hello everyone .
I just put a new set of Mickey Thompson 29.5X10.5W-15's on my car,and they will not hook for sh&%.
I have been running 29X11" hoosiers,at 11.25 lbs ,and they were working til I wore them out.
Now ,I have run the M/T's 29.5X10.5X15 {without the W} in the past ,and they work good.
here is the question...should I be running less air pressure in the W's because of the stiffer carcass{catalog description},and if so how much less.
in the past ,if i dropped bellow 11 lbs ,the car would get very squirmy,almost undrivable ,on the big end of the track,and i only run 1/8th mile.
I am going to test and tune sat at bowling green,and need a starting point....i am thinking ten pounds ,then 1 lb at a time after that....any one with some experiences here would be very helpful!!!
Thanks in advance
Craig

forgot to put in my faves

Don't no how fast your car is,but my car runs a best of 9.67@136 at 9 1/2 lbs.at 3350 on 10.5w's

I run 14 lbs in mine (31 x 10.5 x 15 W )

ps,,,you racing at the Hot Rod event in Bowling Green this weekend ?

if so,,what car are you running ?

I might try and make it there on Saturday....

Doug

I have 10.5W-31's and on Sunday with 10psi, I got a 1.35 60 foot (spinning)then when I dropped it to 9.5psi it ran 1.31 60 foot.

Last pass stayed with 9.5 psi and raised the transbrake launch up to 3,400rpm and got a 1.28 60 foot and carried the front tires a while...

The stiff sidewall seems to like a little more hit???

Cheers,

Arnie

ok
My car has run a best of 6.82 at 98 mph in the eighth.
I have got to wonder how there can be such a variance in the pressures run, on these tires and they still work.I had no luck at all getting any kind of launch.
when i normally stage with the wrinklewalls( old tires),i can get 3000-3300 stall easy ,now with these w's ,all i can get is about 2500.
the one time i tried to "get it up " to 3000,the car creaped through the lights,and the fronts pushed ,the car did not pickup the front end,and it fell off by 4 hundredths.
this car sixty foots(with old tires)between 1.43-1.47 pretty consistantly,but with these m/T's the best sixty foot is 1.49,and i am leaving 500rpm too low.
wierd stuff?
I cant go test at the HOT ROD reunion so that is off....going to test at clarksville wed nite instead.
i think i am gonna end up buying a new set of hoosiers and take my beating on these M/T,s,they just dont want to work.
i never thought it would make this much difference.
Here is my combo:
67 Barracuda,
440
ported 906's
12.0-1 compression,
edelbrock performer rpm,
demon 750'
727...manual valve body,
4.56 dana with superstock springs and a snubber,
3280 lbs with me in it raceweight,
best ET> to date 6.82 @ 98.05 mph
over 1500 passes and counting....
Now i am stumped on air pressure,never had a set of slicks that wouldnt work.????

i cant get this picture up try again

i cant do it.
I cant work a computer for ........

ok

"when i normally stage with the wrinklewalls( old tires),i can get 3000-3300 stall easy ,now with these w's ,all i can get is about 2500.
the one time i tried to "get it up " to 3000,the car creaped through the lights,and the fronts pushed ,the car did not pickup the front end,and it fell off by 4 hundredths."

This has nothing to do with the tires. Something else has changed.
The M/T W series slicks are excellent tires. We have gone 6.67/218 on their 33/10.5W-16's.

How many passes on those tires

nothing else has changed...bob
tires now have 6 passes on them
i believe my stiff rear suspension needs the softer sidewall to work correctly,but we all have opinions,eh?
I was just looking for some experienced advise on these "w" tires.
THANKS FOR THE ADVISE,EVERYONE...
looks like i have to wait til next weekend to test ,as they are haveing a fair at the local track this week.

trying to follow along here...
what air pressure are you runninig in them?
what is the psi in the stage before a run.?
what is the psi in the pit just after a run?

as far as your stall rpm..thats prolly more to the baro change and or jet tuneup ...
i can tell when my car is on or off tune.
buy how fast and the total rpm it reaches on the trans brake..for instance..
so tune up or Atmosphere air is prolly the culprit as to the rpm at stall..
what is your air pressure?

i run these tires and run between 11 1/4 psi to 12psi at night or in cooler weather..
1lb changes in air pressure in a slick is alot..
id do 11psi to start and slowly work up from there
check psi before and after to see the change..
technically the after a run pressure is more pertainent...
i wouldnt run less than 10.5 in any tire on a car 3400 lbs...by the way..
cheapst

i agree,it does not seem likely the tires are responsible for the stall speed change.
it was VERY hot(95 degrees,85-90 % humidity.)
I was just venting ,more or less,about my bad luck with the weekend.
I was running 11.5 lbs ,before the run.
My partner was watching ,and the car is just not acting like it used to.
I am really only running off by a few hundredths,the heat was the real factor on my slow times,but the car is varying too much to win.
I am going to test next wed.,hope to get the air pressure dialed in.

Hey everyone,
Well ,I made it to a test abd tune,and got the tire pressure figured out.
I ended up at 9 lbs,and the car is acting like it did before,right back to normal.
I think I can drop it another lb if it is needed,as I had no ill handling down track from not enough air.
It turns out we had too much timing in it,and that contributed to the bad performance at the track last time.Thought we were at 33 degrees and it was really 37.

the car really likes it at 35 degrees,and thats were its at now.
Going to Owensboro tomorrow,(windy hollow)hoping to win some money so I can race out the rest of the summer for free!!!
Thanks for all the info, and Bob ,you were right about there being something else wrong than the tires!!