Front wheel came off hub after recent tyre change
Discussion
richard sails said:
There is another way this can happen, it is possible to severely overtighten a bolt (or nut on a stud) and stretch it beyond its elastic limit. Future use of the bolt or stud will be compromised, when the stud/bolt is tightened to the original (and correct) setting the bolt does not have the elastic stretch that is should have and clamping forces are greatly reduced. This can result in the bolts becoming loose quite quickly when subjected to vibration.
How do I know this, it happened to me. I had a new (second-hand old) car, I changed two wheels, one came loose within about ten miles, I stopped and re-tightened and double checked the bolts. It happened again after about another ten miles, I then realised something was seriously wrong and carefully took the car home checking the bolts every few miles and yes they were loosening off quite quickly. As I work in engineering I checked my torque wrench calibration and it was spot on. Then I did a bit of digging for information about nuts, bolts and thread performance and I was surprised to see just how much is known about the performance of nut and bolt joints and found out all about elastic limits and clamping forces and how these are important for a good bolting solution.
If a threaded joint has never been over-tightened and is always correctly torqued then all should be well, HOWEVER if the threaded section has been severely over tightened at some time in the past then there is a risk of the joint becoming loose due to vibration. Hence all road wheel bolts/nuts should be rechecked unless you know the history.
The fix for me was to swap the bolts and bin the stretched ones.
How do I know this, it happened to me. I had a new (second-hand old) car, I changed two wheels, one came loose within about ten miles, I stopped and re-tightened and double checked the bolts. It happened again after about another ten miles, I then realised something was seriously wrong and carefully took the car home checking the bolts every few miles and yes they were loosening off quite quickly. As I work in engineering I checked my torque wrench calibration and it was spot on. Then I did a bit of digging for information about nuts, bolts and thread performance and I was surprised to see just how much is known about the performance of nut and bolt joints and found out all about elastic limits and clamping forces and how these are important for a good bolting solution.
If a threaded joint has never been over-tightened and is always correctly torqued then all should be well, HOWEVER if the threaded section has been severely over tightened at some time in the past then there is a risk of the joint becoming loose due to vibration. Hence all road wheel bolts/nuts should be rechecked unless you know the history.
The fix for me was to swap the bolts and bin the stretched ones.
Seen that myself once. When I compared the faulty stud to the new one there was a visible amount of stretch in the affected bit of the stud.
richard sails said:
There is another way this can happen, it is possible to severely overtighten a bolt (or nut on a stud) and stretch it beyond its elastic limit. Future use of the bolt or stud will be compromised, when the stud/bolt is tightened to the original (and correct) setting the bolt does not have the elastic stretch that is should have and clamping forces are greatly reduced. This can result in the bolts becoming loose quite quickly when subjected to vibration.
A good reason not to use copper slip on threads / rattle guns for tightening. :-) BertBert said:
But that's not the circumstances facing the op. Previously the nuts stayed done up ok. Then the tyres are changed and all 4 nuts come off from one wheel. If the nuts have been severely over tightened, then it can only be the fault of the tyre changer, surely?
Bert
As an ex Motor Mechanic of 20 years standing, It is not unknown for bad things to happen like this, and I have seen all the wheel-nuts fail (shear or come off)in one go, when not tightened properly or overtightened. We had two events like this during my time (though not me yer 'oner). Usually there are tell-tale signs that something is not right for a mile or so before complete failure, such as rumbling noise, or steering wheel vibration. The fact that the garage had a sign up suggesting the customer was responsible for checking after xx miles, matters not. It can only be seen a a recommendation only, and does not obviate the garages responsibility!Bert
Edited by 3Dee on Monday 16th March 14:51
BertBert said:
But that's not the circumstances facing the op. Previously the nuts stayed done up ok. Then the tyres are changed and all 4 nuts come off from one wheel. If the nuts have been severely over tightened, then it can only be the fault of the tyre changer, surely?
Bert
It would not be the most recent person to change the wheel, the damage would have been done during an earlier wheel change. By tightening the bolts/nuts to the correct torque this time the required clamping force would not be achieved and the bolts would become loose quite quickly.Bert
I am not saying this is the case this time, it is just a possibility.
BertBert said:
But that's not the circumstances facing the op. Previously the nuts stayed done up ok. Then the tyres are changed and all 4 nuts come off from one wheel. If the nuts have been severely over tightened, then it can only be the fault of the tyre changer, surely?
Bert
Not necessarily. If a bolt / stud has been overtightened at some point in its life, then every subsequent tightening will fatigue them. Not saying that's what happened to the OP, but I've seen enough joints come apart for a whole load of different reasons not to rely on "as long as it's torqued up properly it'll never loosen off"Bert
Bigends said:
PhillipM said:
Mave said:
Something which means that the joint isn't reacted as intended. A bit of dirt or corrosion on the mating surfaces or spigot. Flange geometry allowing a spigot to snag rather than sit down pproperly.
Or refurbished wheels with thick, soft paint under the nut seating surface. That softens even more as they warm up.105nm on the Lotus apparently wasn't enough to go through the coating
In the olden days, when I was lazy. I had a customer return his car to me as the wheel didn't feel right (I had done a tyre).
It turns out that the mating surface between the spigot ring and wheel where covered in rust. This meant all I did was torque tobthe rust, so as soon as he started driving the wheel started wobbling.
Since then I have always cleaned the two surfaces prior to refitting. Never had the issue again.
(I do have the old wheel nut disclaimer on the bottom of my receipt though)
It turns out that the mating surface between the spigot ring and wheel where covered in rust. This meant all I did was torque tobthe rust, so as soon as he started driving the wheel started wobbling.
Since then I have always cleaned the two surfaces prior to refitting. Never had the issue again.
(I do have the old wheel nut disclaimer on the bottom of my receipt though)
Regarding those disagreeing about having to check wheel nuts/bolts after a small distance. Here's my opinion as an experienced Renault, Toyota and Land Rover technician, all at main dealers and I am now studying Motorsport Engineering at University.
Correctly torqued up wheels should not become lose.
At Renault, I was once inspected by Renault UK, to balance a wheel by the repair manual. It went as follows;
- Raise vehicle, as quickly as possible.
- Mark wheel to hub in the position it came off, with the valve positioned at the top.
- Balance the wheel (there were several steps to this but not important for this debate).
- Fully clean hub mating face and the inner part of the wheel mating face.
- Re-fit the wheel back into the pre-marked position.
- Rotate the wheel 180°, so the valve is pointing downwards.
- Torque the wheel bolts to 30 N/m with a recently calibrated torque wrench, in an opposing format.
- Rotate wheel back to valve at top.
- Lower vehicle to then finally torque wheel up to manufacturers recommendation.
Wheel nuts/bolts on road vehicles will have a FOS (Factor of Safety) greater than 5 times the required amount. For example, a Formula One wheel nut will have a FOS of about 1.15. A child's swing at a park, will have a FOS of about 20.
Is it my understanding, if the wheel nuts/bolts become lose it will be because of one, or a combination of the following;
- Fatigued wheel bolt/nut due to previous misuse.
- Hub/wheel mating faces not sufficiently cleaned (very common).
- Bolts/nuts tightened up with an incorrectly calibrated torque wrench.
- Bolts/nuts not tightened up with a torque wrench, normally an air-gun, which perform dependant on their compressors current capacity (this is very common).
- Incorrect torquing sequence.
- Incorrect torque setting for specific wheel (depends on material, size, number of nuts/bolts, etc).
Either way, my conclusion is that it will have been the fault of the garage, as this get out of jail free card they've got dangling in their reception area, that even people on this forum buy into! is deceitful. Could you imagine telling every Land Rover customer, that after paying over £100,000 for their car, then after getting a puncture and we replace their tyre, we tell them they have to bring it back to us to check it's still done up correctly?
Utter nonsense.
Correctly torqued up wheels should not become lose.
At Renault, I was once inspected by Renault UK, to balance a wheel by the repair manual. It went as follows;
- Raise vehicle, as quickly as possible.
- Mark wheel to hub in the position it came off, with the valve positioned at the top.
- Balance the wheel (there were several steps to this but not important for this debate).
- Fully clean hub mating face and the inner part of the wheel mating face.
- Re-fit the wheel back into the pre-marked position.
- Rotate the wheel 180°, so the valve is pointing downwards.
- Torque the wheel bolts to 30 N/m with a recently calibrated torque wrench, in an opposing format.
- Rotate wheel back to valve at top.
- Lower vehicle to then finally torque wheel up to manufacturers recommendation.
Wheel nuts/bolts on road vehicles will have a FOS (Factor of Safety) greater than 5 times the required amount. For example, a Formula One wheel nut will have a FOS of about 1.15. A child's swing at a park, will have a FOS of about 20.
Is it my understanding, if the wheel nuts/bolts become lose it will be because of one, or a combination of the following;
- Fatigued wheel bolt/nut due to previous misuse.
- Hub/wheel mating faces not sufficiently cleaned (very common).
- Bolts/nuts tightened up with an incorrectly calibrated torque wrench.
- Bolts/nuts not tightened up with a torque wrench, normally an air-gun, which perform dependant on their compressors current capacity (this is very common).
- Incorrect torquing sequence.
- Incorrect torque setting for specific wheel (depends on material, size, number of nuts/bolts, etc).
Either way, my conclusion is that it will have been the fault of the garage, as this get out of jail free card they've got dangling in their reception area, that even people on this forum buy into! is deceitful. Could you imagine telling every Land Rover customer, that after paying over £100,000 for their car, then after getting a puncture and we replace their tyre, we tell them they have to bring it back to us to check it's still done up correctly?
Utter nonsense.
Mave said:
So having acknowledged that previous misuse could cause a problem, how is it the fault of the current garage if torque is lost?
I think what the poster is saying is that with a safey factor of 5, it's pretty unlikely that the 4 bolts will have been over-torqued past their elastic limit. That would need 350+lb-ft.Bert
SpeedMattersNot said:
Regarding those disagreeing about having to check wheel nuts/bolts after a small distance. Here's my opinion as an experienced Renault, Toyota and Land Rover technician, all at main dealers and I am now studying Motorsport Engineering at University.
Correctly torqued up wheels should not become lose.
At Renault, I was once inspected by Renault UK, to balance a wheel by the repair manual. It went as follows;
- Raise vehicle, as quickly as possible.
- Mark wheel to hub in the position it came off, with the valve positioned at the top.
- Balance the wheel (there were several steps to this but not important for this debate).
- Fully clean hub mating face and the inner part of the wheel mating face.
- Re-fit the wheel back into the pre-marked position.
- Rotate the wheel 180°, so the valve is pointing downwards.
- Torque the wheel bolts to 30 N/m with a recently calibrated torque wrench, in an opposing format.
- Rotate wheel back to valve at top.
- Lower vehicle to then finally torque wheel up to manufacturers recommendation.
Wheel nuts/bolts on road vehicles will have a FOS (Factor of Safety) greater than 5 times the required amount. For example, a Formula One wheel nut will have a FOS of about 1.15. A child's swing at a park, will have a FOS of about 20.
Is it my understanding, if the wheel nuts/bolts become lose it will be because of one, or a combination of the following;
- Fatigued wheel bolt/nut due to previous misuse.
- Hub/wheel mating faces not sufficiently cleaned (very common).
- Bolts/nuts tightened up with an incorrectly calibrated torque wrench.
- Bolts/nuts not tightened up with a torque wrench, normally an air-gun, which perform dependant on their compressors current capacity (this is very common).
- Incorrect torquing sequence.
- Incorrect torque setting for specific wheel (depends on material, size, number of nuts/bolts, etc).
Either way, my conclusion is that it will have been the fault of the garage, as this get out of jail free card they've got dangling in their reception area, that even people on this forum buy into! is deceitful. Could you imagine telling every Land Rover customer, that after paying over £100,000 for their car, then after getting a puncture and we replace their tyre, we tell them they have to bring it back to us to check it's still done up correctly?
Utter nonsense.
Makes alot of sense.Correctly torqued up wheels should not become lose.
At Renault, I was once inspected by Renault UK, to balance a wheel by the repair manual. It went as follows;
- Raise vehicle, as quickly as possible.
- Mark wheel to hub in the position it came off, with the valve positioned at the top.
- Balance the wheel (there were several steps to this but not important for this debate).
- Fully clean hub mating face and the inner part of the wheel mating face.
- Re-fit the wheel back into the pre-marked position.
- Rotate the wheel 180°, so the valve is pointing downwards.
- Torque the wheel bolts to 30 N/m with a recently calibrated torque wrench, in an opposing format.
- Rotate wheel back to valve at top.
- Lower vehicle to then finally torque wheel up to manufacturers recommendation.
Wheel nuts/bolts on road vehicles will have a FOS (Factor of Safety) greater than 5 times the required amount. For example, a Formula One wheel nut will have a FOS of about 1.15. A child's swing at a park, will have a FOS of about 20.
Is it my understanding, if the wheel nuts/bolts become lose it will be because of one, or a combination of the following;
- Fatigued wheel bolt/nut due to previous misuse.
- Hub/wheel mating faces not sufficiently cleaned (very common).
- Bolts/nuts tightened up with an incorrectly calibrated torque wrench.
- Bolts/nuts not tightened up with a torque wrench, normally an air-gun, which perform dependant on their compressors current capacity (this is very common).
- Incorrect torquing sequence.
- Incorrect torque setting for specific wheel (depends on material, size, number of nuts/bolts, etc).
Either way, my conclusion is that it will have been the fault of the garage, as this get out of jail free card they've got dangling in their reception area, that even people on this forum buy into! is deceitful. Could you imagine telling every Land Rover customer, that after paying over £100,000 for their car, then after getting a puncture and we replace their tyre, we tell them they have to bring it back to us to check it's still done up correctly?
Utter nonsense.
Its amazing how many times I see tyre places tighten the nuts in the wrong order. When they do my cars, I make sure I watch.
That's my assumption, yes.
I have witnessed damaged bolts/nuts and threads before and it's very clear. This is usually because the bolts require excessive force to remove them, are tight during removal of initial release. I have also experienced it when trying to torque the wheels up and the nuts/bolts seem to exhibit more 'elasticity' than normal. Something you would not find if using an impact wrench.
A garage should be confident that its technicians can do wheels up correctly. Otherwise they should not be able to do more complex work, let alone continue with employment.
There is a possibility this may not be the case for HGV's, but is certainly the case for Light Vehicles and the motorsport cars I've worked on.
I have witnessed damaged bolts/nuts and threads before and it's very clear. This is usually because the bolts require excessive force to remove them, are tight during removal of initial release. I have also experienced it when trying to torque the wheels up and the nuts/bolts seem to exhibit more 'elasticity' than normal. Something you would not find if using an impact wrench.
A garage should be confident that its technicians can do wheels up correctly. Otherwise they should not be able to do more complex work, let alone continue with employment.
There is a possibility this may not be the case for HGV's, but is certainly the case for Light Vehicles and the motorsport cars I've worked on.
BertBert said:
I think what the poster is saying is that with a safey factor of 5, it's pretty unlikely that the 4 bolts will have been over-torqued past their elastic limit. That would need 350+lb-ft.
Bert
How about if the threads have been lubed so your steady bolt load is much higher for a given torque? And then if the joint has been lubed so the bolts are loaded in shear as well? Still confident in a safety factor of 5? :-o Bert
Garage does have some liability here.
Are they an ISO registered garage or a "Fred in a shed" set-up?
ISO garages will have set procedures and torque wrenches given individual numbers and should be written on the job sheet once used. This is to cover the garage for insurance purposes if indeed a wheel does come off. The wrench can be checked and therefore resolves the garage from liability.
Ive never seen a wheel fall off in 26 miles thats been tightened correctly. Unless there are discrepancies in the centre flange size thats allowing the wheel to fret, a tightened wheel should be fine till the next service. These are car wheels, not articulated trucks with big heavy wheels.
Are they an ISO registered garage or a "Fred in a shed" set-up?
ISO garages will have set procedures and torque wrenches given individual numbers and should be written on the job sheet once used. This is to cover the garage for insurance purposes if indeed a wheel does come off. The wrench can be checked and therefore resolves the garage from liability.
Ive never seen a wheel fall off in 26 miles thats been tightened correctly. Unless there are discrepancies in the centre flange size thats allowing the wheel to fret, a tightened wheel should be fine till the next service. These are car wheels, not articulated trucks with big heavy wheels.
With these feet said:
Unless there are discrepancies in the centre flange size thats allowing the wheel to fret, a tightened wheel should be fine till the next service.
I have yet to encounter such discrepancies with OEM wheels. With aftermarket it's a different story. That's why spigot rings are needed. If a wheel is refitted without one, the problem you describe can easily happen.I lost a wheel on the M4 when driving an ambulance , luckily no one was in the back and i wasnt going quickly
At that time we were required to torque the wheel nuts weekly, over time incorrect torquing had over tightened the studs and they sheared , once one went they all followed
They changed the requirement so we just checked the torque every 3 months but had to loosen the wheel nuts first , then re-tighten and set the torque.
At that time we were required to torque the wheel nuts weekly, over time incorrect torquing had over tightened the studs and they sheared , once one went they all followed
They changed the requirement so we just checked the torque every 3 months but had to loosen the wheel nuts first , then re-tighten and set the torque.
Red Devil said:
I have yet to encounter such discrepancies with OEM wheels. With aftermarket it's a different story. That's why spigot rings are needed. If a wheel is refitted without one, the problem you describe can easily happen.
Surely you shouldn't get any fretting at all, even if spigot rings are fitted, if the joint is done up properly? The spigot ring is there to centralise the wheel, not to take any loads.Mave said:
Surely you shouldn't get any fretting at all, even if spigot rings are fitted, if the joint is done up properly? The spigot ring is there to centralise the wheel, not to take any loads.
Yes, but the spigot ring means the wheel is centralised when done up, if the wheel is off slightly then it can move if it hits a bump etc. This usually shows as an imbalance to start with, just as a badly balanced wheel would, causing wobbling of the car.With these feet said:
Yes, but the spigot ring means the wheel is centralised when done up, if the wheel is off slightly then it can move if it hits a bump etc. This usually shows as an imbalance to start with, just as a badly balanced wheel would, causing wobbling of the car.
Why would the wheel move due to a bump? The clamping of the bolts should be sufficient to hold the joint together, the wheel shouldn't be able to move around the clearances of the spigot.Gassing Station | Speed, Plod & the Law | Top of Page | What's New | My Stuff