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Tires, tires, tires….

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March 2009
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Today we talk about tires, since tires have been such a hot topic the past few months I thought I would look at the tires for each track as we come to them, this week it’s Martinsville short paperclip shaped track with really tight turns. Long straightaways and I mean really tight turns….. did I say the turns are tight?

Ok let’s look at what Goodyear is bringing to the track this week.

Tire codes for this week are the same for both cup and trucks,: Left-side — D-4108; Right-side — D-4230 NASCAR has set the inspection pressure at 25psi. They do this so that regardless of set up or truck make they ass sit on the scales the same way. The truck series will have Wrangler on the side and the cup cars will have Eagles on the side but it is the same tire.

Tire Circumference: ( or “roll out”) Left-side — 87.3 in.; Right-side — 88.6 in. What this means is the right side tire is 1.3 inches bigger around than the left side, if you remember back a few stories I explained the Styrofoam cup as one end is bigger than the other so it rolls in a circle the same thing apply’s to the tires on the race car by making the right side bigger it makes the truck want to turn to the small side.

Tire Pressure Here is where teams really vary from one to the other. Goodyear has suggested that teams run Left Front — 10 psi; Left Rear — 10 psi
; Right Front — 23 psi; Right Rear — 22 psi as a minimum now teams will watch tire temp’s and adjust the pressure as needed. Looking to get even tire temp’s across the surface of the tire.

This left-side code (D-4108) is the same one run by these teams at Martinsville last season .and they didn’t really have any issues from them so I don’t see this tire being a issue. . . This right-side code (D-4230) is brand new to the Goodyear tire lineup, it has a little different compound to help get more grip from the tire. This is also the same tire that Goodyear will run on all the road courses this year.

The pit window will be determined by fuel mileage more so than tires this week.

This track is very hard to get around fast, it takes a balance to the car that allows it to roll thru the center of the corner and give it good drive off, but it also has to get in the corner good to keep drivers from getting in under you “rootin” you up out of the groove.

If someone gets in the 19’s here they are moving! Look for times in the 19.6’s-19.7 to fill up the top ten spots.

There were 48 teams signed in to run but the car of Mike Garvey withdrew so it will be 47 cars trying to make the 43 car field.

Ok if you got a question on tires or handling now is the time to bring them up! I will do my best to answer them all. I have set up an email if you want to send your questions to me… it is…

If you want to ask .. ask away I would love to try and answer your questions.

Now lets go watch practice

the dr.



  1. Fletch says:

    dr. great example by using the styrofoam cup example. Im wondering if this extra grip will increase engine RPMs or have any negative affects on the brakes. Usually, extra grip means faster speeds. Should be interesting.
    For example, Kurt B turned the fast lap last time I looked. Now, didn’t he have past engine trouble due to the car going faster with higher RPMs than what they had figured for the gear package? How many blown engines or /& failed brakes will we see this weekend?

  2. drflavio309 says:

    no fletch I dont think we will see any grip issues at with this tire….. now on the blown motors or brake failure.. that is a different story!!!
    the dr.

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