Why are wheel nuts tightened so much that they're almost impossible to get off?

[andymax]

I had a puncture last night at slow(ish) speed when I misjudged a sharp kerb and hit the corner of it trying to fit in a narrow parking place.
Anyway it was a complete and immediate deflation. When I got out the car to change the tyre it started to rain heavily( of course it did ).
During the downpour, I struggled for 20 minutes to shift one of the wheelnuts so I could take the tyre off.
I weigh a tad more than 25st. and my full weight on an extended lever only eventually manged to make it shift.
The wheels had been reshod with some Goodyear rubber in February by a well regarded local tyre shop.
I watched as the wheels were put back on the car with a compressed air gun.
Surely these are calibrated so that humans can change a wheel?
What's the answer?

 

[Bobby Dazzler]

I had a puncture last night at slow(ish) speed when I misjudged a sharp kerb and hit the corner of it trying to fit in a narrow parking place.
Anyway it was a complete and immediate deflation. When I got out the car to change the tyre it started to rain heavily( of course it did ).
During the downpour, I struggled for 20 minutes to shift one of the wheelnuts so I could take the tyre off.
I weigh a tad more than 25st. and my full weight on an extended lever only eventually manged to make it shift.
The wheels had been reshod with some Goodyear rubber in February by a well regarded local tyre shop.
I watched as the wheels were put back on the car with a compressed air gun.
Surely these are calibrated so that humans can change a wheel?
What's the answer?

Sorry to hear that. Ask that all bolts are removed and re-torqued to manufacturer specification, correctly and by hand. The best tyre fitters and mechanics will do this as a matter of course. Some will if you ask. Many won’t.

 

[OneForTheRoad]

Most merc wheel bolts along with others ,rust at the ends and seize into the hub. A light smear of copperslip helps no end.

 

[KennyN]

Impact / air guns make things , tight - too tight , and should not be used to finally tighten wheel bolts or anything for that matter , thats why torque specifications are listed for most fasteners.

Correct procedure is a nip up with a bar / socket and torqued to correct spec. around 140n/m in my case followed by a quick recheck after a few miles.

K

 

[daveenty]

The wheels had been reshod with some Goodyear rubber in February by a well regarded local tyre shop.

Not sure why they're well regarded if they do as below...

I watched as the wheels were put back on the car with a compressed air gun.

This is what I meant. OK for running up a nut but the wheel nuts/bolts should always be finalised using a torque wrench.

Surely these are calibrated so that humans can change a wheel?
What's the answer?

The guns are just set to max. The answer is to ask/insist that they use a torque wrench and not their preferred method. Oh, and to check them again after 100 - 150 miles.

 

[Bobby Dazzler]

I can’t recommend my tyre place highly enough. As well as not using air tools and torquing by hand, then invite you back to have them checked after a few miles. Service is first rate too.

 

[Petrol Pete]

What you will see (and I have seen many times) is the tyre fitter will rattle the wheel back on the car , pick up the torque wrench and when it goes 'click' or 'beep' he thinks the bolt has been torqued correctly while failing to notice that the bold didn't even move.

He basically tested a bolt that has been 'rattled' to +180Nm with a torque wrench sat at (say) 100Nm .

I take my wheels off myself when I need new tyres, I know this is not an option for many of us on here.

The rattle guns might come with a torque setting (adjustable) but I have yet to see a wrench calibration tool in a high street tyre shop.

 

[190]

It's wrong to tar all with the same brush but there is only one safe answer and that is every time the trade touches your wheel bolts you have to slacken them off at home and re-torque yourself.

Did yours have locking wheel bolts because they can be impossible to release at at the side of the road without damaging them catastrophically . Mine were ridiculously overtightened and the only way I could shift them was to use an old scissor jack between the garage wall and the end of the socket to force the key hard into the locking bolt and then it needed a long power bar and a lot of force. If the trade would read the instructions for MB's locking wheel bolts it states clearly that they should not be tightened with a rattle gun. If the old original bolts had been available in the box I would happily have chucked the locking bolts which are a liability.

 

[RogerSausage]

I'm an AA man and come across it on a daily basis. Nothing better than being at the side of a busy dual carriageway in the pouring rain trying to smash a locking wheel bolt off because some moron has gunned it to death and the key has already sheared off.

To answer the question why they're tightened that much; simply bad practice and not giving a toss unfortunately.

 

[SpikyMikey]

I'm an AA man and come across it on a daily basis. Nothing better than being at the side of a busy dual carriageway in the pouring rain trying to smash a locking wheel bolt off because some moron has gunned it to death and the key has already sheared off.

To answer the question why they're tightened that much; simply bad practice and not giving a toss unfortunately.

^ this. It's a pet hate of mine. Its not just bad practice, it's laziness.
Any tech who windy-guns wheels back on should have the damn thing applied to their own nuts

 

[giusepppe]

It's wrong to tar all with the same brush but there is only one safe answer and that is every time the trade touches your wheel bolts you have to slacken them off at home and re-torque yourself.

Did yours have locking wheel bolts because they can be impossible to release at at the side of the road without damaging them catastrophically . Mine were ridiculously overtightened and the only way I could shift them was to use an old scissor jack between the garage wall and the end of the socket to force the key hard into the locking bolt and then it needed a long power bar and a lot of force. If the trade would read the instructions for MB's locking wheel bolts it states clearly that they should not be tightened with a rattle gun. If the old original bolts had been available in the box I would happily have chucked the locking bolts which are a liability.

where I had my wheels refurbished and reshod, on one wheel I had to go back to them and take the bolts out with there gun as i could not get a socket on any of them to check the torque settings, had to use to use my spare wheel bolts and replace with new ones, they bell ended all the bolts, apart from the locking wheel bolt, just to lazy to put there socket on properly, they are just too trigger happy.

 

[kcsun]

and also .....
Tossers who use standard sockets rather than the nylon coated ones that don't shred the powder coating on the wheel
kc

 

[Petrol Pete]

where I had my wheels refurbished and reshod, on one wheel I had to go back to them and take the bolts out with there gun as i could not get a socket on any of them to check the torque settings, had to use to use my spare wheel bolts and replace with new ones, they bell ended all the bolts, apart from the locking wheel bolt, just to lazy to put there socket on properly, they are just too trigger happy.

You will probably find that the socket they were using was worn beyond it's serviceable life but no one at the tyre place either didn't know or didn't' care.

 

[Jobsworth]

Wheels always tightened with a torque wrench at my ‘shop. Been that way for 25+ years. Drummed into plenty of apprentices too…

You’ll occasionally see gorillas at tyre shops who’ll put the wheelbolt into the socket on their gun and then apply it to the hub. Makes my teeth itch.

 

[johnsco]

There are two reasons why this occurs:
---- Tyre fitters who are clueless
---- Tyre fitters who are paranoid about wheel bolts / nuts coming loose after they've fitted the wheel.
As said - Use a torque wrench - Not a ratttle gun.
Correctly-torqued wheel bolts will not come loose.
Good practice is to check the torque after 500 miles as the bolts bed in.

 

[ray_hennig]

My local tyre guy tightens initially with a pneumatic gun. Then he finishes off with a torque wrench. This is in France at a place called Maury Pneus; known in our family as Mary's Penis! Not many people know that.

RayH

 

[ALFAitalia]

Rattle gun on is fine...we use them at my work for tyres. But industry standard dictates that they must only be lightly gunned on and they must be finished with a torque wrench. People even come to my work once a year and check/recalibrate the torque wrenches as us required by our insurers. As for those saying that they overtighten with a gun because they worry about wheels coming off...well that's rubbish...it's just laziness. An over tight wheel is just as likely to come off as a loose one. I'd rather my bolts were under done.......you get plenty of warning, noise and shakes before they come of. With a seriously over tightened wheel got just a loud BANG and it's gone.

 

[optimusprime]

It spent ages re painting my alloy wheels . So if i need new tires i remove each wheel, one at a time outside the tire shop , and have the old tire removed and a new tire fitted. And i know i will open a can of worms with this - but i grease every one of my lug bolts . And this way i have never had problems removing any of my wheels in 50 years . I do it ,,you dont have to .

 

[TeddyRuxpin]

I had this on my old BMW E39 - I had a simple flat tyre (and yes, it was of course raining) and had to call the AA to come round with a longer breaker and a couple of feet of pipe extension - I just couldn't get the bolts off. He said he'd never seen any bolts on that tight before...

I've never once been asked what to torque the wheels to (I suppose most people going to a tyre place wouldn't know/care), but on the occasion I've asked them to torque to 130nm, I get a lot of dirty 'how dare you tell me what to do' looks.

I don't bother saying anything now as it's not worth the hassle.

When I go to a tyre place, I drive off around the corner and get out the breaker bar and a torque wrench in the boot to re-do it, just to be sure.

 

[mioba]

You answered the question. A rattle gun is ok for taking things off. Any decent tyre place will use a torque wrench when refitting. I learned this many years ago being in a similar position as you.
I watch my tyre fitters like a hawk. When refitting I insist no rattle guns.
Live and learn.