Front tire pressure adjustments - Page 4

gsa612 · 05-17-2018, 02:44 PM

Quote:

Originally Posted by tony wood

ok this is gonna sound stupid but try ankle weights used them on my stick super stocker was going 10-15 red try 5pd weight

I think that would be taken as loose ballast (illegal).You would need a MD's cert.calling it some form of prosthetic...lol

Tom keedle · 05-18-2018, 04:55 PM

Quote:

Originally Posted by tony wood

ok this is gonna sound stupid but try ankle weights used them on my stick super stocker was going 10-15 red try 5pd weight

damn! never thought of that!

I gotta try it

Tom keedle · 05-18-2018, 05:00 PM

Quote:

Originally Posted by gsa612

I think that would be taken as loose ballast (illegal).You would need a MD's cert.calling it some form of prosthetic...lol

would it be any different if it was 5lbs of lead in a shoe?

Jim Caughlin · 05-18-2018, 06:03 PM

I would think there is grounds to consider that the whole front tire pressure affecting RT's might be somewhat of an urban legend. As a test, I put my car on a flat floor in the shop and put a 3" block in front and behind the front tire at the 40PSI that I normally run and measured the distance between the blocks. I then started lowering the pressure in increments and remeasured the distance. I got all the way down to 15 PSI (which I thought was probably an unsafe pressure to actually race at) and the distance between the block had barely changed. Maybe the 3" height wasn't quite right but it has to be pretty close to the correct height for the photocell. Based on that, I kind of wonder if the real life change in RT is in the drivers head and not a result of the rollout. If you doubt my test, try it yourself.

Jim Caughlin
SS6019

Dave Muller · 05-18-2018, 06:08 PM

Someone has a detailed mathematical analysis of this online that reached the same conclusion. I think you need to focus on other parameters rather than tire pressure.

The Hawk · 05-18-2018, 09:42 PM

A brake pressure switch will work for some, not for others. When I tried one on my Skyhawk, I found out I don't pull my foot up consistently off the brake pedal. Way too much variable with reaction times, went back to button in pedal. Was between .008 and .036 in six runs today testing.

superstock45 · 05-18-2018, 11:03 PM

Trust me from 40-17 works. It's worth about .012-.015

FED 387 · 05-19-2018, 09:10 AM

yep -- it does work ---not sure how much on everyone's car but on 3 specific cars I have seen it will slow down the reaction time--- not going to give you any numbers but it did change the RT

Ed Wright · 05-19-2018, 10:15 AM

I would make sure that 17 psi tire was on the inside at the turn off.

Ed Carpenter · 05-19-2018, 10:32 AM

Quote:

Originally Posted by gsa612

I think that would be taken as loose ballast (illegal).You would need a MD's cert.calling it some form of prosthetic...lol

Was told to do this many many years ago by Tony Cowell.

05-18-2018, 06:03 PM	#34
Jim Caughlin Senior Member Join Date: Mar 2002 Location: Woodburn, Or Posts: 685 Likes: 82 Liked 805 Times in 245 Posts	Re: Front tire pressure adjustments I would think there is grounds to consider that the whole front tire pressure affecting RT's might be somewhat of an urban legend. As a test, I put my car on a flat floor in the shop and put a 3" block in front and behind the front tire at the 40PSI that I normally run and measured the distance between the blocks. I then started lowering the pressure in increments and remeasured the distance. I got all the way down to 15 PSI (which I thought was probably an unsafe pressure to actually race at) and the distance between the block had barely changed. Maybe the 3" height wasn't quite right but it has to be pretty close to the correct height for the photocell. Based on that, I kind of wonder if the real life change in RT is in the drivers head and not a result of the rollout. If you doubt my test, try it yourself. Jim Caughlin SS6019

05-18-2018, 06:08 PM	#35
Dave Muller Member Join Date: Apr 2014 Location: Mesa, AZ Posts: 497 Likes: 162 Liked 223 Times in 73 Posts	Re: Front tire pressure adjustments Someone has a detailed mathematical analysis of this online that reached the same conclusion. I think you need to focus on other parameters rather than tire pressure.

05-18-2018, 09:42 PM	#36
The Hawk VIP Member Join Date: Mar 2003 Location: Littleton,Colorado Posts: 1,194 Likes: 0 Liked 249 Times in 109 Posts	Re: Front tire pressure adjustments A brake pressure switch will work for some, not for others. When I tried one on my Skyhawk, I found out I don't pull my foot up consistently off the brake pedal. Way too much variable with reaction times, went back to button in pedal. Was between .008 and .036 in six runs today testing. __________________ Lane Weber It`s Not What You Drive That Wins....It`s How You Drive It

05-18-2018, 11:03 PM	#37
superstock45 Junior Member Join Date: Nov 2008 Posts: 30 Likes: 0 Liked 0 Times in 0 Posts	Re: Front tire pressure adjustments Trust me from 40-17 works. It's worth about .012-.015

05-19-2018, 09:10 AM	#38
FED 387 VIP Member Join Date: Jun 2006 Posts: 3,421 Likes: 529 Liked 333 Times in 180 Posts	Re: Front tire pressure adjustments yep -- it does work ---not sure how much on everyone's car but on 3 specific cars I have seen it will slow down the reaction time--- not going to give you any numbers but it did change the RT

05-19-2018, 10:15 AM	#39
Ed Wright Veteran Member Join Date: Mar 2005 Location: Sand Springs, OK Posts: 8,132 Likes: 896 Liked 390 Times in 170 Posts	Re: Front tire pressure adjustments I would make sure that 17 psi tire was on the inside at the turn off. __________________ Ed Wright 4156 SS/JA Last edited by Ed Wright; 05-19-2018 at 11:13 AM.