Spinners

[Jac Mac]

Originally Posted by TButtrick

Yep, it can do that to ya as well if your not conditioned to multiple g's!

A SNAKE, since the acceleration can only be transmitted thru the rear tyres, while the braking is applied thru all four and since braking is always from a high to low speed with the benifit of downforce it stands to reason that decelerative g will always be greater than acceleration.

further you can assume that braking will always have drag acting with it , while under acceleration drag opposes it.

Now while braking from say 200mph to 160mph the 'time' will be less than that taken from 40mph to 0mph. Distance taken is not a constant factor in this scenario ( but if you are in the seat approaching an immovable object I am sure you will think it is )

[David Kirkham]

Originally Posted by Jac Mac

Your 'aerodynamic drag' is a factor at high speed, but more important is the aerodynamic downforce added to the cars static weight which increases the grip available from the tyres when operating at higher speeds. After all 'they' say that at around 200mph most modern single seaters develop enough downforce to enable them to be driven on an upside down surface ( and I dont mean any track downunder in S.A. Aussie, or NZ.). To accomplish this there has to be around 2g + of generated downforce.

Jac Mac,

Yes, you are correct. I was attempting to simplify the discussion, but I can see from my earlier post I did a very poor job of "simplification!"

One thing to remember, is down force is by definition drag and Thomas and I use the terms relatively loosely around here. Certainly, down force creates more grip for the tires--braking, cornering, and accelerating (why else would they do it). As such, there is more than 1.5 g's of grip available to the tires when an F1 car is traveling at 200 mph for accelerating, cornering, and braking. Unfortunately, for those of us who have traveled at extremely high rates of speed in a Cobra we have found out first hand this in NOT true as we feel the nose lift and the steering wheel get this funny "light" feeling in it! You can see where my "simplification" starts to get not so simple. (In my mind at least).

Most undoubtedly, I should have been more clear in what I was saying. I apologize for my unclarity. As you type you think what you are saying--but it doesn't always make it to the fingers!

David

[David Kirkham]

Originally Posted by A-Snake

I interpret the above as follows;
The peak acceleration of 1.5G’s of an F1 would be achieved at a relatively low speed. It’s not going to achieve 1.5G’s when the car reaches 200MPH. Nothing to do with tires here. The maximum acceleration simply tails-off.
If he is braking hard from 200MPH to 40MPH wouldn’t the G’s remain much more constant then when the car was accelerating from 40 to 200MPH?

No, braking g's tail off (non linearly) from 200 to 0.

As the car goes slower and slower the down force applied to the wheels becomes less and less giving the wheels less and less grip and hence less and less ability to decelerate the car.

In addition, the aerodynamic drag forces on the car become less and less the slower you go (remember the above drag equation from NASA). The equation states drag is a square function of speed. At 200 mph the F1 cars are set up to give the wheels all the braking force the brake system can possibly manage (to take advantage of the enhanced grip and to cope with the increased rotational inertia of the wheels, rotors, and drive line components). Hence, you can brake at a MUCH higher negative g at 200 mph than you can at 20 mph because of increased grip and increased aerodynamic drag at 200 mph.

If the driver nails the brakes while going 20 mph in the pits he will simply lock the tires up. That does not mean, however, there is "too much brake" in the system. He needs all the brake possible to slow the wheels and rotors when they are spinning at speeds Ahamenajad would be envious of.

David

[roadrod2000]

whatever happened to "righty-tighty, lefty- loosey?

[David Kirkham]

Originally Posted by roadrod2000

whatever happened to "righty-tighty, lefty- loosey?

Doesn't work with left hand threads. That would be righty-loosey, lefty-tighty.

David

[Danr55]

Looks like I could make a buck or two selling safety wire pliers..

[SKINNEDR]

The Pliers can be purchased for less than $6.00 when on sale at Harber Freight Tools...
DEx.....

[JBo]

The proper acronym for knock on equipped Cobras/Shelby Cobras/AK's/COBs/COXs with the proper right and left side pin drive axles, installed on the proper side is "tight ass" or to define better...with an ear in the 12:00 o'clock position, wack that ear with the appropriate to you tool towards the rear of the car to tighten the knock-on. This would work for replica's/continuation and any other cobra type vehicles equipped as defined in the previous sentences. I hope I have this correct, but if I've misspoke I'm sure someone(s) will correct me.

[wtm442]

The first time I went to safety wire my wheels, I was a "little" lost. The article below really helped a lot.

http://performanceunlimited.com/cobr...tructions.html

All of the technical stuff regarding why you need to do it a certain way, or the thoughts why you do not need to do it are nice to read, but .....

I feel better after checking the wires every couple of days, and most important ... the safety wire looks cool Every so often people ask what the wire is for, giving me another reason and chance to talk about my Cobra.

[Ron61]

I used to check mine every day or so, but I left just a little slack in it so that if the spinner did start to back off it would tighten the wire. The spinner only had to move about 1/8th inch to tighten my wire, and I always checked them anyway, so I never had one start to come loose.

Ron

[Randy Rosenberg]

Originally Posted by JBo

The proper acronym for knock on equipped Cobras/Shelby Cobras/AK's/COBs/COXs with the proper right and left side pin drive axles, installed on the proper side is "tight ass" or to define better...with an ear in the 12:00 o'clock position, wack that ear with the appropriate to you tool towards the rear of the car to tighten the knock-on. This would work for replica's/continuation and any other cobra type vehicles equipped as defined in the previous sentences. I hope I have this correct, but if I've misspoke I'm sure someone(s) will correct me.

I was given this same exact information and "term" 10 years ago when I bought my first SPF. I expect it is still true today.

[TButtrick]

I don't know. Mine are still on for tighten toward the front and they're staying that way. Whacking when the ear is at 3 o'clock (or 9 o'clock if they're on backwards ) and striking down works best for me. But then again, aren't those cars built where they drive on the wrong side of the road?