Wltoys K969 122mm wheelbase chassis

The WLtoys K969 is quite good, just don't modify it～

I inadvertently fell into the modification rabbit hole, acquiring a plethora of inexpensive metal parts, nearly resulting in an unfinished project. Fortunately, the tinkering was enjoyable, and the costs weren't exorbitant.

Later, I purchased a 1/24 scale GTR R34 toy model on Pinduoduo, and discovered its exceptional craftsmanship. Its wheelbase measured approximately 122mm, with a similarly proportionate width, suggesting potential compatibility. I subsequently fabricated an extended chassis and driveshaft, only to find incompatibility with the modified gearbox. Despite claiming support for a maximum 122mm chassis, the screw hole positioning proved exceptionally problematic (only two of the four screws securing the gearbox to the chassis could be used).

Consequently, I experimented with a 3D printed chassis designed by an online expert. After at least five major revisions, I finally achieved a flawless installation.

Advantages:

• Wheelbase is customizable
• Accessories such as switches can be added with custom adapters

Potential Pitfalls:

• The ball joints and A-arms from the original model are unprintable with an A1 mini's 0.4mm nozzle due to insufficient precision, rendering them unusable. Utilize original components or metal replacements.
• The mounting holes for the motor determine the gear mesh, and precision issues necessitate allowances for adjustment.

2025.03 - V9 Version

Persistent dissatisfaction stemmed from the tires. Based on calculations using the ratio of the real car's wheelbase to the 122mm model wheelbase, the actual tire diameter should be 30mm. However, the K969 is a 1/28 scale model, and even its largest drift tires only measure 27mm in diameter, making the car appear… as if it's using a spare tire.

Since such a heavy body is unsuitable for racing, I sourced a 3D printable wheel and tire model (https://makerworld.com.cn/zh/models/994637-wltoys-k969-k989piao-yi-lun-tai-27mm-1-28bi-li?from=search#profileId-1018780), retaining the hub dimensions (available internationally), and expanding the tire diameter to 30mm. The result is significantly more aesthetically pleasing.

However, the new wheels are wider, and to accommodate the original small wheels, I previously widened the car's body considerably. This resulted in insufficiently long steering linkages and severe toe-out. This opportunity allowed me to retract all suspension connection points by 1mm, correcting the toe and perfecting the car's width.

After a few test drifts at home, the PETG printed tires perform admirably as drift tires.

Incidentally, I added side skirts to the chassis for enhanced aesthetic appeal.

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This project is nearing completion. For my next endeavor, I'm considering utilizing WLtoys parts, incorporating the rear half of this chassis, the front end of another expert's 3D printed rear-wheel-drive drift car, and a 1/24 AE86 from Pinduoduo (remarkably, also with a 122mm wheelbase) to create a rear-wheel-drive drift car.