Tamiya M-chassis long span front arms

Update 14.Feb 2026:
Added new variant with lowered damper mount.

This model aims to improve front suspension geometry by using modern Tamiya M-chassis uprights, which move outer hinge pin 6mm closer to the wheel without change to the track width. The lower damper mount doesn't change its position, which, in combination with a longer arm, results in softer, more linear damping. As a bonus, this design introduces adjustable camber. This suspension is still compatible with M-chassis rims and provides increased range of movement compared to the stick setup.

There are two variants of the arms - one keeps lower damper mounts in the same position as the stock arms, which makes them compatible with stock shocks. The second variant moves the damper mount lower on the arm, allowing for more upright position of the shocks, which clears the stock damper stay on M05 and MF01X chassis. This allows for use of longer shocks for offroad use. I included custom damper mount for 60mm shocks in the files.

My prototype uses XM-01 (#51748) uprights. M-07 uprights (#51597) should fit aswell. I'm not sure about M-08 uprights, where additional caster angle might create collisions. Additional parts to complete the uprights assembly are:

• four 3x5x3,5mm spacers (Tamiya #19803013)

•  5mm ball joints (5 or 8mm length, depending on the ride height configuration - for more details, refer to XM-01 manual) 

• pivot balls with ball cups and 3x10mm set screws (or similarly sized M3 rods), to build the front camber links - lenght will differ on different models, ball cups have to be cut to correct length.

Additionally, the new uprights require complete M-07 33mm universal driveshafts or DCJs (#42312) and XV-01 outer hinge pins (#19804301). The pins are secured by M2.6x5 screws (#19804310). 

For use on MF-01X, the front knuckles have to be modified as shown in picture. Additional modifications of the chassis might be requred to clear the steering rod in high position. Alternatively, TRF418 knuckles can be used.

In all uses, the steering links require length adjustments - in case of MF-01, stock toe links have enough range, I cannot confirm other Tamiya chassis.