Tamiya bolt on reduction gear

[Doggy]

Well, I guess the best way to find out if they are strong enough is to test them?
Yes FDM technology has weak points, but if this gear with all its faults is good enough for 1/14 truck, then I dont see a problem.
I used the printer just to print the prototype, to see how it sits on the truck, and get correct dimensions I would later use on a mill. I didnt think it would be usable, as theory says that. But I was wrong. I also printed beadlock wheels for my 1/10 crawler, they also never failed, and I guess they were stressed even more.

But yes, when I finish a metal version, I will compare them and do more testing.

[trewq]

Hello all,
I have to give good critics to the reduction gearbox that Doggy has built. And that is not just because I know him and he has taken my 3D printer away from me, but the actual printed gears do work well!

At the moment I am powering Scania R620 which has been bastardised a little to have 10mm more ground clearance and a plastic tub that acts like a halfpipe tipper (lol, my lil guy loves it!).

Having original tamiya axles I have to say that the only big disadvantage of the rig is that it can't climb over difficult terrain uphill as both axles are having opened differentials. I'll post some videos later.

The positive ones are already mentioned, but I'll repeat my favourite ones:
- running stock motor (saves you few bucks doesn't it)
- running stock motor on MFC, without fearing of burning the MFC
- all sounds match the motion of the rig. Previously I've been running Hobbywing 21.5T & Justock ESC but that had problems with sound sync.
- the reduction being installed after the gearbox unloads the gearbox off the drive torque, where the motor mounted reductions load the gearbox much more than the proposed solution. That said, you still shouldn't shift gears under load.
- the rig has lots of power now
- the rig can brake well when loaded heavy

I've also tried a 80T motor from RC4WD, but that was a huge disappointment as this motor has literally no power!

So, with this post, I'm going back to the shop.

Cheers all!

[RCP57]

I just got a couple of these in the mail! I have to say that I am not that experienced with 3d printing but this is by far a much better print quality than stuff I have worked with in the past. My logo on the back of the cases was also a cool thing to see as it wasn't expected. I am excited to be a test dummy for these!

[trewq]

Originally Posted by RCP57

I just got a couple of these in the mail! I have to say that I am not that experienced with 3d printing but this is by far a much better print quality than stuff I have worked with in the past. My logo on the back of the cases was also a cool thing to see as it wasn't expected. I am excited to be a test dummy for these!

I'm jealous now. I haven't got my own logo on the reduction unit...

Just a tip for the prop shafts, make a beefy one as your torque will be more than 6 times greater now. Here is what has happened to my mid drive shaft after ~15 battery packs, most of the time full loaded truck;


I think that the pin has pulled out of the one ear slowly and I never bothered to check the drive train for this kind of issues.
Once you install your reduction gear you should be very careful if you are shifting gears on the move and with load. I have stripped the third gear cause I was full speed in second and then I decided to shift higher (off throttle, but with lots of speed). The third gear is broken now
After that incident I started to shift gears only when stopped and the gearbox unloaded, like if you are on a steep climb and loaded - not the best idea to shift gears then.

The cool thing is that in first gear, you can crawl everywhere with a loaded truck. Like a trailer crawler ha ha ha
There is no problem climbing uphill very steep roads. The only problem is if you wanna go down hill the same way, as the original Tamiya axles are running opened diffs, as soon as you loose traction on one wheel the other one lets go and I ended up having my ~30kg loaded rig going down like crazy. I broke few things too. I reckon I'll wait for Doggy to design and build the remote locker for Tamiya axles and that should solve the problem going downhill.

Enjoy your mods and let us know how you like the truck equipped with these.