Rotor vibration
#106
Race Car
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The light side has to do with the fastener not being new and nothing to do with stretch. Torque specs are usually given for new fasteners. Remember that you are measuring bolt tension indirectly by measuring the friction to turn the nut (torque). If you change the friction between the nut and stud, you change the relationship between the measured torque and the actual bolt tension. The assumption is the used stud likely has some grease or anti-seize on it and nut turns more as freely as when new. If the thread is lubricated, the specified torque may indeed put more tension than specified on the stud.
The light side is also still in the range of specified torque. I'm not suggesting undertorquing anything. Also, the nut material doesn't matter either as long as it is strong enough to maintain the tension force without deforming.
-Mike
The light side is also still in the range of specified torque. I'm not suggesting undertorquing anything. Also, the nut material doesn't matter either as long as it is strong enough to maintain the tension force without deforming.
-Mike
Also, the stud being made of 10.9 material has a much higher dry maximum torque than would be achieved with a lubricated lug nut if one used 96 to 100 ft-lbs or torque on the lug nut.
I have no idea what torque you are using as I was commenting on what Mark was doing.
#107
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You mean your assumption is that there is some grease or anti-seize on the "used" stud. I don't use anti-seize or grease on my race car's wheel studs. They come off far too often to require it.
Also, the stud being made of 10.9 material has a much higher dry maximum torque than would be achieved with a lubricated lug nut if one used 96 to 100 ft-lbs or torque on the lug nut.
I have no idea what torque you are using as I was commenting on what Mark was doing.
Also, the stud being made of 10.9 material has a much higher dry maximum torque than would be achieved with a lubricated lug nut if one used 96 to 100 ft-lbs or torque on the lug nut.
I have no idea what torque you are using as I was commenting on what Mark was doing.
Yes, wheel studs are dry, torqued to spec, and changed every two years.
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-Mike
#109
Race Car
Thread Starter
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Replacing the pads with Hawk DTC-70s and bedding them in well seems to have solved the vibration problem. All hint of vibration is gone and the braking feels great. It appears that excess material on the rotors was the issue.
#111
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as we have verified here , the pads pick up and lay down a coating as they are used. the unevenness is usualy during the bed in process. when they are fully bedded you wont be able to see anything on the rotor races as i showed. (both pics of 1st session and then 3rd session after a race with new pads and rotors)
DCT70s vs PFC11s are very close in performance .
whatever the case.. glad you dont have the vibration. keep the lug nut torques even! enjoy!
#112
Rennlist Member
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The light side has to do with the fastener not being new and nothing to do with stretch. Torque specs are usually given for new fasteners. Remember that you are measuring bolt tension indirectly by measuring the friction to turn the nut (torque). If you change the friction between the nut and stud, you change the relationship between the measured torque and the actual bolt tension. The assumption is the used stud likely has some grease or anti-seize on it and nut turns more as freely as when new. If the thread is lubricated, the specified torque may indeed put more tension than specified on the stud.
The light side is also still in the range of specified torque. I'm not suggesting undertorquing anything. Also, the nut material doesn't matter either as long as it is strong enough to maintain the tension force without deforming.
-Mike
The light side is also still in the range of specified torque. I'm not suggesting undertorquing anything. Also, the nut material doesn't matter either as long as it is strong enough to maintain the tension force without deforming.
-Mike
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by the way, again, my 90ft-lbs changed every session, is 5% from spec on used fasteners.
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#113
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Nope.
Oversimplification of what I wrote go back and re-read.
Actually, you aren't as you actually aren't measuring it. Sorry, I don't buy the human torque wrench business.
-Mike
-Mike
#115
Rennlist Member
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as far as your other posts... i get it. still seems to be a little contrary to what winders said.. but .... ok
you are such a knuckel head.... do you even think about what you are saying in your little inane responses ? news flash... Dave, 5% of the torque values Porsche sets out is perfectly acceptable . especially considering the range of most manufacturers torque values. it takes a GOOD cranking to get to 90ft-lbs.. its not going anywhere. stop being a pain in the ****! you are just spouting to hear yourself talk!
Remember VR, you serous lack the knowledge and experience to even comment here.
The only person trying to get someone "killed here" is you with your circus training advice in leaving your car in neutral when you have brake failure!
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#117
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I'm pretty sure nobody else on this thread/site is cosigning the human-torque-wrench thing, despite Mark's insistance. So it's now come down to trying to convince him... which will not happen.
To slightly paraphrase the Thomas Paine quote, "To argue with a man who has renounced the use of reason [...] is like trying to administer medicine to the dead."
That's roughly where this is at.
To slightly paraphrase the Thomas Paine quote, "To argue with a man who has renounced the use of reason [...] is like trying to administer medicine to the dead."
That's roughly where this is at.
#118
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not in a million years.. i even refereed this a few posts ago.
ive been building engines.. the torque values are always to spec.
I even take other logical
Not really... let me break it down for you... the spec is 96ft-lbs. i torque at 90. its near 5% off of a spec that is designed for worst case scenario . worse case scenario , by definition takes ALL things into account. the more things they have to take into account, the tighter the torque spec. time and heat cycles as well as new vs used fasteners, for example are a couple of them.
no mechanical engineer would ever say that 90ft-lbs for all 5 lugs would be dangerous for use on a race car for 30mins use.
I just went out to the garage and checked the lugs....(from the last race)
and you are right.. this is nothing about advocating anyone here to do the manual torque technique. but Im here to tell you it can be as accurate as someone that uses a torque wrench. in fact, many dont know how to use a torque wrench. some hear the beep and continue a few degrees. its a touch -feel technique that needs to be done with some care.... the lugs can be torque unevenly and that was my point from post one here.
91, 93, 91, 91, 90ft-lbs. yes, im human calibrated.
ive been building engines.. the torque values are always to spec.
I even take other logical
I'm pretty sure nobody else on this thread/site is cosigning the human-torque-wrench thing, despite Mark's insistance. So it's now come down to trying to convince him... which will not happen.
To slightly paraphrase the Thomas Paine quote, "To argue with a man who has renounced the use of reason [...] is like trying to administer medicine to the dead."
That's roughly where this is at.
To slightly paraphrase the Thomas Paine quote, "To argue with a man who has renounced the use of reason [...] is like trying to administer medicine to the dead."
That's roughly where this is at.
no mechanical engineer would ever say that 90ft-lbs for all 5 lugs would be dangerous for use on a race car for 30mins use.
I just went out to the garage and checked the lugs....(from the last race)
and you are right.. this is nothing about advocating anyone here to do the manual torque technique. but Im here to tell you it can be as accurate as someone that uses a torque wrench. in fact, many dont know how to use a torque wrench. some hear the beep and continue a few degrees. its a touch -feel technique that needs to be done with some care.... the lugs can be torque unevenly and that was my point from post one here.
91, 93, 91, 91, 90ft-lbs. yes, im human calibrated.
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#119
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Dave, you and others are getting a little too caught up in the fact that i torque the lugs at 90ft-lbs vs 95ftlbs....... look, ive been racing for many years now. 18 years now to be exact. last i heard, you dont even race.
through racing for so many years and doing things as i do.. ive had NO failures and thats over 1000s of wheel exchanges, and lug tightening. (that even includes a pit crew that forgot to tighten the lugs.
)
what i think folks should really be concerned with as ive never even heard of lugs coming loose unless they were not torqued passed hand tight to begin with.
Now the thing that do fail and i see it all the time, are wheels. start making fun of those that use wheels like these on the track.. even the companies that say that they make "race " wheels. have failures. Personally, i have had great use on a fast heavy car using kinesis and forglines as well as BBS. this should be your safety focus... not 5% variance below torque specs of lug nuts
through racing for so many years and doing things as i do.. ive had NO failures and thats over 1000s of wheel exchanges, and lug tightening. (that even includes a pit crew that forgot to tighten the lugs.
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what i think folks should really be concerned with as ive never even heard of lugs coming loose unless they were not torqued passed hand tight to begin with.
Now the thing that do fail and i see it all the time, are wheels. start making fun of those that use wheels like these on the track.. even the companies that say that they make "race " wheels. have failures. Personally, i have had great use on a fast heavy car using kinesis and forglines as well as BBS. this should be your safety focus... not 5% variance below torque specs of lug nuts