Well there made from 6061 T6 billet aluminum & cnc machined & hve 1/2 wheel studs pressed into the back side & there torqued to specs as if they were the wheel being installed on the vehicle.
Boyd Coddington,Jesse James wheels are made from the same material ,NO safety issues there.
Check out the front hub set ups on factory dually 1 ton truck, they all have factory style spacer that sets the dually front wheel center farther out to allow for the tire to clear the suspension & they use the same wheel bearing as the single wheel 1 ton trucks.
Using a 1.25-2.0 wheel spacer with a 15x8 wheel is not any different then buying a heavier 15x10 wheel with more back spacing.
I have cherokee wheels on my ranger & im using 1.5 wheel spacers on all four corner's so as to make the whole vehicle have th wider stance along with giving me the extra turning clearance for the 31x10.50 Yokahoma Geolander A/T.
spidertrax's statement:
Spidertrax has been providing the off-road market with quality wheel spacers for over 7 years. With our vehicle specific designs, aluminum anodizing for critical corrosion resistance, and our unmatched competition tested no risk money back guarantee, it's easy to see why Spidertrax Wheel Spacers are the #1 choice among four-wheelers. All Spidertrax Wheel Spacer Kits come complete with 2 6061T6 anodized aluminum wheel spacers, pre-installed wheel studs, lugnuts, and Loctite. Proudly manufactured in the United States of America.
there are other companies making them as well & they can be purchased from Ebay in either a 2 pc or 4 pc set