View Full Version : Corner weighting gnomes...

04-12-2004, 10:50 PM
...came to my house and set up my Golf.

Understand that I still have OEM struts and springs on my '96 GTI when I tell you this:

Someone asked what the car weighs so I went back to the slip that I got in post-race impound at the VIR regional a couple weeks ago. I hadn't looked at it since because I knew (a) what the car weighed at Roebling a month before, and (B) what the AC system weighed when I took it off.

I got to looking this evening and was absolutely floored to learn that the cross-weights are a mere 20# different - on 2700+ pounds of VW with fixed perches. This MUST be well within the per-wheel margin of error for their scales.

Pretty freakin' amazing.


Greg Amy
04-13-2004, 10:11 AM
Actually, Kirk, it may be surprising, but it really shouldn't be.

Give it some thought: the manufacturer has to build these cars to millimeters of tolerance across the whole chassis. Struts are made to specs, chassis is built with robots to provide consistent manufacturing, and if you look at the repair manual you'll see chassis repair specs that are +/- millimeters front to rear. We've gotten so good at building things it shouldn't come as a surprise we can do it accurately.

Of course, all of this is given serious consideration during design, and you KNOW that the chassis guys are watching the numbers.

Hell, it's only when we start messing with these things in the aftermarket that we screw them up and need the corner scales...<grin> I would not be surprised to find most stock vehicles are straight and true like that, assuming they were not hit hard some time in their lives...

04-13-2004, 12:09 PM
There is a reason that the guys who drive lawn darts bring their own scales and scale platforms to the track. Don't ever trust scales at Tech for anything other than gross weight.

I went gnutz a few years ago at a track when I ran a sports racer over the scales at Tech before Saturday qualifying. The weight was right, but the cross weights were insane. I had just scaled the car the week before on my own scales, and the differences were wild. I checked all my perch-height measurements (I kept track of these), and looked for anything that might have moved. Nothing was 'off', so I was baffled.

I finally walked over to the Tech shed with my laser level and checked the pads on their scales. Way off of true. My $19.95 laser level from Harbor Freight saved me much screwing around that weekend. It did not, however, save the RR wheel bearing that decided to 'check out' on me 2 laps from the end.

04-13-2004, 03:59 PM
never mind http://Forum.ImprovedTouring.com/it/biggrin.gif

[This message has been edited by zracer22 (edited April 13, 2004).]