Recommended Posts

Quite some time ago now, when I started collecting parts for the War Rig, my tire order got messed up and I ended up with 12 free rock crawler tires. I thought it was time to do something with them and initially had the thought of using them for a 6x6 truck, with dual wheels on the rear of the truck (Using up 10 tires). So I made up 10 wheels, using a very similar design to those I made for the War Rig, with slightly adjusted wheel dimensions to accommodate the slightly smaller tires. Half way through this process I thought about having a generic set of double wheels I could fit to any 'standard' Tamiya axle. So I started off with a wheel that would fit the tire onto a Tamiya vehicle:


Then made some hubs to fit the wheels to. These have 12 holes, 6 with threads for ease of screwing the wheels on, and 6 plain holes should I want to put bolts through the hub and use nuts to secure the wheel to the hub for a more realistic look:



As I didn't fancy machining 12mm hex slots into the back of each hub, I just drilled and machined them to fit the standard axle and pin arrangement used on most Tamiyas, effectively incorporating the 12mm hex into the hub.

This left me with a hub that can have wheels attached on the deep or shallow side:

Shallow side outward for standard track


Deep side outward for wide track (Only 2 of the 6 retaining bolts are fitted):


That's not all however, but fitting the wheels narrow side outboard, I can then add a wheel spacer I designed and then add another wheel:



I've just used the Hi-Lift here as a test bed to try the fit, I also had a Mad Bull I wanted to test drive them on. As the Mad Bull uses splined shafts for the hexes, I had to make 2 hubs with 12mm internal hex slots to fit over the Mad Bull 12mm hexes, however the fit came out ok.




The fit came out pretty well, it was certainly noticeable however that there was more weight at the rear of the car. Running it (Silver can and 3S LiPo) the grip was excellent, far better than standard Mad Bull tires (I put this down to softer compound and 2 narrower tires v 1 wide one). It was also noticeable that the tires actually squealed under wheel spin and skidding, which was quite entertaining. The downside however was that the tires kept partially coming off the wheels, this could be sorted by glueing them on but I don't really want to do that. So for the time being they have put to one side to wait the right project to put them on, I'm still thinking about possibly a 6x6 crawler / trail runner with dual wheels on the rear, or maybe all round.


  • Like 5

Share this post

Link to post
Share on other sites

Living up to your user name again, I see...

  • Thanks 1

Share this post

Link to post
Share on other sites

Gearhead RC did something similar with a central hub and more/less offset depending on how the wheel is flipped.  What they didn't do, though, was come up with a spacer to go double wheels on an axle.  As usual, you make nice stuff with the machine tools available to you!


Share this post

Link to post
Share on other sites

Top work as ever Martin! I love the look of the Madbull with the dual rears 😍👍🏻

Share this post

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now