can someone tell me if you must always shim kingpins to get them to fit inside the rims? if so how much preload, car is hd 12th scale lmk thanks !!!

Well -- I've had a close fit a time or two, but never had to do anything fancy... Keep in mind that the 12th scale kingpin is shorter (as are the front springs) than the 10th scale parts... Also -- make sure the steering knuckes are "right side up" (verify vs the drawings in your instruction manual). The front axle is not centered on the trailing axle setup for 12th scale front ends and if it's swapped L-R, then it could cause a problem...

Sorry I can't be more help...

Hey Martin,
This is Skip Hall, give me a shout with your mailing address so we can send the stuff. I'll answer any questions for you also.

Happy New Year To All !!!
Skippe 1