Left hand threads

Here is what appears to be the answer.

moparmax.com/columns/magnante/v_5-1.html

Lang, read that a few days ago, don't know if it's 100% accurate, going by a few subsequent replies. Seems the idea may go back to very early days of road transport, but may be like a lot of things, open to interpretation??

There has got to be a real reason.

The various stories about tradition or marketing just don't do it. The car manufacturers of the 30's had a pool of the most brilliant engineers in the world. These blokes don't cause special non-standard production runs unless there is either an economic, performance or safety benefit. Every upholstery clip going into a vehicle has to be tested by those three requirements.

Of course fins and chrome strips come under economic because fashion drives sales but even the fashionable fins must meet the three requirements in regard to their physical design, manufacture and attachment. If you are going to put left hand threads on a car opposite to both fashion and what the buyers are used to and expect, there has to be bloody good reason.

Lang,
Take on board your post, especially about there being a pool of the best minds in the business, also the performance and safety aspects.
Perhaps economics may or may not enter into it so much, as I'm thinking that once you set your screwcutting machinery up, you let it rip and churn them out by the thousands+,
so possibly no extra costs involved.
But, as you say, there had to be a reason for doing it in the first place. I have had very little to do with vintage vehicles, but those early jiggers with the removable rim (from the actual disc), would they have been made to suit them?
Possibly something to do with the way the actual centre was affixed to the hub?
If counter-rotation were such an issue, most spider rims be they 5 or 6 cleat, don't seem to have the same problems.
I read in another post here about the Rockwell axle fitted to coaches being both L as well as R/hand. In a safety bulletin from MCI (coach builders) they are very specific about the correct mounting of Budd (or steel disc) wheels, yet even they changed to all R/H studs/nuts when using the full alloy wheel. Perhaps at the same time they may have altered the centre mounting on the hub, or the technique of the way the retaining cup washer/stud held them on? I can also see where once the wheel mounting holes become a bit elongated they would constitute a hazard, having driven a Benz truck where that did actually happen, luckily on the rear drive, not the steering.
Interesting............
dave

Lang M80
Read your last link n go onto next page etc
they found [strike]LH[/strike] Whoops RH thread on our passenger side(yanks Driverside) undid
and the other side did even get tighter
HNY
cya
§

The Japanese still employ this practice to today .. with the letter L or R on the thimble, and nuts having a zinc plate (silver appearance) or cad (gold looking appearance) for what thread they are supposed to be used on...pretty clever really.

....although back to the point...WHY ???

Because A: Read Swishys answer on page 1
B: Read Swishys answer on page 2

My 2 cents worth is;
That the left hand threaded studs are required for LHS mounted Stud piloted Wheels & are not necessary with Hub Piloted Wheels..

BISTBC.

235mack wrote: Because A: Read Swishys answer on page 1
B: Read Swishys answer on page 2

...reading again through it all, it's dieseldogs' reply 177758 that has it nailed....a great explanation.

Defective

What about cars with LH thread and no duals - outnumber trucks by 100? to one. There must be some base reason.

Lang