Re: New wheels - 17" rear 18" front
Posted: Sun Nov 12, 2017 2:58 am
doing a dykem/prussian test would be good to seeNavy Lifer wrote:Nice demo - the pattern measures out to 4.75 vs 4.72, admittedly not very much, but clearly different enough to indicate that a wheel for one pattern does not center up as intended on the other pattern.kevink wrote:I have heard this, too. The common argument is that they are all 4.750" (which is exactly the same as 120.65mm) and if a wheel or car is said to have a 120mm bolt pattern, the manufacturer is just stating the size as 120mm instead of 120.65mm. I don't think this has ever been proven. I never really cared or thought of a way to actually put this to the test... until now. I drilled two bolt patterns in a piece of 0.250" thick aluminum on my mill which does bolt circles. I made one pattern 5x4.750" and the other one 5x120mm. My studs measured 0.545", so bored all the holes to exactly 0.546" with a boring bar. The initial hole was made with a 0.500" end mill, so there was no chance of a twist drill walking. The bolt circles are perfect. Well... the 120mm bolt pattern fit over my studs perfectly and tightly. The 4.750" bolt pattern only fit over the portion of the studs that is not threaded and a smaller diameter than the threaded portion. It was clear that each stud was not centered in the 4.750" pattern's holes. You can sort of make this out in the photo. That being said, I still have yet to hear of a failure by using 5x4.750 wheels on a 120mm car. The difference is pretty small (about 0.013" per stud).Maxspeed96ct wrote: Some call it 5x120, 5x120.65 or 5x4.75, depends on the manufacture. Its the same
My issue is the act of torquing the wheel nuts (spec to 140 lb/ft) will result in very heavy contact on the most-inboard point (radially) on a Corvette wheel, effectively "pinching" the wheel and heavily loading a very small area, and leave the rest of the seat taper less loaded. It will also place a bending load on the wheel studs as the wheel nuts are drawn to full torque.
Try putting some Prussian Blue or Dykem on the tapered wheel seats of a Corvette wheel on 120mm pattern and just snug up the lug nuts, then check the contact on the seats. Then do the same with the correct 120mm wheel.
bill did you see these ?kevink wrote:Are you thinking of wobble nuts?
https://www.hdwheelsusa.com/products/pcd-adjusting-nuts