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How to weigh your street rod at home

6K views 50 replies 23 participants last post by  47dodge 
#1 ·
I am trying to find out how to weigh my street rod at home with a bathroom scale. Years back where was a magazine that told how they used boards so not to ruin the bathroom scale, but I can't find the magazine. Can any one tell me how to make this setup and the formula? Thanks
 
#27 ·
Hi whutzat - if you have a dragstrip nearby; they should have scales there. They have an in-ground set @ SIR; I believe it also has the printout setup. Also my buddy at his wrecking yard has a scale with printout slip to drive across. So, dragstrips and wrecking yards - check 'em out.


Pete
 
#28 ·
Whutzat's original question was how to use a bathroom scale to weigh a car. I'm confused that you don't like the answer?!? It works quite well, within spitting distance of the precise answer and, well, it uses a bathroom scale like he wanted!!

The way I have been weighing my cars in recent years is to take a couple news papers to the local recycling center. They weigh your car before and after you dump the junk and give you a check besides! For that you get an accurate printed document of your vehicle's weight.
 
#30 ·
find yourself a local circle track guy or scca club racer hand them 20 and a six pack. and you probably will get more info than you know.
i do it all the time with my scales for people..it really fun to see somethings that people think are light turn out to be tanks and some things you wonder how i could be that light and so close on corner wieghts.
 
#32 ·
willys36@aol.com said:
Whutzat's original question was how to use a bathroom scale to weigh a car. I'm confused that you don't like the answer?!? It works quite well, within spitting distance of the precise answer and, well, it uses a bathroom scale like he wanted!!

The way I have been weighing my cars in recent years is to take a couple news papers to the local recycling center. They weigh your car before and after you dump the junk and give you a check besides! For that you get an accurate printed document of your vehicle's weight.
The weighing the car with the bathroom scales is defiantly a cool method and 30 years ago I would have had to try it. But now I just don't have the energy and so many other things need my attention and that is how I related to the question. I just wanted to throw out a few alternatives. It is so fast and painless just to drive across the scales. I get weighed multiple times a day when I am driving, Just to haul one lead of corn to the ethanol plant involves weighing at least four times if everything goes right getting loaded.


I like the weighing the car at the recycle center method. Do they pay you for the old newspapers?
 
#34 ·
Brian_B said:
Speaking of...the college where I work part time has a huge sundial out in front of the main entrance. I mean this thing must be 10' across.

What does that have to do with a college, expecially one that tries to teach the latest technology (we are in AR)? :confused:

Could it be because latest technology has yet to meet the accuracy of a sundial? :)
 
#36 ·
Just remember, when all of the newfangled timekeeping devices fail, the guy who knows the principle behind the sundial will still be able to tell time.

Don't think it can't happen, I was watching a show about the electromagnetic pulse bomb.

Pulse bomb can't mess up an old bathroom scale though.....



hahahahahahahaha

Later, mikey
 
#37 ·
powerrodsmike said:
Just remember, when all of the newfangled timekeeping devices fail, the guy who knows the principle behind the sundial will still be able to tell time.

Don't think it can't happen, I was watching a show about the electromagnetic pulse bomb.

Pulse bomb can't mess up an old bathroom scale though.....



hahahahahahahaha

Later, mikey
Unless I'm standing on it. Then the bomb will do some damage!
 
#38 ·
red65mustang said:
have no idea where "North Fork" CA is but fair to good chance this link will help find one

QUOTE]
He's in the foothills N.E. of Fresno, pretty well isolated. Beautiful country. Let us know how the bathroom scales work out. Dan
 
#41 ·
red65mustang said:
dinger, what county is he in...my link lists all licensed scales by county....

curious if he did look on the link map and found one close by....

cause....he ain't been around for awhile
He's in Madera County, probably an hour or less from Yosemite National Park. I haven't been up that way for 5 or 6 years, it's pretty rugged country, very nice if you like the outdoors.
 
#42 ·
4 pieces of copy paper and an accurate tire pressure guage. Cheapest easiest way. (no, I haven't sniffed too much nitrous)


On a flat surface, slide a sheet of paper behind, in front of and on both sides of a tire. Measure the distance front/aft & side to side. Multiply width by length, for total square inches of tire footprint. Check tire pressure. Multiply psi x the square inches. Do the same for the remaining tires. Add thewm together. and you have your weight.

I was within 8# on a 2700# race car, and a 3100# 65 chevelle.

Slide the paper in until it stops, and keep them parallel /square.



Fire suit on, blaze away!
 
#44 ·
Any scrap yard will weigh it for you for free. If you know or can befriend any local oval track racers, they can check it by individual wheel (corner) weight and maybe they'll even help you balance it out. This will go a long way towards optimizing handling. You would be amazed at how much weight is transfered, and to where, by little changes in spring pre-load at any given corner of the car. Do this while sitting in the car or put weight equal to yours in the seat.
 
#45 ·
Scales

Hi guys,
I am a scale tech by trade and specialize in vehicle scales. The bathroom scale scenario is a joke. Bathroom scales in general are crap. Placing a board between a couple bathroom scales is a bad idea. First the scales..they never work right..second the board in between or "weighbridge" :sweat: is going to have some deflection..in this case probably alot of deflection.
Deflection in a vehicle scale is a very bad thing. You can take your vehicle to a truck scale to get your weight..I would recommend a CAT scale only because I have installed a few and most CAt scales consist of 3 seperate weigh decks that will sum into a gross weight but if you position the car so that the front axle is on deck 1 and the rear axle is on deck 2 this will give you front and rear loads and gross. Keep in mind that you will be getting a weight that is rounded up or down to the nearest 20 lb increment. Also, even though truck scales are regulated by the county they are in and calibrated usually every 90 days this does not gaurantee that there is not an error in the scale. If you want to get a solid weight down to the lb. you really need to buy or find someone that can rent you racing scales or sometimes called wheel weighers. These , if calibrated properly, will get you a solid weight and should put you within a couple pounds accurately. I say calibrated properly because even the scales we purchased that were factory calibrated were off round 2-4 lbs at each wheel. When your weighing race cars this is not good. Make sure the scales and vehicle are level. We just did a new electric vehicle that is going through testing for production and this is the way to go. A weigh ticket at a truck scale will run about 8-15 dollars depending where you go.
Please no bathroom scales :spank:
 
#47 ·
Don't want to argue but the original question was how to weigh a car 'at home'. The bathroom scale system does that. And deflection of the board has zero impact on the result as long as the middle of the board does not touch the floor. Link between the tire and scale can go between California and New York and back as long as it is, a) carrying the weight of the wheel and, b) transfers the weight to the scale. Shape of the member between those two points is immaterial to the result. Granted the accuracy is not the best with the cheapie scale but again, the criteria was 'at home'. In fact I have used the method many times to size out coil springs for MII front end conversions and it works great. Wouldn't want to sell gold bullion using it but for car work it gets you in the ball park.

I am cheaper than the rest of you. If the car is drivable, I throw in a few old newspapers, go to my recycling center, get the car weighed, toss out the newspapers, get the car re-weighed, take my $0.17 check for the paper and a free, pretty accurate weight slip. Such a deal!
 
#48 ·
And the checkered flag goes to...

Beenaway2long said:
4 pieces of copy paper and an accurate tire pressure guage. Cheapest easiest way. (no, I haven't sniffed too much nitrous)


On a flat surface, slide a sheet of paper behind, in front of and on both sides of a tire. Measure the distance front/aft & side to side. Multiply width by length, for total square inches of tire footprint. Check tire pressure. Multiply psi x the square inches. Do the same for the remaining tires. Add thewm together. and you have your weight.

I was within 8# on a 2700# race car, and a 3100# 65 chevelle.

Slide the paper in until it stops, and keep them parallel /square.
I just posted this same method in another thread a couple of days ago.
Although the question was how to use bathroom scales at home, This is the way us backwoods dirt track boys set our cars up. In case you've never raced small dirt tracks, the expense is high and the payout is low so running down with $20 to the local scale just to see how many lbs.you've shaved off your total weight can get expensive over a season. and as for taking the 12 pack with $20?
I DON'T THINK SO!!!! Thats for starting the celebration after the race, when your tearing down your engine for inspection because some rich punk with a shiny car got butthurt when your beatup junkyard dog lapped him twice in a 50 lap feature. LOL
 
#49 ·
willys36@aol.com said:
I am cheaper than the rest of you. If the car is drivable, I throw in a few old newspapers, go to my recycling center, get the car weighed, toss out the newspapers, get the car re-weighed, take my $0.17 check for the paper and a free, pretty accurate weight slip. Such a deal!
LOLOLOL, you got me there! LOL

Brian
 
#51 ·
I am cheaper than the rest of you. If the car is drivable, I throw in a few old newspapers, go to my recycling center, get the car weighed, toss out the newspapers, get the car re-weighed, take my $0.17 check for the paper and a free, pretty accurate weight slip. Such a deal!
At the local recycling center here they leave a drop off area open all the time. You don't get paid after regular business hours but you can run across the scales 24/7 with a big digital readout right next to the scale.
 
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