Originally Posted by k.c.
Help me understand. I'm fairly mechanically inclined, but is an 8.5" 10 bolt as strong as an 8.5" 12 bolt?(Prolly not, but close?)
There is no 8.5" 12 bolt, as someone pointed out, its 8.875" in the 12 bolt. I would also like to politely disagree with Triaged... the number of bolts on the cover is inconsequential. A GM axle is named for the number of bolts holding the ring gear to the carrier, period. A good example is the 12-bolt that I had in my 73 wagon. It was a 12 bolt, with most internal parts interchanging with other 12 bolt axles, but the cover was held on with 10 bolts. To call that axle at 10-bolt would be ridiculous because the strength, parts interchange, and ring gear are all 12-bolt pieces.
There were 10-bolt axles with 9, 10, and 12 bolts on the cover. There were 12-bolts with 10, 12, and 13 bolts in the cover. But the important nomenclature refers to the guts; if its 12 inside, its a 12-bolt axle, regardless of how many bolts are on the cover. This is a common misconception and often times cause for debate, but it started out because most GM axles follow the bolt-naming rule; a 10-bolt axle almost always has a 10-bolt cover, so people assumed that it was called a 10-bolt because of the cover, but its just not true.