Accurate Frame Weighings, what do you use?

[SkipdiverJohn]

Since I've now got a nice little collection of older steel machinery, including some high quality ones made of various types of Reynolds tubing, curiosity has got the better of me and I want to be able to weigh them with more accuracy than using a Fisherman's spring scale. Can anyone recommend a scale that is not overly expensive, is sufficiently accurate, and will go high enough to weigh a complete bike as well, not just the frame? I've seen loads of different luggage scales online and wondered if anyone has a particular preference?

 

[newfhouse]

Since I've now got a nice little collection of older steel machinery, including some high quality ones made of various types of Reynolds tubing, curiosity has got the better of me and I want to be able to weigh them with more accuracy than using a Fisherman's spring scale. Can anyone recommend a scale that is not overly expensive, is sufficiently accurate, and will go high enough to weigh a complete bike as well, not just the frame? I've seen loads of different luggage scales online and wondered if anyone has a particular preference?

What counts as sufficiently accurate or precise? My digital bathroom scales have a resolution of 0.1 kg. They may not be NPL accurate but they do seem consistent. I reduce measurement errors (and make life easier) by holding the bike, frame, whatever and then subtracting my own unladen weight. I suspect it’s a method that is less useful for lighter objects below a few kilos, but my kitchen scales work up to 5 kg.

 

[SkipdiverJohn]

100g is nearly a quarter of a pound, so no good for weighing a bare frame. I'd want accuracy to within an ounce or so if weighing a frame, because the difference between two butted steel frames of the same size but different wall thicknesses is only going to be in the order of a few ounces, and light things are more difficult to weigh accurately than heavy things because any tolerances are greater in percentage terms. When I weigh myself on my analogue bathroom scales I'm not bothered if the reading is a pound or two out, because I weigh roughly 200 ponds, but if I'm weighing something that may only weigh between five and six pounds, every ounce matters.

 

[newfhouse]

I'd want accuracy to within an ounce or so

I understand.

if I'm weighing something that may only weigh between five and six pounds, every ounce matters.

I‘m trying to imagine some ultra light weight method of balancing a frame on kitchen scales, and failing.

How about making a wooden beam balance and calibrating it using old fashioned greengrocers’ weights?

I’m sure someone will be along in a moment with more sensible suggestions...

 

[rogerzilla]

Digital kitchen scales. Accurate to 2g. They agree exactly with the ones at the post office, too.

For an accurate bare frame weight you have to knock out the headset cups or make suitable compensation.

 

[winjim]

I’m sure someone will be along in a moment with more sensible suggestions...

Buy a suspension balance would be my suggestion. Something like this, max 15kg with a 10g delta means it should manage most whole bikes, or 30kg with a 20g delta for heavier stuff. 5kg with a 5g delta would be more precise for just frames. Only €92.82 including (German) VAT, shipping within the EU ought to be a doddle.

https://www.kern-sohn.com/shop/en/industrial-scales/hanging-scales-crane-scales/HDB-N/HDB-XL

 

[winjim]

Do consider that the more accurate and precise you want your measurements to be, the more important it is to think about regular calibration, although to be honest, for amateur bike stuff you can probably let that slide a bit.

 

[SkipdiverJohn]

For an accurate bare frame weight you have to knock out the headset cups or make suitable compensation.

I understand that, but if I weigh all my frames with the headsets and BB axles intact, but everything else removed, the results will still be meaningful - since any given headset and square taper BB is pretty much like any other.
maybe I should say I'm most interested in the differences in weight between say a frame made of no-name gas pipe, a Raleigh 18-23, a R500, R501, R531 main tubes, R531 tubes & forks, and a full R531ST frame. It's the incremental differences that interest me more than the absolute weight.
I'm leaning towards some kind of luggage scales for hanging a suitcase off by it's handles, as it's easier than trying to balance a frame on platform scales.

 

[Gravity Aided]

I use an airline baggage scale. Inexpensive, digital ones are quite accurate. I also use them for weighing panniers after packing to determine balance.

 

[winjim]

Inexpensive, digital ones are quite accurate.

How are you assessing their accuracy?

 

[Gravity Aided]

Against a known weight.

 

[Stompier]

I understand that, but if I weigh all my frames with the headsets and BB axles intact, but everything else removed, the results will still be meaningful - since any given headset and square taper BB is pretty much like any other.
maybe I should say I'm most interested in the differences in weight between say a frame made of no-name gas pipe, a Raleigh 18-23, a R500, R501, R531 main tubes, R531 tubes & forks, and a full R531ST frame. It's the incremental differences that interest me more than the absolute weight.
I'm leaning towards some kind of luggage scales for hanging a suitcase off by it's handles, as it's easier than trying to balance a frame on platform scales.

How will you use this knowledge of small differences in frame weight, when you have it?

 

[SkipdiverJohn]

How will you use this knowledge of small differences in frame weight, when you have it?

I may not use it in any practical sense but I am curious all the same. Some of my bikes feel noticeably different to ride than others, some less so. One 531 frame in particular rides very well even on relatively skinny tyres pumped up fairly hard, and I'm interested to see if there is much correlation between the amount of steel in my frames and their perceived ride qualities, or whether geometry differences play a bigger role. I won't be binning anything just because it weighs half a pound more than something else.

 

[rogerzilla]

Bare frame weight is a good guide to tubing quality and useful for exposing fakes. That "Hobbs" I was sold on eBay had a bare frame weight of over 5 1/2 lb, which is gaspipe. Even plain gauge 531, main tubes only, is only a touch over 5lb in that size.

 

[woodbutcher]

I use this , accurate to two decimal places. (maybe even three dec. places ) and you can change the settings from metric to imperial if you prefer !

Chinese of course but simple to use with a nice big hook that usually fits under the saddle rim if lm weighing the whole bike .