MF-01M - A mid motor 4WD rally M-chassis

[Honza 1099]

I skipped the last race due to weather, so first race of the V2 was this weekend. And it was quite successful. Well, except for another broken front arm. Luckily I have printed couple of spares. I got TL-01 hinge pins for the future interation, which should help to hold the printed parts together .

I know I should've used firmer dampers on this surface, but I love how it leans into corner 😃

[JimBear 812]

5 minutes ago, Honza said:

I know I should've used firmer dampers on this surface, but I love how it leans into corner 😃

Almost Citröen 2CV style, there!

 

[Honza 1099]

5 minutes ago, JimBear said:

Almost Citröen 2CV style, there!

Yep, that's what happens when you run dirt settings on a higher grip surface 😃 I run stabilisers on my main car, but that's not an option here (yet? 😁)

[Honza 1099]

Missed another race this weekend due to illness... But at least I finally got into uploading all modifications I'm using on my chassis.

Here's my Printables collection that contains them:

https://www.printables.com/@HonzaP_226225/collections/125847

[CRC505 152]

This design is really great, I want to make one too

[Honza 1099]

1 hour ago, CRC505 said:

This design is really great, I want to make one too

Thanks! Go ahead and share your build here, it's always great to see another build

[Honza 1099]

Another race This time, the Mazda wasn't the only m-chassis on the start

Finally got to finish my own mini rally tires. They are old, slightly worn clones of Tamiya tires made of softer compound - they work much better than Tamiya's own tires.

Another, not pictured, modification is installation of stainless steel hinge pins - although it didn't help with front arms breaking, it at least held them together to get over the finish line.

I also involuntarily tested water resistance of THW-1060 😁 

 

 

[Honza 1099]

From the series "why Tamiya haven't thought of that?", I finally tried whether I can run a single propshaft for multiple wheelbases, since my design allows for the propshaft to stick out of the bevel housing - this is an L propshaft on M wheelbase. In the same way, M-propshaft could be used for the shortest wheelbase. 

[Honza 1099]

The last race resulted in DNF in the last SS due to driver's error. Good news is that the suspension mount worked as anticipated and it didn't break other parts of the chassis.

Over the summer break, I'm planning some modifications. I'm waiting for delivery of #51748 parts tree to test some new ideas..

[Honza 1099]

One #51748 set on its way, so in the meantime, I tested an idea to use 33mm CVDs with them. I thought that I'd need 4mm hexes to compensate for longer swingshafts, but turns out, that it's not needed. Wheel axles used on XM-01 are shorter just by those 3mm.

This means that I'll be able to make slightly longer front arms. With starting length of 20mm, each milimeter counts.

[Honza 1099]

Still need some more parts, but looks like XM-01 uprights will work:

With same width and lower damper mount in the same position as stock, arm was extended by 6mm and it achieved same lever ratio as rear arm, so it should provide nice linear damping. I plan to add downstops and move the damper mount down, together with custom damper stay in the future.

So far, it is assembled on a spare chassis. Since MF-01X mounts ball joints from the bottom of the upright, I had to cut part of it.

Btw have you ever wondered why bearings stick out of M-07/XM-01 uproghts? It's because older M-chassis use 6mm hexes and that's depth of hex inside the wheel. Newer chassis use 5mm hexes, which wouldn't fit.. But with bearing sticking out, it clears the wheel easily.