wheel rotation on a pumpkin

The place for all things Tamiya.

Moderators: scr8p, klavy69

Jamied
Regular Member
Posts: 4
Joined: Wed Aug 26, 2020 5:52 pm

wheel rotation on a pumpkin

Post by Jamied »

Hi, new to the forum and in need of help please.
I'm building a tamiya midnight pumpkin, all was going well till I put on the rear wheels and found that when I manually turn one wheel the opposite wheel turns the other direction.
I've revisited the gearbox a number of times but cannot seem to find the fault.
Your advice would be greatly appreciated.

User avatar
RC10th
Approved Member
Posts: 4699
Joined: Sat Feb 16, 2013 9:51 am
Location: Australia
Has thanked: 50 times
Been thanked: 1492 times

Re: wheel rotation on a pumpkin

Post by RC10th »

Congratulations, you've correctly assrmbled your pumpkin.

All jokes aside that is exactly what should happen due to the differential in the gearbox.
I was old school - when old school wasn't cool !

Jamied
Regular Member
Posts: 4
Joined: Wed Aug 26, 2020 5:52 pm

Re: wheel rotation on a pumpkin

Post by Jamied »

Really! Wow
The wife was having a real laugh at me.
So what happens when I power up the motor, will it run with the wheels going opposite to each other or will it just sort itself out?

User avatar
romulus22
Approved Member
Posts: 2545
Joined: Wed May 19, 2010 7:30 pm
Location: KY
Has thanked: 885 times
Been thanked: 769 times

Re: wheel rotation on a pumpkin

Post by romulus22 »

Correct. Everything will be good. If you want to check it for giggles. If you hold the opposite wheel when turning one. You will then turn the motor.

When just spinning one wheel the motor magnets are providing resistance so you are just spinning the spider gears in the differential. When you spin one forward the spider gears cause the other wheel to spin the opposite way. The spider gears allow the outside wheel to spin faster while going around corners.

Jamied
Regular Member
Posts: 4
Joined: Wed Aug 26, 2020 5:52 pm

Re: wheel rotation on a pumpkin

Post by Jamied »

Thank you, I understand now, thought I was going nuts!

User avatar
Lowgear
Administrator
Posts: 4319
Joined: Tue Feb 07, 2006 1:00 pm
Location: New England
Has thanked: 120 times
Been thanked: 754 times

Re: wheel rotation on a pumpkin

Post by Lowgear »

The same principle applies to full size vehicle axles as well. This is known as an open differential. A locked differential means that both wheels receive equal power. This is achieved by using what's known as a locker or having a posi unit installed.

Jamied
Regular Member
Posts: 4
Joined: Wed Aug 26, 2020 5:52 pm

Re: wheel rotation on a pumpkin

Post by Jamied »

So your saying, if I have some popeye spinnich and with one arm lift up the rear end of my transit van, and the other hand I spin a wheel, the opposite wheel will rotate the opposite direction,
I never knew that! I'm impressed!

User avatar
Lowgear
Administrator
Posts: 4319
Joined: Tue Feb 07, 2006 1:00 pm
Location: New England
Has thanked: 120 times
Been thanked: 754 times

Re: wheel rotation on a pumpkin

Post by Lowgear »

Yup, that's what would happen. :)

Create an account or sign in to join the discussion

You need to be a member in order to post a reply

Create an account

Not a member? register to join our community
Members can start their own topics & subscribe to topics
It’s free and only takes a minute

Register

Sign in

  • Similar Topics
    Replies
    Views
    Last post

Return to “Tamiya Forum”

Who is online

Users browsing this forum: No registered users and 7 guests