Wheel Truing

[nigal]

Recently we gained access to a Pro Wheel Shaver II and my son shaved and sanded his 4 wheels (I helped him get the blade straight). We then performed a wheel only roll test. The table we used was 6 feet glass with one end raised 0.25". I verified the side to side level on the narrow dimension.

The first test we ran was with the inner hub (non spoke side) parallel to the table edge. Each of the 4 wheels rolled straight initially (18-20"), but then all 4 wheels veered right towards the table center (some more than others).

The next test we ran was with the outer side (spoke side) of the wheel parallel to the table edge (if the wheel still veered towards the center, then we could conclude that the table was not level). Each of the wheels again initially rolled straight, but then veered left towards the table's edge, opposite of the first test.

Does this indicate that the inner wheel edge is higher than the outer wheel edge? Or is this to be expected because the wheels always veered in the direction that the hub sticks out?

Also, for a wheel only test, how far should they roll straight? All the way across the table?

I thought I should ask before having him shave more surface off of the wheel.

[nigal]

I just noticed that I made a mistake in the first post. The wheels always veered in the direction opposite of the inner hub i.e. hub parallel to edge of table - wheel goes right; spoke side parallel to edge - wheel goes left.

[WarpSpeedINC]

The wheel usualy pulls to the spoke side, if the tread surface is flat, because this is where the majority of the wheel weight is located.
I don't think this is much of a concern when mounted on a car, although the roll test does get worse with rpm!?!

[nigal]

Thanks WarpSpeed, that is what happened, the wheel always pulled to the spoke side. So, is there any validity in performing a roll test? Should we be looking for wobble instead? or should we just try to measure the wheel using a dial caliper and look for symmetry?

[WarpSpeedINC]

I have never liked the roll test, for the balance issue mentioned above, and that even if they are machined round, you can't tell if they are concentric to the bore. In other words, you could roll the wheel, and have it roll smooth, but the axle bore could be moving up and down, and you would never notice.
The only true way to measure a wheel, is to mount the wheel on a smooth, snug fitting shaft, such as a proper size gauge pin. This way, the wheel can be rotated about the axle bore centerline, with out slop effecting the measurement. With an dial indicator mounted on the tread surface, you can measure actual wheel run-out, of how true the wheel is to the axle bore centerline.
Here is a very good picture of this being done. Fixture and picture compliments of Pinewood Daddy.

This is the only "true" way to measure a wheel, be it stock out of the box, or machined. The roll test tells us very little, and the spin test can look terrible on the best wheels, because of the wheel wanting to orbit around the axle from no load being applied. Measuring like above, or running down the track are the only way to properly grade a wheel.
Good Luck and Happy Racing!!
Warp Speed Inc.

[woodenwonder]

If you don't have the equipment to check properly and still want to do the roll test you can insert a round wooden toothpick through the hub and watch for the ends of the toothpick bobbing up and down. Keeping in mind that toothpicks are not perfect either. But this will help you evaluate a number of wheels to pick the best ones if you don't have the equipment.
Just my 2 cents. Good Luck.

[nigal]

Thanks everyone! I thought my son had done a pretty good job on the wheels and I really couldn't figure out why they didn't roll better. I found a dial indicator like the one above for $19.95 on Amazon (from Grizzly). Since my son already talked me into getting most of the other Pro Series tools, what's another $20.

[pwgrasshopper]

mount the wheel on a smooth, snug fitting shaft, such as a proper size gauge pin

Warp, wheel bore diameters vary so I figured a range of pin sizes would be important to get the snug fit you mention. I looked at a few sets online a while back and was surprised to see a hefty price of $50 and up, up, up. Would a few key sizes do the trick (if so which ones) or would a set be best? Thanks!

[Pinewood Daddy]

pwgrasshopper said:

Warp, wheel bore diameters vary so I figured a range of pin sizes would be important to get the snug fit you mention. I looked at a few sets online a while back and was surprised to see a hefty price of $50 and up, up, up. Would a few key sizes do the trick (if so which ones) or would a set be best? Thanks!

The pic is my setup. ;D Warp - Thanks for the publicity!

The indicator and stand (with extra tips) cost me $19 from ENCO. I designed the fixture and base, and had it made at work. All hardened. All flat and square within .0002. The fixture not only checks OD run-out, but also side run-out by turning it on it's side (without having to adjust the indicator). The pin is held in by 2 set screws. There is a .097 pin it in. It's never been changed. It's a bit tight on some wheels, but works fine. I burnish all wheels by pushing in the tightest gage pin I can fit in the hole, without shaving it, and rotate it a few times. That compresses and smooths the plastic. I have .096 thru .099 pins. You can get then thru MSC Industrial Supply (www1.mscdirect.com/CGI/NNPDFF?PMPAGE=1356&PMCTLG=00) for less than $2 each.

Advance notice - I finished checking 45 kits of wheels last night. The numbers differ from MaxV's (new batch??). Some of the molds must be in bad shape. Some wheels have little bumps on the front of them, there must be pits in some of the molds.I found (6) #2's with .041 to .027 side run-out!! But there were (6) #2's with only .004 to .006 side run-out. The data's still raw in a spreadsheet, I'd like to clean it up a bit in the next few days.

[Buckeye]

This is the type of setup I use to measure my wheels. This is a picture of Randy's setup at Max. Velocity:

Anybody using a lathe only needs the dial indicator to check wheel runout.

[Pinewood Daddy]

buckeye said:

This is the type of setup I use to measure my wheels. This is a picture of Randy's setup at Max. Velocity:Anybody using a lathe only needs the dial indicator to check wheel runout.

Note that the chuck has a rubber band holding it from rotating. Spin the wheel on the gage pin only. Otherwise the runout of the chuck will be added to the reading.

[nigal]

I received the dial indicator and we used the pro hub tool to hold the wheel. With my help, my son was able to get most of his wheels to with 0.001". The system seems to work okay, but I can't really recommend the dial indicator from Grizzly. Perhaps the ENCO one is better quality.

[Pinewood Daddy]

nigal said:

The system seems to work okay, but I can't really recommend the dial indicator from Grizzly. Perhaps the ENCO one is better quality.

The ENCO indicator is the cheapest one I could find. On sale, they have the indicator, adjustable magnetic base and 22pc tip set all for $19. That's cheap!! It works fine for what I do with it.