Race Car Tech Discuss anything related to road racing and auto X.

Clever car weight determination

Thread Tools
 
Search this Thread
 
Old May 22, 2007 | 01:50 PM
  #1  
calculon's Avatar
Thread Starter
On flats
Tenured Member: 20 Years
iTrader: (29)
 
Joined: Oct 2004
Posts: 1,379
Likes: 0
From: Albuquerque
Clever car weight determination

LINK

Anyone that knows their car's weight from an actual scale wanna try this and report back for the rest of us in towns that don't have corner scales?

Curious how accurate it could be. . . lots of variables that decrease its validity

It'd be interesting to see.
thanks
ryan
Reply
Old May 22, 2007 | 04:14 PM
  #2  
jgrewe's Avatar
GET OFF MY LAWN
Tenured Member: 20 Years
iTrader: (1)
 
Joined: Feb 2005
Posts: 2,837
Likes: 2
From: Fla.
Good for general idea of weight but as you say the variables will kill the accuracy. The biggest being the contact patch isn't a rectangle.
Reply
Old May 23, 2007 | 06:23 AM
  #3  
moremazda's Avatar
Gone Race'n
Tenured Member: 20 Years
iTrader: (4)
 
Joined: Dec 2001
Posts: 1,550
Likes: 4
From: Rockford, IL
Originally Posted by jgrewe
Good for general idea of weight but as you say the variables will kill the accuracy. The biggest being the contact patch isn't a rectangle.
But if all of the tires are the same size and model you can get a very good approximation on corner weight percentage.
Reply
Old May 23, 2007 | 07:13 AM
  #4  
wrankin's Avatar
Old Rotary Dog
Tenured Member 15 Years
 
Joined: Feb 2003
Posts: 1,461
Likes: 2
From: Durham, NC
Tires with stiff sidewalls will also throw this calculation off. You also need a very flat smooth surface to do this on.

But as a first order approximation, it's probably not too bad. My gut feeling tells me it's possibly good to +/- 100 lbs or so on each wheel. If I get the chance I'll try and remember to try this out on the FC (which is corner balanced and I do know the weights).

The engineer in me cringes when he sees them carrying their calculations out to seven significant digits - implying accuracy where there is none.

-bill
Reply
Old May 23, 2007 | 10:58 AM
  #5  
j9fd3s's Avatar
Moderator
Community Builder
Liked
Loved
Community Favorite
iTrader: (3)
 
Joined: Mar 2001
Posts: 31,833
Likes: 3,232
From: https://www2.mazda.com/en/100th/
this is prolly good if you've already built the car, and are just setting it up....
Reply
Old May 23, 2007 | 05:27 PM
  #6  
scotty305's Avatar
~17 MPG
Tenured Member: 20 Years
Liked
Loved
Community Favorite
iTrader: (2)
 
Joined: Jan 2004
Posts: 3,478
Likes: 334
From: Bend, OR
They said "if you get within 10% of the weight stated in your owner's manual, good job!"


10 percent on my car would be about 279 lbs; I don't think any of us would be satisfied with the results. I've measured corner weights on a set of racing scales, so maybe I'll try this just for kicks.

-s-
Reply
Old May 24, 2007 | 08:45 PM
  #7  
NeoTuri's Avatar
The shy megalomaniac
Tenured Member: 20 Years
Liked
iTrader: (2)
 
Joined: May 2003
Posts: 881
Likes: 79
From: Atlanta, GA
Originally Posted by jgrewe
Good for general idea of weight but as you say the variables will kill the accuracy. The biggest being the contact patch isn't a rectangle.
I just tried one of the tires, and yes, the contact patch is not a rectangle.

I had a feeling my calcs were going to be off as I could see how much surface area fit inside of the "rectangle" but didn't touch the tire.

My car weighs about 2700lb, and I got 1000 lbs on one corner using the calc.
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
cristoDathird
Introduce yourself
28
May 30, 2019 08:47 PM
astrum
2nd Generation Specific (1986-1992)
24
Nov 15, 2017 08:44 AM




All times are GMT -5. The time now is 12:48 AM.