Park Tool DS-1 Hanging Scale & Table Top Scale

[2ndgen]

I just picked up a set of Park Tool scales.

What's the best way to test them for accuracy?

Thanks.

[5 8 5]

Some scales have a calibration feature. You have to use a specified calibration weight to check the accuracy.
I don't think either of your scales have this feature. Best thing to do is weigh something (eg a wheel) on both.
The small scale should be more accurate (2g resolution) whereas the hanging scale is 20g.

[Rippin]

A calibration weight kit would do the trick (search the internet).

[goodboyr]

There is another thread on this forum complaining about the accuracy and repeatability of the DS-1. However, I just got one and there is a trick to using it. When I first tried it, I checked it against a 20 kg test weight that I had previously checked via post office scales. I use the test weight to check the calibration on my Quarq. The DS-1 was off by several percent. And every time I shut it off, turned it on and tried again I got a different reading. Then I noticed that there is a "tare" button on the device. I assumed that it zeroed itself when you turn it on. When I used the tare button, it read spot on. So the trick with the DS-1 is to tare it first after you turn it on. If you just turn it on without doing that, it can be out by several percent, and it is not repeatable. When I tared it, it read within .02% of the test weight.

[2ndgen]

Thanks guys.

Will take all these suggestions into account.

My bike at the shop came in at 16.5lbs with accessories (roughly bike + .85lbs).

On the DS-1, it read 17.01lbs consistently with the KK wireless computer (sans cadence sensor),
Arundel Mandible Cages and the Topeak Carbon Micro Rocket Pump all mounted.

One of them (or both) have to be wrong.
Will let you know what I come up with.

[2ndgen]

Update:

So, I weighed my CAAD9 on a bathroom scale.
I got 16.40lbs (as compared to the LBS's 16.50lbs weight).
[With Arundle Mandible Cages, Kurt Kinetic Speed Sensor & Magnet, mounting
brackets for KK Computer & for Topeak CR Micro Rocket Pump still mounted.]

My DS-1 is more likely to be off at 17.01lbs.
I'm going to try goodboyr's method and see what I get.
I've picked up a 14lb Scott and my CAAD is way way closer to it than to my 19lb Lager SS.

[2ndgen]

There is another thread on this forum complaining about the accuracy and repeatability of the DS-1. However, I just got one and there is a trick to using it. When I first tried it, I checked it against a 20 kg test weight that I had previously checked via post office scales. I use the test weight to check the calibration on my Quarq. The DS-1 was off by several percent. And every time I shut it off, turned it on and tried again I got a different reading. Then I noticed that there is a "tare" button on the device. I assumed that it zeroed itself when you turn it on. When I used the tare button, it read spot on. So the trick with the DS-1 is to tare it first after you turn it on. If you just turn it on without doing that, it can be out by several percent, and it is not repeatable. When I tared it, it read within .02% of the test weight.

Did the test finally. (just got back from my trip)

My CAAD9 is 16 lbs 10 oz without accessories (consistently time after time).

So, I need to drop another 300g to get down to the 15lb range.
But now, I'm actually thinking about going down to 14lb just out of spite!

EDIT:
DS-1 Hanging Scale and DS-1 Tabletop Scale are within 1g of each other. Not bad.
At least now I know I have a good reference point to work from.
Thanks goodboyr!

[2ndgen]

I've got my bike now at 15.87lbs/7210g (I think).

I wondered if my handing scale being out of plumb would cause a misreading in the scale.
So, I played around with it. When plumbed (with a level), I consistently got 7210g.
When it was slightly tilted to one side by a mere 1 cm, I'd get 7240g.
When it was slightly tilted to the other side by a mere 1cm, I'd get 7150g.

Question:
Which would be the most reliable weight there?

a) The heaviest
b) Or the lightest weight
c) The middle weight when perfectly plumbed

Of course I'd love the lightest weight, but I'm going to assume
that the scale is most accurate when in a plumb position.

[Rick]

I work in a place that has a very rigorous calibration program for all our scales, and we have a lot of scales. So I just take something to work, weigh it, then bring it home and re-weigh on my Park DS-1. It is always within 1 gram.
Find someone who works with a calibrated scale and just compare weights.

I think the vertical reading would have to be most accurate, since that is the way it was intended to be used and is undoubtedly calibrated that way. Similarly, all table top scales should be on a surface that is absolutely level. Our calibrated scales have bubble levels and adjustable legs so they can be levelled precisely (the bubble levels are also calibrated!)

If your table is slanted by about 5°. it will make the reading appear light by about 4%

[2ndgen]

I work in a place that has a very rigorous calibration program for all our scales, and we have a lot of scales. So I just take something to work, weigh it, then bring it home and re-weigh on my Park DS-1. It is always within 1 gram.
Find someone who works with a calibrated scale and just compare weights.

I think the vertical reading would have to be most accurate, since that is the way it was intended to be used and is undoubtedly calibrated that way. Similarly, all table top scales should be on a surface that is absolutely level. Our calibrated scales have bubble levels and adjustable legs so they can be levelled precisely (the bubble levels are also calibrated!)

If your table is slanted by about 5°. it will make the reading appear light by about 4%

Thanks Rick.

I'm betting the most plumb position is the most accurate too.

[PoorCyclist]

Very interesting,
I found almost .4 lbs difference after I tared my feedback sports scale and tried to get more plumb.

It would seem, plumb would have the least friction and most accurate.


So does the alignment of the moon affect the reading too?

[2ndgen]

So does the alignment of the moon affect the reading too?

If it does, when cycle of the moon would give me the lightest readings?

[PoorCyclist]

So does the alignment of the moon affect the reading too?

If it does, when cycle of the moon would give me the lightest readings?

Probably full moon when it reflects the most "light" matter, take it out to your yard and weight it to get the best weight.

[Jamescarter]

Both of them are good scales but hanging scales are more accurate as compare to others . If i had to bought a scale i will prefer hanging scale because these are available in low prices with good quality !