Home  
Site Partners: SpotterGuides Veloce Books  
Related Sites: Your Link Here  

Go Back   TenTenths Motorsport Forum > Racing Talk > Racing Technology

Reply
 
Thread Tools Display Modes
Old 16 Aug 2008, 01:31 (Ref:2269905)   #1
215maloo
Rookie
 
Join Date: Aug 2008
Posts: 2
215maloo should be qualifying in the top 10 on the grid
Corner weights without scales

Hi,

Looking for info on corner weighting a car without access to scales. I understand their is a method that involves balacing one end of the car on a pivot point and then levelling it ???

Any information on this method would be appreciated. I'm also interesting in what its limitations are (apart from being a little less accurate than scales).

thanks

Last edited by 215maloo; 16 Aug 2008 at 01:32. Reason: typo
215maloo is offline  
Quote
Old 16 Aug 2008, 11:07 (Ref:2270048)   #2
AU N EGL
Veteran
 
AU N EGL's Avatar
 
Join Date: Jul 2006
United States
Raleigh, North Carolina
Posts: 4,418
AU N EGL should be qualifying in the top 10 on the gridAU N EGL should be qualifying in the top 10 on the grid
Think it might be esiear to spend the $1800 for scales and do the corner balance properly.
AU N EGL is offline  
__________________
"When the fear of death out weighs the thrill of speed, brake." LG
Quote
Old 18 Aug 2008, 14:17 (Ref:2270968)   #3
adambrouillard
Rookie
 
Join Date: Apr 2008
Posts: 31
adambrouillard should be qualifying in the top 10 on the grid
That seems like it would work if you can find measuring spots on each side of the chassis that are totally equal, then find the exact centerline of the other end. Your chassis would have to be perfect as small deviations can make big differences. I use a set of $300 modified ruggles style scales that work pretty darn well, although they are a little harder to level accurately. This dude makes them.

http://motors.shop.ebay.com/merchant/sprintracerman
adambrouillard is offline  
Quote
Old 18 Aug 2008, 17:31 (Ref:2271074)   #4
Andrei
Rookie
 
Join Date: May 2005
Romania
Germany
Posts: 47
Andrei should be qualifying in the top 10 on the grid
If I have really understood your question, you really want to know the corner weights. As far as I am aware, this is only possible to measure with some sort of scales, professional or not.
What you suggest is finding the CG height, but this is only (really) usefull if you know the corner weights.
Andrei is offline  
__________________
Propper planing prevents ****-poor performance. (Alwin Springer)
Quote
Old 18 Aug 2008, 20:27 (Ref:2271175)   #5
GordonG
Racer
 
Join Date: May 2004
Posts: 155
GordonG should be qualifying in the top 10 on the grid
Mumford Beam

There was an article a few years ago in Racecar Engineering (Might have been Race-Tec) about the Mumford Beam. I have used this exclusively for cornerweighting ever since.

All the ideas about using bathroom scales just arent worth bothering with. There isnt the accuracy or repeatability on them, even if you use 2 on a corner.

The mumford beam is just a see saw that you place the wheels of one axle on so that the pivot is halfway between the 2 wheels. I made mine in 2 hours from 2 lengths of scaffold tube (for my lightweight car I could have used much lighter tube) welded about 4" apart with a bit of angle iron for the pivot. This can if necessary be taken to the race/test day strapped to the trailer.

To use, you place the beam under the front wheels, with the rear wheels on a level piece of floor (you only need 2 level patches - use ply or old copies of Race Tec to level the patches if necessary). Pick a horizontal surface on the chassis, and adjust the rear spring platforms so that that surface is truly horizontal (use a spirit level). Then place the level on the mumford beam, and adjust the front spring platforms until that too is level.

Now, when the car sits on a flat surface it will be level, and there will be equal weight on the front wheels. If the car has even left/right weights, there will also by definition be equal weights on the rear wheels and equal diagonals. Even if your car has uneven side-side weights, you still ahve equal front weights, which is arguably as good as equal diagonals as braking is where corner weights have most effect. At worst, it is better than guessing or using even spring platform positions, and your settings are 100% repeatable which ensures consistency.

Enjoy.

G
GordonG is offline  
Quote
Old 19 Aug 2008, 16:45 (Ref:2271640)   #6
Speedy1
Rookie
 
Join Date: May 2007
United Nations
100km north of San Fransisco
Posts: 47
Speedy1 should be qualifying in the top 10 on the grid
thanks for sharing

a great, simple concept that makes perfect sense for finding left to right balance ...
have you tried the technique for front to rear balance?
only caveat: an oval track car often needs to be imperfectly balanced to get the most from the tires
wonder how it might be applied in that arena?





Quote:
Originally Posted by GordonG
There was an article a few years ago in Racecar Engineering (Might have been Race-Tec) about the Mumford Beam. I have used this exclusively for cornerweighting ever since.

All the ideas about using bathroom scales just arent worth bothering with. There isnt the accuracy or repeatability on them, even if you use 2 on a corner.

The mumford beam is just a see saw that you place the wheels of one axle on so that the pivot is halfway between the 2 wheels. I made mine in 2 hours from 2 lengths of scaffold tube (for my lightweight car I could have used much lighter tube) welded about 4" apart with a bit of angle iron for the pivot. This can if necessary be taken to the race/test day strapped to the trailer.

To use, you place the beam under the front wheels, with the rear wheels on a level piece of floor (you only need 2 level patches - use ply or old copies of Race Tec to level the patches if necessary). Pick a horizontal surface on the chassis, and adjust the rear spring platforms so that that surface is truly horizontal (use a spirit level). Then place the level on the mumford beam, and adjust the front spring platforms until that too is level.

Now, when the car sits on a flat surface it will be level, and there will be equal weight on the front wheels. If the car has even left/right weights, there will also by definition be equal weights on the rear wheels and equal diagonals. Even if your car has uneven side-side weights, you still ahve equal front weights, which is arguably as good as equal diagonals as braking is where corner weights have most effect. At worst, it is better than guessing or using even spring platform positions, and your settings are 100% repeatable which ensures consistency.

Enjoy.

G
Speedy1 is offline  
Quote
Old 22 Aug 2008, 12:50 (Ref:2273321)   #7
GORDON STREETER
Veteran
 
GORDON STREETER's Avatar
 
Join Date: Nov 2006
Spain
Kent+Mojacar Spain, but not always ?
Posts: 9,400
GORDON STREETER is going for a new world record!GORDON STREETER is going for a new world record!GORDON STREETER is going for a new world record!GORDON STREETER is going for a new world record!GORDON STREETER is going for a new world record!GORDON STREETER is going for a new world record!GORDON STREETER is going for a new world record!
If its a light "ish" car you can use bathroom scales (if you know how) and will work just as well as some of the corner weight ones that are sold .

Last edited by GORDON STREETER; 22 Aug 2008 at 12:52.
GORDON STREETER is offline  
__________________
Balls of steel (knob of butter) They're Asking For Larkins. ( Proper beer) not you're Eurofizz crap. Hace más calor en España. Me han conocido a hablar un montón cojones! Send any cheques and cash to PO box 1 Lagos Nigeria Africa !
Quote
Old 27 Aug 2008, 01:31 (Ref:2276010)   #8
Mackmot
Veteran
 
Mackmot's Avatar
 
Join Date: Feb 2000
United Kingdom
Melbourne, Victoria, Australia
Posts: 2,188
Mackmot should be qualifying in the top 10 on the grid
http://www.demon-tweeks.co.uk/produc...T&pcode=P/PPP2
Mackmot is offline  
__________________
A Saudi saying, "My father rode a camel. I drive a car. My son flies a jet-plane. His son will ride a camel."
Quote
Old 28 Aug 2008, 10:08 (Ref:2276772)   #9
GordonG
Racer
 
Join Date: May 2004
Posts: 155
GordonG should be qualifying in the top 10 on the grid
you cant transfer weight aroudnd the car, from left to right or front to rear, just by playing with spring perches, whcih is all you are doing when setting corner weights whether using scales or mumford beam.

The mumford beam simply allows you to get equal weight on the 2 front tyres. The corresponding weight distribution across the rear tyres will be whatever it takes to support the CoG of the car. IF the car CoG happens ot be on the centreline then you will have equal rear weights also, and happily equal diagonals (which is what most people aim for with scales). So this works perfectly for your typical central driving position single seater.

If your CoG is to one side, the rear tyres will take all this weight differential if the fronts have equal weight. However, I've found this is still a good approximation even with a 2 seat car, and importantly it allows you to be consistent.

G
GordonG is offline  
Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Corner weights for hire? EdLeake Racers Forum 4 16 Aug 2008 11:36
Corner Weights FilW Racing Technology 28 2 Aug 2003 08:27
corner weight scales kartingdad National & International Single Seaters 1 3 Jul 2003 12:48
Scales and flat patch Andrew Jones Racers Forum 5 20 Feb 2003 18:23
1-10 scales Guido II Announcements and Feedback 1 8 May 2001 11:11


All times are GMT. The time now is 23:08.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Original Website Copyright © 1998-2003 Craig Antil. All Rights Reserved.
Ten-Tenths Motorsport Forums Copyright © 2004-2021 Royalridge Computing. All Rights Reserved.
Ten-Tenths Motorsport Forums Copyright © 2021-2022 Grant MacDonald. All Rights Reserved.