Tire rotation: when to torque lug nuts: tire in the air or on the ground?

On the ground, for the following reasons:

1) there's no chance that the car will fall off the jack while you are exerting force on the lug nuts

2) you won't stress the transaxle parking pawl, if the car is on the ground and the parking brake is firmly set.

Just make the lug nuts fairly tight, like 25-30 ft-lb, before lowering the car to the ground. This ensures that there's no gap between the hub and the wheel.

 

Tighten by hand in a five point "star" pattern while the car is on the
jack.

Lower car and tighten to correct torque, 76 lb ft.

Could be 'guestimated" with a lug wrench... better done with a torque
wrench.

More.

FWIW, the 2008 Owner's Manual says you should use wheel chocks
when jacking the car up. Funny though, a pair isn't included in the OEM
equipment...

I'd gladly trade the near useless cargo net and first aid kit I got for a
pair of gen-you-whine Toyota wheel chocks. :glare:

 

I think Patrick Wong's reason # 1 is the best. The kids in the tire shop will do the "zshoop-zshoop" thing to your lug nuts with the car on the lift, but then they're not likely to torque it off the lift. On a jack, man, I'll try to find a rock or something to use as a chock.

 

I follow the same method as Patrick. I would add that its difficult to get 76 ft lbs (or 100 ft lbs in the case of my Explorer) on the nut with the wheel in the air. The wheels will tend to rotate while you are tightening. Using a air impact wrench makes it possible, but the torque will not be accurate unless they use a special torque limiting extension. A hand operated torque wrench is the best way to tighten the wheel nuts.

 

Yes, this is true if both front wheels are elevated, as one wheel rotates in the opposite direction from the other.

If only one front wheel is elevated, then the CV joints, differential gears and parking pawl will be subjected to some stress as you tighten the lug nuts on the elevated wheel.

 

I think the Prius should be equipped with a service manual and diagnostic software on DVD and a USB to Data Link adapter. They could make it an extra cost option for a few hundred $, but it would be better if they just included it in the price of the car. :madgrin:

 

The software should run on any modern laptop. :madgrin:

 

Nah. 76 ft lbs is nothing compared to the amount of torque that the parking pawl will see if the (3000 lb) car is on an even moderate hill.

You really aren't going to snap anything in the transaxle with 76 foot pounds. If you do, then you'd want to find out while the car's in a garage instead of parked somewhere (and starting to roll downhill).