complexx

The platform of the car is a formula style design, more specifically formula sae. Our dillema is determining which threading direction to use on each side of the car and also whether we should alternate the threading from front to rear as well.

I understand that you have to consider the forces in braking and acceleration and use that to determine which threading style to use but I don't know enough to determine which way to go.

Thanks for the help.

-Frank

A930Rocket

Just a guess, but I'm thinking the right sides are clockwise and the passenger sides are counter-clockwise. As the car moves forward, the wheels rotate in the same direction to spin them on and keep them tight....

Nordschleife

Bugatti used to arrange the threading so that the wheels torqued themselves up under use. Given that even a wheel bolt was a work of art, this is hardly surprising.
In a racing environment, it would be better to have all wheels being done up and undone in the same directions on each wheel, much easier on the guys using the tools under pressure.
R+C

RedlineMan

On the other hand...

You rarely see a professional team doing both sides of the car. It is usually one guy doing each side for sports cars.

I spent some time around a 911GT1 / 96 Prototype, it had right hand threaded nuts on the left and left hand on the right. You did indeed have to pay attention, and one would more than occasionally find themself working the wrong direction. Now, the Carrera Cup cars are all right hand thread.

I can't imagine it is a critical item for an SAE car. They simply do not go that fast or brake that hard, I wouldn't think.

A930Rocket

That seems backwards... Wouldn't the rotation of the wheel help to keep them spinning in an "on" direction?

Greg Fishman

John,
Did you just work on the GT1 at the races or were you part of the Cincy based team?
That car was gorgeous and was on display at RRII.

Jim,
Maybe a set of removable baffles like the Fabspeed SuperCup exhaust has.

brucegre

Cup cars with centre locks are all right hand thread - all the way around. Now, they're also torqued to 350 ft-lbs, but at least we never get confused on which way is off.

If you really want to go directional, just remember, you hit them towards the back of the car to tighten. So the driver's side is RH and the passenger side is LH. Which means right is left and left is right. Too confusing for me.

Cheers,
bruce

RedlineMan

Hey;

I spent a brief time around it when it first went into private hands, after Rohr sold it. I can honestly say it is the neatest thing I have ever experienced in a race car. Fabulously exotic, achingly beautiful (in my opinion), and yet peel off the front nose, or climb inside and... hey... this is a 911! There was the steel tub... just like a street cars. The rear assemblies were a different matter, as the pic shows! I'd give my left nut to own that car. Would then cost the right one to maintain it...



Chrysler was the last company I know of that did the Lefty-Righty thing. As late as the early 60's perhaps.

A930Rocket

So much for my logic...

adrial

Brake at ~1.5G's...

I would design for braking as I believe that is a larger force that occurs more often at a maximum amount than acceleration (less accel in higher gears)...

http://fsae.com/eve/ubb.x is a great resource...

RedlineMan

Oh...

Accelerative forces are squat.

My point was not to dissparage SAE cars, nor do I not think they can throw some mean Gs. However, while they can scoot right along, they are NOT dealing with nearly the inertia of a sedan, and in that light "they do not brake that hard." Their brake torque-to-weight ratios must be fantastic.