33 car penalties

After being a non-event (The 33 car from Richmond was “just barely legal” and NASCAR was checking with RCR to make sure they didn’t have a mistake on their build sheet) for a couple of days, the situation changed today when a 150-point, $150,000, 6-week crew chief/car chief suspension was announced based on violations from the New Hampshire car.

The primary part of the penalty (meaning the part besides actions detrimental to stock car racing) was

33 car body location specifications in reference to certified chassis did not meet #NASCAR-approved specs

The chassis is the tube frame that makes up the skeleton of the car. NASCAR specifies the chassis down to the exact size tube, wall thicknesses of the tube, and precise location.  Prior to hanging the body, each chassis must be taken to the NASCAR R&D Center to be verified, which is done using a Romer arm.  The chassis is then tagged with RFID tags that are scanned at the racktrack to ensure that no changes have been made.

After the chassis is certified, the team can hang the body.  Instead of making measurements of the body directly, certain points are called out by their position relative to spots on the chassis.  The violation was in the position of the bodywork, which suggests that any advantage that may have been gained was aerodynamic.  A violation of the chassis might have been dealt with even more severely because the chassis is the primary protection mechanism for the driver.  RCR confirmed in their statement that the body was too high relative to the chassis – something that one could argue might have provided an aerodynamic advantage by putting the spoiler up further in the air.

If this is the same issue that their Richmond car received such intense scrutiny for, it makes sense.  Cars are built weeks ahead of time, as the hauler has to get them to the race track Thursday night, so it is likely that the body was already hung on the New Hampshire car by the time NASCAR told RCR that there was an issue with the Richmond car.

That moves Bowyer from first to last in the Chase, and leaves him without two very important members of his crew for the next six weeks.

UPDATE:  RCR reveals that the out-of-tolerance measurement was 60 thousandths (0.06) of an inch.  For reference, a sheet of paper is 0.004 inches, so 60 thousandths of an inch would be 15 sheets of paper.  They also will argue in their appeal that the problem was created by the tow truck driver who pushed the #33 to Victory Lane after it run out of gas.

@bobpockrass reports that the general tolerance on the measurement in question is 70 thou, which means that the car was 0.13 inches off – more than an eighth of an inch.  If you’re trying to be ‘just legal’, you don’t miss by 1/8″.

Check back:  More as it develops.

Great post from Dustin Long on the inspection process.

An earlier post from me (on the old stockcarscience.com site) about the tolerances and Hendrick Motorsports’ situation last year.


  1. Great information! Thanks. Didn’t know NASCAR uses RFID chips on the chassis. Boy the rule book is pretty tight.

  2. What would be the margin of error of the measurements? How often is their equipment calibrated? Why were the RFID chips and the “Claw” not accurate enough at the track? If NASCAR is going to be this precise they better be this precise with all 12 cars during the Chase.

  3. Most engineers will tell you that .006 over the entire surface increases proportionly. They knew what they were doing.
    Explains why Harvick and Burton also made the chase. Wonder what Budweiser thinks?

  4. Welcome back. Thought you had retired. Have not been able to get to the vidios (not computer literate enough.) Hymie Escalanti (sp) put out a series of vidios many years ago trying to do interest students in math and science also.

  5. Trying to get my contacts at the tech center to share the actual numbers, but the issue is that the body was “outside” of allowed tolerances. On the yaw of the car, which caught out the 48 car, the tolerance was 0.070″ and the 48 car was measured at 0.076″. The debate was that Rohmer arm used to measure positions has a tolerance of +/- 0.002 on any single axis. The question was, can NASCAR actually measure to this level of precision. Different story if the car was laser profiled, that has a much tighter tolerance band.
    At this point it is difficult to sort through the PR flak and figure out if the 33 was 0.060″ outside the tolerance limit, or the tolerance is 0.060″ and the 33 was slightly outside of that.
    Will continue to pursue this.

  6. Yeah, and Carl Long’s engine was oversized by 1/6 of one cubic inch. That is how precise and exact NASCAR is with their measurements. And that is why they have limitations for them, too. Otherwise, everybody would be exceeding the limits as far as NASCAR would allow. You have to draw the line somewhere.

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