My 4.10's are going to eat up my street tires at the track and I would like to run some drag radials or slicks...

If drag radials, what's the biggest that would fit without too much banging? 275/15, 315/15?

If slicks, I'm not familiar with inches as far as slicks are measured in, so what would you suggest?

I guess it would be smarter to mount some drag radials on my current 15x7 wheels since my tires are about 50% and then I wouldn't have to buy new wheels with the slicks...how long do drag radials last on the street? (I don't drive the camaro in bad weather, so that's not a concern) For now, the radials will have to do, because money is obviously a set back...

Thanks.

EDIT: I just realized my topic is kinda off, since I decided that drag radials would probably be a smarter move...sorry about that...also, my 350 doesn't have anything more than 350hp, so take that into consideration as well.

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-'82 Z28 (350, carb'd, 4.10's, Super Comps, plenty of goodies)
-'91 S10 (nice daily driver)

AIM me at: Unitedhope
ICQ me at: 77979548

[This message has been edited by crazeinc (edited September 11, 2000).]

 

One of my friends has had pretty good luck with 26x10 inch McCrearys. He has them set up on 15x7 rims and they just clear. They hook better than ET Streets, on the street. They're a little wide, so they balloon a little, but with 4.10s it won't matter. The best thing about them is, if you have a dirt track nearby, you might be able to get them for free. Just dig through the used piles in the infield. I've gone through 3 sets of 27.5 x 10.5s this summer, and all I've paid for, is mounting and balancing.

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91 Firebird Formula. Converted to carb. Holley 750. Forged Flat top pistons. 10.5 to 1 compression. ZZ-9 Cam. Ported L98 Heads.
150 shot NOS, 700r4 w/ 3000 rpm converter and 3.73s in the back. Headers w/ full dual exhaust. 27.5 inch McCrearys. (free slicks)
12.98 @ 106 Natural,
11.83 @ 113 NOS.

 

You can fit 26x10 slicks on 15x7's??? No way, that's sweet...McCreary's, eh? better go look for some

 

The key to having the proper sized tires is the backspace. My rims are 15x10 with 5 1/2" backspace. With rear disk brake the park brake cable bracket is about 1/4" from the rim. If I remove the park brake I could probably go to a 6" backspace. Depending on the tire size I would then have to do a little inner fender massaging with a hammer.

For the last 2 seasons I ran 26x10.5 MT ET streets. The width is measured at the sidewall since this is a DOT tire. There was no problem fitting these tires. Even if have poor backspacing the tires will only stick outside the fenders unless you have about a 2" drop.

I now have 28x9 MT drags. These are measured across the tread. After installing them I figure I can still go to a 28x10 or 28x10.5. Doing some measurements I think the tallest tire you can stuff under the fenders is 30" tall. A 9" wide would have to do or more fender massaging would have to be done.

Metric size conversion is width x ratio / 2540 x 2 + rim size.

275/60R15 would be 27.99 or 28" tall.

Tires height and gears go together. When you see a race car with 5.13 gears in it, it also has 33" tall tires. Using the same low gears on 26" or 28" tires changes the entire powerband of the engine.

When you can't go any wider then go higher and compensate with gearing. My 26" tall tires were driven with 3.27 gears. They needed 3.90 gears but that wasn't an option. I had 2 choices to get the perfect gear/tire combination. 28" tires and 4.10 gears or 30" tall tires and 4.56 gears. I got a deal on the 28's so I went with them. The tallest tire is best because it also makes the biggest contact patch on the ground length wise. The bigger that contact patch, the more rubber to grab the pavement. A wide 26" tire isn't as effective as the same width 30" tall tire. Just as long as the gearing is there for the 30" tire it will do much better.

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Stephen's racing page

87 IROC-Z Pro ET Bracket Race Car and knocking on the SuperPro ET class
383 stroker (carbed) with double hump cast iron heads and pump gas
Best ET on a time slip: 11.857
Best corrected ET: 11.163
Best MPH on a time slip: 117.87
Best corrected MPH: 126.10
Best 60 foot: 1.662

Racing at 3500 feet elevation but most race days it's over 5000 feet density altitude!

Member of the Calgary Drag Racing Association

 

Thanks for the info Stephen, I'm trying really hard to understand all of what you wrote, but there's a lot of info in those paragraphs

Do I necessarily need more backspacing than I currently have if I ran a 26x10.5 (like your old seasons) in order for it to fit? I guess I'm trying to get away with more traction without having to pay for a whole lot...

otherwise I would just buy some Weld's and get 28x10 slicks with 6" backspacing and be done with it, but this isn't the case right now.

Thanks for the info, again.

 

If you wanna stuff a 10.5 tire under the wheel well you will need 5.5" back spacing.

Steve

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Spohn Performance, Inc. - F-Body Suspension Specialists

 

You should run the smallest tire you can to reduce the unsprung (also rotating and rolling) weight. I run a 28x9 ET Drag which I can't even spin off the line.

My friends NMCA super street car runs mid 8's (1.26 60ft) on a 10.5 tire (@3400 lbs).

Miles

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88 427 Camaro
12.18 @ 113mph 1.75 60ft
http://www.geocities.com/MotorCity/Track/5604/

 

thanks for the info guys....I can get some 28x9x15 slicks for $200 brand new, but I guess that still means I'll need the proper backspacing...

 

sorry for my lack of knowledge, but is it possible to put more backspacing on a wheel, or do you have to get one already made with a certain backspacing?

If it's the first choice, how much would it be to jump from the stock backspacing to a 5" backspacing?

Thanks again.

 

MT recomends an 8" rim for the 28x9 tires. I have mine on 10" wide rims and 5.5" backspace. They fit really well so a 7" or 8" rim will fit better.

The backspace is built into the rim. lets say you have an 8" rim with 4" backspace. That would put it right in the center. You can't stuff it any further under the car (5" backspace) without cutting the center out of the rim but you can pull it out with spacers (3" backspace). Backspace is measured from the edge of the rim down to the center section where the drum/rotor ride against.

Pull a wheel off. Put a straight edge against the drum/rotor. Measure off the straightedge to the inside. The inner fender is about 6 inches away. The caliper bracket for the bark brake is about 5.75" Also measure to the outside to see how far the fender lip is away. That will give you an idea on how large a rim and tire that can fit. Left and right sides are different since the diff sits slightly offset so if you go to the max on one side, it may rub on the other.