Hi Kai!
Let's see what Kyosho America says:
Upgrading Your RB-5 to the Mid-Arm Conversion
To upgrade your RB-5 to run the latest mid-arm conversion setup, you will need the following parts:
- LA243 - This comes with a front and rear arm. You only want the rear arm. So the customer will have to buy 2 of these.
- LA232 - This comes with 2 complete dogbone and axles built. The dogbones are what you want. The axles are too narrow.
- W5183-2 - This comes with both shock shafts.