Springs test results
#1
Tech Adept
Thread Starter
Springs test results
A while ago i tested the Xray black springs to work out what the "C" meant, recently i tested some other springs and below are the measured results. I've put them all in Xray "C" values which are N/mm. To convert to lb/in multiply by 5.71.
Xray springs are very accurate to their advertised value.
I tested two of each spring type.
Measured Results
new style HPI springs (black)
Blue - 2.50
Silver - 2.79
Pink - 2.93
Gold - 3.31
Schumacher
white - 2.48
blue - 2.86
Yokomo
Black - 2.20
Blue - 2.24
Yellow - 2.44
Pink - 2.43
Conclusions:
- all springs tested are linear
- HPI Blue (advertised 2.68) is really 2.5
- HPI Silver (advertised 2.96) is the same as an Xray 2.8
- HPI Pink (advertised 3.15) is the same as an Xray 3.0
- HPI blue, silver and pink measured softer than their advertised rate
- Yokomo springs are junk
Hope this clears up a few myths out there
Attached is the full spreadsheet.
Chris...
Xray springs are very accurate to their advertised value.
I tested two of each spring type.
Measured Results
new style HPI springs (black)
Blue - 2.50
Silver - 2.79
Pink - 2.93
Gold - 3.31
Schumacher
white - 2.48
blue - 2.86
Yokomo
Black - 2.20
Blue - 2.24
Yellow - 2.44
Pink - 2.43
Conclusions:
- all springs tested are linear
- HPI Blue (advertised 2.68) is really 2.5
- HPI Silver (advertised 2.96) is the same as an Xray 2.8
- HPI Pink (advertised 3.15) is the same as an Xray 3.0
- HPI blue, silver and pink measured softer than their advertised rate
- Yokomo springs are junk
Hope this clears up a few myths out there
Attached is the full spreadsheet.
Chris...
Last edited by gameover; 04-11-2010 at 03:51 PM. Reason: added attachment
#2
You mention their advertised rates, but what were the actual rates?
#3
Tech Adept
Thread Starter
the actual rates are the numbers shown, the measured results.
#5
Tech Adept
Thread Starter
ok i think i got it working now, forum doesn't seem to like Excel files.
#8
Tech Adept
Thread Starter
i think the issue is in the consistency of the springs. The spec of the HPI silver should make it the same as a 3.0 Xray spring. Maybe some HPI's are actually closer to the specs? You would definitely feel it in that case. I actually tested 3 HPI Silver springs i had and there were all pretty close to each other (within a few %).
Were the springs you tried the new style HPI's, the black one's with the paint mark or the solid colored older style ones?
To test i put a 1.5kg digital scale on my CNC milling machine, put the spring on it, put a shock body and collar into the chuck. I set the height so that the scale is just registering (like 1-2grams), then zero everything. Then i step the mill down in 0.5mm increments and record the weight measured on the scale.
Were the springs you tried the new style HPI's, the black one's with the paint mark or the solid colored older style ones?
To test i put a 1.5kg digital scale on my CNC milling machine, put the spring on it, put a shock body and collar into the chuck. I set the height so that the scale is just registering (like 1-2grams), then zero everything. Then i step the mill down in 0.5mm increments and record the weight measured on the scale.
#9
Have you tried measuring Tamiya springs?
In particular White and blue, as these seem to be the two that keep cropping up.
Skiddins
In particular White and blue, as these seem to be the two that keep cropping up.
Skiddins
#10
Tech Adept
Thread Starter
#11
Tech Champion
iTrader: (9)
[QUOTE=gameover;7259160]i think the issue is in the consistency of the springs. The spec of the HPI silver should make it the same as a 3.0 Xray spring. Maybe some HPI's are actually closer to the specs? You would definitely feel it in that case. I actually tested 3 HPI Silver springs i had and there were all pretty close to each other (within a few %).
Were the springs you tried the new style HPI's, the black one's with the paint mark or the solid colored older style ones?
QUOTE]
I have both old and new, from memory the new black with paint silvers are fractionally stiffer than the old chrome silvers.
For me, the xray spring proves very smooth and stable, where the HPI gives a much more agressive feel with more corner speed.
Were the springs you tried the new style HPI's, the black one's with the paint mark or the solid colored older style ones?
QUOTE]
I have both old and new, from memory the new black with paint silvers are fractionally stiffer than the old chrome silvers.
For me, the xray spring proves very smooth and stable, where the HPI gives a much more agressive feel with more corner speed.
#12
To test i put a 1.5kg digital scale on my CNC milling machine, put the spring on it, put a shock body and collar into the chuck. I set the height so that the scale is just registering (like 1-2grams), then zero everything. Then i step the mill down in 0.5mm increments and record the weight measured on the scale.
The preload you apply also is another source of errors (when you say you zero the scale) as it creates a deflection however small of the spring. This means you're not measuring the actual load needed to deform the spring, but something a bit higher. The fact that the scale reads 1-2 grams does not mean the load is the same either, as explained above.
What you need to use is a dynamometer and a good one at that. Typically, if you want gram accuracy you need .01 accuracy as errors multiply. Similarly, if you quote .01 gram accuracy, you need .0001 accuracy in your measurements to make sure errors are not going to trickle down (actually up) to .01 figures.
#13
Tech Elite
iTrader: (15)
A while ago i tested the Xray black springs to work out what the "C" meant, recently i tested some other springs and below are the measured results. I've put them all in Xray "C" values which are N/mm. To convert to lb/in multiply by 5.71.
Xray springs are very accurate to their advertised value.
I tested two of each spring type.
Measured Results
new style HPI springs (black)
Blue - 2.50
Silver - 2.79
Pink - 2.93
Gold - 3.31
Schumacher
white - 2.48
blue - 2.86
Yokomo
Black - 2.20
Blue - 2.24
Yellow - 2.44
Pink - 2.43
Conclusions:
- all springs tested are linear
- HPI Blue (advertised 2.68) is really 2.5
- HPI Silver (advertised 2.96) is the same as an Xray 2.8
- HPI Pink (advertised 3.15) is the same as an Xray 3.0
- HPI blue, silver and pink measured softer than their advertised rate
- Yokomo springs are junk
Hope this clears up a few myths out there
Attached is the full spreadsheet.
Chris...
Xray springs are very accurate to their advertised value.
I tested two of each spring type.
Measured Results
new style HPI springs (black)
Blue - 2.50
Silver - 2.79
Pink - 2.93
Gold - 3.31
Schumacher
white - 2.48
blue - 2.86
Yokomo
Black - 2.20
Blue - 2.24
Yellow - 2.44
Pink - 2.43
Conclusions:
- all springs tested are linear
- HPI Blue (advertised 2.68) is really 2.5
- HPI Silver (advertised 2.96) is the same as an Xray 2.8
- HPI Pink (advertised 3.15) is the same as an Xray 3.0
- HPI blue, silver and pink measured softer than their advertised rate
- Yokomo springs are junk
Hope this clears up a few myths out there
Attached is the full spreadsheet.
Chris...
#14
Originally Posted by defcone;
Why are yokomo springs junk?
#15
Tech Adept
Thread Starter
I think that is a serious source of errors. Your scale has an error of grams (at best) so I wouldn't rely on the values it reads.
The preload you apply also is another source of errors (when you say you zero the scale) as it creates a deflection however small of the spring. This means you're not measuring the actual load needed to deform the spring, but something a bit higher. The fact that the scale reads 1-2 grams does not mean the load is the same either, as explained above.
What you need to use is a dynamometer and a good one at that. Typically, if you want gram accuracy you need .01 accuracy as errors multiply. Similarly, if you quote .01 gram accuracy, you need .0001 accuracy in your measurements to make sure errors are not going to trickle down (actually up) to .01 figures.
The preload you apply also is another source of errors (when you say you zero the scale) as it creates a deflection however small of the spring. This means you're not measuring the actual load needed to deform the spring, but something a bit higher. The fact that the scale reads 1-2 grams does not mean the load is the same either, as explained above.
What you need to use is a dynamometer and a good one at that. Typically, if you want gram accuracy you need .01 accuracy as errors multiply. Similarly, if you quote .01 gram accuracy, you need .0001 accuracy in your measurements to make sure errors are not going to trickle down (actually up) to .01 figures.
the absolute load on the spring is not critical, actually when i calculate the final rate i ignored the first reading at 0.5mm to remove the variation. It takes the same weight to compress the spring from 1.0mm - 1.5mm as it does from 4.5mm to 5.0mm, its only the relative difference that is important for these linear springs.
Last edited by gameover; 04-11-2010 at 08:39 PM. Reason: wrong words in places