This is a quick follow-up post on the tire swap from 325/50-15 M/T ET Radials to the Hoosier 18155 10.5 x 28 stiff sidewall bias ply slick (CO7 compound).

As of today, the car has 12 passes with the new Hoosier slicks on the car. Initial results were promising although the incrementals all seemed slower than I would have liked to see.

Well, all 12 passes were in bad air, hot/greasy track conditions and so far the tires have yet to show any signs of tire spin. They seem to be a very capable tire under marginal track conditions.

Here's four sample passes from today at my local track (Mason Dixon Dragway) which is far from a well prepared starting line.

12:06 pm (short shifted 1-2 by accident)
1.346 60'
4.016 330'
6.249 660'
109.85 mph
8.186 1000'
9.832 1320'
136.59 mph
87.1 degrees
40.3% humidity
60.1 dew point
29.45 barometer
2553' D/A

1:25 pm (proper shift points)
1.346 60'
3.992 330'
6.216 660'
110.01 mph
8.154 1000'
9.805 1320'
42.14 mph (bad data)
88.3 degrees
39.2% humidity
60.4 dew point
29.45" barometer
2368' D/A

2:44 pm (short shifted 1-2 again) :clonk:
1.350 60'
4.008 330'
6.237 660'
109.67 mph
8.178 1000'
9.832 1320'
135.74 mph
84.0 degrees
45.7% humidity
60.8 dew point
29.43" barometer
2395' D/A

3:36 pm (proper shift points)
1.348 60'
3.995 330'
6.217 660'
110.09 mph
8.151 1000'
9.800 1320'
136.30 mph
84.3 degrees
42.0% humidity
58.7 dew point
29.42" barometer
2405' D/A

As you can see, the car is quite consistent now after the tire swap. If the driver was paying better attention to his driving all four would have been much tigher in consistency.:o

I must say this tire gave me really good confidence on a track that normally makes me nervous while staging wondering if the car will hook or spin. Ever pass today had pretty high wheels up launches even considering the less than optimal air conditions.

The biggest down side for me is the fact that the ET has slowed as well as losing some MPH from the radial. Stability on the top end isn't great, but I'm getting used to the bias ply float again.

If the car had 4.33 gears, these tires would likely run closer to what the D/R tires used to, but for now I'm gonna leave the 4.10's in and deal with the car running slower than I'm used to. It's consistent and hooks on hot greasy tracks which for me means they met there highest priority or goal.

Thanks go out to Ed for urging me to go with the Hoosier over the M/T stiff sidewall slick.

I'm guessing there may be a slight break in period with the tire. The first few passes had the car 60's in the 1.37 to 1.38 range. The first T&T runs at PINKS MIR on Friday saw 60's in the 1.39-1.40 range. Then first qualifying pass Saturday for the show, BAM a 1.35. Move to today at Mason Dixon with the runs posted above and all but one in the 1.34 range. Kinda curious to see what they might do when the fall air/track conditions come around.

EDIT: tire pressures today were set at 16 psi cold, around 17 3/4 psi hot.

wow...16 lbs of pressure??? It sounds like that would hook on wet grass.

It sounds like they are working for you Todd, I too will be curious how they work when the good air comes back around, compared to the drag radials. I managed a 1.40 this morning, track temp was already 130*, then went 1.41-1.43 the rest of the day, won two rounds, went .001 red in the 3rd and watched the rest of the day.

Were definately in some of the bad air months, although this does seem a bit early in the season for it.

Air quality sure does seem to affect the cars performance not only in ET/MPH, but how much torque/power is there to 60' well. I'm able to see a noticable difference in power on the data logger by how high or low the converter is flashing for a given days air conditions. Have been as high as 6150 rpm on the best air days, as low as 5750-5800 in the current bad air.

Good to hear that they are working so well for you. The Hoosier stiff wall has been one of the best things I've put on my car. I'll take consistency over lower e.t. any day when bracket racing.:thumbsup:

Were definately in some of the bad air months, although this does seem a bit early in the season for it.

Air quality sure does seem to affect the cars performance not only in ET/MPH, but how much torque/power is there to 60' well. I'm able to see a noticable difference in power on the data logger by how high or low the converter is flashing for a given days air conditions. Have been as high as 6150 rpm on the best air days, as low as 5750-5800 in the current bad air.

What suspension mods due you have? Are you leaving on the trans brake or foot braking it?Thanks...Allen

What suspension mods due you have? Are you leaving on the trans brake or foot braking it?Thanks...Allen

Front suspension is basically stock with Global West Del-A-Lum bushings, Moroso springs, QA1 double adjustable shocks.

Rear suspension has Wolfe Racecraft double adjustable lower control arms as well as their spherical housing bushings and single anti-roll bar. The upper control arms along with a special instant center relocation devide I designed & built. Rear coils are a set of Moroso springs, two sets with the like coils matched (lighter 120 #/in installed) and QA1 double adjustable shocks.

Car is launched off the footbrake at 2500 rpm.

Good Info Todd..

When I look into different tires I will surely be talking to you for some advice and more experience..

Tom

Front suspension is basically stock with Global West Del-A-Lum bushings, Moroso springs, QA1 double adjustable shocks.

Rear suspension has Wolfe Racecraft double adjustable lower control arms as well as their spherical housing bushings and single anti-roll bar. The upper control arms along with a special instant center relocation devide I designed & built. Rear coils are a set of Moroso springs, two sets with the like coils matched (lighter 120 #/in installed) and QA1 double adjustable shocks.

Car is launched off the footbrake at 2500 rpm.

Could you pm me the info on the special instant center relocation? Im trying different things with mine and trying to get my 60 foot down. I have to run a 275 radial to run in a class I run and having some issues.

Good Info Todd..

When I look into different tires I will surely be talking to you for some advice and more experience..

Tom

Sure thing Tom. It's still early in the usage of these, and as time goes by I'm sure to learn a bit more about how they perform under differing conditions.

Could you pm me the info on the special instant center relocation? Im trying different things with mine and trying to get my 60 foot down. I have to run a 275 radial to run in a class I run and having some issues.

Don't really have much to share other than they work just like any of the No Hop style bars from Dick Miller Racing or Art Morrison. Mine are just mounted to the frame instead of the rear.

With the 275 tire, front end travel (and ride height) is critical as are shocks, converter, gearing, rim width, tire pressure and in higher power applications, potentially needing to use a timing retard off the line.

Hi Todd,

Great info and results here.

Could I ask why you chose the stiffwalls?
How are they wearing so far?

Have used up many Hoosiers over the years.The DO5 compound was too soft for the heavy cars. We've had feathering and balling problems with them in the past. The average Hoosier tire may have lasted us 45-50 passes. Always a great traction tire but didn't last long.
Last year we switched to Goodyears with good results. Still have some feathering but regular rotation keeps them in shape.

It's almost time to replace the Goodyears now and saw your posts on the new Hoosiers and have heard of other good results with the D06 compound. Maybe a good time to switch back to Hoosier.

Thanks

C07 will get it done, if you dont want to use radials, the stiff sidewall is the next best thing.

Hi Todd,

Great info and results here.

Could I ask why you chose the stiffwalls?
How are they wearing so far?

Have used up many Hoosiers over the years.The DO5 compound was too soft for the heavy cars. We've had feathering and balling problems with them in the past. The average Hoosier tire may have lasted us 45-50 passes. Always a great traction tire but didn't last long.
Last year we switched to Goodyears with good results. Still have some feathering but regular rotation keeps them in shape.

It's almost time to replace the Goodyears now and saw your posts on the new Hoosiers and have heard of other good results with the D06 compound. Maybe a good time to switch back to Hoosier.

Thanks

The stiff sidewalls were chosen due to vehicle weight and wanting the sidewalls to last longer. Also the stiff sidewall seemed like a good compromise between the regular bias and the radial (either slick or D/R).

Haven't looked, but I doubt there's any visible wear to the tread. I try to keep burnouts as short as possible.

Speaking with Hoosier, they felt I should be able to get 60-80 passes on the tires, possibly more.

Pics from this past Sunday.

http://i.pbase.com/o6/78/220978/1/80438510.DL8AxLpC.DSCF9351.JPG

http://i.pbase.com/o6/78/220978/1/80438511.Ip67FEzy.DSCF9352.JPG

http://i.pbase.com/o6/78/220978/1/80438515.YEbl0AuC.DSCF9353.JPG

http://i.pbase.com/o6/78/220978/1/80438516.QFadhlqP.DSCF9354.JPG

BTW, after this race at Mason Dixon, several racers complained about the start line condition and lack of traction. This one of the first times in quite some time that I wasn't one of them. Feels to good to ba able to make consistent runs on a marginal track. While I really do like the D/R tires, I'm convinced at the ET range I'm running, they are the wrong tire for the job if you have to race on sub-par track conditions.

Like many racers, I don't much care for losing ET & MPH with a parts change, but sometimes it's imparative to do so in an effort to get down a tricky track surface.