September 9, 2012

Story & photos by Albert Vandervelde

There are an endless array of tire and wheel choices these days, with a lot of great options. If you think we have a hard time keeping up with the most cutting edge out advances, think of the wheel guys trying to make rims that work with every tire. It might seem simple, as there are DOT specs for tires and rims. Most revolve around the bead retention area and the small hump you will find slightly inside the outer bead edge. Of course we throw that out the window with our great desire to run low tire pressure and beadlock wheels. I ran into this issue recently with the BF Goodrich Krawlers I’ve been running. I’ve had no issues with tires leaking air on my Allied beadlocks with 35” and 37” tires but have been having some issues with the 39” tires. A call to Allied shed some light on this issue and provided a pair of fixes. Greg at Allied classifies the 39 Krawler as a “thin” beaded tire. This would mean the thickness of the rubber at the bead. Beadlocks clamp the tire to the rim via a ring that crushes the tire and clamps it to the wheel. These thin beaded tires are just thin enough that the ring Allied uses bottoms out on the rim before the tire is tight enough. At higher pressures, air bubbles out around the beadlock.

Fix 1 – order your wheels for “thin beaded tires”. Allied machines the bead lock lip slightly lower so the steel rings they supply clamp fully onto the tire.

Fix 2 – if you already have a set of Allied wheels, you can purchase the optional aluminum rings which are also machined with less of a lip so the tires clamp fully onto the wheels. This was our choice and our issue went away. They look pretty cool too.

During this conversation with Allied, the entire tire bead issue brought up another point that I never thought of. The conversation came out of the fact even with beadlocks (any brand) some tires tend to “burp” air around the inner bead area or come off easier than others, which, is general left stock on most beadlock wheels. I’ve also found over the years that some non-beadlock wheels have more issues than others keeping tires on at low pressure. I always chalked this up to the bump inside the rim not being large enough on some wheel models. This has lead me over the years to prefer certain brands of wheels just for this reason when beadlocks are just not practical. For this reason, I’ve tended to buy American Racing AR 767 steel wheels. I’ve had fantastic luck with tire pressure in the low single digits on these wheels but in the current crazy of larger wheel diameters, American Racing has not kept up with much more than 15 inch rim sizes for the AR 767 wheel.

Greg and Mike at Allied said one of the biggest issues comes from certain tires with an overly “thick” bead area. The DOT bump inside the rim is set at a specific distance from the rim edge and if a tire is slightly thick it will not slide fully over the DOT bump but will rest partly on this bump. While the tire might hold air fine at street pressure, it increases the chance of the tire slipping off the inner bead. The fix he said for those with a chronic problem of losing inner beads is to file or die grind the inner edge of the tire bead area so the tire can slide over the DOT bump – try it if you have been having issue it just might fix this issue for you.

September 9, 2012