On my rockwells I flipped and rewelded the centers on the rims after the tires were mounted. I figured everything was thick enough so no worries. I also welded the split rings on AFTER mounting. Again, some 6011 rod to burn through the CARC (deeelish!) and those rings are on permanently. It looks like I'm going to toast these (old-ish) tires before long, but that's ok because the rims are cheap (as you well know).
With my 52/53's (16.00x20), I had to get the TDS tire guys to use their big ass tire crane to push down on the bead to mount while we they hit it down with a duckbill mallet. Hey, another thing - the big ass tires want to grab the rim and roll when mounted. It might be good to take a grinder and radius, yes, grind on the rubber, of the inside edge of the outside bead, or in other words, the first part of the second tire bead that touches the rim. Loads of lube will help the mounting, but it also increases the chance that your tires will spin on the rim at LOW psi.
Now. I wheel these things at 0 psi. I've already spun one wheel past the point where I can fill it up. I suggest that you keep at least a few PSI in there if you can.... this might stop them from spinning (or do the new fangled screw locks... I had always intended to drop a box of 5/16" lag bolts in each wheel but christ if I had the time).
Big tires are cool.
Oh yeah, and with regards to filling these, take all precautions stated. If you're not a believer, look at the sidewall, and look at how many single square inches are on that sidewall (the area of the sidewall, which is 1800 square inches on a 53). Then multiply by PSI inside the tire. You realize that there are TENS OF THOUSANDS of pounds of force that will accellerate that 15 lb ring at many hundreds of times the force of gravity*. Split rims are shaped charges in disguise and that ring will cleanly separate body from appendage if given the chance.
Bob
*The math
· sidewall area of a 16r20 is 1800 in².
· a 53 fully aired up is like 90 psi, and 1800*90=162 THOUSAND POUNDS OF FORCE
(granted, you'd never air this up to 90 unless you were working on the FANTASTIC M1070 SuperHET, aka the best truck ever made)
· Ok, so let's go to SI units because they are easy. Let's say, that ballpark, the force on the ring is 10,000 times gravity, or will produce roughly 100 km/s². Over just 10 cm of distance (let's say that the tire will stop pushing the ring after only 4 inches), this will accelerate the ring for only .0009 seconds. That's fast enough, however, to accelerate it to 89 meters-per-second.
Coming back to English measurements, that equates to about 200 mph.
Ok, this is all totally back of the envelope and rough, and the tire probably blows out maybe twice the distance (resulting in about, say, 3-something times the total speed), but a 15 lb ring going that fast is going to be really painful. Shit, I dunno. My math is rough but bottom line, those rings go HELLA fast.
Bob
