Strange case of a sheared lug nut

Fortunately, I drove to Nandi Toyota, which is quite near my residence and I was able to get this fixed.

BHPian Bsimhan recently shared this with other enthusiasts.

I had wheel balancing, rotation and alignment done at a reputed place last week. I was shocked to find that one of the bolts (front right tyre) had sheared off and the lug was completely missing.

I didn't notice this at the tyre centre, but found it the next morning when I removed the car cover. I had to leave to on a long trip to Tirunelveli the following morning and I was in a bit of a panic.

Fortunately, I drove to Nandi Toyota, which is quite near my residence and I was able to get this fixed. I learnt a lesson that it's necessary to check the work at the workshop itself. Had I not looked, it might have led to drastic consequences. In fact, I asked the people at the tyre centre to tighten the lugs with hand tools as I was been a victim of over-torqueing a couple of times, when I had a flat on the highway.

I had to literally stand on the wheel spanner to get it loose. I suspect that something about the way the lug nut was torqued let to the shearing. I did follow up with the guys at the tyre centre, but it was the case of bolting the shed after the horse had fled. Though they didn't say that I was lying, they implied that they had completed the job to the utmost satisfaction of their supervisor. I just wonder if any of my fellow BHPians have faced this sort of issue after balancing and rotation.

I'd like to add too that the trip to Tirunelveli went well. Great roads.

Here's what BHPian Researcher had to say on the matter:

I had faced the exact same issue of shearing back in March 2020 just days before the nationwide lockdown. I had given my SX4 for the 90k kms service and the chap must have over-tightened the lugs after cleaning the rear drums.

Soon after, the left rear tyre started losing pressure (found later to be a nail) and when I got the tyre guy to check it, he could not remove the lug easily. Just as I was about to tell him to be careful and not break anything, he stood on the wheel spanner and the lug sheared.

I could not replace the part instantly as I had already begun an unavoidable 400km trip. So after consulting the mechanic, I risked going on 4 out of the 5 lugs with careful speeds without crashing on potholes and made the destination without any issues. Upon reaching, I contacted my usual parts guy who arranged them immediately and I got the same replaced promptly.

The guy who replaced the parts told me a few things:

• Never over-tighten wheel lugs. Keep the wheel locked in air while tightening, and once you feel its fit, there is absolutely no need to apply more force.
• If you are unable to remove an over-tightened lug, try adding an extender, tube or pipe to the end of the spanner. It helps reducing the effort one has to make while loosening and avoiding the shearing.
• During wheel rotation at every oil change, check for rust in threads of the lugs. He suggested that instead of replacing them outright, one can apply a paste he showed (something blue, unable to recall). As a jugaad, he suggested one may also apply a few drops of used engine oil (not sure how effective).

Experienced BHPians may comment on the above and suggest more effective ways.

Here's what BHPian condor had to say on the matter:

I have had one such instance when the wheel alignment shop guy was swapping the wheels during rotation.

Going by this lone experience which happened right in front of me, I guess that in your case, the process had started when he tightened the lug nut that day, and the shearing process completed in the in-between period.

Here's what BHPian Kosfactor had to say on the matter:

Agree that we must not over tighten lug nuts, the problem is knowing when to stop, it is usually based on whatever the 14 year old had for breakfast or lunch that day!!

In my vehicles when the ASC removes the wheels to clean the brake discs \ drums, they use a Torque wrench while fitting it back. Set to 110-120nm - the actual value is 105nm for alloys for that model. They over tighten it slightly to stop erring on the side of lose lug nuts.

The standard value depends on vehicle models and wheel type (Steel \ Alloy) can be anything between 80 - 120 nm. It is worth knowing the exact value and insist on getting the wheels tightened at the ASC with a Torque wrench if it was removed elsewhere. I have a habit of checking them regularly while cleaning to see if they are tight, I have once seen them loose after a highway run as someone tightened it using a cross wheel spanner.

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