bolt pattern centered on redrilled axles?

[dartmeister]

I've got a really goofy question if anybody wants to throw in their two cents. I got my axles back from the machine shop yesterday and the guy did an excellent job getting the studs centered in the wheel stud holes, but it appears to the naked eye that the whole bolt circle pattern is off center a little. So, just out of curiosity I throw the rearend back together and bolt on a couple of bare wheels (no tires) and check the runout on the smooth inside diameter of each wheel. In one revolution of each wheel I got .050" out of round on the right side and .075" out of round on the left side. (my wheels are in very good condition and appear straight) In anybody's humble opinion does this sound acceptable? Do you think this is enough to cause an imbalance condition? Any replies to this bizarre question are appreciated.

[Jack Z]

dartmeister:

I've never checked the runout of a wheel so I don't know if your numbers are OK or not but I wanted to suggest that you check the runout of the axles as opposed to the wheels. You can do that by checking the runout of the brake drum pilot (the raised 2 1/2" or so diam. hub in the center of the axle flange) or the wheel stud circle. To check the drum pilot, just put your dial indicator tip against the outside diameter of the pilot (out of the way of the wheel studs) and rotate the axle. To check the wheel stud circle, put your dial indicator tip against the outside surface of one of the wheel studs (close to the axle flange to minimize the error if they're a little crooked) and record the indicator reading. Then rotate the axle so that the indicator tip is on the same spot on the next stud and record that reading. Do this for all five of the studs and then compare the readings. I would guess that if the runout at either of these places is more than 10 or 20 thousandths, it's probably not good.

[GRUP]

I CHANGED THE OFFSET ON A SET OF 15x6 1/2" RIMS ONE TIME, WITH A DIAL INDICATOR. AFTER I HAD THEM REWELDED I CHECKED THEM AGAIN AND THEY HEATWARPED. THEY HAD ABOUT .010/.010 (RADIAL/AXIAL) BEFORE WELDING AND ABOUT .030/.040 AFTER WELDING. I WAS CONCERNED. THERES A SECTION IN THE FACTORY SERVICE MANUALS THAT GIVE YOU SPECS. ON RADIAL AND AXIAL RUNOUT AT BOTH THE RIM AND TIRE. I DONT REMEMBER THE EXACT NUMBERS, BUT I THINK THEY WERE VERY TOLERANT. YOURS MAY BE BORDERLINE THOUGH. I REMEMBER THE TIRE NUMBERS WERE VERY LENIANT, LIKE .090. HOPE THIS HELPS

[turbododge]

Any good machine shop should be able to center the pattern on bearing locating surfaces within .005 inch.

[dartmeister]

Jack Z, good idea on just checking the wheel stud pattern with the dial indicator. That would eliminate any irregularities that may be in the wheel. But, unfortunately for the axles sake I think the wheels are straight and true. I'll recheck it tomorrow and compare.
GRUP, I had no clue information like that might be in the service manual. I guess it goes back to the old saying "when in doubt, read the instructions"! Looks like I have a little reading to catch up on.
Sound advice I'm sure Turbododge, with the key word being "good"!
Thanks a bunch guys for the excellent advice on such an oddball topic. See Ya

[Billydelrio]

IF you can't mamage to set up a dial on the axle studs, you might try this.
rotate rim two holes on the axel. If dial's high and low readings are in the same spot on the rim, the rim is not true. If the dial's readings are the same, but 144 degrees from the previous spot, the axle is off center.
It is possible for both to be off center, in which case you could index the wheel to the axle to get the best numbers.
Just and idea
Billy

[dartmeister]

Good thinkin' Billy, It's definately worth a try. Thanks again for the most excellent input, I knew I could count on the members here to cover all the angles! I was gonna recheck the axles tonight after work, but the wife and I did the dinner and a movie thing, and tomorrow I have to dig a fifty foot long ditch for the natural gas line out to the garage so I don't freeze this winter. So hopefully tomorrow night. Whew, I hope I didn't put anybody to sleep with that reply, I almost nodded off myself.
See Ya