Steel wheel alignment bumps??

[KevinW]

Been searching here, TC and the web on what the bumps (little weld spots) are used for on steel wheels, but cannot find the post I remember.  I know they are for lining up the marks on the tires for better balance.  But I cannot remember if the marks (on tire, the high radial point) line up or opposite, and if there are no marks, use the valve stem hole?  Got new radial TAs and have a wicked shimmy above 60mph. Going to take them back on tuesday for a redo, but I want to get all the info before I go, thanks

[JohnZ]

Been searching here, TC and the web on what the bumps (little weld spots) are used for on steel wheels, but cannot find the post I remember.  I know they are for lining up the marks on the tires for better balance.  But I cannot remember if the marks (on tire, the high radial point) line up or opposite, and if there are no marks, use the valve stem hole?  Got new radial TAs and have a wicked shimmy above 60mph. Going to take them back on tuesday for a redo, but I want to get all the info before I go, thanks

The little "BB's" welded to the rim flange (on some cars after '69) aligned with a mark on the tire to match the high radial runout point on the rim with the low radial runout point on the tire (or vice versa - can't remember which); at any rate, it only mattered with original tires and rims. There's no industry standard for this today on aftermarket tires or rims; only plant-installed OEM tires and rims are marked today, with wax/paint dots or tape markers.

Go to www.gsp9700.com and use the locator there to find the shop/dealer nearest you that has a Hunter GSP-9700 balancer; in addition to balancing, it also identifies both lateral and radial runout of the tire/wheel assembly, and applies a road force to measure vibration resulting from any tire construction issues. Just "balancing" does nothing for vibration caused by radial or lateral runout or road force variation. You can balance a square wheel/tire perfectly, but it won't run down the road smoothly.

[big iron]

When you find a dealer make sure they have been factory trained on how to use the GSP-9700. The Hunter GSP-9700 is a very good piece of equipment but only as good as the people trained to use it.
Bob

[KevinW]

Thanks guys.  the ta radials have the high radial runout marked with a spot.  I will try having that lined up with the BBs on the rim (I have factory originals) and see how that goes (warrenty work, which I am going to watch closely this time).  If that does not do it, there is a gsp-9700 5 min from me at a Mercedes place.  Not sure how much THAT will cost!

[big iron]

All Mercedes dealers are required to use the GPS-9700 but they are expensive. You might try Discount Tire if you have one in your area.
Bob

[KevinW]

Ok, went back to the installer, show them the BBs and marks.  We aligned the BB with the marks and rebalanced.  There was one rim/tire that was a little wobbly, but not as bad as the spare, that one went to the left rear. Watched the tires spin up and 3 out of 4 were perfect.  All balanced to 00/00.  Took it out for test up to 75 mph, very smooth now!  Thanks!

PS, the amount of weights it took to balance was about the same as wnen the BBs were not aligned, go figure.