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Old 02-11-2014, 04:33 PM   #20 (permalink)
fritz
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Join Date: Aug 2010
Location: Andorre
Posts: 90
Drives: 2010 370Z M6
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I wrote up on this a few years ago: I also know kenchan won't let his wheels near an installer so that's excellent advice and we probably agree.

Just do the job right. Diving from one idea to the next occasionally strikes lucky until the next time.

"on car wheel balancing" is useful when the wheels and tires are fitted wrong.
Are the spacers true in thickness and in absolute roundness?
The thickness of each must not vary by more than one or two (no more!) thousandths of an inch.

Gotta get the overall wheel/hub clearance to the factory 0.1mm. (DIY tolerance will be at least 0.3mm with spacers), or reduce tolerances elsewhere to compensate.
Offer the spacer to the wheel: junk spigot rings of plastic. Best ask your machine shop to machine 4 spigot rings of ally which are a press fit to the spacer and a .05mm clearance to the wheel center.
Be sure the spigot rings are deep enough to engage the wheel itself and not just the taper.
(You have now "saved" .05mm)

Hub to spacer: centralise the spacer accurately with spring steel. Some key rings have a small tape measure attached. The spring steel is often 0.1mm or less and, if lucky (or the spacer Mnfr sloppy) that can go between the hub spigot and the spacer for an almost zero clearance.

If not then use thin elec tape .004" and be sure it does not wrinkle when you slide on the spacer. Now cross-tighten and then torque the spacer evenly to the hub. The tape can GTH.
(you have now fudged or "saved" .03mm or better)
Total tolerance is now .05 +.03 =.08mm. Good enough for any true race car.

Next (probably not necessary unless you still have a problem)
Balance each wheel and mark the weight. Rotate the wheel through 90 deg and re.balance.
If there's a difference go elsewhere.
Do the same to all wheels, leaving the new weights in place.
Fit tires (the red..or yellow balance markers and the circumferential line, if any, are as good as leaving the wheel only weights in place).... and balance them.

Fit wheels to car and cross tighten tightish.
Have the wheels lightly touch the ground and cross torque.

Testing:
Front alignment must be parallel or slightly toed in, Camber equal on each side: Tires new
Rear alignment must be to the car itself and preferably with equal cambers!
Slight Steering shake when cold is normal due to flat spot when parked, then there should be none.
If the shake gets worse with distance travelled then one or more tires has a delamination (easily visible out of round when rotated, hot, and quite common.)
Cause? Robust Kerb crashing!
Be sure that ride heights (floor to wheel arch) are equal ...within a cm---at both wheel pairs.

All 4 wheels/tires done that way will be good for top speed, be quieter, and eliminate vibrations you did not know you had.

Note: If a salesman or tyre fitter or manager or any-one starts hyping "stud centering" or "bolt centering" they want profit, not truth, so go elsewhere!

AND, according to one ex frequent poster on this site "Anything Fritz writes is b/s"
So, therefore everything suggested here is done at your own risk!

Fritz
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