NORCAL TBSS

iTrader: (3)

Try to make me understand this.

i see you guys running 30 inch tall tires why?

I have 275 40 17 drag rads trap 112 mph and works perfect. 80 percent of the guys here are trapping less mph but they are running a much taller tire why??

Let me drop some numbers down for you guys maybe you can tell me what im not seeing.

The gearing in our trannys in 3rd are 1.0 and seeing that lets start from there.


Lets say you have 3.23 gears redline is 6000 rpms
with 275 40 17 top speed of 3rd is 140 mph
with 305 35 18 top speed of 3rd is 145 mph
with 295 45 17 top speed of 3rd is 152 mph
with 345 35 18 top speed of 3rd is 152 mph (28 inch tall tire)
with 305 45 18 top speed of 3rd is 159 mph (29 inch tall tire)

Lets say you have 3.42 gears redline is 6000 rpms
with 275 40 17 top speed of 3rd is 134 mph
with 305 35 18 top speed of 3rd is 138 mph
with 295 45 17 top speed of 3rd is 143 mph
with 345 35 18 top speed of 3rd is 143 mph (28 inch tall tire)
with 305 45 18 top speed of 3rd is 150 mph (29 inch tall tire)


Lets say you have 3.73 gears redline is 6000 rpms
with 275 40 17 top speed of 3rd is 123 mph
with 305 35 18 top speed of 3rd is 126 mph
with 295 45 17 top speed of 3rd is 131 mph
with 345 35 18 top speed of 3rd is 131 mph (28 inch tall tire)
with 305 45 18 top speed of 3rd is 138 mph (29 inch tall tire)


Now lets say you have 3.90
with 275 40 17 top speed of 3rd is 117 mph
with 305 35 18 top speed of 3rd is 120 mph
with 295 45 17 top speed of 3rd is 126 mph
with 345 35 18 top speed of 3rd is 126 mph (28 inch tall tire)
with 305 45 18 top speed of 3rd is 132 mph (29 inch tall tire)


Now lets say you have 4.10s
with 275 40 17 top speed of 3rd is 112 mph
with 305 35 18 top speed of 3rd is 115 mph
with 295 45 17 top speed of 3rd is 120 mph
with 345 35 18 top speed of 3rd is 120 mph (28 inch tall tire)
with 305 45 18 top speed of 3rd is 125 mph (29 inch tall tire)


My tbss is 4.10 gears and 275 40 17 on it and redline is 6500
at 112 mph im going thru the traps at about 6000 rpms which is perfect.

I see thes guys trappin like 105-110 running 28 or even taller tires... Just trying to understand why???? Your just throwing valuable time away by moving all that extra tire. You want to go thru the 1/4 mile traps on the top of 3rd not midway thru it.

Maybe someone can shed some light on this. If you trap 105-115 mph and have 3.73 gears dont see why you need anythign bigger than a 275 40 17. May look funny but if your going to spend your money on a wheel/tire combo get something that will make your truck run better not somethign that will add extra weight and wont put you in that sweet spot going thru the traps.


I can see taller tires for those guys running the 1/8 mile only but not 1/4.

I have mt drag rads and i ran a 1.7 60 foot time my 11.9 run and guy before me blew rear end and i was waiting there. My old sti wrx ran low 1.6 60 foot times and this truck at the street races launches just as hard. Great tire and its the lightest drag rad you can get in 17s.

Derek @ EDO

iTrader: (73)

What about with a 3.90 gear?

NORCAL TBSS

iTrader: (3)

added.

Derek @ EDO

iTrader: (73)

Sweet, thanks!

NORCAL TBSS

iTrader: (3)

derek what tires do you run on your truck and what is your trap mph?

Derek @ EDO

iTrader: (73)

I run the 28" Hoosier slicks, on motor I trap 108-109 on spray (125shot) 117-119
depending on the 60ft.

NORCAL TBSS

iTrader: (3)

yah for spray that tire is about right (dont know what your redline is at)

for a guy though trapping 109 a 28 inch tall tire is just killin him.

we did on my friends 04 silverado ran a 13.7@101 with a few bolt ons on a 305 45 18. he changed to 17 inch wheel and 275 40 17 ran a 13.32 same exact set up. Truck ran much better with that tire on it.

Derek @ EDO

iTrader: (73)

I agree 100 percent!

I shift at 6100rpms

For the turbo setup ill be shifting around 6200.
Hopefully ill have over 700RWHP with an 80e.
Im shooting for mid to low 10's. Im trying to see if i should change my tire size or gear ratio.

LowBlack99

iTrader: (3)

I would guess and I'm no expert, that tha taller/bigger tire helps to hook trucks with less weight over the rear axle? I've always heard a tenth of the line is worth 2 tenths in et? Also you can have a high trap speed and still blow the tires away on the line. Mathematic equations are good on paper but just like dyno's do not accurately simulate real world conditions. I can understand wanting to cross the line at the the peak of 3rd but is it at the expense of a few tenths off the line? We could all argue the point till were blue in the face but it all comes down to what works best for you combo. Also Take this into account? I have a stock 3.42 rear with a 29.xx tire, If I go to a 4.10 on a 29 then what would be my final drive ratio? Hypothetically 4.10 on a 29 would get me out of the hole faster? Now then a smaller tire would reduce my final drive ratio and in theory should get me out of the hole faster. But if I couldn't hook the smaller tire due to the increased gear ratio then my et would be ? Lower? Races are won on et not trap speed. There are Infinite tire/gear combos that work for some but not for all. It really just depends on your setup.

NORCAL TBSS

iTrader: (3)

if your shifting at 6200 and that 28 inch tall tire max in 3rd gear is 130 mph