Kyosho Mantis EP FWD build

[EvolutionRevolution]

This will be a report of a build that I started long ago, took pictures of, and wrote a report about, but didn't post on here.

What I started with is this Mantis GP wreck, bought two years ago:

Of this wreck I found I could reuse everything but the GP exclusive parts (the alloy chassis was also wrecked, as some screws were ripped out of the holes).

I then went parts hunting, and picked up quite a few parts over several months. I also bought an incomplete EP chassis to get the EP motor plate, which appears not to have been sold separately . The result was the following collection of parts for my build:

- non-motor chassis half (front bulkhead, MI-7B)
- gearbox (MI-8)
- stock suspension incl. all uprights, excl. kingpins
- TF2 kingpins
- stock upper & steering links
- rear bumper
- various screws
- body mount mounts (MI-2)
- MI-18 EP frame set
- MI-1B bumper
- MI-19 EP small parts set
- MIW-4 steel drive gear
- MIW-3 turnbuckle set
- wheels (Kyosho, bright green)
- MIW-2 shock stay set (FF)
- MIW-6 ball diff (actually the same as the Ultima ball diff, different part number)
- IHW-15 Mini Inferno Rear oil Shock Set (Teflon Touring Shock (S)) x2
- Kose TF-2 universals
- GPM alloy C-hubs
- GPM alloy front & rear arm mount
- GPM universal foam bumper
- Kose alloy wheel hexes
- ball bearings
- MIW-8 swing bar set (in mail)

Another part that I haven't been able to find is the main gear, so I will be adding a main gear adapter suitable for normal spurs instead:
- main gear adapter, 1 mm crosspin, 5 mm shaft (GPM for Axial SCX-10)

More later.

[EvolutionRevolution]

So I started off with the EP frame set (first picture), one part from the EP small parts set (2nd), and the rear frame off the GP chassis (3rd):

These go together like this:

Resulting in this:

Technically I could leave off the MSC servo mount, but it adds a bit of rigidity to the chassis and especially a place to which the receiver or ESC can be attached.

The Mantis normally uses small springs mounted in the arms for suspension action, but Kyosho made optional parts to use actual oil shocks instead. Since I am aiming at a full-option build, I will be using real shocks instead of the springs. So I remove the springs and the setscrews used to adjust them from the arms:

As at that time I didn't have the optional shock mounts yet, I continued with assembling those parts of the arms I could do then. These are the arms, arm mounts, and hinge pins:

And this is how the rear arms attach:

I am not yet attaching the front arms, as they can only be attached when the gearbox is ready.

This is followed by the rear bumper and the body mount mounts ("mount mounts" because they don't include the actual body posts...):

I will only use the rear mount mounts, as the front mount mounts can only be attached when the gearbox is ready.

[EvolutionRevolution]

So:

I then continue with the c-hubs and rear uprights (only mounting rear uprights now):

Then I assemble the parts for the front uprights:

As can be seen, these have a strange, multi-part design with reversable bearing holders (for no obvious reason). The high placement of the control arms has a reason that I will show later.

At this point, I was somewhat stuck as I still lacked kingpins and the turnbuckle set that would replace the stock steering links and one-piece camber links. So I continued with the gearbox internals.

First, the idler gear. This has a rather complex design and mounts on an axle with a small pin. The axle then sits on two bearings:

I then continue with the layshaft. In stock form this uses a gear that likes to fail under heavy loads. Fortunately, Kyosho made a steel replacement gear:

Layshaft parts excluding spur gear and assembled layshaft:

[EvolutionRevolution]

Gearbox halves:

And the idler gear and layshaft go in like this:

Note that the gearbox contents can be mounted with the layshaft pointing to the right or the left, allowing any rotation direction on the motor. This is also because the Mantis chassis could be build as a front or rear wheel drive version.

Gearbox closed and temporarily attached to the chassis (it snaps into place):

C-hubs attached to front arms:

I then looked through my Kyosho TF parts to see whether I had kingpins and universals that fit. I discovered TF-2 kingpins fitted like a glove, and also found an unused set of Kose universals with alloy hexes:

This allowed me to attach the front uprights to the c-hubs:

The Kose universals use screw-on dogbones, and I will need to add some locktite to the threads later on to avoid them unscrewing themselves while running the car.

I then received the turnbuckle set for the Mantis:

The long turnbuckles are for the steering links and the short ones for the camber links (one-piece camber link shown too):

[EvolutionRevolution]

Steering links attached to front arm assemblies:

Rear camber links attached:

And here's a temporary assembly of the front end with camber links installed:

It's quite busy, and now you can see why the front uprights have that strange design: the steering links have to be raised above the gearbox. The servo will mount on top of the gearbox, and the optional shock mounts attach with the same screws as the servo, making access to the gearbox for maintenance a real pain in the behind. More on that in the next update.

[clm]

Kyosho Kyosho Kyosho... that is some weird overly engineered idler with about twice the number of necessary parts lol.

[EvolutionRevolution]

Kyosho Kyosho Kyosho... that is some weird overly engineered idler with about twice the number of necessary parts lol.

Yeah, this chassis has some weird bits that make you wonder wtf were they thinking:

- The chunky space frame chassis that is made out of somewhat rubbery fiber reinforced nylon and that isn't really straight no matter how you look at it.
- On the GP version: the plastic brake drum that doesn't brake, it melts. That's one way for Kyosho to sell their optional steel brake disc, I guess...
- The overengineered front uprights.
- The way the steering servo mounts, both on the FWD and RWD versions - although FWD is worse. Especially with the optional oil shock mounts.
- There's nearly no place to mount the receiver (and ESC op the EP version) close to the ground.
- The asymmetric stick pack battery holder (top-bottom) on the EP version.
- The way the gearbox is designed means accelerating will result in less power being transferred to the drive wheels than expected...it's like they simply flattened a mid-motor 2WD buggy gearbox without taking into account that moving the motor away from the wheel axles would change the handling characteristics. The really weird bit comes from the left-right symmetry of the gearbox, which means the idler could have been left out and the motor simply mounted pointing to the other side. But then they couldn't have fit in a full-size spur on the EP version.
- The EP version comes with a drive train that is more or less sealed except on the gearbox itself .

But let's continue with some overengineered stuff. So Kyosho made some optional shock mounts for this chassis that allow the use of oil shocks. There's two different sets, MIW-1 and MIW-2, for the RWD and FWD version, respectively. It is not possible to use the MIW-1 set on a FWD car because the steering servo won't fit, but a RWD car can use the MIW-2 set (resulting in different suspension geometry at the front).

So the MIW-2 set comes with this huge instruction sheet:

...which fails to mention anything about which shock oil or springs to use

The rear shock mount is easy:

It only offers one placement option for the shocks. There's two sets of holes because two shock lengths can be used.

The front end shock mount consists of these bits, which I can't mount to the car yet because they can only attach when the gearbox is ready (and the servo too):

Yeah, the shock mount is split over two halves. Here we do get an additional mounting option.

Now getting the shocks that can be used was a bit problematic. The shock mount instructions offer four options for the shocks:
- Kyosho's plastic W-5141 Sport Shocks (S)
- W-5153 Teflon Touring Shocks (S)
- W-5151 Touring Shocks (SS)
- W-5152 Teflon Touring Shocks (SS)

The SS (super short) shocks were out because I wanted to build the car with a rally game shell. The sport shocks were out because they are not that great. Which left the Teflon Touring shocks. Unfortunately, those were nigh-impossible to find for a decent price. But wait! While browsing Ebay I spotted some Mini-Inferno option shocks that looked really similar. So I bought some:

These are W-5153 Teflon Touring Shocks (S), sold under a different part number (all hail Kyosho and their tendency to reuse parts for different cars). Likewise, the front set for the Mini-Inferno are the SS versions of these shocks. Difference in price: 25-30 bucks for these vs. 80-90 bucks for a vintage set.

So, blue teflon shocks. Except I don't know what oil to fill them with...

[Mr. ED]

I always wanted to do a total custom build of this chassis. Bit jealous now.
Thanks for the story and pictures though. At least I get a better idea of what's included a,d what's out in the field.

[EvolutionRevolution]

By that time I had also received the ball diff, which ended up costing me way more than expected (Fireboy + customs duty = about 80 Euro):

As you can see, that diff actually is a Kyosho Ultima ball diff, sold under a different part number. I guess Fireboy knew that too...

I haven't assembled it yet, because I want to use ceramic diff and thrust balls as accessing the diff will be difficult once the gearbox is assembled.

All that time I had tried to get my hands on the spur gear, but it remained elusive. So instead of that I bought myself this GPM spur gear adapter for the Axial SCX-10:

The bore on the spur adapter is correct for the layshaft, but I will have to enlarge the crosspin hole on the adapter as it is too small. I will also have to modify some of the plastic parts for everything to fit. Then I'll be able to use standard spurs.

And then a few months later I came across these vintage Mantis option parts by GPM:

The rear arm lock was quickly installed:

Close-up of the c-hubs:

And a test-fit of the c-hubs and front arm lock:

[EvolutionRevolution]

I always wanted to do a total custom build of this chassis. Bit jealous now.
Thanks for the story and pictures though. At least I get a better idea of what's included a,d what's out in the field.

Don't worry, it has been sitting on my shelf in its current state for about nine months now. Last week I finally found the last option part I needed. Then there's quite a bit of work ahead. So you still can finish yours before mine.

Now if I really wanted to go all out on this, I'd consider replacing the shock towers and chassis side plates by carbon fiber parts. Although...rugged as the chassis is, you could build it as a Maxxum FF Mk. 2 buggy...

[Mr. ED]

Exactly why I was fund of the design, so many potential projects.
They had the rwd mantis in a lhs, but I wanted the fwd. When the shop closed down I called the owner to see if he still had it, thinking it might be wort getting the rwd at a good price.
No luck.

Looking at yours is enough now

[Lonestar]

Great thread, thanks for taking the time to document it this thoroughly

I'm thinking this is one of the designs that were actually NOT done by kyosho engineers themselves, but bought off someone else's - the famous "b-grade" cars (like Raider, Rocky, etc...). I've always been told K always had this dual "sourcing" strategy...

Cool car nonetheless, so atypical !

[Mr. ED]

Come to think of it. The rwd was much later on also sold, mostly in germany, by Hype. The same company that sold a cheaped down version of the triumph... Chadori or chadory.
You may find some parts or cheap donor car for mantis spares on ebay germany. Hard to find though as most people only post pics with the body on

[Lonestar]

Different target group

[EvolutionRevolution]

Exactly why I was fund of the design, so many potential projects.
They had the rwd mantis in a lhs, but I wanted the fwd. When the shop closed down I called the owner to see if he still had it, thinking it might be wort getting the rwd at a good price.
No luck.

Looking at yours is enough now

Especially since the only difference between the RWD and FWD is the steering servo mounts. The whole suspension and the bumper can be swapped from one side to the other to convert one version into the other...

Also the bodies Kyosho made for these cars are gorgeous.