Re: Tamiya bolt on reduction gear
 

Just a quick update.
So far shifting servo is not an issue. Partly due to fantastic functions on my spectrum radio where I have reduced servo speed on the throttle channel to a very low percentage, so that the throttle does not go to 100% instantly. It takes a slow ramp up.
The result is a scale looking motion of the truck and a reduced motor/esc/battery load on the take off and breaking.

So, to get back to my third gear issue;
- when taking off with no cargo the third gear acts the same way as when the truck is loaded. I'd reckon that the engagement of the dogs for the third gear are not latching fully, and the same are damaged as well.
In this situation (due to my throttle signal conditioning) the load on the ESC'a BEC is not a problem. The voltage is being held stable.


Now, to touch the AWD GRU and the powered front axle;
- plastic front axle has proven the concept of simple add on FWD. it does make a world of change, and it certainly would be a game changer on my 6x4 Scania R620.
- my choice would always be a full metal axle.
- the 3 speed Tamiya gearbox does seem to be the weakest link on the AWD equipped unit. Mostly due to added load of the FWD, but that should not be a problem when all metal parts are used (metal AWD GRU, metal Front Axle, proper telescopic props hafts (not like the **** I've been making for the test purpose).
- the all opened differential truck with AWD does not get stuck easy. Totally feels like a crawler in an way. Really AWSOME fun to drive this thing around, if only it had a radio that could've been set up like my spectrum to limit the throttle and a steering speeds in order to make things look and feel real...
- the Tamiya steering system is even bigger **** with AWD. I am a strong believer that the hydraulic steering is a must(!) and I'll see if I can convince Doggy to add the hydraulic cylinder in the design files. I'll do the rest of R&D fabrication for this.

Re: Tamiya bolt on reduction gear
 

Just a couple of thoughts: The Tamiya gearbox is pretty much bullit proof if out together correctly. It has a bit of internal slack, but is very durable.
As for the steering, hydraulic steering would be a cool feature, but I think you will be more than happy with moving the servo between the frame rails. I normally use Hitec645MG servos for steering, and they are strong enough.

Re: Tamiya bolt on reduction gear
 

Hello
Look's good. I like it especially with disconnectable front bridge and option to leave battery on it's original place.
Shouldn't the gru be right under the top of the chassis line? The trailer will hit gru if you move the kingpin to correct position (about 10 mm backward from the middle axle, like for example Scania r620 has in real world).

Regards

Jukka

Re: Tamiya bolt on reduction gear
 

Just found this thread,, very interesting and inspiring. Printing technology is going to be more and more frequent and being used for more critical parts, in some cases the only way to make a part is to print it as no milling machines can get to cut areas, they are usually printed in metals then heat fused together. Pretty sick technology that some very intelligent folks have solved. I wonder how much cost would be to have them outsourced and printed in metal? But if proving to hold up in plastic then great, metals fail also. Those types of printer are still too expensive for the normal "hobbyist ".

Keep at it! You are definately putting a lot of time and effort into this hobby, I may not be into the trucks as much as equipment but I appreciate your dedication to this any advancement is awesome!! But I think you may have inflated rcp's head a bit with putting that logo in the part!! Lol!! Naaaa, man , keep up the good work!!!

Re: Tamiya bolt on reduction gear
 

Have there been more developments on this project? I'm very interested in the GRU along with front drive output! Looking to convert my King Hauler to a 6x6 and this looks to be perfect. :)

Thanks!
Tommy

Re: Tamiya bolt on reduction gear
 

Saddly no. I moved to another city, started working, and stil didnt setup my new hobby workshop. I hope to set it all up next month and continue the work ;)

Re: Tamiya bolt on reduction gear
 

Sad to know you haven't been able to work on it, but happy the work will continue soon!

Re: Tamiya bolt on reduction gear
 

Howdy,
I was wondering if you ever got the AWD GRU finished? It looks like what I need for my truck. Looks great. Keep up the good work. Thanks

Re: Tamiya bolt on reduction gear
 

Hi, I did one prototype and gave it to trewq for a few months to test it. He managed to brake something inside, and I still didnt get the time to disassemble it and see what went wrong. I believe something snaped as the truck had fixed drive shaft.
I will do my best to do some work on it soon, as my other projects are near finish now.

Re: Tamiya bolt on reduction gear
 

Now I wanna buy one of them fancy reduction thingies.

Re: Tamiya bolt on reduction gear
 

nice design!

Re: Tamiya bolt on reduction gear
 

I want to buy a reducer on the gearbox for a Tamiya truck. I live in Russia. In Russia, bad roads and heavy loads. We need a powerful reducer!

Doggy! Can you send two reducers to Russia?

Re: Tamiya bolt on reduction gear
 

I like the pricetag on this one!

Re: Tamiya bolt on reduction gear
 

I wish Photobutt would let us see the pics o fthe d@m thing, & how it's mounted! Do you still have that pic? If so would you consider mailing it to me?

Re: Tamiya bolt on reduction gear
 

Are you still making GRU..