Tamiya Grasshopper Rear Sus and Gearbox conversion Final (3/31)

Design Finalized & New Upload (2020.3.29)

to make sure my thing is properly searched, I am publishing my final things for grasshopper mk2 gearbox and trailing arm design.

Design Update! (2020.3.15)

After going thru some test runs, I have decided to change the design of center gear nut, and new hub has to be used accordingly.

New Design : Gearbox5_nut_new.stl

• changed the center nut’s spline design to ‘key’ type, with simpler design, my printer was able to print the design properly, tested to endure number of high torque runs.
• new hub joint part is required for this design : Tamiya 53790 (used in TT01)

Please change the nut only if you already build the gear box, you will notice the change is not that difficult, you can easily disassemble gearbox not having to remove the hole gearbox mount and rear arms.

Please check out my youtube video installing and testing the new design nut and hubs!

step by step instruction for install
https://youtu.be/8ZGd0Yozjg4

testing the new design
https://www.youtube.com/watch?v=yceloJpPOZY

final test run!
https://youtu.be/q1BWPxbzri8

beach run with grasshopper mk1
https://youtu.be/_Ai3INqZkYw

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Initial Upload (2020.2.25)

Again, this is an upgrade to my forever favorite tamiya grasshopper!

Grasshopper’s gearbox with rigid axle is what makes this car very unique, and everyone loves it’s durability, simple structure, and even very good performance on easy roads! which made it a perfect beginner’s buggy for everyone in this globe around my age^^

This conversion kit enables users to simply upgrade their hopper or hornet into a VW dune buggy style ‘trailing arm’ based independent suspension, with new designed gear box enabling rear positioned motor for better rear grip and shock absorbing.

I tested the kit and am pretty satisfied, except the center gear nut(Gearbox5_nut.stl), which is not strong enough for life-time warrantee. This nut part have endured more than 3 pack runs, but will need to be upgraded to metal parts (will update when metal part is available and tested) if you are a serious heavy user. If you are not, this PLA nut may be enough, you can always reprint if it wears out.

The benefit of conversion :

• far enhanced rear grip, -> better road holding in any roads
• higher road clearance -> better performance in rough terrain, such as grasses and sands
• scale look -> similar architecture to real dune buggy, or more scale vehicles such as wild one/FAV

This kit is a hop-up kit, just print, assemble and attach it to it’s chassis, without any cut or modification to your original grasshopper/hornet kit.

However you need below additional parts to make this kit run :

• Tamiya 53790 (used in TT01)
• Tamiya M03/05 30mm drive shaft (9805503), OR M03 option swing shaft(54410)
• Tamiya Frog/Brat’s wheel axle hub(9808039), OR Frog/Brat option Universal Shaft set (53908)
• 6 O-rings for axle/joint hub, OR some silicone pipe
• 70mm damper/spring, I used DT03’s front CVA shock set
• 2 more 1150 size bearings

All the hopper/hornet’s internal gear parts will be reused.

I will update with further build instructions in my youtube channel soon, but I guess the build is pretty straight forward if you have basic RC skills.

Few things to be careful when building the kit :

1. You need to be very careful with screw holes. 3D printed parts are not as durable and acurate as commercial kits, you need to trim every screw holes with 2.6mm drill bit before screwing.
2. Some parts will warp during printing, do set your printer well to minimize any warps

Please visit my youtube channel for further information later. I will upload detailed build instruction video soon!

• Test run : https://youtu.be/Z_58uAlQDb8
• Build instructions : to be updated!

Please post comments in thingiverse or youtube for any feedback or queries!

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Please find my other grasshopper upgrade parts also!

1) grasshopper front suspension upgrade parts :
https://www.thingiverse.com/thing:3860829

2) grasshopper rear suspension upgrade parts – MK1, hornet style upgrade
https://www.thingiverse.com/thing:3815254

3) grasshopper driver figure :
https://www.thingiverse.com/thing:3803664

4) spot light :
https://www.thingiverse.com/thing:3840276

5) Mini action cam(SQ23) holder with driver figure for Grasshopper
https://www.thingiverse.com/thing:4018398

Enjoy!