Originally Posted by
InspGadgt
Here is the only thing I disagree with you on. I don't believe every form of rubber has been tried sufficiently. All the forms of rubber that have been tried have been based on rubber similar to or already available as a TC tire. That rubber just is not going to work on a pan car. Tamiya did have a brief time trying a rubber cap that would glue on over a foam tire. That rubber did work quite well but they were a pain in the butt to mount and looked like crap because you ended up with glue all over the place. I think if they had spent more time developing that into a proper rubber tire instead of a cap, it would have had a good chance of being a good rubber tire. No one else experimented with a rubber anywhere near that. Proline tried their version of a capped tire but it was a hard rubber like what was found on touring cars at the time so it never stood a chance of working well.
Gadget - it doesn't matter how many types of rubber you try, the mechanics of how the different tyres behave remains the same.
A rubber tyre is a homogenous construction where there is a single contact patch acting on the sidewalls. Once the grip is overcome (static friction) the patch snaps to the straight ahead and the speed has to come right off (sliding friction is less than static friction) to restore the static friction. No matter what construction you have (air filled, foam filled, insert filled) the tyre will generate side grip by the angle of the contact patch relative to the sidewalls.
A foam tyre is heterogeneous in that it is not of uniform composition. Each cell of the rubber is flexibly connected to the next one. When one area of the tyre loses grip it snaps straight ahead, but the bit it is connected to doesn't as the connection is flexible. That characteristic allows the tyre to have some parts with grip, and some without, leading to a progressive slide that is easy to control and, in effect, never completely losing grip.
Almost every type and compound of rubber has been tried with the same effect - pan cars are nasty to drive on rubber! please don't let me stop you having another go, but please also forgive me if I don't hold my breath!!
Good luck...
Originally Posted by
EDWARD2003
Another "been there, done that" which does not work for a pan car.
I had one of those AYK diffs and it was awful. I also had an Alpha Track Parts diff in the early '80s which was also nasty to drive. There rear of the car becomes twitchy and unpredictable because the diffs are not very smooth and they are completely open, unlike a ball diff.
Putting oil in them is a crude tuning device where even a small change of oil can turn the car from a rotation to die for into an under/oversteering beast. Also, for some reason I never understood, the oil goes off and he handling changes during a run.
Again, if this had been a killer move we'd all be driving them now! Sorry to burst another balloon...
