Could I trouble an explanation on the torque issue?

personally think ya'all are on drugs!

Lugs NOT torqued will cause sideloading and perhaps effect
the breaking/rotors.....

Its all quality of slug (rotor steel) and shoe and driving style.
Ceremics are cooler so a semi met will retain heat and cause
rapid warpage. I can see that happening a lot with the home
wrench saving LOTS of mony on shoes therefore using the
incorrect heat range of pad.

Over torque will only deform the wheel and or stud
causing failure there but the OFFSET cannot be changed
the rotor does not "move" any appreciable amount????!

Otherwise I want some of you all'* pipeweed

No weed smoking here by anyone.

If the lugs are over torqued, the rotors can prematurely warp, it'* as simple as that. It is caused by clamping down too much on the center portion of the rotor causing differing stresses/strains to build up in the rotor. Over time and a few heat cycles, these stresses and strains can become permanent in the rotor and will make it warp.

And this isn't even getting into the cast in stresses that are a part of the casting that can be effected by the pour and vent locations in the casting process. I always make it a point to buy rotors from well known, name brand suppliers like Raybestos or Bendix to ensure that the parts are high quality.

A good slug of steel has a lot to do with the quality of rotor, but not everything. Even a $100 rotor can be warped by over torquing the lug nuts.

The point is to always ensure the proper lug torque on your wheels. Undertorquing your wheels can not only screw up your rims/studs, it can also screw up your car if a rim desides to leave completely. Over torquing is just as bad as it can cause premature stud fracture as well as warping the rotors.

Before you go saying anything about race cars and the like, you must remember one thing about them. Their rotors are not a single peice. Pretty much all race setups utilize a center hub that the flat rotor bolts to. Not only does this design minimize the defects of single casting rotors, but it also effectively isolates the rotor from the hub so lug torque is no longer a factor.

Well I can see the' ideal' concern perhaps with composite rotors

However the face of the rotor meets the wheel against machined
surfaces that aint gonna warp due to torque....

The mating surfaces are THICK at wheel & hat - overtorque will
either rip out the stud or hammer the wheel/lug...

Sorry I completely and totally disagree with this logic....

Anyway thanks for the 'splanation and I'll bite my tongue in the future!

I got my car 5,000 miles ago with new brakes. Already the rotars are warped. I'm sure the dealorship put the cheapest rotars on money can buy.

Well I go based on personal experience. One of my first posts to this board was to figure out why I had such a horrible vibration on the highway and during braking. Some one suggested that I jack up the car, remove all the lug nuts and re-tourque them to 100ft/lbs. As soon as I had done that no virbration or shaking during braking. I'd have to say that torquing them to the correct specs had something to do with solving the problem. That was my personal experience.

I went back to the C5 Forum and ran a quick search... then to Google.. Wow, lots of info on this topic!

Here are the addresses and an except from a few of the posts.

Note, when I had new tires put on the Bonnie, even though I specified hand torque... the car started to pulse when braking shortly after the replacement. I retorqued the wheels right away and the pulsing went away...

and I'm too old to smoke

http://forums.corvetteforum.com/show...or+torque+warp
MacShee
CF Member
Member Since: Oct 2002
Manhattan
NY Re: Warped Rotors (Richin Chicago)

This is the reason GM did away with the wheel locks mid-run of the C5 2002 MY. It seems the dealers, who install the locks - not the factory, were prone to using impact wrenchs when putting the locks on. This is the single biggest reason the rotors develop run-out problems.

My rotors (all 4) developed the problem after the first 3500 miles of incredibly easy-easy braking. I was stunned. They were turned by the dealer (same dealer who created the problem) under warranty (for which GM reimburses them - see a pattern here?)

I had a lengthy conversation about rotors with one the Corvette Engineers last April during the 50th AE Press Event at the Indianapolis Motor Speedway. After that conversation, I have no doubt that the run-out problems are caused by OVER or UNDER TORQUING the lug nuts.

They should be torqued in the "star pattern" three times for each wheel, 50lbs, 75lbs, and then the final 100lbs. How many "wrenches" are gonna actually do this?

Either find a good mechanic/dealer who will do this, or get yourself a torque wrench and do it yourself. Keep in mind that retorquing a wheel/rotor that already has lateral run-out will do nothing whatsoever to "fix" it. Only 'truing' or turning can fix that.

My "turrned" and properly torqued rotors have over 7000 miles on 'em and are dead-solid-perfect, even after some incredibly hard "both feet on the brake pedal" stops to check the ABS and impress friends, and myself.

Most of the aftermarket rotors that are of two-piece design (esp. floating hat types) should be fairly immune to the torque sensitivity, and thats why they seem to be "warp proof".

http://forums.corvetteforum.com/show...ght=rotor+warp
Originally Posted by Patches
No! They can damage your lug nuts, wheel studs, rotors or wheels. Should always tighten in 3 passes using 35, 70 and 100 ft. lbs. in a star pattern using a torque wrench.

No air tools!

I agree, I had to have my rotors replaced - they were all warped. Who do you think paid for this one?!
__________________
MRHTRD

http://forums.corvetteforum.com/show...ght=rotor+warp
CF Senior Member
Member Since: Dec 2002
Tracy
CA

My Corvette Photos
Re: help with rear brakes and rotors (rons85)

Yup - rotors warp. I had that happen on my honda. Every time America'* Tire would torque the rims on - pototo chip discs. I don't let them near my car. I'll buy their tires - but I just take the rims over in the truck.

http://www.brakewarehouse.com/brkewrhsefaqs.htm#top61
What do you mean, rotors must be torqued?
Lug nuts or wheel studs need to be tightened in a cross-pattern and to a strength recommended by the manufacturer.
Most carmakers recommend somewhere between 80 – 100 torque pounds.
If one lug nut or wheel stud is 20% tighter than another, you can have a run out on the rotor greater than 0.005, which translates to a “warped rotor.”
Whether you’re a do-it-yourselfer or taking your vehicle to a shop, make sure this procedure is being done.

http://ca.autos.yahoo.com/maintain/b...s_pads_a1.html
What causes a rotor to warp? Overtorquing or unevenly torquing the lug nuts with an impact wrench is a common cause. For this reason, most experts recommend using a torque wrench to tighten lug nuts when changing a wheel. There are also special torque-limiting extension sockets called "Torque Sticks" that can be safely used with an impact wrench to accurately tighten lug nuts. But a plain impact wrench should never be used for the final tightening of the lug nuts because most provide no control whatsoever over the amount of torque applied to the nuts.
Overheating can also cause rotors to warp. Overheating may be the result of severe abuse or dragging brakes. Defects in the rotor casting, such as thick and thin areas can also cause uneven cooling that leads to warpage. Hard spots in the metal due to casting impurities can be yet another cause.

http://www.autoguide.net/diy/kevin16.shtml
Warped Rotors: More common in newer cars, but possible on all disc brake systems. Rotors warp due to being overheated or incorrect tightening of the wheel. A warped rotor will give a pulsing feeling when applying the brakes. This pulsing can be annoying and dangerous. Most newer cars have rotors which are very thin and warp very easy. Furthering the problem, the manufacturer does not leave enough material to resurface the rotor. Check with you mechanic to make sure you can safely have the rotors machined or replace with new rotors. To resurface, the rotor is placed in a lathe and a cutting tool removes a few thousandth'* of material from the braking surface. This restores the flatness of the rotor and eliminates the pulsing sensation in the pedal. Make sure when your mechanic puts everything back together that he torques the lug nuts to proper specifications and never uses an impact wrench. If the lug nuts are not tightened evenly the rotor can warp and you are back to square one. Note: Some shops use a torque stick, which attaches to an impact wrench and does not allow the torque wrench to tighten more than it should. This is acceptable. If your mechanic does not use a torque wrench or torque sticks, find another mechanic.

http://www.canadiandriver.com/articles/jk/020109.htm
Incorrect tightening of the wheel nuts also can warp a rotor. When installing a wheel, snug up the wheel nuts and then tighten them in two stages using an alternating criss-cross pattern. Using a torque wrench is critical on modern vehicles. Some shops tighten wheel nuts with air impacts. Others use "torque sticks" designed to limit the torque on the nuts. Neither is accurate enough for today'* cars. Make sure they use a torque wrench. If you experience brake pulsations after changing a wheel, loosen the wheel nuts and retorque them. If this is done as soon as possible, the rotor will usually correct itself. Leave it too long (more than 1000 km) and it remains warped.

wow that'* some good research.

I have 2 GM'* now one 87 GP and a 01 SSEi. The 87 has 135k on it and is on the 3rd set of front rotors. The SSEi has 75k and those look to have been replaced just before I purchased it at 64k. The SSEi is the worst with hard pulses at anything above 75 mph, by 30 you’re off the pedal and thinking about ejecting. The rotors look good but run out is beyond turning I would bet.

I also have a friend with an 01 Monte who is on his 4 set, the first ones gave out under 10k, and the dealer replaced them 2 more times before warranty ran out. I personally rented a new 04 Monte last year and with less than 4k on the dash the fronts were trashed. From what I have learned from several GM techs the metal used in these rotors was softer than the semi-met pads the factory used. This may sound strange but if you buy a good set of afermarket rotors the problem seems to be eliminated. This was the case with my 87, purchased the best set the local parts store had and they have been good for 30k now....

I plan to put a set of cross drilled and gas vented on the SSEi, these sell on eBay for about $150 in a set of 4. The last set I purchased on there from Irotors said "made in China" but went on my Mustang GT with Hawk pads and are the best stock brakes I have ever used. After a very hard 35k on them they still have 0 run out and I just changed the pads. I have never torqued the lugs and just pound them on with the gun every rotation, but do agree that can cause stress on the disk.

Well, my STE had stock rotors until just recently when I didn't replace the pads in time and grooved the crap out of them, so I had to get replacements. (well, the pads were fine, but being stupid my friend and I were coming home from the dragstrip on a two-lane road in BFE and we were going 130ish and somebody pulled out in front of us, and both feet went to the floorboard on the brakes, my pads were gone by the time we were stopped) The stockers weren't warped at all, just grooved all to crap. The GTP had stock rotors until a few months ago when we put the Grand Am brakes on them. The stock rotors had about 28k on them and had no warping. The SSEi as I already stated has over 125k on it with factory rotors, and I believe we've replaced the pads maybe twice, but definately at least once. And we do some hard braking (can't count the number of deer we have barely missed in that thing, god damn do these cars stop!), but it does have a bit of highway miles. My Calais definately has factory rotors on it, either that or they are really old, and they aren't warped either. They are rotted through in some spots, chipped in others, and have a lot of pits in them, but they aren't warped at all, and it has 186k on it. (but they are in really shitty shape and should've been replaced a few years ago) My sisters GP and my dads TGP however did have some warping problems, but both of those cars *appeared* to have factory rotors and have over 100k on them.

Proper maintenance procedures, and not stopping like a madman will do wonders for rotor life. Autocrossing and things like that are obviously not good for your brakes either.

Shawn