marks
 Cred: 8131 (Admin) Joined: Mar 05 |
| Posted: November 20th, 2008 Edited: November 20th, 2008 | Quote, Reply |
This discussion is regarding: Climbing Rubber Test
If you climb make sure you check out the first test in the newest addition of Spadout "SpadLab". We'll be doing hundreds of tests to help you select the greatest gear on the market. During this test we tested all the climbing rubbers on the market to determine which was the stickiest.
Results: Climbing Rubber Test
Feedback is greatly appreciated. |
we_dodger@yahoo.com
 | Posted: November 21st, 2008 Edited: November 21st, 2008 | Quote, Reply |
I know that the coefficent of friction is highly dependent upon the tempature of the materials. how was this simulated for climbing on real rock? how did 68 become a standard? I don't think that each material changes similarly through temperature changes??
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Sakshama
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It is a great test, thank you for doing it. I would like to know how the rubbers will behave on full human weight and different weights. Depending on the manufacturing technology there should be differences and maybe some more science will come out off it in form of some curves of weight to angle ratio. |
manacubus
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Thanks for doing this. I love talking climbing rubber, and this is a great first step. It is an interesting test, however it's not overly relevant without consideration of temperature and rubber deformation.
A manufacturer could easily make a very soft rubber which would blitz your test rig, but be completely useless for climbing because it would deform and fail while edging. It's a constant balance.
Similarly, a manufacturer may make a rubber which excels at a temperature of 4 degrees Celcius (which is the temp most rubbers are designed to be optimal) but which is complete crap at 25 degrees. Consistent usability over a range of temps is also a constant balance.
I would like to see your friction test, along with an edge deformation test, at a range of temperatures. Now THAT would yield some truly useful and interesting results. |
marks
Cred: 8131 (Admin) Joined: Mar 05 |
| Posted: November 21st, 2008 Edited: November 21st, 2008 | Quote, Reply |
Great feedback thanks.
Regarding temperature:
68 degrees (obv. Fahrenheit) was decided upon because it was the standard temperature of the lab and therefore made the test as simple and as easy to control as possible. 68 degrees is not an unusual climbing temperature but your correct so is every temperature from 32 - 90 degrees (and die hard climbers on both extremes).
Regarding weight:
We wanted to do a slide test that operated by increasing the angle of the granite (or plastic) because we believed this would better relate to the climber's experiences. We also did not want to use samples of the rubber provided by the manufacture (which could have provided larger sample sizes) because they could manipulate their sample. This limited us to a maximum consistent sample size of 2x2 inches. The real challenge then was creating a heavy enough weight that would not flip the sample during the steep tests. This lead to the decision to use the 15oz, low profile weight.
Future Tests
We're all for doing future tests. Obviously we still have all the rubber samples ready to go. We could do a climbers weight (though what is a fair amount of weight to put on a 2x2 inch space to reflect climbing is an interesting discussion by it self). This would have to be a spring scale test to avoid the flipping problem.
Variable temperature is also an option so keep the feedback coming. It is relatively difficult to have a static temperature of the slab without having the entire room at that temperature. So we could do some tolerance by changing the room's temperature then do cold temperatures outside. |
t99d33
| Posted: November 21st, 2008 Edited: November 21st, 2008 | Quote, Reply |
A way you could increase the weight is to hang it from a point drilled in the top of the steel plate.
You may need to glue the plate to the rubber.
Drill a pit in the center of the plate deep enough to accept a sharp point.
Make a question-mark shaped hanger for the weight with a sharp point on one end that fits into the pit. The hanger then circles around and down below the sample approx 2 feet so when you put a weight on it, the center of gravity will be very low and stable. So it will just hang off the point in the pit.
An edging test could be done by making the hangar attach rigidly to the sample, so the sample can't rotate. YOu would need to shape the edge of each sample so they are all uniform - simulating a moderately worn edge. Keep the center of gravity well below the sample. This time you want the weight hanging right below the edge, not below the center of the sample.
I like the test at 68 F better than something colder since higher temperatures are where shoes tend to slip.
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Climber625
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This study is curious given that the results have little to no relation to both my personal experience with the ability of different climbing rubbers and what the shoe companies think about the rubbers. Stealth Onyx rubber performing better than Stealth HF? Or how about the FriXion RS and Vibram XSV better than the Vibram XS. There is obviously a lot more going on here and this study seems to have little validity for actual climbing. |
wuontherock
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Nice,
Good job guys; I wish I had the time & money to do stuff like that.
Depending on the time & funding you have, you could test a range of temperatures & weights. You could find that the best rubbers may be different for light / heavy climbers, cold / hot temperatures or combinations... that'd be neat.
It would also be useful to see how consistent the angles were. If the angles varied alot more than the average differences among rubbers, then the average differences may be trivial.
You could do a really easy stats test to show which (if any) rubbers are "significantly" better or worst than others. Heck, if you post all the raw data (individual measures used to calculate means), I'll be happy to do it! Same goes if you do extra tests.
Keep up the good work,
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helios
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Lots of good feedback regarding weight and temperature. However, before spending too much time and effort into perfecting real world conditions, I would try to establish some sense of validity in the method. Could you add a negative control or two? Simply repeat exactly this experiment on rubber you know does not perform well as a climbing rubber. I suggest sneaker rubber or a standard "non-sticky" rubber. (Of course most sneakers will have tread, so good luck with that.)
If either of these controls produce a high result, then we know you need to go back to the drawing board. |
Troy
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helios said:
Lots of good feedback regarding weight and temperature. However, before spending too much time and effort into perfecting real world conditions, I would try to establish some sense of validity in the method. Could you add a negative control or two? Simply repeat exactly this experiment on rubber you know does not perform well as a climbing rubber. I suggest sneaker rubber or a standard "non-sticky" rubber. (Of course most sneakers will have tread, so good luck with that.)
If either of these controls produce a high result, then we know you need to go back to the drawing board. |
We had a negative control which was an old well used madrock shoe (we just didn't post it's results), but a cheap tennis shoe wouldn't be a bad idea.
We also repeated the test with several of our shoes by cutting two pieces of rubber the same way then testing them. We got results that were exactly the same by testing in that manner (which really means that any difference cutting had on the micro level was below the level of detection of our test).
Furthermore, we verified our findings AGAIN by doing a pull test with a larger weight (we used a pull force scale and a pulley system to test), and observed that the rubbers stacked up in the same manner.
So, we think (unless science and rubber are both colluding against us) our findings are good... and we welcome anyone else to repeat our tests, or any suggestions about more controls. Now what the results MEAN, however, and how they are interpreted is quite another story.
We have a test on the drawing boards to measure how well a shoe edges, and another test which will shed some light on durability issues. Unfortunately (or fortunately, depending on how you view it), we've got a couple other tests coming up that will get done before we are able to revisit this test. |
joeleol
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my personal opinion regarding rubber i have used in order from most to least sticky:
five ten HF
five ten C4
Evolve
Sportiva
five ten ONYX
Mad Rock
Boreal |
nhluhr
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I'm sure I'm echoing another post but it is well known that although there is a "Coefficient" of friction, it is absolutely not constant as often imagined. Temperature, pressure, humidity, etc all come into play in defining the coefficient of friction between two surfaces.
I'd like to see this test reproduced over a range of temperatures and also over a range of pressures (maybe rig a spring to apply a set amount of force and use a spring scale to pull the sample, thusly giving you a force required vs force applied.
This would result in a temperature/pressure dependent SURFACE chart for the coefficient of friction... (like, a 3d topo chart). You would only have to do like 4 temperatures and 4 pressures but it would be good to illustrate how each brand of rubber responds to these variables. I would recommend a HOT, Room Temp, Cool, and Freezing temp (to simulate the temperatures climbers most frequently find themselves). For pressure, everything from sample mass alone to full body weight on the sample size if you can rig it. |
marks
Cred: 8131 (Admin) Joined: Mar 05 |
| Posted: December 4th, 2008 Edited: December 4th, 2008 | Quote, Reply |
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nhluhr said:
I'm sure I'm echoing another post but it is well known that although there is a "Coefficient" of friction, it is absolutely not constant as often imagined. Temperature, pressure, humidity, etc all come into play in defining the coefficient of friction between two surfaces.
I'd like to see this test reproduced over a range of temperatures and also over a range of pressures (maybe rig a spring to apply a set amount of force and use a spring scale to pull the sample, thusly giving you a force required vs force applied.
This would result in a temperature/pressure dependent SURFACE chart for the coefficient of friction... (like, a 3d topo chart). You would only have to do like 4 temperatures and 4 pressures but it would be good to illustrate how each brand of rubber responds to these variables. I would recommend a HOT, Room Temp, Cool, and Freezing temp (to simulate the temperatures climbers most frequently find themselves). For pressure, everything from sample mass alone to full body weight on the sample size if you can rig it. |
Thanks for the feedback! I agree multiple temperatures would be an excellent test and we are in the process of designing a suitable test. We're also interested in measuring edging power and durability. So keep the feedback coming. It will take ~ a month to get you guys the next test because we're really going to step up the range of tests. The number of readers (about 30k unique readers in 2 days) allows us to invest in this research so expect great things.
Everyone: thanks again for the feedback. In the mean time enjoy a couple new tests coming out in the next week! |
darrenv04
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Hey guys, great work. And a great first step. The static friction that you have measured is only part of the picture. In this experiment there is a very limited load on the samples. The samples do not experience any of the deformation that they would in a real climbing situation. In a real climbing situation what is important is how the rubber deforms around the small imperfections in the granite when there is a much larger load. A softer rubber will likely perform much better. This is the "weight issue" that keeps coming up. Put 75 lbs on a quarter sized piece of rubber. Place the rubber on a level piece of granite and see how much force is required before the initial slip. (this is similar to what you described to verify you results, now just do it which weight). (75 lbs if you assume a 150 lb guy with weight spread evenly between his two feet. And I used a quarter b/c who really stands on a 2x2 in section anyway). I would love to see the results of this test. I believe they could be very different. |
jrmontag
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Just came across a blog with some more info on friction as relates to climbing (as a physicist in training, this stuff intrigues me to no end!). Thought folks might enjoy the read:
http://www.theshortspan.com/features/friction.htm
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marks
Cred: 8131 (Admin) Joined: Mar 05 |
| Posted: December 8th, 2008 Edited: December 8th, 2008 | Quote, Reply |
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jrmontag said:
Just came across a blog with some more info on friction as relates to climbing (as a physicist in training, this stuff intrigues me to no end!). Thought folks might enjoy the read:
http://www.theshortspan.com/features/friction.htm
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Ya that's a good article. There are so many interesting elements in play here. The next rubber test is in the planning and we have some interesting ideas coming our way. Petro Grips just sent us custom samples of their simulated sandstone (imo a very good fake). They made custom, flat (though textured) samples. This will be a great addition.
I'm also interested in testing larger samples on "real world" conditions. This is quite complex to standardize and control (these tests take hours to do so you can't keep the temperature constant outside; therefore all tests need to be done in the lab). |
ajniskan
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One interesting addition would be the rubber used by Millet. It seems they make their own rubber, so it would be nice to know how it compares to the rest :) (at least Replikan and Okto both have the Millet rubber, the most inexpensive model, Rock has something entirely different). |
ABeee
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This test may show the coefficient of friction of each different type of rubber--but the information is actually useless to a climber because the rubbers perform totally differently when they are weighted. Further, climbers of different weights will find some rubbers more sticky than others.
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extremist
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I was here before but I was probably not registered. I believe the testing is exactly what is needed regardless of the exactitudes of the parameters. It is a much needed baseline to establish further experiments.
By putting out any kind of experiment and opening the results to the users we all have a chance to input variables not included that are important to each of us. Temperature, longevity, 'edgibilty', stickyness, and so on.
What is even better is that the companies making these products hear about independent testing and will hopefully make every effort to improve their product. Competition is the game after all. We all win when the manufacturers keep improving the products. Private testing is just one way of the herd being heard. -- ghd |
simonbaker
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Thanks for the hard work doing this test.
I agree with concerns about the weight used. It seems perfectly typical for a climber to put entire weight on tiny part of shoe, such as edging. It would be good to see test with more weight data points, at least with the drag test.
A drag test could be rigged with a heavy pendulum with over-bar like a ski chair lift, with over-bar contact on the rubber.
I just can't understand the summary chart at the top of the article with "overall" scores. How was the overall score arrived at? The mu scores seem much closer together.
It would be nice if you sorted all the lists by best to worst.
Regards,
-SB |
dihhuit
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Most of the forums that I have read agree that Five-Ten makes the best rubber, yet their rubber performed rather poorly in your test...Perhaps you aren't testing the right property of the rubber? The property that makes a good climbing rubber is not its coefficient of friction, but its viscoelastic properties. These rubbers deform under compressive stress, "seeping" into imperfections in the surface, but then remain rigid under shear stress. Like sticking lots of little fingers into the pores of the rock face. I don't know how you would test the viscoelasticity of the rubbers, but that perhaps explains some of the differences between your test results and the real world experiences of some of the climbers who have responded. |
ryanutz
| Posted: September 28th, 2009 Edited: October 2nd, 2009 | Quote, Reply |
I do have a hard time believing that Evolv (although I love their shoes and the company) is stickier than Five-Ten rubber. I remember a sit-down-start boulder problem I was working. I was wearing a pair of Evolvs, and my feet were skating like I was trying to stand up on ice. I switched over to my old reliable Five-Ten Anasazies with the original C4 rubber. I stood up on them like I was standing on the flat ground. Waaaay stickier. |
ryanutz
| Posted: October 2nd, 2009 Edited: October 2nd, 2009 | Quote, Reply |
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marks
Cred: 8131 (Admin) Joined: Mar 05 |
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I can't expand too much on this at this time but lets just say more tests are coming. This has been discussed in great detail but testing rubber in a way that matches all experiences is impossible.
Similarly consumer reports gives cars one overall rating. Obviously different driving styles etc. will create different results.
But good things are coming. |
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