RC Car: Radio Shack Thunderfox

[Kanoe]

If this post is in the wrong section, please move.

I recently got my RC Car from my parents that i had as a birthday present in the mid 90's and having been trying to get it back to working order with little to no success so far.

I thought the tricky bit was going to be getting a new battery for it but nope, that seems pretty standard and is no problem at all.

The trouble im having is wheels and tires, the plastics and rubber are gone and im trying to find something else that might fit the bill but annoyingly nobody puts dimensions on anything! (not even the manufacturers sites have that info).

So i thought i would go to a physical model shop for assistance. Nearest one is like an hours drive away so was reluctant but went anyway yesterday and got to the store and spoke to the owner about it to see if he could assist and he basically laughed at me and said good luck and that was it.

Think I have found some that might do the trick, especially for the fronts but again cant find sizes.

I dont want to bin it, it was expensive, even back then, and im sure it still works, but disappointed it looks like its going to end up in the bin.

[Jonj1611]

No idea mate, though did find this online : If you have bad tyres and can't find a spares doner with good ones then it's quite cheap and easy to switch the outboard drive cups to tamiya boomerang/hotshot/bigwig etc ones and you can then choose whatever hex wheels you like

Not sure if that's any good to you or you may have already seen it

[Kanoe]

yeah i saw that on my dive down the rabbit hole but couldnt really get what they were on about

[Jonj1611]

Going to guess it changes the size of something to accept new wheels/tyres

https://www.ebay.co.uk/itm/196068352473 - They aren't the right ones but might give you an idea what you are looking for

I guess if you change them to something that fits more readily available tyre/wheel sizes then you can fit Tamiya parts for instance

[Kanoe]

thats the thing, i couldnt find the exact ones they were on about and other drive cups i found didnt remotely look like they would fit

[MLyons]

Do you have any picture or measurements of the hex that's used to attach the wheels?
Any sort of picture of where the wheels are mounted would help.

[Kanoe]

Yeah I can try and upload some photos. I think that's part of the problem the backs are not hex fit.

Fronts are bearing as its only 2WD.

I think the grasshopper II front wheels might do it but again can't find anyone giving the dimensions!

[DanceswithUnix]

If the alternative is scrapping the car, then 3d printing some tyres in TPU filament could be an option.

Not as grippy as proper tyres, probably OK for an offroad sort of vehicle.

[Kanoe]

Yeah, getting some wheels and tires and will try and design and print some adapters for the back wheels.

Never tried designing anything for 3d printing so that's going to be a learning curve and a half!

[Kanoe]

After a busy weekend of messing about the car is up and running. Took about 8 prototypes to get the wheel adapters just right but now it probably works better than it did originally! Took me 2 days to realise that the back left and right were completely different and needed different designs.

For future reference for anyone else (read me in a few years when I forget):

- Pack of Tamiya Grasshopper II Wheels and Tyres
Wheels and Tyres
- Pack of Metal Bearings (for front wheels)
Metal Bearings

For the fronts file the axels/bearings so they fit. The axels are 5mm and the inner diameter of the bearings are 5mm so needed to file them slightly to get them on but with that done they are a perfect fit and good match for the originals in size and style.

For the rears the left and right side are different:

Right:
- Wheel needs middle drilling to 5mm to fit on the rear shaft which is 5mm to fit properly
- Needs right hand adapter that was designed and 3d printed (link to come to for stl file)

Left:
- Wheel needs middle drilling to 5.5mm to fit on rear shaft which is 5.5mm
- Needs left hand adapter that was designed and 3d printed (link to come to stl file)
- Don't overtighten nut otherwise wheel will get drive from shaft not the diff, make sure when moving the wheel it freely drives the opposite wheel in the opposite direction

STL Files for Both Sides