Torquing Wheels - Proper Method

[packick]

After working on my classic and reinstalling a wheel/tire while it is in the air, I tighten the lug nuts as much as I can, then lower the car all the way to the ground and re-tighten all of the lug nuts to 90 ft. lbs.

A friend of mine said I should only lower the car until the tires just touch the ground so they won't spin, then torque the nuts to 90 ft. lbs. That way, he says, allows the wheels/tires to move inward when the final torque is applied. Lowering the tires all the way to the ground puts the whole weight of the car on the tires and does not permit the wheel to "move in" when the torque is applied.

Who is right?

[JFranklin]

90 FT# seems way too much does the manual call for that much. most cars I own require around 60 -65 #.

The wheel is not going to move inward when you tighten after it is on the ground if you tightened some in the air.

Edited October 21, 2012 by JFranklin (see edit history)

[Dave Mellor NJ]

That's like trying to change a flat when the wheel was put on with an impact wrench.

[packick]

Sorry, but 90 ft. lbs. is what most people in our club torque their wheels at. After seeing one of our members lose his wheel from not being torqued enough, we did a bit of research as to what the torque should be and we determined that 85-90 ft. lbs. was best. I have used this torque setting for many years on all 4 of my classic cars (and modern cars) and have never had a problem, even removing them.

[DAVE A]

For the tiny amount of movement that you are going to get, there is more than enough flex in the tires to allow for the wheel to "move in" when you do the final torque.

[joe_padavano]

For the tiny amount of movement that you are going to get, there is more than enough flex in the tires to allow for the wheel to "move in" when you do the final torque.

X2. This is exactly how I've done it for decades. As for the correct torque, your factory service manual will tell you what it should be. On 1960s-1980s GM cars, the 7/16" lugs typically call for 80 ft-lb, the 1/2" lugs are 90-100 ft-lb. The 9/16" lugs on my crewcab dually call for 140 ft-lb.

[trimacar]

Remember not to have paint under the lug. I drove a car once that had a wheel fall off (Model A) because the paint was so thick under the lug nuts that they wouldn't seat.

Yes, I know it sounds crazy that they'd all come off at once, but they did, with no prior indication of trouble, just a "thunk" from the left rear brake backing plate hitting the pavement at 35 miles per hour, and a wheel/tire rolling past me on the left..........

[Pete O]

Don't forget to use the "star" method to tighten the lugs in a sequence that moves to the opposite lug each time. This ensures that the wheel is aligned on the hub, kind of like a torque sequence for a cylinder head

[Rusty_OToole]

You are right. The method you are using is correct, the same as used in all garages for the last 100 years. Pete is right about the star pattern or every second nut on a 5 bolt wheel.

[Restorer32]

Very unlikely that your friend's wheel came off because the lug nuts were not tight enough. Far more likely that there was paint under the nuts or that the nuts were bottoming out on the drum allowing the wheel to "wobble" ever so slightly causing the lug nuts to slowly back off. All in all though, better too tight than not tight enough, if only for peace of mind.

[RonHeberle]

I always do the final torque with tire just touching the ground without all the weight on it using the star pattern.

[mrpushbutton]

a 7/16-14 bolt, tightenned to 80 ft. lbs. is going to have a clamp load value in excess of 10,000 lbs PER BOLT. Restorer32 brings up a very valid point re: too much paint. A certain large American auto/truck manufacturer here in town had a problem a while back with tires failing on a big-selling model of SUV, they paid my former boss, a registered professional engineer specializing in the design and testing of the bolted joint to "prove that our lug nut vendor is making defective products". After much research and analysys it was determined that the lugnut vendor was by far the most uniform and repeatible manufacturer in the chain. The biggest problem: the machining of the beveled countersink in the wheel by......................the vehicle manufacturer. There was tool chatter which resulted in radial high and low "bars" which meant that the lug nuts were only seating on a percentage of the area available. They were torquing the lugs just fine, using the latest torque-angle systems available, but the steel lug would beat down the riser-bars and pretty soon there's no tension on the nut and it dances its way CCW until they all come off, the rim and tire go adios and it passes you on the expressway.

In the end, torquing is about creating clamping load between two objects. Oh, and Impacts are all over the map--yeah, they are "tight" but inconsistent as all get-out.

[Matt Harwood]

I also was taught to run the star pattern and to sneak up on the final reading. Don't go right to 90 lb-ft first, do 60 all around then the final torque. On the expensive 3-piece alloys we used to put on Corvettes, we'd sneak up on it with 30-60-90 to avoid any possibility of damage. Probably not necessary, but it has become habit and it never hurts to be cautious.

On new wheels, remember to re-torque them after some driving.

[joe_padavano]

a 7/16-14 bolt, tightenned to 80 ft. lbs. is going to have a clamp load value in excess of 10,000 lbs PER BOLT.

While I agree with your point, the fact is that torque is a very poor and inconsistent measurement of clamping force. Obviously thread pitch matters, but more importantly, variations in friction between the nut and the lug and between the nut and the wheel will have a tremendous impact on the actual clamping force for a given torque. If the friction force is high enough, you'll get zero clamping force at 80 ft-lbs. Of course, if the friction is that high, the nut isn't going to back off, either...