All pads contain a variety of metallic, organic, and ceramic components in their cake mix.
What every brand is selling, their secret blend of materials.
Some companies spend 40 cents on pad materials some $ 1.20. Since all backing plates are identical. research, testing, advertising and marketing expense are the only variables.

http://www.ae-plus.com/Journals/Mate...0materials.pdf

A serious problem is the reduction of copper in pads to reduce the copper in dust and road runoff stormwater polluting streams and waterways.

http://envsun.chem.chuo-u.ac.jp/paper/APM-Sb%202007.pdf

http://www.penerbit.utm.my/onlinejou.../JT46AJUN5.pdf

Whenever I adjust rotors, I always check tires and wheels for changes in radial runout stiffness as this can add to the vibration runout of rotors since they are traveling at same rotational speed.

Don't always believe that even Dealer master techs are brake engineers.

 

Ain't that the truth. Well, I measured again yesterday and the left rotor runout is waaaaaay down from where it was. The right one is still at 9 or 10 thousandths. I think they were probably taking the standard amount off, maybe one or two thousandths per side of the rotor, which would not have been enough to get rid of shudder when I measured a whopping 13 or 14 thousandths before they cut the rotors. So I think they just need to take off more on the right rotor. On the left, I'm getting 3 or 4 thousandths, but I'm willing to live with that. The brake manual I downloaded says a max of 0.0014", but I think if I just get them to cut the right one one more time, it'll be cool. I guess since the rotors they sell are $140 a piece, they're just not wanting to take the rotors down 40 thousandths every time they cut. But my rotors were $45 bucks, so it's not that big a deal if this is the last cut I can get before they're almost down to min thickness.

I think that all this mess started b/c the cheap rotors from NAPA were only guaranteed to have a max of 0.004" of run out, and that's enough of a bump for the rotor to start picking up pad material and then it just built up to the 12 or 13 thousandths I measured when I first got that dial gauge off Amazon. Sometimes cheap really is cheap. Not gonna know for sure unless I try, or find a post on a forum of people who have tried them. Hopefully, my experience will help someone in their decision-making.

 

You still haven't told us how much runout the hub has? Or whether your wheel bearings are out of spec.
Any defect in an item can cause all the others to go out of spec.

 

Dang, that's true. I forgot that. Man I was all geared up to bust up into that dealership today and get some respect. I guess I'll go home and measure the hub runout first. I sure am getting tired of taking the calipers off, though. And my back is sore from moving junk around the office at work today. I seriously doubt that runout in the hub is an appreciable contribution to my shudder at this point, but I suppose it's better not to leave any stone unturned. What specs are there for the wheel bearings?

 

It's all full delineated in FSM most are 0.001" the lower the better.

Research WHY the dealers like on the car brake lathes as they miscut rotors to compensate for bearings, and hub problems.

 

Okay I forgot to come back on here. I measured the runout on the hubs and they were both below 0.001". Maybe not even half a thousandth. I took the car back to the Nissan dealership and they cut the rotors again. Runout is still four or five and two or three thousandths on the the other. I still feel the pulsation. After they'd cut the fronts the second time and still had my car, they had said it was the rears and recommended that I get them cut. I said no. I was not about to pay them $108 more dollars to do that. I measured the runout back there and it's minimal. Two or three thousandths, if that. But it's the rears and it could probably be five thousandths before shudder was really pronounced. I noticed that these "Premium" rotors from NAPA are made in China. They're cheaper now than when I bought them, too. Also, the "Ultra Premium" rotors NAPA sells are cheaper too. (Dunno if they're made in China or not.) I found a thread I posted to back in September with the prices and I was asking people what they thought of them. Nobody really had any opinions on them. Well, I took that one for the team and I will tell anyone not to put "Premium" NAPA rotors on their G35 sedan. The next rotors I get will be Infiniti rotors from everythingg35, assuming they're still around and have them priced reasonably when I'm ready to buy them.

 

Centric makes decent ultra premium BLACK HAT Rotors which often meet oem specs of 0.0028" runout if installed and properly indexed on good hubs.

Warped Rear rotors GENERALLY cause a front rear surging feeling in seat when warped due to additive effect of their additional friction coming and going during stopping.

What is radial force stiffness variation in front tires. Tire/wheels with full front loaded weight [ say 1,000 pouns] squishing them down on Hunter machine should be better than 5 pounds surely no more than 7 pounds.

Perfection requires lots of time, money, and more money.

 

What is "radial force stiffness variation"? I have BF Goodrich TA's or something. It's been just about the best tire I've had in a long time. They've lasted longer than I anticipated. If "radial force stiffness variation" information is available for these tires, I suppose I can find it.

I would tend to think that perfection requires lots of time and money, but I know for sure that I got my 97 Maxima to stop as smooth as butter with a front rotor resurfacing. I replaced the rotors on that car at least once too and it was smooth as butter then too. I only bought Nissan stuff then. I was not about to pay Infiniti $140 per rotor and I didn't think to check everythingg35 when I bought the ones I got at NAPA. So I think perfection in my case could have been achieved simply by buying better parts. Sometimes cheaper doesn't matter and sometimes cheaper sucks booty!

 

Radial force variation is the the difference in sidewall spring stiffness at different ponts around the tire circumference. Measured on a Hunter 9700 radial force tire balancer.

The difference between a standard balancer is that the tire is not compressed/loaded with the body weight so the balancing is far from REAL WORLD OPERATING CONDITIONS.

At 60 mph a 26" tire rotates 13 revs per second so the tire with a SINGLE stiff spot pushes upward 13 times per second too fast for shocks to damp.

Each above average/norm stiff spot creates a vibration. Every point on tire should be within 5 pounds of the same average stiffness.

Depending on inflation PSI tires have 1000-1500 pounds per inch of spring like stiffness.

Measure the wheel center to tire tread center jacked of ground and the amount the tire compresses to ground to determine tire side wall stiffness.
For example 13" unloaded and 12.25" loaded with 1000 pounds =~~~~~ 1333 pound per inch side wall stiffness.

 

Ahhhh. Sounds like lots o' work.

 

Maintaining as new or in as designed condition is always lot's of work. 99.9% of owners are numb and don't bother or won't spend money.
Maybe 100 out of 100,000 owners in US will try to maintain.

 

wow this is one of the most informative threads I've read in a while. So to answer the question in the thread i just posted: Yes I need to have an on car lathe cut the rotors to stop pulsation?

 

How are the Brake shims sold? Do I have to pay $50 for each wheel for shims or one for the rear and one for the front?

 

Did I have a link to the NAPA site posted earlier? Has it been removed? IIRC, they were not as expensive as $50.

 

IRS is much more sensitive to rotor runout than domestic vehicles with solid rear ends which tend to damp and mix side to side vibrations.