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Author Topic:   Choosing tires???
Eljojo
Member
posted November 11, 2002 09:45 PM
Our track has a fairly open rule on the tires the pure stocks run. It has to be a DOT radial with a speed rating less than "H". What would you suggest--go for some honkin' 275/60/15's or stay with the smaller sizes say 225/60/15 to reduce sidewall flex? We've got a 7" wheel rule. The track is usually tacky and fast, high banked 4/10ths red clay. Suggestions please...


racer17j
Member
posted November 11, 2002 10:30 PM
we used to run 235'70/15 firehawk ss when we had that type of tire rule


snowman
Member
posted November 12, 2002 02:30 AM
Hi Eljojo, I have never been in your exact position, that is, never had a wide variety of tires to choose from.......The track has always had more limits........ Speaking from limited experience, here goes........

At first glance, the answer seems simple enough.......Go with the wider,low profile tire......for best performance.

Considerations for the height......Gear ratio, a smaller tire means more RPM for the same speed......Do You need more or less RPM ? A taller tire will have more sidewall flex........(not particulary a good thing).....and will need more air presure to keep it on the wheel.

Considerations for the width.......(for now lets assume that wider is better)........ In my mind, the 7 in. wheel is the problem....I have not mounted a 60 series tire on a 7in. wheel......I suspect that by the time you had enough presure in it to keep it on the wheel,the tread would be convex........You may be better off going with something a bit narrower......(but if you have one laying around, mount it up.....see what it looks like)

Some years ago, I became interested in racing when my employer built a car.......At the time, the track tire was a 10in. asphalt take-off.....the tire compounds were in the 60's, with a soft sidewall......

We found some tires with softer compounds, but much stiffer sidewalls........Much more economical.......so we ground off the compound numbers......and ran our "bootleg" tires.......

The driver smoked the competition......our conclusion, The softer (but stiffer) tires were better.......The problem with our "conclusion" was.....Well, it was wrong....lol We should have concluded that it was just better for this driver.......We sold some tires to the other guys.......and, none of them did as well with the stiffer tire as they had with the more flexible tire............

I should add,that this tire is very stiff.....stiffer than DOT tires......

Now the interesting part, The track has since allowed IMCA tires......so the drivers have a choice.....10in. Hoosiers or the IMCA............Seems like a no-brainer, go with the 10in. ......Right??? Well, most of the guys who switch to the IMCA tires don't go back to the "better,wider tires".

It appears that on some tracks, the narrower tire will "bite",while the wider tire will skate across the bumps.....So, on dirt,wider is not always better......

It was not my intention to babble so much but, there is much to consider.....I'm hoping that somewhere here there is something that helps.

I have a bomber, enduro type car. Rules say max. width 70 series......I run a 225/70/14.....as I want more RPM..... On my streetstock.....I run the Hoosiers.......

My best guess for you.....wide low profile...........A set of Goodyear Eagles would be so nice...........

There are tools in the tool box that you can use to help determine (rpm wise),what you should use........

Best of luck to You,
Snowman


wrenchjockey
Member
posted November 12, 2002 01:43 PM
Two words.....Cooper Cobra. 'Nuff said.


fairlaniac
Member
posted November 12, 2002 08:38 PM
We thought we'd try the Cooper, only to find it 15 durometer points (Shore "A" hardness) harder than the Firehawk (now Indy 500). We picked up an interesting tire for our last race of the year. A Goodyear unidirectional Police issue tires 225/70/15, a hardness of 45 durometer.

------------------
Doug
"Lift for a second, that's where you'll finish!"


hoosier_baby_3D
Member
posted November 12, 2002 11:42 PM
In our purestock class, we have to run 8" Hoosiers. They will not allow us to run anything else.

------------------
"Blood, Sweat, and Gears"


jesse
Member
posted December 07, 2002 04:13 PM
i've run cooper cobra's for five years and they seem to hold up better than any other tire brand out there.


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