Can a brake rotor warp because of overtightening?
Can a brake rotor warp because of overtightening?
(OP)
Can a brake rotor warp because of overtightening a road wheel. My guess is - no
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS Come Join Us!Are you an
Engineering professional? Join Eng-Tips Forums!
*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail. Posting GuidelinesJobs |
Can a brake rotor warp because of overtightening?
|
Can a brake rotor warp because of overtightening?Can a brake rotor warp because of overtightening?(OP)
Can a brake rotor warp because of overtightening a road wheel. My guess is - no
Red Flag SubmittedThank you for helping keep Eng-Tips Forums free from inappropriate posts. Reply To This ThreadPosting in the Eng-Tips forums is a member-only feature.Click Here to join Eng-Tips and talk with other members! |
ResourcesWhat is rapid injection molding? For engineers working with tight product design timelines, rapid injection molding can be a critical tool for prototyping and testing functional models. Download Now
The world has changed considerably since the 1980s, when CAD first started displacing drafting tables. Download Now
Prototyping has always been a critical part of product development. Download Now
As the cloud is increasingly adopted for product development, questions remain as to just how cloud software tools compare to on-premise solutions. Download Now
|
RE: Can a brake rotor warp because of overtightening?
Rotors vibrate from uneven wear due to uneven cooling when stopped with very hot brakes. The area between the pads cools off a lot slower.
Regards
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Can a brake rotor warp because of overtightening?
It seems to be a fairly commonly held belief amongst car techs that overtightened lugnuts can result in rotor runout - examples can be found at valvoline's car maintenance site, this carquest tech bulletin http://w
http://www
It's not clear whether what is being measured (runout) is a result of warpage or uneven wear. It seems as though either one might cause "pulsating" brakes.
RE: Can a brake rotor warp because of overtightening?
I think that's a big if, and easily checked by anyone with a dial gauge and a bit of nous.
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: Can a brake rotor warp because of overtightening?
Regards
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Can a brake rotor warp because of overtightening?
RE: Can a brake rotor warp because of overtightening?
Having had a lot of problems with warped rotors on this car, the components were carefully examined. The only thing that stood out was the very large chamfer on the inside of the lug nut holes in the rotor. The chamfers appeared to reduce the material thickness around the hole substantially.
The chamfers are an aid to installation over the studs but appear so large that high nut torque may cause local dishing of the area around the hole due to a large area of unsupported metal around the hole. I can think of no other reason why the wheel nut torque would cause significant distortion in the rotor.
RE: Can a brake rotor warp because of overtightening?
RE: Can a brake rotor warp because of overtightening?
We measured rotor runout on 400 cars with the rotor on the bench, with the rotors in subassembly, and with the rotors mounted on the completed vehicle using the on-line automated wheel torqueing equipment. These rotors were "special" hand picked rotors with less than 8 microns of runout on the bench check. At that time our spec. was 15 microns maximum. The result was a HUGE variation (80 microns from memory) between the bench check and the completed vehicle check. We then took ~20 of the cars with the worst case runout and performed torque test (torque pattern, torque increments, etc.) a saw HUGE differences again. Aluminum wheels acted different than steel wheels, etc.
We installed some on-line equipment to phase the rotor and hub assembly to to best phasing. We began hourly checks of the automated lug nut torque equipment. We changed the spec. from 15 to 10 microns for the rotors and from 30 microns for the rotor and hub subassembly to 20 microns. We changed the design of some of the wheels to create a more uniform clamp load.
All of these things in combination greatly reduced customer complaints.
Another interesting bit of information that came out of this study is that if the rotor had a "prime number" (i.e. 31, 37, 41, etc.) of cooling fins it reduced brake noise and brake jutter. Also, if a current was applied to the rotor during machining (a patented process developed by our rotor supplier) it changed the resonant frequency of the rotor and reduced brake noise and brake judder.
One additional thing I just remembered. The residual stresses in the rotor imposed by the casting process causes the rotors to "grow" at different rates when they begin to get hot. We changed the mold cavities to achieve a more uniform cooliing rate. BTW, we discovered that Brembo does an excellent job of controlling residual stresses and even used the Brembo rotors as service parts for a short period.
I hope this helps.
Regards,
Greenlight
RE: Can a brake rotor warp because of overtightening?
RE: Can a brake rotor warp because of overtightening?
I visited ORNL and they have been studying brake rotors for a while. One gleen of info they said for rotor failures they had studied was not to combine these two activities: Similar to driving in rolling stop-n-go traffic where you keep your foot on the brake applying pressure but still moving, followed by high speed and pressing the brakes two times or more. They had some failures and had to explain why, I should have more definitions but it's been four years. Here's the links:
http://www.ms.ornl.gov/htmlhome/rsuc/rotor.html
http:
_______________________________________
Feeling frisky.........
www.tailofthedragon.com
RE: Can a brake rotor warp because of overtightening?
I can believe that overtorquing certain wheel designs would result in disc distortion.
RE: Can a brake rotor warp because of overtightening?
RE: Can a brake rotor warp because of overtightening?
RE: Can a brake rotor warp because of overtightening?
RE: Can a brake rotor warp because of overtightening?
OK!
What happens is that the rotor wears as the pads skim the high points, so it develops a thickness variation as a result of the runout. One solution is to use a particular pad material that grinds off the high spots
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: Can a brake rotor warp because of overtightening?
FAO Greenlight.
I am very interested in the statement you made below.Can you expand on the method of applying current during machining and how (and how much) the resonant frequency changes.Any info links etc would be greatly appreciated.
Thanks in advance.
"Also, if a current was applied to the rotor during machining (a patented process developed by our rotor supplier) it changed the resonant frequency of the rotor and reduced brake noise and brake judder."
RE: Can a brake rotor warp because of overtightening?
I also know that they stumbled on this because the machining equipment had an internal short that caused the current to be applied.
Try researching patents at www.USPTO .
We ran several rotors on a brake dyno and the results were extremely significant in reducing brake squeal and less significant (but still effective) in reducing brake "jutter". We tried several different brake pad materials and it worked with all of them.
RE: Can a brake rotor warp because of overtightening?
Thanks for that.It sounds like somehow the natural frequencies were lowered as a result of the application of current.I will try and find more detail.Thanks for your reply and if you get any more info it would be great if you could let me know.
Cheers
W
RE: Can a brake rotor warp because of overtightening?
Can you say which Japanese Motor manufacturer you worked for and can you confirm if the rotors machined using the new (increased damping) method actually went into production or was just a test/development idea which went no further.Thanks.
W
RE: Can a brake rotor warp because of overtightening?
Here is a link to a good article on thickness variation by carroll smith: http://ww
-Jon
RE: Can a brake rotor warp because of overtightening?
That backs up my observations with a very plausible and creditable explanation.
Regards
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.