Quote:
Originally Posted by xlr8tr
Curious Richard, would the 295 and 355 kuhmo's fit on the JBL? Section widths of 12.1 and 14.2" respectively. One would think with current state of the art tires the numbers would be even better, assuming you could keep oil in the engine  |
The Comp chassis would accept the section widths that you quote as there is room for the increased wheel width while maintaining the same outside dimensions and therefore the motion ratios would still be correct. (Just add the required 2 inches to the backspacing)
More contact patch does indeed equal more grip if the suspension geometry is correct for the tyre construction. I am not familiar with the Kunmo sidewall design so I cannot give you a honest opinion on how they might work on the JBL.
The camber curves were designed for the Hoosier radials of the time and by good fortune the Michelin Pilots of the era were very close on the sidewall angle deflection numbers. The tyre pressures required were quite different between the two brands because the Michelin sidewalls were much stiffer than the Hoosiers.
And to Mark's comment "The up and down movement of the rockers is very fast even on a seemingly smooth road".
He nailed the reason for the front end rocker design there. The motion ratio is about 1.2-1 on the rockers. This was to increase the damper shaft motion and speed as very short shaft displacements are extremely difficult to valve for and control.
There are other reasons for this motion ratio as well that have to do with creating a rising spring rate curve that worked with the very high moment around the design roll axis.
This same philosophy was finally applied to the rear of the later cars with the introduction of the pull rod design.
Since Mark has examples of both chassis possibly he could comment on the differences that he feels in the dynamics of the two designs.
The pull rod car should give a much more stable transfer of weight and rotation about the roll axis. Transition from one direction to another should be quicker and more predicable as well.
Of course things being as they are when doing vehicle design, the best laid plans of Mice and Men etc...................