Was looking at some old drag pictures form the late 50's early 60's and my daughter asked me a questions I didn't know. Alot of the cars had a wide white mark painted on the rear tire that ran from the rim to the tire edge. What was the purpose of this stripe?
Yep, pretty certain it was so the crew could watch for how much wheel-spin was happening. Same thing with 1/2 painted rear wheels, 1/2 red, 1/2 white, for example.
A lot of NHRA teams still paint their slicks to gauge wheel speed and slippage. -Lee Atomic Radio www.atomicpinup.com
How? Timing light? teehee Seems that would only work if the tire was pretty much static and the wheel was spinning. Is that all?
Slippage of the tire on the wheel. The onboard computer monitors actual wheel speed. -Lee Atomic Radio www.atomicpinup.com
Most drag tires don't slip on the wheels anymore in this era of rim screws and (for pros) bead locks. A camera next to the car at the line will tell you how much tire slippage you've got, it's easier to measure with a painted stripe.
If they were looking for the tire slipping on the rim, they wouldn't have painted a huge stripe up the tire. It would have been a small mark that went across the rim and tire. The big stripe on the tire was strictly for watching tire spin. If you've ever seen a painted propeller you get the idea of what it looks like. Originally teams would film it with a movie camera to review later. With the advent on Video it gave them real time access. Now with computers it isn't done on the classes that allow on board data sensors, but you will find others that still do it. There is an art to "Reading" the stripe as its spinning and good crew chiefs could get useful data from watching it.
If you painted onto the thread the pattern of the paint left gave you an indication of tire contact, an old Autocross trick.
You'll notice one of the crew with a video camera at/near the start line. They'll view the tape after and look for wheel spin (tire to pavement actually). How much, when, etc. "IF" concerns were tire spinning on the wheel, you'll usually see a small mark on the tire, usually near the valve stem. After a pass you'd look to see if the mark still lines up with the stem. Not so much an issue with bead-lock stuff currently being used
Here's what I meant by 1/2 painted wheels: I know, "How come the fronts are painted that way?" Because the team probably painted up a bunch of wheels that way and they sometimes wound up on the front.
I'm 12 yrs old when I see this for the 1st time. It's on the back of a Mustang Fasback with slicks, parked in the street in Brooklyn, which was unheard of. I didn't care what the reason was at the time, but I was impressed to fuck! Man, I stopped my bicycle and just stared. Good stuff! Hey, anyone eat those little desert cakes that looked like that (1/2 chocolate and 1/2 vanilla icing)?
Cool! What am I seeing aft of the rearend that appear to be red, and too thin/long(?) to be the leaf springs?
Sounds like Tastykakes! They're a Philadelphia thing.. about the only good thing from there actually.
Thats old style drag bars. They pull the back of the car down when the axle tries to wind up. They were used on '62-'63 Fords and then about '64 or so they started using the ones that went towards the front of the car. These are Traction Masters...you don't see them very much. Tom Culbertson drug them out of his garage and put 'em on. They seem to work pretty good. They were a pair he used on his Ford drag cars in the early sixties. A lot of history in these. We didn't even clean 'em up...just put 'em on.
THAT'S IT!!!!!!!!!!!!! B&W's. THANKS. I loved those things when I was a kid. Well, still would if i had one
We use to paint a stripe on the front tire also to see if it jerked the front wheels first or rolled out then lifted the wheels . You would be surprised what you can see if you slow the video down . I drove my buddys 68 camaro and they vidoed me running a 10.70 pass lifting the front wheels three times . Changed some front springs and shocks , tuned in carb and ran a 10.47@ 129 . I used to remember t=how many frame to one rev of the tire . Now I just Love Rust !!!!!!!!
We still use it. When running a car often the driver is not aware of all the crew needs to know. His sensations on how the car peformedare often vague and irrelevant because his skill is leaving on the tree. Some are down right ignorant when asked but since they can cut a great light you have to live with them. Many a crew chief including me puts a vertical stripe on the rear slick so he can watch "the Hook" I also often had it videoed so we could watch it later too. Evrytime the slick goes around spinning it costs about 1/10 of a second in lost et. In fact if it spun ten turns you lose a second. You learn to spend a good deal of your time playing with shocks , tire pressures , suspension bump stops and ride height trying to get this down to a minimum. The less experienced are restting their timing or changing jets or something sexy totally oblivious to the real job at hand that gives extraordinary times , Extraordinary "bite" That is what it is for and how it is used. typical comment from learning racers is "it didnt spin that much" Get them to add the stripe to the slick (or the old two colour painted wheel) and you will hear shortly. "Man I didnt think it spun that much!" The stripe gives your eye a point of reference in relation to the track and a poor traction is no longera guess but is obvious. Some cars actually can pick up a second with a good crew chief and little tricks like this and never touch the engine to get it.
They were used to verify the amount of tire spin. On the Golden commandos car used in the example photo, those were probably wheels that the Plymouth engineers who made up the team scored from Chrysler's crash test inventory. Wheels painted like that were used in crash testing while being recorded on very high speed film. It makes for easier analysis of the dynamics on film later. I'd suspect that they ran them on the front so other competitors wouldn't ask why they were only on the back. Back then when the factory guys got involved, they brought the engineering tricks with em, along with package trays made out of lead sheet! Cool stuff.
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