O.K, I have been doing a lot of searching online and I'm suprised at how little and how scattered the info is on building one of these cars is. I have decided to post a few of my questions here to see what I can find out. First off, I am interested in building a 1/4 scale slingshot dragster powered most likely by a Saito twin. I know there are more powerfull engines out there but I feel the Saito matches the nostalgia theme the best. This whole thing started with a set of chrome spoke wheels I found on Tower hobbies. They are just over 4" in diameter so that equates to a 17" 1:1 wheel which is what a lot of the guys were running back in the day. Now, the questions.....

1. What size tube does everybody seem to use? If I base it off of 1 5/8 tube from a 1:1 chassis then that comes out to .406" is this right? 3/8" is .375 so should I err to the small side?

2. My previous tubers were all made with stainless .250 tube with a .035 wall thickness. While this brazed well, it is really heavy so what material is most common. I found a supplier of 4130 tube but it is really expensive.

3. I cant seem to find any good photos of the common rear diff setup that most are using? I do like all the custom billet diffs I've seen but I also have read where people use some other type that uses "universals" or "uni" what the heck is this? Is it a universal joint from a socket?

I could have written that post myself! It's awesome to see that someone else is excited about slingshots too. I have all the same questions, but I also want to know more about the power transfer to the rearend. My impression from the videos I've seen is that these are all running centrifugal clutches. There has to be a more exciting option than that. I also want to know what folks are using for wheels and tires. Actually, I can do whatever I need to on the wheels because I have machine tools to make my own, but the tires are more challenging. Running the kart tires on the rear is close to scale, but these do seem a bit on the heavy side for the kind of power the motors are putting out. (which I'm guessing is around 5hp?)

From what I've seen, if you wanna go fast you gotta run foams on the rear. If a scale look is what your after (as I am) you can run rubber tires on the rear. As far as clutches go, I think everybody runs centrifugal clutches. I was thinking that the Elcon 4 shoe for the baja 5b would be a good choice to adapt to the twin I'm gonna use. Although rigging up some kind of servo operated trans brake would be really cool.