SOLVED. Kid's chapter book - boy invents frictionless substance? [s]

[Peter]

I would've read this in the late 70s or early 80s and would imagine it's not much older than that. I believe the main character is a kid inventor who comes up with some kind of grease or gel that completely eliminates friction. I remember he was able to coast for a long distance on his bike, for example. I think some bad guys were after the formula.

The only other detail I remember is about the kid's father. He worked as a tour boat captain or something similar, and he wore an eye patch and walked with a limp even though he had both eyes and both legs were fine. He thought it made him look more like a pirate, which was good for business. At one point in the story he injures his non-limping leg and starts limping on that leg instead of his usual. He also switches the eye patch to the other eye to make things symmetrical.

It was remembering the father that made me think of the book again. My wife hurt her leg and has been limping on and off the past week or so, and she mentioned that she felt lop-sided. So I offered to kick her in the other leg, to balance her out. That's just basic science, but she declined my offer.

[Chris]

This sounds like it might be right:

[Peter]

That sounds like it, all right! At least, I recognize the title, and how many stories can there be where a little kid invents a frictionless substance? Thanks!