ibedayank
Well-known member
well hack boy it sure beats doing the job over because you screwed it up and then do it the second time for FREE
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Torque Wrench vs Torque Sticks for wheels?
- Thread starter maxcarp709
- Start date
well hack boy it sure beats doing the job over because you screwed it up and then do it the second time for FREE
abvw
Well-known member
Wow. You guys just aren't listening. You are acting like children with your fingers in your ears, unwilling to hear something you don't want to hear.
Acceptable runout is .002". That's half the thickness if a sheet of paper. It doesn't take much to feel pedal vibration.
Over torque can cause a rotor to "festoon". Uneven torque, or even tightening using a ring pattern instead of a star pattern can also cause this VERY COMMON PROBLEM.
What I think you guys are struggling with is the idea of a puny bolt effecting that big lump of hard steel. Chances are, none of you have ever checked your brake job with a dial indicator. You need to think of steel as a spring. Each lug compresses it. It swells between them. If you torque the first fastener to full spec, you can warp it just like a head.
My guess is, none of you check your work and most average customers won't be sensitive enough to notice the vibration or care until wear increases to unacceptable limits.
I'm an aerospace engineer. Sounds like I have a few colleagues here. If you don't want to listen to us, Google the topic for yourselves. The advantage of boards like these is that we can learn from each other. I certainly don't know everything, but I know how brake rotors work. Don't want to believe me, Google it for yourself.
There's a lot more mechanics/technicians here, seems like we all share the same experience contrary to what you engineers preach. If everything on paper and theory applies in reality then we wouldn't have so many imbiciles even though we're all supposed to be educated.
You will need tons and tons of lateral pressure on one side to "warp a rotor" (like a seized caliper pin), and even then, you're more likely to chew the pads up and break the rotor off the tophat before it "warp".
There will always be measurable runouts due to imperfections (defect in manufacturing or installation errors), but as long as the rotor thickness is even throughout then the clamping force of the braking system is unaltered, thus no change in the hydraulic pressure to be felt in the pedal.
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^^^^^^^^^^^^
There are two measurements in play.........rotor thickness variation and rotor run out. The run out is easily changed by over torque at the wheel. The hub is the part that damaged and the rotor is attached to the hub. Small hub distortions make for out of spec rotor run out. The driver may see steering wheel vibration or pedal pulsation or both during braking.
There are two measurements in play.........rotor thickness variation and rotor run out. The run out is easily changed by over torque at the wheel. The hub is the part that damaged and the rotor is attached to the hub. Small hub distortions make for out of spec rotor run out. The driver may see steering wheel vibration or pedal pulsation or both during braking.
ibedayank
Well-known member
^^^^^^^^^^^^
There are two measurements in play.........rotor thickness variation and rotor run out. The run out is easily changed by over torque at the wheel. The hub is the part that damaged and the rotor is attached to the hub. Small hub distortions make for out of spec rotor run out. The driver may see steering wheel vibration or pedal pulsation or both during braking.
add to this heat that is created when you step on the brakepedal if it is warped it will heat up one area more then the others and metal shrinks after it turns blue and cools down further warping it.
sberry
Banned
Torque wrench keeps records up to 50 times.
What would that have to do with it? Match it with an invoice? Lets say this. Are you any less liable if the wheel falls off anyway?
sberry
Banned
If the wheel falls off it doesn't matter to me how you did it. I will have some disagreement with Adam on causes of rotor problems on cars but none here on nuts and bolts. The only thing a torque wrench tell is how hard it is to turn a bolt. 40% of it is used to overcome thread friction on a good NC lightly lubed fastener and absolutely unpredictable all the way to seizure, compound it with dry threads which just got removed thru a dry nut from stuck and a fool with an air gun at hi speed adding heat and pressure.
It isn't that the torque wrench is so good but it actually forces the tech to stop and slowly tighten the last stage. I am a 40 yr veteran with an air gun, I have watched others but in my case I had it splained repeatedly by a book learned engineer till it made sense in its own way and I am deliberate with the gun, most tire jocky types are not. They got to be trained like chimps so to speak.
It isn't that the torque wrench is so good but it actually forces the tech to stop and slowly tighten the last stage. I am a 40 yr veteran with an air gun, I have watched others but in my case I had it splained repeatedly by a book learned engineer till it made sense in its own way and I am deliberate with the gun, most tire jocky types are not. They got to be trained like chimps so to speak.
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sberry
Banned
It took me a while, not an exception but finer threads on wheels give more leverage, more heat when spun fast and dry like a stud on a car. My method is to spray everything screwed together with Liq wrench or similar, Kroil is great for this and in the case of wheels ran slowly till snug, move on to the next and come back with a tighten pass with the gun set correctly and watch the socket rotation and I can come really close and consistant and if I am feeling insecure walk around the car with a 1/2 ratchet once its on the ground and make sure,,,, make sure they aint stuck and cant be removed with the factory tire tools.
I am not sure about the new battery guns, the air can be set and the speed varied. When so much was done with a common 4 way and guys used a pattern the speeds and power were slow and low.
The only reason there is a "dry torque" is they cant train all the chimps to do it the correct way, the same way. Its about like electrical grounding, lots of opinions and really only one right way which is lightly lubed and slow installation to correct torque.
A stick may or may not work, I am not sure but using one isn't a permit to go like a bat out of hell just to feel good about oneself, use a t wrench helps and gives the tech a chance to feel it and make sure its tight.
I am not sure about the new battery guns, the air can be set and the speed varied. When so much was done with a common 4 way and guys used a pattern the speeds and power were slow and low.
The only reason there is a "dry torque" is they cant train all the chimps to do it the correct way, the same way. Its about like electrical grounding, lots of opinions and really only one right way which is lightly lubed and slow installation to correct torque.
A stick may or may not work, I am not sure but using one isn't a permit to go like a bat out of hell just to feel good about oneself, use a t wrench helps and gives the tech a chance to feel it and make sure its tight.
You will need tons and tons of lateral pressure on one side to "warp a rotor" (like a seized caliper pin), and even then, you're more likely to chew the pads up and break the rotor off the tophat before it "warp"
For those of you without your fingers in your ears, just for fun, exactly how much clamping load do you think you can get with a 100ftlbs of torque on a 1/2" lug bolt? Lets just see if we can get in the right ballpark.
a) 100lbs
b) 1,000lbs
c) 10,000lbs
What do you think lug clamp load does to the free edge of the rotor?
1) Nothing, no effect. Clamping the hub has no effect on the rotor's free edge.
2) Any torque/preload will deform the rotors outer edge.
3) Clamping creates internal stresses that seek to be relieved during the next thermal cycle.
For those of you without your fingers in your ears, just for fun, exactly how much clamping load do you think you can get with a 100ftlbs of torque on a 1/2" lug bolt? Lets just see if we can get in the right ballpark.
a) 100lbs
b) 1,000lbs
c) 10,000lbs
Quite a poorly proposed problem. To many factors like lube and thread pitch are not in the equation. C is your expected answer but that could be off by 50% depending on conditions.
If your driving an old Jag then 1 is the correct answer to the second part.
lg
no neat sig line
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What would that have to do with it? Match it with an invoice? Lets say this. Are you any less liable if the wheel falls off anyway?
Yes, I am less liable if I did everything correctly and wheel still falls off. [emoji90] happens. Knock on wood I got into a habit of double and triple checking critical torques.