I just rotated my tires. One tire had been repaired for a leak and, although I told the guy at the garage 80 ft-lbs on the lug nuts, it ended up quite a bit more than that. ( He told me not to worry, the guys "look that stuff up"...) I couldn't loosen the nuts with the small lug wrench Honda provides. I had to use a pipe around it to give me enough leverage to loosen the nuts. I suspect it was tightened to at least 100 ft-lbs. Question: is the 80 ft-lbs indicated in the owner's manual a minimum tension, maximum tension, or neither? I would like to know if damage can be done to wheel if too much tension is applied. Obviously, at some point the bolts would shear, I imagine, but is 100 ft-lbs, e.g., going to damage the wheel? They are 17" alloy wheels.

If I was out on the road and that tire had failed, I wouldn't have been able to change it. This is one reason I like to do everything I can on my own... just can't trust anyone.

 

My Fords have roughly the same stud size and even with aluminum wheels, 100 ft-lbs is the recommended torque. My Japanese cars recommend 76-80 ft-lbs for some reason. I don't think 100 ft-lbs is enough to be of concern, but I have had alignment shops tighten beyond that on one of my Fords. The only issue that caused was stripped lugs and wheel studs. A minor pain, but I don't go back to that shop.

I take 80 ft-lbs as the number to tighten to so that's where I set my torque wrench. There is no measurable efficiency gain for me to set to 70 ft-lbs so I set to the exact number called out. When a tolerance is given on torque, I usually go right in the middle.

 

Maybe because Japanese are not as strong? This is a weird idea, but as a smaller person myself, 80 ft-lbs is doable. Or maybe because the lug wrench is so short?

 

I doubt they are weaker (or stronger). They need to be tight enough to not fall off and strong enough not to break when over tightened with an impact wrench. If you are an engineer deciding what torque to use, a one in a million failure is too high. Just look at how many Hondas are made in a year.

 

You must be a politician. What does the number of Hondas produced have to do with my question?

When I originally read the owner's manual, I was surprised at the 80 ft-lbs number because I had always heard 100 as a kind of standard. So I assumed that there must be a reason for this lower number. I'm trying to determine what this reason is. Also, Honda's lug wrench is shorter than others I have received from OEM manufacturers. So, is it reasonable to assign the lower number to the shorter lug wrench? Or to the composition of the wheel? Or so ladies and old men (like me) can get the nut off on a highway?

 

The lug nut torque is dependent of various factors such as bolt size, bolt grade, etc.

Car manufacturers do not use a standard bolt size, bolt thread, etc. That is why there would be different torque recommendations. There are various diameter lug nut sizes among car makers. Even Honda/Acura has variations; so, 80 ft-lbs is not the recommended torque all across the board for Honda/Acura.

Dorman Wheel Nut Torque Specs

Many stock lug nut wrenches provided with the car are just barely adequate to gain enough leverage. That's why I carry a breaker bar in the trunk and do not rely on the stock wrench.

 

Thank you. I should carry a pipe or longer lug nut wrench, just in case. Rotating the tires myself has proved a little exhausting. These tires are heavy! In the future, I can see just having the Honda dealer do the rotation and oil change, but I'm not quite there yet! Maybe when I reach 70.

Wow, the variation is enlightening. I see where I got the 100 from... GM cars.

 

That would be called designing for abuse loads. Believe it or not, it drives a lot of design, not just in cars, but appliances and many other items. If all you needed to do was to design to actual loads, a lot of things would cost less and weigh less. But the consumer would be pissed when his 85 lb. dobie climbed on the dishwasher door to lick the plates and the door broke. Well, even that's changing as I've noticed dishwasher doors have become a lot flimsier in the last 15 years as they try to squeeze out every penny of cost, but it used to be a consideration (not necessarily the dobie but an XX lb load on the door).

 

It all comes down to what is an acceptable failure rate. If a wheel stud breaks every million hours and there are 100 million cars on the road, that's 100 failures per day (assuming most people drive 1 hr/day). Combine that with other things that might happen at the same time or as one failure in a series of failures, and the lawyers start getting rich from lawsuits if too many bad things happen, even if the rate is low. Even with low rates, the number can be big enough to cause concern when there are a lot of cars on the road.

 

I want to say stock steel wheels get torqued to 80-85 ft lbs. Stock aluminum rims or some aftermarket aluminum rims are torqued to 90 to 100 ftlbs, or whatever the owner is comfortable with. My self, I trend to the upper end of the torque spec, but then I'm the guy changing the flat. Had to do this, this past summer on the wife's car, when she ran over a truck tie down ratchet (caught the edge of the sidewall with the handle of it). But then, that's why I buy the road hazard (cheap new replacement). But then I torque it to what I'm comfortable with.