7 replies to this topic

[Tampabay racer]

Can someone tell me the body heights are for all three classes? I can seem to never pass tech on our monthly races...

[John Streisguth]

1.375" for Can-Am, GTC, and F1 with the rear wings. 1.125" for non-winged F1s.
 
It's all right here:

IRRA™ website

[Fast Freddie]

The problem with body height measurement is that it's taken on a flat tech block with the car setting on all four tires or the guide and rear tires.

The problem with that is the diameter of the rear tires affect that measurement. The height of the body with a .8125" tire will be shorter than the height using a .8225" tire. When you see a maximum body height measurement of 1-3/8" or 1-5/8 in reality it's not refering to the body at all but the distance from the block surface to the top edge of the body. It's always a good rule of thumb to cut your body 1/16" less than the legal height. This should be just about right if your running .062" clearence and just a tad short if your running .050 clearence.

The ISRA North American rules are the only set of rules I know of were the body height is measured on a tech block with wheel cutouts. That way you get a true body height measurement unaffected by different tire diameters. So when you cut your bare body to exactly 1-5/8 you can be sure it will pass tech.

That way you can also run the same body, let's say a GTP body, on the flat track with a .032" clearence or on a high banked track with .062" clearence just by swapping chassis and tires, or in some cases just tires.

[Mopar Rob]

Brian,

So in a nutshell cut you Can-Am body in the rear at 1.300" to compensate for the .050" clearance plus a little wiggle room in case your tires are big.

[Noose]

That's right, it is the height of the body on the test block and that's how it was intended to be written and not for manufacturing. It is not a big problem in tech these days.

[The Number of]

That's right it is the height of the body on the test block and that's how it was intended to be written and not for manufacturing.  It is not a big problem in tech these days.

 
  And this R4 will go into history as the year of the great body height bounce.  

[The Groove]

Brian,

Go to the Precision Slot Cars WEBSITE select category "Retro", and go to page 2, Retro tech tools.



They are so easy to use and make checking body height a breeze!

[Noose]

Rich,

Great advice as those are the tools I use!