Using a rear stand, can i put the front on a bathroom scale.. .
then using just a front stand, can I then put the rear on a bathroom scale, add the two numbers together and get an accurate weight?
I have to do one end at a time, since I have only one scale ;D
Just look up your particular model and year's wet weight. the way you are doing it involves too much math because you have to consider the weight displaced at each end...
only if your bathroom scale is made for fatties the size of Peter Griffin+
Also, depending on the angle, there will be different amount of weight on either end. youd have break up the weight using vectors.
If you REALLY wanted to weigh your bike. Just bring it to a scrap metal yard and ask the guy if you can hop on for 2 seconds.
If you pick up a nail its not my fault.
Quote from: lemond on October 29, 2008, 07:49:30 PM
Just look up your particular model and year's wet weight. the way you are doing it involves too much math because you have to consider the weight displaced at each end...
You ever heard of mods?
Quote from: He Man on October 29, 2008, 07:49:44 PM
only if your bathroom scale is made for fatties the size of Peter Griffin+
Also, depending on the angle, there will be different amount of weight on either end. youd have break up the weight using vectors.
If you REALLY wanted to weigh your bike. Just bring it to a scrap metal yard and ask the guy if you can hop on for 2 seconds.
If you pick up a nail its not my fault.
You'll get no more than 230 LBS on the scale at one time (unless your weighing a Harley). So any scale will work.
If you lift the front end and rear approximately the same amount when weighing it, your going to get fairly accurate results, with best results seen when the bike is completely level with the scale.
When I weighed mine this way, I used a 2x4, which approximately the same height as the scale, to lift the front while I weighed the back. Then I used the rearstand to lift the back (about the same amount) while I weighed the front. I got almost exactly 400 LBS for my bike, which I would think is slightly low, though I have replaced or removed several parts, plus the tank was low on fuel.
Just get a better scale, they make lots of bathroom scales for fat people.
Then just support your bike under the center so the whole weight is on the scale. It's worked for me.
Make friends with someone at your local post office. They have a large floor scale in the rear parking lot where they load the vans.
Quote from: lemond on October 29, 2008, 07:49:30 PM
Just look up your particular model and year's wet weight. the way you are doing it involves too much math because you have to consider the weight displaced at each end...
Not really, if you can keep the bike level while you do it, the math becomes just adding the two numbers you get. It's pretty insensitive to small errors too, so long as you keep the wheels within 1 inch of level, you'll have an error of less than 1 part in 1000 (assuming a ~55 inch wheelbase and a c of g height of 25 inches) - the calculation for the error factor is (1/(C*tan(sin
-1(x/W))))/W - where x is the height difference between the two wheels. W is the wheelbase, and C is the height of the center of gravity.)
Which just means "keep it level on the bathroom scales by proping the other wheel up to about the same height as the scales, and you'll be fine".
So long as your scales go up to 220lbs or so (and I find it hard to believe anyone would sell bathroom scales in America that wouldn't weigh at least that much) your plan will work fine. (personally I wouldn't bother with the stands, I'd just roll it onto the scales at one end and a block of timber about the same thickness at the other, and hold it upright while I read the scale, then swap the scale and timber around and do it again, then add the two weights - you'll easily get within a few oz of the actual weight.
big
I thought this would work, thanks for confirming ;D
Most landscaping supply yards have drive on scales that are very accurate. I used the local one to weigh my truck, car and bikes! [thumbsup] Also, most high end motorcycle shops that prep for racing have them.
I usually take bikes to a certified scale at the scrap yard for an accurate total weight, but I use the bathroom scale method to determine weight bias with and without a rider. If you use the bathroom scales, play around with the weight bias, it makes a BIG difference in how the bike handles.
^
I had considered bias.
I'm buying ducpainter's blown up 750ss, swapping in a 900 and going to use it for track duty (since it's already setup for that)
One thing I have in mind to explore is cutting the whole back off of it and building an aluminum sub frame.
I really want to take weight off this bike. Cheap and/or free things will be done first, of course.
Another thing id really like to do is put holes in all the gears under those side covers to cut down on rotating weight.
I should really buy a Bridgeport.
;D
Quote from: He Man on October 29, 2008, 07:49:44 PM
snip
If you pick up a nail its not my fault.
Now we know how IZ gets all them nails in his tyrz ;)
Why not just use 2 scales. Their cheap enough.
Not cheaper than me ;D
Have a weigh in party and invite all your friends with a "bring your own scale and carton" entry fee. What with 10 scales, bikes and cartons the end results could be worth reporting or even filming.
When I wanted to weigh my Boss Hog V8 motorcycle, I built a raft and floated it in the pool at the local Days Inn.
Then I loaded my bike on to the raft and measured how much the raft sank.
Then I removed the bike and loaded the raft with M&Ms till the raft displaced the same amount of water.
Then it was a simple task of counting the M&Ms and multiplying that number by the average weight of an M&M.
The nice thing about using M&Ms is that you can use this method year round. Even in the summer, they won't melt in your hand.
However, if you choose this method, learn from my mistakes. Don't use regular M&Ms. Use the ones with peanuts inside. They are larger so you won't have as many to deal with.
Around here the highway weigh stations have a digital read-out that stays on when the weighmaster is gone.
Wait for a quiet night drive out and park on the pad.
The pad is large enough for the whole bike. And you can stay on the bike for a total if you like.
I would guess it is pretty accurate...
Quote from: Monsterlover on November 06, 2008, 12:39:22 PM
Not cheaper than me ;D
Buying a track bike (and not just a beaten-on Gixxer or SV), replacing the motor with a fresh 900, trying to rationalize a multi-thousand $$$ CNC milling machine ... and you won't drop $15 on a scale at Target?
My compliments, sir -- seems to me like your priorities are spot on!!! [clap] [clap] [clap]
Thank you, thank you <bows>
I don't recall mentioning a CNC mill. I can rationalize anything ;D
But maybe I posted on here about a bridgeport knee mill? Can't remember. Still though ;D
Ok, Ill get the damn scale [roll]
;D
The good thing about having 2 scales is you can compare them to each other, then worry about which one is *right*. ;D
[laugh]
quite true
Quote from: Speeddog on November 20, 2008, 05:01:11 PM
The good thing about having 2 scales is you can compare them to each other, then worry about which one is *right*. ;D
Then when you're pissed at the GF you can swap in the scale that reads a few pounds on the high side.
Quote from: Speeddog on November 20, 2008, 05:01:11 PM
The good thing about having 2 scales is you can compare them to each other, then worry about which one is *right*. ;D
Every analog bathroom scale I have seen could be adjusted. So, theoretically you could set the scales to be even. But then you have to worry about repeatable precision.
I just weighed my M695 using a thin digital bathroom scale:
~ half tank fuel
~ Termi low CF pipes
R = 194lbs = 51.1%
F = 186lbs = 48.9%
Total = 380lbs
Now I'm curious how things distribute with me on there, but I'll need a helper or two for that.
BK
Use a front and a rear stand alternately. . .
Ok, I did not get a second scale.
I weight the 750ss tonight.
354 pounds total (half gallon or so of fuel and no oil, chopped frame)
Quote from: BK_856er on November 23, 2008, 04:01:55 PM
I just weighed my M695 using a thin digital bathroom scale:
~ half tank fuel
~ Termi low CF pipes
R = 194lbs = 51.1%
F = 186lbs = 48.9%
Total = 380lbs
Now I'm curious how things distribute with me on there, but I'll need a helper or two for that.
BK
Just to update with me geared up on the bike (180lbs) and a slightly different fuel load:
R = 308lbs = 54.6%
F = 256lbs = 45.4%
BK