Do you use a torque wrench or go by feel?
Discussion
MikeStroud said:
Baldchap said:
Always amazes me how many wheel nuts aren't properly torqued by professionals.
As far as I can tell all the tyre places seem to use a power/air gun and tighten till it stops. Never noticed them checking/setting the correct torque for the particular car they are working on.Am I mistaken? Or do they use the same torque setting for every car they change the tyres on?
There also fastidious about telling you to come back after 100 miles for a check the torque was s still correct.
I realise there franchised so you don’t get the same level of service everywhere but I can’t fault them.
Local BMW stealership recently told me the brake pads and disks are very low need changing and are close to be img dangerous.
Would I like the disks and pads changing sir. Erm not at £800. Took it to ATS, they took the wheels off got me in and showed me the pad thickness (6mm left) and measured the disk with a micrometer. Everything well within spec.
I found the wheel nuts on my modern had been tightened to THREE TIMES the book torque!
On the classic , I always use a torque wrench where the manual stipulates it. But BEWARE! Have you ever calibrated your torque wrench? I ruined a part by using a wrench that underread by 30%!
Calibration is easily done, by fixing the square drive bar in a vice and hanging a known weight from the bar. Move the weight outwards until the wrench clicks. The it's simple arithmetic to calculate the torque it clicked at - dos that agree with the dial?
JOhn
On the classic , I always use a torque wrench where the manual stipulates it. But BEWARE! Have you ever calibrated your torque wrench? I ruined a part by using a wrench that underread by 30%!
Calibration is easily done, by fixing the square drive bar in a vice and hanging a known weight from the bar. Move the weight outwards until the wrench clicks. The it's simple arithmetic to calculate the torque it clicked at - dos that agree with the dial?
JOhn
Both depending on circumstance. There are bolts on my bike that are supposed to be at 8Nm, overtighten them and strip threads inside an ally engine casing and it's going to be an expensive job. On the other hand the rear axle nut is something like 120Nm, so I usually just go for about 15 stone feet
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tapkaJohnD said:
I found the wheel nuts on my modern had been tightened to THREE TIMES the book torque!
On the classic , I always use a torque wrench where the manual stipulates it. But BEWARE! Have you ever calibrated your torque wrench? I ruined a part by using a wrench that underread by 30%!
I've been reading around this and many people seem to think the beam type wrenches win for long term accuracy and reliability.On the classic , I always use a torque wrench where the manual stipulates it. But BEWARE! Have you ever calibrated your torque wrench? I ruined a part by using a wrench that underread by 30%!
tapkaJohnD said:
I found the wheel nuts on my modern had been tightened to THREE TIMES the book torque!
Had they actually tightened them to that, or was that the torque you needed to free them?A lot of tyre places just stick them on with an impact driver and don't bother even trying to get the right torque. I bent the standard wheelebrace in my ZX trying to changing a wheel once. I bought a decent one after that.
Edited by RizzoTheRat on Tuesday 29th June 10:28
I have 4 torque wrenches. If we're talking a "bog standard" M6, M8, M10 8.8 bolt, I do them by feel. I've done enough to get them about right.
But anything special gets the torque wrench - especially if the spec calls for it to be tightened to yield - camshaft cap bolts on the RS motor, for example. Absolutely critical to not overtorque them since they'll shear off and make grown men cry otherwise.
And on the Big Block V8 cam bolts, I have a bolt stretch gauge I use
However - I'm not convinced on the accuracy of torque wrenches more. With the overlaps in my range, I reckon there's a good 20% variance between some of them. They are all mechanical "click" ones. Is there:
a) A simple way to (re)calibrate them
b) Are digital ones more reliable about maintaining calibration - and should I replace them all? With what?
c) Are some of the digital adaptors better - such as Sealey STW290
But anything special gets the torque wrench - especially if the spec calls for it to be tightened to yield - camshaft cap bolts on the RS motor, for example. Absolutely critical to not overtorque them since they'll shear off and make grown men cry otherwise.
And on the Big Block V8 cam bolts, I have a bolt stretch gauge I use
However - I'm not convinced on the accuracy of torque wrenches more. With the overlaps in my range, I reckon there's a good 20% variance between some of them. They are all mechanical "click" ones. Is there:
a) A simple way to (re)calibrate them
b) Are digital ones more reliable about maintaining calibration - and should I replace them all? With what?
c) Are some of the digital adaptors better - such as Sealey STW290
F20CN16 said:
If the correct torque settings are available in a haynes or other workshop manual, I just can’t see why you wouldn’t! I like to take the guess work out. It’s usually stressful enough working on cars.
Be careful of the stated torque settings in the Haynes Book of Lies. I’ve learnt from (costly) personal experience that the torque settings stated in Haynes aren’t always correct.B'stard Child said:
MikeStroud said:
Baldchap said:
Always amazes me how many wheel nuts aren't properly torqued by professionals.
As far as I can tell all the tyre places seem to use a power/air gun and tighten till it stops. Never noticed them checking/setting the correct torque for the particular car they are working on.Am I mistaken? Or do they use the same torque setting for every car they change the tyres on?
Mine spin the bolts in with a air gun but stop before the dugga dugga point - the then had tighten with a proper torque wrench it's always at least a 1/4 to half turn before the wrench clicks
Went to a fast fit company who are very "quick" once - the "technician" wound in all the bolts to 20 dugga duggas he then went round with a torque wrench and "checked" every bolt - each one clicked before any movement
I pointed out the stupidity of this "check" and got absolutely nowhere with the "technician" or the "manager"
I re-did all the wheel bolts when I got home and Christ they were bloody tight - I needed a little leverage on a breaker bar to crack them free
I've never had a car spare wheel kit supplied with anything other than a bit of bent steel bar to tighten the nuts up with, with my Mark 1 leg applied to the other end to loosen or tighten as appropriate.
105.4 said:
F20CN16 said:
If the correct torque settings are available in a haynes or other workshop manual, I just can’t see why you wouldn’t! I like to take the guess work out. It’s usually stressful enough working on cars.
Be careful of the stated torque settings in the Haynes Book of Lies. I’ve learnt from (costly) personal experience that the torque settings stated in Haynes aren’t always correct.
HustleRussell said:
My Dad is a proper time served mechanic and has great feel for how tight things should be. He only resorts to a torque wrench when it comes to things like head bolts. I would love to have this skill. I do use a torque wrench for wheel nuts.
Pretty much the same. Still remember breaking the head of a 6 mm bolt as a apprentice 40 years ago. Anything really important or over 12 mm the torque wrench comes out Gassing Station | Home Mechanics | Top of Page | What's New | My Stuff