Now that looks like a real kit.  

I was expecting a M07 like tub, but this ends up being more of a spine chassis.

For completeness, here's the box without the art sheets on it. 

Here's a close up of the hop up parts we're starting with.  ... that 3racing swaybar set is a problem.  But we'll get to that later. 

Ebay is a great source for screws.  Cheaper than McMaster, but delivery sucks.  My friend and I, both hate phillips head screws.  There's the titanium screw set option, and aluminum screws... but these cars build up lighter than legal anyhow, so why not go steel?  

That's all of the steel screws in the car, that aren't wacky, special, Tamiya screws.  In the end, I think the car had six phillips head screws left on it, after using those screws instead of the factory screws.

The leftover hardware is quite the impressive pile.



Waiting for the screws delayed the build by two weeks.  But it was totally worth it.  Speaking as someone who's built the car...

So lets get to the build? The manual is typical Tamiya.  Busy, but clear.  The full size fastener drawings help a lot.

Atypical of car builds, we don't start with shocks.  Or a differential, but we start this one with the rear suspension mounts. 

Look at that wasp wasted beauty.  The car gets really narrow around the motor mount, and I understand the reasoning there is to provide chassis flex, and improve rear traction.  Both the lower chassis, and the upper chassis bridge are narrow like this.

Just like the M07, you drop locknuts into pockets in the chassis tub. 

And here, we start off with "no, tamiya, you're wrong".  The first screw is already one I bought instead of tamiya's screws.  Tamiya's screws are GOOD.  Just, they're phillips head. 

And the front mounts are in place.  This allows a lot of things.  A little bit of track adjustment, but mostly wild toe adjustments.  Shims are nice instead of needing to replace suspension blocks. 

The rear arms are the same as the M07.  But there's a problem.  That rear droop adjuster hole, wants to occupy the same volume as the differential.  

Side cutters took care of that ear.



And now we do the rear suspension mounts.  Here's the stack of parts you put together to make this work.  You have the outer aluminum washer to spread the load.  Then the two inside washers that adjust toe 

While I didn't take photos of it, every time I put a screw into plastic, I did the usual tapping  using a thread forming tap.  So those suspension balls screwed in nicely.

And from the bottom.  You can see where the droop screw ear would have interfered with the diff. 

Now we get to build the gearbox.  Like the M07, we get a metal motor plate. 

This ends up being a 4 gear transmission.  So the motor applies torque to the chassis in a direction that helps settle the chassis, instead of attempting to pull a wheelie, like on the M06. 

The motor plate drops into the gearbox half.  

Next up, is building the next two stages of the gearbox.  

They stack easily, and don't have the "this is hard to do" aspect that the M05 chassis had.

And they drop in to the gearbox half, just like the motor plate.

The other half of the gearbox attaches easily.  With.. just two screws.  That's not a lot of parts to handle all the power of this thing.  But there are a lot of other ways that this assembly gets held together.  

Here's pinion access.  This is a really good setup.  The M07 is "deep dark holes" while this is very nearly classic rear motor off road car easy.  

Now we have a gearbox, it's differential time.  We've done this a bunch of times here, but for those who are just seeing this for the first time, lets walk through it.

Here's the stack of parts.  The diff gears need to be cut out of the sprue.  I'll warn you now, the sprue gates into the parts from the back, so there's little "nubs" on the back of all the gears.  Be sure to trim that off. 

Everything trimmed.  

The drive cup fits nicely into the diff housing.  I put a little green slime on both the o-rings and the stub shaft.  

I also grease the closing gasket.  That's why the paper looks dark there.  I don't bother oiling or greasing the spider before I drop it in.

It'll get soaked in sillicone grease anyway.  

My fingers were nasty and sticky.  I filled the diff with 3000 cst diff oil, as the manual recommends.  The "yellow" bottle in your kit, is your diff oil, in spite of it not being labeled.

The diff feels quite stiff.  It's smooth as one would expect.  But I think I may move to a lighter oil for pavement use. 

The diff drops in nicely into the back of the chassis. And this is where things get a little weird. 

The transmission fits beautifully.  It fits.. tightly.  But you'll note that the front of the transmission just floats there.  That.. doesn't change. 

The bridge gets installed, and the rear two screws get installed.  It only takes five screws to remove the transmission so you can get to the diff.  

Only six screws here.  And it feels pretty solid. 

The rear camber link balls installed.  

Camber links, mean we need hubs and drive parts. This pile of parts becomes the CVD's, and assemble into the full uprights.  

I didn't get pictures, but there's lots of spacers in here.  1.5mm spacers between the bearings, .2mm spacers on the drive hex side. 

The part I hate most, about building cars, are turnbuckles.  High point, the car comes with full turnbuckles.  Downside, they're short, tiny, and hard to deal with.  

And, installed.  

The M08 is, just like the M07. And it's a real touring car.  This is where it really shows.  The car is tighter than my TA07.  

Here we get the battery wings.  This is how we, eventually, retain the battery.  This.. could.. if done right.. mean we get more ground clearance, but with the existing battery setup, there isn't that benifit.  Yet.  

Might it fly? 

Next up is the rear shock tower.  I bought the carbon one.  

Being lazy, I didn't treat the edges on this one.  

This, might be my biggest complaint with the car.  Between this, and the front bridge..

So this is a narrow, not well triangulated bit of plastic.  That takes the full load of the shock tower.  I want this in aluminum.  It also provides for much of the stability of the top half o the gearbox. 

And the tower installed.  It looks fit for purpose.  

So that's the butt end.  Lets go up front.  

Just like the M07, here's the front end suspension bits.  Mostly assembled.

And right side up.

This bolts to the bottom of the car.  It's a nice way of doing the attachment.  Provides a nice wide base for the pins, and isn't difficult to do.  

Oh, look at those hex head screws.  The gap in the chassis tub you see, is because this is being built as a 239mm chassis, as opposed to the 210 size.  

On top, we get put on the pivot balls, and steering posts.  I wonder if anyone is using shims to adjust camber gain on these cars... 

The front hubs share the spacer that we've seen before on the M06.  This is proper here, I think.  As opposed to the M06, where they could have mounted the steering gear on top of the front bridge. 

These C hubs are "new".  They have inserts in the lower holes, instead of the typical tamiya molded in correctly sized hole.  They seem fine, but we'll need to see how durable they are, long term. 

And installed on the car. 

Camber links installed. I really enjoy how much this looks like a "real" touring car. 

The only bit I don't like, is the lack of camber gain adjustment positions.

The steering servo installed.  This car is designed to accept shorty servos natively.  Like the M05 and M07.  I wonder why the M06 isn't...  

The steering gear, is "large" but has adjustable ackerman.  And largely slop free. I like this bellcrank setup.  Perhaps more than the one in the M07.  

Another view of the bellcrank.

Steering links installed.  

Look at all that travel. 

And to the left. 

The big advantage to putting the servo up here, is you are now able to easily adjust wheelbase length.  here, I've installed the upper chassis posts.  This is a big point of flex in the chassis.  This is where you get "pitch" bending movement.  While the rear, is where you get horizontal flex. 

And here's the bridge parts that go from the battery compartment to the front chassis towers.  

I also bought the front carbon shock tower.  And installed that.  Again, couldn't be bothered with edge prep. 

You're "supposed" to apply glue, or at least sand the edges of carbon parts. 

So the bridge feels like the softest part of the car.  There's a lot going on here, and potentially a lot of stresses, from the steering system (which mounts at the back) the swaybars, (second set of holes in the front), body mounts, and shock tower.  I'd like to see this in carbon injected plastic, or even aluminum.

And the final steering link.

The front bridge uses some really long, custom screws a the back, and that's a place where I had to retain the phillips head screws.  I think the screws are aluminum as well.  I also installed the bumper.  

Allright, chassis done?  So next comes the springy bits.  

I chose to install the 3 racing swaybar set.  Surprisingly, it comes with the wrong cups to fit the front arms.  That's.. frustrating.  

I was waffling on what shocks to use.  These are super short shocks, so I went with those instead of the shocks I bought for the M06. 

Pistons.

Seals.

And ready to fill.  If you want this in more detail, I will happily do a post on just building shocks.  

Shocks and swaybars installed.  The whole car feels serious.  It's got all the right adjustments, all the right parts.  I like it, a lot.  And it's easy to work on. 

The springs the M08 comes with, are the softest I've gotten with any Tamiya kit.  They're these soft gold ones, like you'd find in the rear of the M06 kit. 

So, the biggest reason I bought, and built a M06, was because my M08 was coming.  Lets... talk about the two.  

The M06 is a hot mess.  It's got patches on patches.  The suspension parts

The knuckles have extensions on them for the steering link.  It's got adapters so you can hook up the swaybar.  The rear swaybar is this giant wing shaped thing that looks like it belongs on a off road car. 

  It's got no way of setting droop that doesn't involve tearing apart the shocks.  It's a situation bad enough, that the car comes with shorter shock shafts.  Since we're talking about shocks, the rear shock tower is messy, and misses all the chances to bind it to the tub.  The front shock tower is on a flexible tower.

This doesn't even address diff access, which requires disassembling 2/3 of the car to get to.

It's definitely from the "early M05" generation of car designs.

The M08.. seems thoughtful throughout.  Diff access is a half a dozen screws.  Droop is easy.  Chassis flexibility is easily tuned.  The swaybar setup is sane.  It's all, just.. as a touring car should be.

The weight difference is shocking too.  The M06 is more than 100g heavier than the M08. 

The M06:  882g.

The M08: 743g.



I mean, where did all the weight go?  I wonder how light the M06 can get.

So.. while it hasn't hit the track yet.  I really like the M08 on a practical level.  The bigger front bumper makes me happy too.  

I can't wait to get this out on the track and see how it goes.