tire height calulations
tire height calulations I changed my tire size due to the MT drought we have been having. I went from a 25.8 inch 315/35/17 to a 295/45/17 and its killing my track times. I'm about 2 mph slower on the 1/4 times. Is this normal? Where can I find a calculator that will let me see whats going on. I've either got to go back to shorter tires or restall the convertor or anybody else got any ideas?
Last edited by NC98Z; Sep 18, 2008 at 01:53 PM.
He now has a taller tire so a taller gear would just make the situation worse.
I you are getting great traction i would go bigger on the stall. But a bigger stall may also lower the mph, but should in return lower you et as well.
Did your actual et time get worse? Don't forget that air temp and humidity have a big factor on power.
I you are getting great traction i would go bigger on the stall. But a bigger stall may also lower the mph, but should in return lower you et as well.
Did your actual et time get worse? Don't forget that air temp and humidity have a big factor on power.
11 Second Club
Joined: Jul 2005
Posts: 1,089
Likes: 3
From: West Linn, Oregon
try the calculator in my sig it may help you figure out what is going on. It showed me that I had the same results running 3.73's and 28" (275/60 15's) tires then I would have running the stock size tire with 3.42 gears...
You change took you up ~ 2" as well, from 25.68" to 27.45", meaning you dropped about the eqivalant of a gear size, so that may be your issue and may cause shifting timing issues as well...
You change took you up ~ 2" as well, from 25.68" to 27.45", meaning you dropped about the eqivalant of a gear size, so that may be your issue and may cause shifting timing issues as well...
I have a tire queston as well sorry to invade your thread
I am using 26 inch et drags right now and I am wondering at 12 psi how much they grow on the big end compared to 28 inch et radials(17psi) at 130mph
will the difference on the gear calculator be the full 2 inches or less
I am using 26 inch et drags right now and I am wondering at 12 psi how much they grow on the big end compared to 28 inch et radials(17psi) at 130mph
will the difference on the gear calculator be the full 2 inches or less
He now has a taller tire so a taller gear would just make the situation worse.
I you are getting great traction i would go bigger on the stall. But a bigger stall may also lower the mph, but should in return lower you et as well.
Did your actual et time get worse? Don't forget that air temp and humidity have a big factor on power.
I you are getting great traction i would go bigger on the stall. But a bigger stall may also lower the mph, but should in return lower you et as well.
Did your actual et time get worse? Don't forget that air temp and humidity have a big factor on power.
Last edited by NC98Z; Sep 19, 2008 at 10:10 AM.
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11 Second Club
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From: West Linn, Oregon
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Verdad Gallardo I have a tire queston as well sorry to invade your thread
I am using 26 inch et drags right now and I am wondering at 12 psi how much they grow on the big end compared to 28 inch et radials(17psi) at 130mph
will the difference on the gear calculator be the full 2 inches or less
I am using 26 inch et drags right now and I am wondering at 12 psi how much they grow on the big end compared to 28 inch et radials(17psi) at 130mph
will the difference on the gear calculator be the full 2 inches or less
TECH Regular
Joined: Sep 2008
Posts: 425
Likes: 1
From: Scottsdale, Arizona
When I was drag racing I would use a lower gear like a 4.10 vs. 3.90. Then I found that I could use a high growth tire to make up the difference in gear ratio at the top end.
Now this being a door car and tire selection might be different too. I have had good luck running that way. My best times with a dragster of course was 6.97 @ 198MPH. Oh what fun that was.
Now this being a door car and tire selection might be different too. I have had good luck running that way. My best times with a dragster of course was 6.97 @ 198MPH. Oh what fun that was.
Last edited by mebuildit; Oct 2, 2008 at 09:46 AM.
