Steve, the rears in the graph don't travel to 8mm. They travel to 4mm (.156 inch) and the load is 1,400 pounds. For all practical purposes at 4mm travel the rear is solid. And more stuffs going to break than bending the thin shim/washer. Wonder what the rear bump stop looked like after being test squashed by 4mm (.156 inch). Wonder what Jim Dragos rear bump stop looks like after deforming the shim/washer. Jim, did the rear bump stop have memory and return to original shape? If it didn't return to original shape please post a picture.
I reread all the posts in the Mazda Spec Miata Shock Upgrade thread posted 8/14/18. Many comments about using the what I'll call normal ride height of aprox. 4 5/8 inch and no one from the special test team mentioned anything about oversteer/understeer or deforming any parts. That troubles me because Jim Drago setup his car for Sebring much higher than normal and his shim/spacer was deformed. With that sort of banging to deform the shim/spacer more parts will fail. With a car setup at normal ride height of 4 5/8 inch parts are going to fail quicker than Jim's part failed from his higher ride height at Sebring. Jim, thank you for posting your shim/spacer picture and setup heights. Many racers travel on the Gators and the shocks/mountings should withstand such treatment as most of us are not professional drivers with the capability to stay off the Gators therefor for the shock manufacture to say stay off the gators is unrealistic. Using the normal ride height of 4 5/8 inches with the shock rod mounted higher, there would be more shock travel before the shock body top mashed anything.
I am going to record to recognize this day in Mazdaracers history... You hit many good points and I am in agreement with all 100%
I did not look at the bump stop as I had a flight to catch.. The guys are off today and we are slammed so not sure when, but I will pull all four shocks off and take a look and report back.
In hindsight... I wish I would have looked at the shocks after Homestead, Turn 1 there is very fast, I would guess 115 or so and I put the car on the wall at apex which is directly over rumbles that are not intended to be driven over. Did that do it? I don't know. I dropped a wheel or two for certain over the weekend at Sebring as well, did that do it? No idea. I don't think that normal driving at Sebring caused it only because I didn't feel any big shunts off the stop? Maybe driving 15 years on the bilsteins the bounce wasn't as drastic as predicted? Sebring is definitely the exception, not the rule.. So I think this should be worst case scenario.. It is by far the bumpiest we go to.
We will work around it, it will end up being fine I'm sure, there are some smart people on the case. But, I too am surprised that we didn't start with a shorter shock body in the rear.