This subject has come up in the past more than once. Murray worked at an advertising company that had the Dunlop contract. Rake and trail has been understood for a very long time. It is what prevents the gobbly wobbly wheel as described in a Bill Crosby funny piece. When the videos were made, countless thousands of folks were riding bikes without the problem. Look at post number two. High bars, master cylinder, speedo tack arrangement. Mid to late seventies Japanese. I have one or two of that vintage bikes. I used to race against those kind of bikes in the production classes. None of the problems reported actually occurred. A couple of problems we did have with early Japanese. Crappy brakes before discs. Bikes that did not go where you pointed them, and flexi flyers when the engines got bigger.
The double F was a problem at the track, especially as the horsepower was increased. I can quote verse and chapter for those that would like to learn more.
My friend Bruce recently retired from Canadian Honda, after 39 years. Never heard of the problem.
What both of us do not know, is how to check and calibrate ABS front brakes. Jumping on the binders to see what happens, may not be very scientific.
With the above, we need to differentiate between gobbly wobbly, and fine handling. Both were lacking in early Japanese street bikes.
A piece of paper, a pencil, coffee cup and ruler, are all you need to work on your own rake and trail design.
Gobbly wobbly wheels on shopping carts have neither on the non turning wheels. The turning wheels vary.
UK