Tamiya FWD FF03 transformed to KR-MF 2020

The 1/10 FWD class is on the rise with events such as the ETS and UK clubmans running the class. As you would expect, once racers becom...

The 1/10 FWD class is on the rise with events such as the ETS and UK clubmans running the class. As you would expect, once racers becoming involved the classic motor in front of front axle design is being challenged as drivers look for that edge. A fantastic example of pushing the boundaries is the KR-MF 2020.

Kevin Kreft started with a basic FF03, and started to modify it way back in 2018. Over this time it has transformed massively from the original Tamiya to something quite spectacular and unique. So let's take a closer look.

One of the most striking things you notice is that the steering servo is at the front of the gearbox. This provides direct steering and the slight bump steer this solution provides is a desired effect. The TRF420 aluminium mount (3451236) is used alongside new TRF420 suspension system.  All ballcups are the new Tamiyas Open Face Reinforced Adjusters (54869)

The shocks are the TRF Super Short BigBore Damper SET (42353 & 42344). The carbon side braces also couple up as the motor mount.

Long pushrods connect to the rocker arms. This is part of the design to move all of the weight as forward and close to the motor as possible.

The anti-roll-bars needed a lot of work. Guided by ball bearing and mounted through 3D printed parts. A big challenge was bending the anti roll bars. However the end result went on to become perfect, symmetrical and flat.

The gearbox is a custom build. It only uses two gears, this involves the motor rotation being opposite to the driven wheels. There is theory that it can lead to a little bit of understeer. It was important while doing the gearbox layout, to rise the differential to 19mm above the chassis plate (to center diff). That way you not only reach optimal cvd angles, but also avoid collisions with other parts. The spur should sit just several millimetres above the suspension arms. The spur gear shaft with counter gear sits 27.25mm above the chassis plate and 17.71 millimetres behind the gear diff (measurement is center to center).

The geardiff has 52 teeth (48dp) the counter gear is 20 teeth, resulting in a 2.6 internal ratio. The spur gear is 80 teeth (64dp) and pinion 46 teeth to give a final drive ratio of 4.52. A 41 teeth pinion provides a 5.07 ratio. There is space for a slightly larger spur, maybe 84 teeth, and the KR-MF can go lower than 4.5 with larger pinions and smaller spurs, but this has not been tried as it is optimized for for the E.T.S. and Tonisport Onroad Series.

A new front bumper assembly I don’t use a standard bumper but a carbon plate to keep the front short and stiff to prevent the bodyposts and body from wobbling and disturbing the performance.

Unfortunately this solution would ruin the front of the chassis pretty fast outdoors as the front edge of the chassis is unprotected. As you would want to protect the chassis from scratches, so a small lip was 3D printed that will take the impacts for the chassis edge.

The rear has horizontal body posts. With this all the shaking and vibration of the body should be a thing of the past.

When installing the electronics a lot of time was taken to black out the esc and rx. This involved 3D printing a new case for the receiver as the old one is very high and has the antenna hanging out. The antenna is now inside the case and it is much lower. Soldering also took a lot of time. Due to the cable tunnel, it is not easy to reach the lower motor cables and get through with the soldering iron.

The car got a Muchmore Fleta ZXV2 13.5t and LRPs new 4000mAh 1/12 sized lipos. The motor is maybe a little strong, but will be fun outdoors.

Setting up

Working on the left and right balance was quite tricky. Even though the servo is on the left hand side, the motor has a heavy endbell alongside all of the cables making that side more heavy, so the lipo was offset 2mm to balance it out.

Looking at front / rear balance. It was good to compare it to some of the other chassis available Here all f/r weight balance data:

  • Tamiya FF03: f=64.15% r=35.85%
  • Awesomatix FF: f=62.30% r=37.70%
  • Serpent X20 FWD: f=63.42% r=36.58%

  • KRMF 2020: f=64.15% r=35.85%

Recognise those numbers somewhere...Exactly! It is the same f/r balance number as the FF03. Is this bad or good?  It will handle differently as the majority of the weight is in a different place compared to the FF03 and the fact is that the KRMF is within 0.7% of the Serpent X20 FWD's f/r balance, It should be a good thing.

This chassis looks amazing and I cannot wait to get it out on the track to see how it performs one racing is safe to start again.

Thanks to Kevin Kreft for the photos and information of this excellent project, looking forward to a track report.
tamiya 2535937006730542029

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