Accurate scale???
 

I have been using a digital hanging scale to weigh bike frames and finished bikes.

The scale has become innacurate, giving different weights every time.

I have replaced tha batteries and it appears to be working . it is just wildly inacurate

Please please please, someone, tell me you have a scale that can accurately weigh light (under 1 lb ) and heavy (50 lbs) items.

The one I use is over $500 but vey accurate. How much you want to pay? Smiles, MH

I have a Park Tool one, and I noticed that a local coop's scale (same model) was a little optimistic in its weighing. Great for feeling good about a big bike weighing less than what I hoped, but ultimately not accurate. My PT unit has many fewer weighings on it, but curiously, it gives two different weights when you toggle between Bald Eagle Units and Metric (if you calculate the conversions). I go for the lower number. :lol:

A friend [MENTION=340794]Dfrost[/MENTION] gave me a tiny hang scale years ago and I've used it to corroborate other scales' readings as it has matched them well, so now it can do so for my PT scale. This sounds like a bad response: "Why doncha just buy another hang scale and see how it does?"

How long have you had this scale? What brand and model?

Does anyone know where to get calibration weights of size, accuracy and cost appropriate for bikes? Say an ounce and a pound or metric items in that ballpark. Also where one could take say a 10 pound barbell weight and weigh it on a calibrated scale? (Of course, everybody is going to know you are buying or selling pot, so keep an eye out behind.)+

I’ve never had good luck with hanging scales being or staying accurate. I use a kitchen scale for smaller items and a bathroom scale for larger. Just weigh yourself first, then weigh yourself holding larger item (e.g. bike), and take the difference.

Plastic bag with a measured quantity of water in it.

Of course that depends on the temperature of the water. I’ve got a cousin who weighs the water when he makes coffee because the volume isn’t anccurate enough for him in all conditions.

I use a cheap fish scale from some Taiwanese manufacturer. Is it accurate? I have no idea. It’s at least reasonably consistent.

IMHO, if you are wanting accuracy, you need two different scales to weigh items < 1 and > than 50.

About half a percent from 15 to 35 degrees, the former about a tenth of a percent lighter than at standard temp.

Weigh the bike with flat tyres; a smallish one will have a volume of around a sixth of a cubic foot, which weighs 0.0807 - five more of those gets you to 90lbs but weighs that much.

When E.T.s sold motor-bikes they'd get tested with the smallest madman they could find, and just enough fuel to do one run.

Hookes law works. No batteries needed. In this case, I did check the scale by putting the green dumbell on a digital scale and finding that it weighed 12 lbs. This is good enough to weigh a complete bike.

https://cimg4.ibsrv.net/gimg/bikefor...b41f81e211.jpg

The mechanics of measuring using a load cell are equally reliable, but the electronics can sometimes go bad. No lead solder, bad capacitors, components made at the lowest cost possible are the usual culprits.

Get some calibrating weights and go crazy.

I use this for shipping and bikes. Just weight myself with and without the bike in hand, and do the math. Works for me!

Scale

Guy

A scale is most accurate in the middle of the range and worse at the extremes.
I use a Park and all I want is a ball Park number.

I use a CJ4000 digital scale for coffee. Up to 4 kilo to a 1/2 gram. And a far from new bathroom scale (using me with or without bike). Maybe I can read it to a half pound. It does correspond nicely to the doctor's scales. I step on it before I go.

But accuracy? Until you calibrate them, who knows? And all my water measuring devices are glass containers that get bigger as they go up, so the error in the judged contents goes up as you fill it. Measuring cups. Cooks don't seen to have our obsession.

I use a digital kitchen scale for lower weighted items. It works great and can accommodate anything you can get to balance on it; from pool cues to wheels to pedals.

I’ll use a digital hanging scale/luggage scale for heavier items.

John

Thanks smd4! Anything you could want there. Even sets with 1 and 2 gm weights to calibrate my AR turntable with the little balance scale AR provided that I've still got! But some of the clear plastic nickle sized weights have run off. (Bought the turntable 1970 to take to college. Still works well. Did buy a new drive belt for it 20 years ago.)

This is what I do.

During the pandemic I got these scales from a fishing equipment store. I had decided I wanted to see if I could build a fendered bike in my (large) size weighing no more than 10kgs with what I had in my parts bin.

https://cimg9.ibsrv.net/gimg/bikefor...1925a1bae1.jpg

What a 64cm bike weighing 10.00kg looks like:

https://cimg5.ibsrv.net/gimg/bikefor...ab8ca9be4b.jpg

I have no idea how accurate it really is, but I learned a lot (the French really know how to do light) and it kept me off the streets for weeks. :)

I have a scale built into my bike stand (from Performance) which I use for ball park weight, it seems reasonably accurate, but I don't care enough to even check the accuracy. The only time I'm really concerned is for shipping and I use a high-end bathroom scale.

My scales all tell me that my bikes are too heavy and that I've recently put on 5 pounds. That can't be right.

I've never needed to accurately measure weight, but if I did, I'd probably look into the stuff that McMaster Carr sells. It's probably not the cheapest, but at least they can give you an indication of the accuracy.

For under a pound, the kitchen scale will do pretty well.
For 50 pounds, this hanging scale says it is accurate to 0.1 kg. Only $140.

Steve in Peoria

Answer, for yourself, what accuracy you need to have and whether that accuracy is meaningful or actionable. While I love a good engineering pursuit - for the fun of it - I probably couldn't tell the difference between an 8.0 kg bike and an 8.2 kg bike on the road.