What is the deal with lug nuts?

[FoneRunner]

Maybe I could do some research and call some manufacturers, but I think the people on this forum are plenty educated enough to answer this question:

My 98 4Runner has 6 lug wheels, and so did all my checy trucks. My F150 has 5 lugs, my wifes 99 Landcruiser has 5 lugs(even though FJ80 and earlier had 6 lugs)and all my BMW's have all had 5 lugs. My 67 VW Beetle had 4 lugs and I see a lot of small cars these days with 4 lug wheels. My buddy has a Chevy 2500HD with 8 lug wheels, and tractor trailers have 10 lug wheels.

Here's the question: On what do the car manufacturers base the number of lugs they are going to outfit a car with?

 

[ToyTech99]

There's really no simple answer to your question, but here's my take on it:

Generally, the more lugs per hub indicates a "heavy duty" application. Have you ever looked at the amount of lugs on the big "earth mover" trucks? You know, the ones with tires that are like 12 feet tall? Well, they are intended for extremely heavy work and require a lot of lugs for safety.

On production vehicles, you'll see 6 lugs on some trucks and SUVs and 5 lugs on others. It's not just the amount of lugs that matter, but also the size of the them. Thicker wheel studs generally have a higher shear strength than thinner studs.

Smaller cars typically have either 5 or 4 lugs per hub. If you've ever seen a smart car (you know, the smart for two small car), you might have noticed that they only have 3 lugs per hub. I guess the idea is that it's a small and lightweight car, so 3 lugs are all it needs.

Personally, I like the idea of 6 lugs per hub on the 4Runner. It keeps with the "tough" image that I have of the 4Runner. But if Toyota ever went to 5 lugs instead, it would still be just fine and completely safe. That's my take on it.

 

[FoneRunner]

That's what I figured too and what started me thinking about it was when I was looking at the different model Landcruisers. The FJ80 has a 6 lug wheel on a solid front axle. Starting in 98 they went to a IFS system and a 5 lug wheel. The general consensus seems to be that the UJZ100 has better off road capabilities than its predecessor(although that is a much debated point), so my question was why would they use less lug nuts in a wheel that presumably should be tougher? Otherwise, I would be totally content with the more lugs nuts, the more capable/tough/rugged the vehicle.

One thing you mention that I hadn't thought of was the size of the lug itself...maybe I'll pull one loose from the Landcruiser and compare it to the 4Runner...Thanks Toytech!

 

[Kmvreter]

Simple math (from a wheel guy.) Size and # of studs = torque retention for desired wheel mounting clamping force based on expected load rating. Lots of other factors play into this but it needs to meet SAE testing.

 

[Jeff Kleb]

Lug Nuts


The general school of thought is that more lugs = more capacity; although that is not always true.

For years, half-ton trucks typically had five lugs. Chev put six lugs on some of their 4x4 half-tons, however. Most trucks that were 3/4 ton or greater came out of the factory with eight lugs (F-250, F-350, etc.). Oddly, Ford made both an F-250 and an F-250 Heavy Duty back in 1997 and 1998; and the former came with seven lugs while the latter trucks had eight. Confusing, eh? The half-ton trucks were available with 17-inch wheels, while the heavier versions only had 16-inchers.
:boxer:

Old - very old - Mustang coupes with six cylinders had four lugs, while the V8 cars had five. Doh! Later on, they all had four lugs - regardless of whether the car had a four-banger or a 5.0L (302) H.O. V-8 under its hood. This stayed a practice with Ford until the 1994 revision, when they all went to five lugs and the four-cylinder engine was discontinued.

I had a five-ton International diesel truck (24-footer) that was a 1993 model. It had six lugs, but they were HUGE; requiring an air impact wrench to loosen them. They also had "left-handed threads" on the driver's side of the truck, which meant that you had to turn them clockwise to loosen them. I always had to let the tire guy know that, or they'd never come off.
:bravo:

I drive heavy-duty straight trucks and tractor-trailers. I can't recall off the top of my head how many lugs they have, but it must be 10 or 12. The drive axles also have two wheels on each one, so that is yet another set of bolts that must be removed and replaced. Glad I don't have to do it!
:

Anyway, the number of lugs is kind of like where to put the fuel filler door; up to the manufacturer so long as it works for them and is considered safe and applicable to the particular vehicle. (I still can't figure out why so many cars, especially Fords, have the fuel door on the passenger side. Duh! At least they finally fixed the 2005+ Mustang and switched it back to the left side after 30 years.) I used to like my 1978 Oldsmobile because it was underneath the rear license plate and was accessible from either side of the car.


~ Sorry for the off-topic rant! ~
:snacker:

 

[FoneRunner]

How about that...I knew I would learn something today!:thanks:

 

[Markjr]

ok for cars 4 lugs have fewer rim options, some of my friends were going to switch there hub so it went from 4 lug to 5 lug cause they make way more rims for 5 lug patterns but as for for big trucks its just heavy duty.

 

[techno]

The 75 series Landcruisers all had 6 lugs, but when Toyota updated those models with the 78 & 79 series Landcruisers, they switch to 5. This was a really big in Australia and it cost many companies lots of dollars. These models are very popular with mining type companies who will run very large fleets. The aussie outback is very tough on vehicles and the fleets have large reserves of spare wheels and tires as a result. Now, when the companies started upgrading their fleets they also had to manage the wheel reserves too and throw away plenty of good usable wheels that no longer fitted anything.

 

[Uneek]

I had asked about this with the Tundra during its introduction, why it went from six to five lugs. The response was, the studs on the second gen Tundra are nearly twice the size of the first gen, so Toyota could use five rather than six.