When did car lug nuts go from five to four per wheel?
What is the correct procedure for tightening four lug nut wheels?
Lots of cars still have five lug nuts per wheel. The procedure is the same as four five lug nut wheels. Do opposite ends before going to adjasent nuts.
Can’t answer the first question, but for the second one its:
1 3
4 2
That’s that pattern I’ve always used. Y ou can also use any of the various rotations and reflections of it, as they’re all equivalent.
Or even adjacent ones. 
When the majority of cars produced were compact and lighter. Heavier cars, Crown Vics and such, still have 5. With minimal force,Start at 12 o’clock, go to six oclock, Nine then three, then back to 12. This is to snug up the wheel, then repeat with a torque wrench to suggested setting. If you have lightweight wheels you could bend the wheel, easy to do on the donut spares.
This question is nonsensical. Car lug nuts did not go from five to four per wheel. For decades, there have been some cars with 4 lugs and some cars with 5 lugs, as there are today.
I still have a car with one nut per wheel.
Steering wheel?
My Smart uses 3 bolts (not nuts on studs) per wheel.
No, the road wheels.
It’s a '69 MG, with wire wheels. Instead of the four or five (or three) lug nuts, it’s got one nut right in the middle, about three inches across. The nuts are different threads on either side of the car (so it the splines on the hubs wear out, the wheels won’t try to unscrew themselves when you drive). To get the nuts on and off, the car comes with an octagonal wrench and a big, lead mallet.
It’s called a “knockoff.”
Created mostly for road racing classes (i.e. the factory cars that run at Le Mans, early F1 cars, etc), so that pit stops could be as fast as possible. Whack the pretty chrome thing, and the nut comes off.
Most serious race cars still use a 1 nut design, but it is usually a hexagon. Now removed with an impact gun, rather than a soft mallet.
My old ragtop had knockoffs - IIRC the turning forces are supposed to be transmitted by the cone thingys on the inside of the wheel that mate with a cone on the hub, the splines theoretically shouldn’t be doing any work.
Once, when I’d taken my car in for it’s MOT, the guy showed me another car that had braked hard in an emergency - the front hubs stopped - but the wire wheels kept turning :eek: the splines stripped off completely! (there was a little body-work to be done on the front-end too!)
After that I checked the knockoffs were tight on my wires pretty much every time I drove!
You beat me to it, Robot Arm. When my '66 MGB roadster is completely restored, it will have winged knockoffs on wire wheels. (They look better than the big hex nuts.) Right now it has the four-lug steel wheels that were standard with the car at the time.
NTChrist: I think the federal government mandated the big hex nut knockoffs instead of the winged ones in 1968 for safety reasons. There was always the possibility that a big rock could hit a wing just right and loosen it.
A friend of mine had a Renault Le Car back in the '80s that had three lug nuts per wheel.
While I’ll agree that is a possibility, it’s so remote as to border on silliness to worry about it. There’s also the possibility that all three interlock switches on my microwave oven could fail and cook me when I open the door with it running. I don’t worry about that either. 
Q.E.D.: I agree. Nevertheless, whenever I’ve read about the knockoffs, the text says that the hexes were mandated over the wings for safety reasons.
1968 saw other “safety” changes for MGBs coming to the U.S. The beautiful black crinkle-finish dashboard was replaced with a padded one. This resulted in the loss of the cubby (glove box) until another change to the dashboard came along a couple of years later. The switches were also changed. There used to be three toggle switches in the middle of the dash. These were changed to rocker switches to prevent injury in case someone’s face hit them in a crash. And while the steering wheel looked the same, the horn was relocated to the directional indicator stalk intead of remaining in the middle of the wheel. (I have an original '69 steering wheel that I need to sell, since I’m getting a new wheel for my '66.)
From photos I’ve seen, the MGBs in England kept the same crinkle-finish dash layout for a few years after the changes to the U.S. models. Of course, anyone who wanted to could retrofit an old dash to a U.S. car.
Correction: The new hubs are octagonal, not hexagonal.
My truck has eight lugs per wheel. Changing a flat sucks.
It was for safety, pedestrain safety. 1968 is also when flush exterior handles first appeared on cars in America. Knock offs could really do some damage to a lower leg in a near miss.
Shades of “Ben Hur.”
My truck has 6 lugs per wheel. Could be worse, though. Our wildland engine, on a Dodge chassis, has the 12-lug axles.