about to trade wheels and wanted to know if my stock lugs will fit these wheels
i have the longer ones for the rears and the regular ones for the fronts since my amgs are staggered
Staggered wheels don't require different size bolts front to rear, the staggering is accomplished by making the rear rim wider and perhaps moving the center section along the width dimention to make ET adjustments. The center sections dimensions and the bolt mounting surfaces will still be the same wheather it's a front or rear wheel, (of a matched staggered set). Different size bolts are needed for differently designed wheel types in relation to the cars they were designed for.
In general bolts need to stick out the back side of any wheel between 17mm and 20mm. Less that 17mm is too few threads for safety, too much more than 20mm and it becomes possible to start hitting something and doing damage.
Take whichever bolt your in doubt of and just dry test it with the new wheel off the car. Hold the bolt in place with one hand and measure the threads sticking through the mounting surface with the other.
If the measurement isn't in the 17 to 20mm range, then simply add or subtract mm's to calculate which new size bolt you need.
The terms regular and longer are meaningless, you need to speak in bolt size language, (ie. 12mm x 1.5M, 26mm, R14, Hex 17)
I too have staggered SL55 wheels on my 129, the bolts in the above example are made for these wheels, front and rear take the same bolt.
12mm = bolt diameter
1.5M = metric thread size
26mm = shank length of bolt (bolt head not included)
R14 = Ball Seat Radius, in this special case it's 14 only because SL55 wheels are drilled to take a 14mm R14 bolt, normally this would be R12 to match 12mm bolt diameter, & R14's normally go with 14mm bolts
Hex17 = Metric Wrench size to install/remove bolts
When I received the above bolts from Rad USA Direct, I checked them right away on both a front and the rear of my SL55 wheels unmounted, I got the exact same measurement front and rear of the staggered set.
Be carefull with longer lugbolts on the rears especially, as they can cause damage to brakes if they are too long. I recomend that you standardize the bolt lengths for all four wheels and remove all different sized bolts from the car so you don't ever chance mixing them up.
I'm not familiar with the wheels your putting on, are they also drilled for 14mm R14 bolts? If they are you need a similar bolt as in the example above, a 12mm diameter with a R14 ballseat, the length required you'll need to measure as already mentioned above.
If you need assistance just go to the RAD USA direct website and call them, they will know exactly what you should need.