I found these wheels at a Dollar Store! 
  
They were packaged sepparately and sold as toys with an optional launcher. 
  
 
  
The wheels are about 10th scale and are very nicely detailed, perfect size for Triangula! 
 
 
 
I removed the nylon launching parts and finally found a good way to mount these to Triangula! 
  
I am grinding the square mounting post down so that it fits inside a thick piece of plastic tubing. 
Then I found another length of plastic tubing that fits inside the first length of tubing, and it fits the front axle mounts!!! 
 
This set-up works Great on the rears too!