Why do wheel spinners tighten clockwise on the left?

On bicycles the pedal rotates counter clockwise to the clockwise direction of the pedal lever on the right and vice versa. No clue on the lotus.

 

It's always been a bit of a mystery to me as well. To add to the mix, Chrysler had left-handed lug nuts on one side (can't remember which right now) for many years. What an irritation.

I think the "engineering" behind this is mostly due to overthinking the problem. If the knockoff is on tight and the splines are in good shape, there really isn't any apparent force attempting to turn it either way by simply rotating the wheel.

The example of the bicycle pedal is somewhat different. The shaft that the pedal revolves around is directly threaded into the crank arm. There is a rotational force applied to it when pedaling that needs to be counteracted by having threads cut such that they tighten rather than loosen on both sides. This was a concept that I discovered and appreciated in my youth.

 

Opposite of rotation as you are looking face-on at the wheel.

If you are looking at the passenger side of a car while it's going forward, the wheels on that side are turning clockwise ----
If you are looking at the driver side of a car while it's going forward, the wheels on that side are turning counter-clockwise.

In both cases, the nut needs to tighten in the opposite direction.

 

I had a racer friend that put a solid splined axle in his race car and it was backwards. When I started helping him he told me keeping the rear wheels tight is something we had to stay on top of. Having worked on a number of center lock race cars I realized quickly that his was backwards. Off was not to the front. I removed everything and installed it properly and we never had a loose wheel again. I am not an engineer, but I know it won't stay tight the other way.

 

Except for Lotus (probably some others) that seem to work just fine the other way around. I doubt it REALLY makes any difference which way they turn as long as they start out tight. The best way of course is to have a cotter pin like an F40.

 

"Forward off, Back on" was how I was taught, true of early 70s race cars, true of same era Rolls, Dodges etc.. No idea why. But, like in the above, it works, if you reverse them it doesn't.

 

I still feel pain watching the 288 GTO on YouTube of a car going down the highway, and watching the left side spinner coming off and flying thru the air. Car did not crash but he sure got it off to the left shoulder, and you could watch the wheel/tire speeding down the freeway ... Think it was in Japan, don't have a link to it.

 

You are correct that if the nut is properly torqued down, it does not / should not matter which hand the thread is. (And, yes, for a road car, why the hell not put in a cotter key for good measure !)

The idea behind the direction is this ---- that IF the nut is loose / comes loose, its rotational inertia will help to prevent it from unscrewing further and coming completely off if it is threaded in the forward direction. This is really kind of a belt & suspenders idea, because once that thing has come fairly loose, odds are nothing is going to have a 100% chance of keeping it from unscrewing further anyway regardless of thread direction --- because in addition to the forward rotational inertia, you typically have braking inertia in the opposite direction, lateral inertias from cornering, random inertias from wheel bouncing from the suspension, etc. all acting on the nut. Not to mention the now already loose wheel constantly pushing outboard on it.

This does not matter significantly much with lug nuts / lug bolts because their mass moment inertia is so low and their thread diameter is so small, but the center nuts have a significant amount of inertia (especially the knock-off ones with large "ears") and a large thread diameter.

 

Lotus ?! pffft --- they're British ---- they do everything ass-backwards !

 

I think the British invented the other method as well. Whateva

 

But looking at racing and race car building through history and now-a-days, ass-backwards seem to work

 

Chrysler vehicles had left had thread studs on the left side up to 1972. Not sure, other than conformity, why they finally changed. I learned the hard way when I stripped out the studs and lugs on my step father's 72 Dodge. I switched my studs and lugs on my formerly owned 69 Charger and 70 Challenger to RH thread.

 

I was being facetious --- I also own a Lotus

 

Esprit V8

 

The 1950s Jaguar D-Type wheel spinners/knock offs have the same male taper as the Elan.
So do the F40 and modern Porsche and racing car centre lock nuts.
They are all threaded the same as the Borrani & Dunlop (MG, TR, Morgan, Austin Healey etc) female taper spinners, ie tighten clockwise on the left hand side, anticlockwise on the right.
As far as I know the Lotus Elan are the only ones made the other way round.

 

drawkcab-ssa gnihtyreve od hsitirb eht taht eurt toN

 

im not sure if this has been answered but there is a sound engineer reason right why the older centerlock wheels had left and right hand threads.

it counteracts the inertia from wanting to spin off the nut if it becomes loose. my old alfa gtv have conventional 4x108 lug nuts. they also have opposing threads. in the 70's this was deemed unnecessary, what are the odds of all 4 lug bolts falling off? To simplified parts inventory and eliminate that young mechanic from mushrooming your lug nuts with a cranked up impact driver at the local tire garage. Oem have long restored to common thread bolts on all wheels.