RC Truck and Construction  

Go Back   RC Truck and Construction > RC Tech section. > Mechanical tech

Mechanical tech This is for the mechanical parts of a model. Gear reductions, Axles, Transmissions, General drive line


View Poll Results: Would you buy this if it went into production?
Yes I would buy a metal version 11 31.43%
Yes, but I would like a cheaper plastic version 17 48.57%
No, there are better options out there 7 20.00%
Voters: 35. You may not vote on this poll

Reply
 
Thread Tools Display Modes
  #41  
Old 07-05-2016, 08:07 AM
Doggy's Avatar
Doggy Doggy is offline
Newbie
 
Join Date: Oct 2015
Location: Croatia
Posts: 124
Doggy is on a distinguished road
Default Re: Tamiya bolt on reduction gear

Tnx Rimrock.

Well the first idea was to create something just by expanding what is already there. When you look at the Tamiya truck, and when you change all the stuff you ont really like, you end up just with a cabin, so why buy Tamiya in the first place?
I liked the 3speed from the hilux, first gear for crawling, and others for normal driving. But yes, 2 speed would be enough. I plan to develop such gearbox in the future.

Thing about this simple mod is, you use your stock out of the box tamiya truck, fit AWD GRU and front axle, and you have 10mm more in height, and AWD. GRU gives you probably slower 1st gear and more torque than Servonaut, and when you want to go faster, you have 2 extra gears, and it still is very fast in 3rd gear.

I think using 3speed with GRU changes everything. I am playing all mornign with AWD, and it is awsome. Before the truck wasnt able to climb 5mm bump unless you hit it fast. Now I can use it like a crawler, only the height of the front bumper limits where you can go with it. I guess I need to make offroad version of the front bumper
Reply With Quote
  #42  
Old 07-05-2016, 11:42 AM
Doggy's Avatar
Doggy Doggy is offline
Newbie
 
Join Date: Oct 2015
Location: Croatia
Posts: 124
Doggy is on a distinguished road
Default Re: Tamiya bolt on reduction gear

Standard GRU's will be ready to ship tomorrow. Please PM me if you want one.
Reply With Quote
  #43  
Old 07-07-2016, 12:23 PM
trewq trewq is offline
Newbie
 
Join Date: Jun 2016
Location: Croatia
Posts: 24
trewq is on a distinguished road
Post Re: Tamiya bolt on reduction gear

Quote:
Originally Posted by Doggy View Post
I think using 3speed with GRU changes everything. I am playing all mornign with AWD, and it is awsome. Before the truck wasnt able to climb 5mm bump unless you hit it fast. Now I can use it like a crawler, only the height of the front bumper limits where you can go with it. I guess I need to make offroad version of the front bumper

I have to say that I totally agree with this statement.
I've had bone stock R620 Scania with the MFC III, and that combo was not really interesting for any "scale" play.

I've tried a 80T motor, but having so many windings with such tin wire, the motor simply had no power. I've boosted the MFC's output, run a 10T pinion... you name it. It just didn't had power to move.

Then I went with a good old Hobbywing Justock ESC & 21,5T motor. This setup had lots of power, lots of torque, decent low speed & torque resolution, but the problem was with lack of synch between the MFC's sounds & effects and the motion of the truck. And that was so obvious that it really had no sense to have MFC, specially for that price! At least in my books.

Then Doggy came out with his crazy idea. He started modelling the GRU and he sent me few pictures. I came to see him one day, and his unfinished truck that he used to run on 3S just felt so different. I asked him for one GRU and few hours later I had my tractor truck modded & pulling. Then my 3y.o. son came with an idea to make it a tipper truck, and since then we have been abusing the plastic 3D printed GRU with no success in breaking it.
The best thing is, all MFC functions are there. Sound is in synch with motion, and things do look SCALE.

Donít get me wrong, I still want one made of metal, just cause I like it. But until that becomes available Iíll continue to use the plastic GRU, even on my next 6x6 or 8x6 project.
Reply With Quote
  #44  
Old 07-16-2016, 04:38 PM
bigford's Avatar
bigford bigford is offline
Big Dawg On The Bone
 
Join Date: Oct 2010
Location: mastic beach,ny
Posts: 1,952
bigford is an unknown quantity at this point
Default Re: Tamiya bolt on reduction gear

Ivan
I got the gru installed in the globe liner you need to make
a little room for the shift rod in the back cover. But so far
It looks great
Reply With Quote
  #45  
Old 07-16-2016, 05:31 PM
bigford's Avatar
bigford bigford is offline
Big Dawg On The Bone
 
Join Date: Oct 2010
Location: mastic beach,ny
Posts: 1,952
bigford is an unknown quantity at this point
Default Re: Tamiya bolt on reduction gear

Drilled a hole for the shift rod.. smooth gru now to see the pulling power
Way to go ivan!!!
Reply With Quote
  #46  
Old 07-16-2016, 05:52 PM
Doggy's Avatar
Doggy Doggy is offline
Newbie
 
Join Date: Oct 2015
Location: Croatia
Posts: 124
Doggy is on a distinguished road
Default Re: Tamiya bolt on reduction gear

Great to hear you got it! Thank you for the info about the hole, it seems that there are different versions of the tamiya gearbox, as on euro style trucks its right in the place. I will have to make it bigger so one size can fit all versions.
Reply With Quote
  #47  
Old 07-16-2016, 06:27 PM
bigford's Avatar
bigford bigford is offline
Big Dawg On The Bone
 
Join Date: Oct 2010
Location: mastic beach,ny
Posts: 1,952
bigford is an unknown quantity at this point
Default Re: Tamiya bolt on reduction gear

Just match the outer case to the hole in the inner case for the shift to pass through. Test drive later
Reply With Quote
  #48  
Old 07-16-2016, 06:45 PM
Doggy's Avatar
Doggy Doggy is offline
Newbie
 
Join Date: Oct 2015
Location: Croatia
Posts: 124
Doggy is on a distinguished road
Default Re: Tamiya bolt on reduction gear

I guess the outside contour doesnt match the bump on the gearbox case where the shift rod goes too?
This should be easy fix to make universal version to fit both types.

Reply With Quote
  #49  
Old 07-17-2016, 08:34 PM
bigford's Avatar
bigford bigford is offline
Big Dawg On The Bone
 
Join Date: Oct 2010
Location: mastic beach,ny
Posts: 1,952
bigford is an unknown quantity at this point
Default Re: Tamiya bolt on reduction gear

ivans 4:1 with 97 pounds on it

https://youtu.be/rLkZ433gmf4

106 pounds
https://youtu.be/odwRWeD11Y0
Reply With Quote
  #50  
Old 07-17-2016, 09:38 PM
Doggy's Avatar
Doggy Doggy is offline
Newbie
 
Join Date: Oct 2015
Location: Croatia
Posts: 124
Doggy is on a distinguished road
Default Re: Tamiya bolt on reduction gear

Great to see you fit it!

Its not 4:1, its 6,4:1 !

And i think the reason you wer not able to pull 106 pounds is in your motor! Try stronger motor, 55T doesnt have enough power, and now you need power to get the best results with GRU.

Its simple, you can find out how much GRU can pull when you brake it. Try stronger motor, 27T maybe, or 23T if you have. You will have to brake something under load. Trewq broke 2 driveshafts allready and something in the gearbox, but GRU is still in perfect condition.

If you want to test, try it, if you brake something on GRU, I will send you free replacement parts
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Reply With Quote
  #51  
Old 07-17-2016, 09:45 PM
bigford's Avatar
bigford bigford is offline
Big Dawg On The Bone
 
Join Date: Oct 2010
Location: mastic beach,ny
Posts: 1,952
bigford is an unknown quantity at this point
Default Re: Tamiya bolt on reduction gear

i'll swap out motor this week. also I have a different rear suspension in the peterbilt
Reply With Quote
  #52  
Old 07-17-2016, 09:49 PM
Doggy's Avatar
Doggy Doggy is offline
Newbie
 
Join Date: Oct 2015
Location: Croatia
Posts: 124
Doggy is on a distinguished road
Default Re: Tamiya bolt on reduction gear

I just unmuted the video, that sound, sounds like your gearbox dropped out of gear or you broke the GRU?
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Reply With Quote
  #53  
Old 07-17-2016, 09:52 PM
bigford's Avatar
bigford bigford is offline
Big Dawg On The Bone
 
Join Date: Oct 2010
Location: mastic beach,ny
Posts: 1,952
bigford is an unknown quantity at this point
Default Re: Tamiya bolt on reduction gear

It pulled my younger 97 pound test load after the 106
Reply With Quote
  #54  
Old 07-18-2016, 07:18 AM
trewq trewq is offline
Newbie
 
Join Date: Jun 2016
Location: Croatia
Posts: 24
trewq is on a distinguished road
Default Re: Tamiya bolt on reduction gear

That is the sound of the dogs skipping the selected gear within the Tamiya 3 speed.
My gearbox does that in 3rd gear when loaded. 1st and 2nd are good.

I am sure that I'll end up using metal gears within the Tamiya 3 speed for my next build
Reply With Quote
  #55  
Old 07-18-2016, 07:52 AM
Doggy's Avatar
Doggy Doggy is offline
Newbie
 
Join Date: Oct 2015
Location: Croatia
Posts: 124
Doggy is on a distinguished road
Default Re: Tamiya bolt on reduction gear

Well its just a matter of finding out whats the first weak point in the transmission so we can plan future upgrades.
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Reply With Quote
  #56  
Old 07-18-2016, 08:23 AM
bigford's Avatar
bigford bigford is offline
Big Dawg On The Bone
 
Join Date: Oct 2010
Location: mastic beach,ny
Posts: 1,952
bigford is an unknown quantity at this point
Default Re: Tamiya bolt on reduction gear

I would like to see the slop in the slides go away
Reply With Quote
  #57  
Old 07-18-2016, 08:40 AM
Doggy's Avatar
Doggy Doggy is offline
Newbie
 
Join Date: Oct 2015
Location: Croatia
Posts: 124
Doggy is on a distinguished road
Default Re: Tamiya bolt on reduction gear

Mark I am sorry my english is not that good, so I dont really understand what you mean by that?
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Reply With Quote
  #58  
Old 07-18-2016, 08:42 AM
trewq trewq is offline
Newbie
 
Join Date: Jun 2016
Location: Croatia
Posts: 24
trewq is on a distinguished road
Default Re: Tamiya bolt on reduction gear

Quote:
Originally Posted by bigford View Post
I would like to see the slop in the slides go away
I assume that you are referring to the slop in the tamiya 3 speed gearbox, where the dogs and the actual gears latch?
Reply With Quote
  #59  
Old 07-18-2016, 07:57 PM
fhhhstix's Avatar
fhhhstix fhhhstix is offline
Out of control
 
Join Date: Aug 2010
Location: Kirklin IN.
Posts: 3,770
fhhhstix has much to be proud offhhhstix has much to be proud offhhhstix has much to be proud offhhhstix has much to be proud offhhhstix has much to be proud offhhhstix has much to be proud offhhhstix has much to be proud offhhhstix has much to be proud of
Default Re: Tamiya bolt on reduction gear

Quote:
Originally Posted by trewq View Post
That is the sound of the dogs skipping the selected gear within the Tamiya 3 speed.
My gearbox does that in 3rd gear when loaded. 1st and 2nd are good.

I am sure that I'll end up using metal gears within the Tamiya 3 speed for my next build
It is not the Trans thatís the problem it is your bec. In first gear youíre not overloading the esc and the bec is able to keep the servo in position. In second which is center for the servo you wonít notice losing bec much. Now third is a different story when you pull a heavy load the esc losses its ability to put out full bec to the receiver. To test this run the truck with a load and if it seems like its slipping in third gear add a receiver pack to the receiver and try it again and I can guarantee the trans wonít drop out of gear.
__________________
AKA "00" Biddle


RIP FreddyGearDrive 2-12-59/12-19-11
Reply With Quote
  #60  
Old 07-19-2016, 03:30 PM
trewq trewq is offline
Newbie
 
Join Date: Jun 2016
Location: Croatia
Posts: 24
trewq is on a distinguished road
Default Re: Tamiya bolt on reduction gear

Hmm, thanks for sharing this with us. I'd probably overlook this.
I'll run the HV esc then, and straight of the 2s batt.

To bad my main output shaft is broken. I'd test this straight away.
Reply With Quote
Reply

Tags
3speed, gearing, reduction, tamiya


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 05:31 PM.


Powered by vBulletin® Version 3.8.6
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.