Alright. Using these calculations
Careful Calculations Affect Ring Design we need to figure two things: 1)Ring Shear and Groove Yield.
Using the above calculations and SWAGing material as HR1018 (45K material - for comparison Hardened 8620 is 110K material) and using [MENTION=85512]eddiebx[/MENTION] and [MENTION=65614]Antman[/MENTION]s dimensions then we can calculate the force required to shear the snap ring is 21,900 lb. you have about 1,000 lbs there at rest.
BUT! You also have to calculate groove yield! Lower number of the two fails first. That number calculates out to be only 10,900 lbs. Still a K (safety factor)of around 10. Now groove yield is the BEGINNING of failure. Catastrophic failure is going to be much higher number.
Now, I do not know the material spec and Bilstein might even use their own materials with custom hardening, but I picked pretty much the worst case scenario and am confident the ring would not fail before the groove if installed properly. Good snap rings are cheap so My figures are probably way conservative. Please don't take these numbers as real. I did this just to see what forces COULD be in a snap ring failure. Too many unknown variables (exact measurements, material spec) to get real numbers but you get the idea.