02 GrandAm brake rotors

Why do the front brake rotors have oversized holes in them......I would think that it wouldn't be good for them to be able to move between the axle hub and wheel. Could this be the reason I need to have the brakes
turned every time I switch back from my steel snow wheels??
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Do you mean oversized holes where the studs go through, or the centre hole is oversized? The centre hole should not be, but the holes for the studs should....and no, it doesn't matter. As long as the rotor, hub, and wheel are clean when they are installed, the clamping pressure from the five lug nuts will be more than sufficient to hold the brake rotor in place.
T = KDP
1200in*lbs = (.20)(.5")P P,000lbs/lug nut
P = 12,000lbs*5 lug nuts = 60,000lbs clamping force
Steve

--
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com ).
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Are they over torqueing when switching wheels?

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
That would be my suspicion as well - problems often seem to result from this on these cars, if they are gunning the lug nuts on with an air gun without regard for torque, the rotors can warp when they heat up.
--
Robert Hancock Saskatoon, SK, Canada
To email, remove "nospam" from snipped-for-privacy@nospamshaw.ca
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Especially if there is dirt/rust on the rotor/hub/wheel and if they do not tighten the lug nuts in the roper order.
Steve

the
--
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com ).
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Robert Hancock wrote:

Do you know what the torque specs might be?
My g/f's Alero is notorious for warping rotors at the rate of an oil-change.
-marc
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
100 foot-pounds. They're also supposed to be tightened in a star pattern.
My guess would be that uneven torque on the lug nuts would be even worse than overtorquing..
--
Robert Hancock Saskatoon, SK, Canada
To email, remove "nospam" from snipped-for-privacy@nospamshaw.ca
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Robert Hancock wrote:

Cool, that's about what I guessed. Last time I had the wheels off, I just cranked them on "fairly" tight... definitely in a cris-cross star pattern. I didn't think the torque mattered that much.
I'll be sure to pull out the torque wrench when I get the rotors turned.
Thanks, -marc
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
At the dealerships these days, they use torque sticks. It's an attachment that goes onto an impact gun. The gun will jump when the proper torque has been achieved. And,... it will go no farther.
If you don't torque the lugs evenly, your rotor can warp.
Just because you saw them use an impact gun, when they tightened the lugs, it doesn't mean that they did it wrong. If you see a 6" to 8" extension on the gun, they are doing it correctly.
GMdude.
P.S. Unless you purchase a torque stick for your impact at home. You should use a torque wrench to tighten your lug nuts.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I always use a torque wrench on my lug nuts and I tighten them in steps (25, 50, 75, 100 ft lbs) in a criscross pattern. I've only had one pair of rotors warp and those were turned prior to it happening so I'm guessing that they ended up being too thin.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.