26" vs 28" slick: pros and cons of each
09-25-2000, 10:40 AM
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Car: 2000 Trans Am
Engine: LS1
Transmission: T56
26" vs 28" slick: pros and cons of each
Can someone help explain what the advantages and disadvantages to each are?
I have 3.50 gears in my Ford 9", and Im figuring that the 26" are better sine they are not as tall but beyond that, what should I be looking for?
Thanks
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-86 IROC
Vortech stuffed EFI 406 in progress
-=ICON Motorsports=-
I have 3.50 gears in my Ford 9", and Im figuring that the 26" are better sine they are not as tall but beyond that, what should I be looking for?
Thanks
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-86 IROC
Vortech stuffed EFI 406 in progress
-=ICON Motorsports=-
09-25-2000, 11:59 AM
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What's up Guido? Well, i once read an article that said you only need 28" slicks for high horsepower applications like low 10's and in the 9's. The reason for this so that the tire has more room to absorb the shock and push you foward at the same time. Ever see Billy Glidden lauch? Done perfect. 26" tires are just about the average size for almost any application, but once you really get the horse, they dont absorb as much and instead of grapping and pushing you foward, the tire wants to spin on the rim or just spin period. When ever my car gets done, i will have 28" slicks by 10.5" wide. I know I'll need them. 
Hope this answered your question.
BTW, a 350 trans? i hope you have lots of money for rebuilds, it wont last long in your beast of a car, TH400 all the way.
Hope this answered your question. BTW, a 350 trans? i hope you have lots of money for rebuilds, it wont last long in your beast of a car, TH400 all the way.
09-25-2000, 03:01 PM
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well another aspect is that the 26 inch tire will affect your gear ratio differently than the 28" one.
The taller the tire the "less" gear you have.
So if you are running out of "gear" at the end of the quarter with a 26" tire then go to the 28" tire and you will have a couple more rpms there at the end!
Does this make sense?
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The taller the tire the "less" gear you have.
So if you are running out of "gear" at the end of the quarter with a 26" tire then go to the 28" tire and you will have a couple more rpms there at the end!
Does this make sense?
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3" custom FloPro Catback
14X3 K&N open element
15.6 best 1/4 mile before any mods
09-25-2000, 05:25 PM
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No flame intended, but 85cam you are wrong about your last statement. If you are running out of 'gear' at the end of the quarter mile, switching to a taller tire would make that even worse. You need to go to a numerically higher gear ratio or get a shorter tire (which will affectively raise the ratio) to get more rpms at the end of the track. Just FYI.... 
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09-25-2000, 05:32 PM
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85cam, I'm also assuming you are meaning getting higher rpms at the end of the track.
After re-reading your post I think I know where you might be coming from.....if you switched to a taller tire you would have more rpm to play with since you be crossing the line at a lower rpm which would give opportunity for a gear shift. If that's what you meant, my mistake...
After re-reading your post I think I know where you might be coming from.....if you switched to a taller tire you would have more rpm to play with since you be crossing the line at a lower rpm which would give opportunity for a gear shift. If that's what you meant, my mistake...
09-25-2000, 08:30 PM
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Car: 87 IROC L98
Engine: 588 Alcohol BBC
Transmission: Powerglide
Axle/Gears: Ford 9"/31 spline spool/4.86
You have 3.50 gears and 26" tall tires. Going to 28" tall tires would be like going to 3.25 gears (not exact but you get the idea).
Advantages of taller tire is that you have a larger contact patch on the ground. The amount of rubber on the ground is greater with a taller tire. You also have a taller sidewall which helps absorb the shock load of a launch. There is also more rubber on a taller tire. Larger curcumferance equals less rotations per mile equals longer tire life. At least for street use.
Disadvantages: It takes more power to turn a taller tire. 60 foot times will get slower. If the car is set up with the proper gears for 26" tires then 28" will slow you down.
The goal is to have the engine at red line in high gear at the end of the 1/4 mile. Usually the tallest tire you can squeeze inside the wheel wells is what you want. Then change the gearing at max out in the 1/4 mile.
My race car "had" 26" tall tires and 3.27 gears. I was shifting at 6400 and crossing the finish line at about 5500. I needed 3.90 gears for those tires. Since that wasn't available I went to 28" tall tires and 4.10 gears which did the same thing. I also could have gone to 30" tall tires and 4.56 gears but I got a good deal on the 28" tires. Now with the different gearing and tires I shift at 6400 and cross the finish line close to 6400. At least I almost did on one pass before the engine blew up
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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 results before the engine blew up
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
Advantages of taller tire is that you have a larger contact patch on the ground. The amount of rubber on the ground is greater with a taller tire. You also have a taller sidewall which helps absorb the shock load of a launch. There is also more rubber on a taller tire. Larger curcumferance equals less rotations per mile equals longer tire life. At least for street use.
Disadvantages: It takes more power to turn a taller tire. 60 foot times will get slower. If the car is set up with the proper gears for 26" tires then 28" will slow you down.
The goal is to have the engine at red line in high gear at the end of the 1/4 mile. Usually the tallest tire you can squeeze inside the wheel wells is what you want. Then change the gearing at max out in the 1/4 mile.
My race car "had" 26" tall tires and 3.27 gears. I was shifting at 6400 and crossing the finish line at about 5500. I needed 3.90 gears for those tires. Since that wasn't available I went to 28" tall tires and 4.10 gears which did the same thing. I also could have gone to 30" tall tires and 4.56 gears but I got a good deal on the 28" tires. Now with the different gearing and tires I shift at 6400 and cross the finish line close to 6400. At least I almost did on one pass before the engine blew up
------------------
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 results before the engine blew up
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
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