Correct slicks?

[stevepye]

I want to build the Attempt 1 as a dragster, but the kit-supplied slicks look too wide for a 450 hp engine. Granted, the car didn't weigh much, but still, 10-inch slicks with that hp output and torque? It's a 1962 era, by the way.

Thanks in advance.

(And, don't tell me to ask my dad! lol!)

Edited August 29, 2012 by stevepye

[Ace-Garageguy]

I haven't dug out my material on the Attempt yet, but I have a feeling you're right about the slick width. Accelerating the extra rotating-mass of an un-necessarily wide slick would be a detriment to vehicle acceleration

Revell did make two widths of M&Hs, 10s and 8s I think, that may fit the kit wheels correctly. Right off hand I don't know of any 8" goodyears. I'm pretty sure AMT also made narrower M&Hs and also Firestones, way back when.

A quick google search turned up images of Attempt in the NHRA Museum, and those don't appear to be 10" slicks in the photo. The front tires don't match the kit offerings either.

http://www.tachrev.c...A_Museumpg4.htm

Edited August 29, 2012 by Ace-Garageguy

[Casey]

I don't know if these are 10" wide or not:

Pics found here: http://www.jalopyjournal.com/forum/showthread.php?t=456675

[Fat Brian]

I think the tires from the Orange Crate reissue would look right for those, they appear to be 8 inch slicks.

[LoneWolf15]

Alot of the AMT kits carry this style of slick .

[stevepye]

I was wondering about using Firestone pie-crusts on Halli's.

Of course, it probably depends upon what I can talk dad into giving me.

Edited August 30, 2012 by stevepye

[Ace-Garageguy]

Are you building is as a correct representation of the streamlined Attempt One car, or as the basis for another dragster? Or as the bare-chassis version of Attempt ? Goodyear was one of Thompson's major sponsors on his record runs, and that's what was on the car in the NHRA musuem when it was photographed, but the kit slicks, while being Goodyears, aren't the right vintage or width IMHO.

[stevepye]

I am building it was a free-lance dragster. A local hero-type car. I like the four-cylinder approach, and I will probably do my own body panels in aluminum. I was just curious as to the width of the kit-supplied slicks. Seems that a 211 cid engine might not handle those 10" M&H's.

[Ace-Garageguy]

I am building it was a free-lance dragster. A local hero-type car. I like the four-cylinder approach, and I will probably do my own body panels in aluminum. I was just curious as to the width of the kit-supplied slicks. Seems that a 211 cid engine might not handle those 10" M&H's.

You're correct in thinking that 10" slicks may be overkill for such a small displacement engine. Only a dyno sheet showing torque and power curves could start to accurately determine a 'yes' or 'no', but it looks to me like the real car in the NHRA museum had 8s on it, and Micky Thompson didn't miss a trick.

More tread width than is necessary to adequately hook up the available torque is a waste of energy, in increased weight and rotating mass of the tire.

Rotating weight affects acceleration more than non-rotating weight. Mass at the periphery of a wheel affects acceleration twice as much as non-rotating mass does; that is true irrespective of wheel diameter. You can show this with the formulas for rotational kinematics, or (more simply) by noting that a point on the outside of a wheel has a tangential speed equal to the forward speed of the vehicle.

Mass at the axis of a wheel has the same effect on acceleration as non-rotating mass.

Mass partway between the axis and the outside of a wheel has an additional effect on acceleration in proportion to the square of (distance from axis) / (wheel radius). E.g., mass halfway between the axis and the edge of the wheel counts 125% as much as non-rotating mass; 125% = 1 + (0.5 squared).

All this means is that slicks that are wider than necessary will actually make the car accelerate more slowly. Of course the whole point of drag racing is......to accelerate more QUICKLY than the other guy. So too-wide tires are dumb, and slow.

[Guest G Holding]

Don't forget the height also is critical...

[Ace-Garageguy]

Don't forget the height also is critical...

That's an excellent point too. Changing tire height (diameter) will have the same effect as changing gear ratos. One of the reasons the whole big-and-little look for hot-rods came about is that the dry lakes racers (especially before quick-changes were available, and available gear sets for a particular junkyard-axle were limited) could tune effective final drive ratios by changing rear tire diameters.

In drag racing, a tire that's too tall for the available torque will make the car bog off the line, while one that's too short will tend to spin and smoke and hook-up poorly and have the engine winding too tight through the traps.

You don't have a whole lot of diameter choices in scale, but there are enough vintage ones available to get the right look. I really don't know what's available in resin or other aftermarket.

Edited September 1, 2012 by Ace-Garageguy