Renn 208,

Good questions. The bolt and support plate are items used in Nascar race set-ups and are sold by AFCO and Coleman racing for use as seen in the photos, to load the spring and adjust ride hts. of the race car.

However I did do a quick calc. and the 1" diameter bolt has an area of 0.785 inches squared and using a safety factor of 2 on the 600 lb/in spring at max commpression would be 1200x4.5"=5400lbs of load on the bolt. 5400lb/0.785" squared= 6880psi. This is the stress to the bolt. Grade 8 bolt steel has a strength of at least 60,000 psi. So plenty safe on compression or tension.

It is more calcs for the bending forces and I don't want to go through that calc. I will let the final durability determination be the performance on the car where it is seeing 1G corner loads two to three times a week.

Jeff