billcoe Posted February 24, 2009 Posted February 24, 2009 Thought this was damn interesting, sorry if it's been posted before. Scale of 1-10 with 10 being best. Evolv TRAX XT-5 9.7 La Sportiva FriXion RS 8.4 Vibram XSV 7.9 Mad Rock FX5 7.9 Vibram XS 7.8 Stealth Onyx 7.3 Stealth HF 6.1 Stealth C4 5.9 Mad Rock Formula #5 4.3 http://www.spadout.com/r/climbing-rubber-test/ Testing Setup The test setup was designed and built by Steven Won, a physicist at CERN and an avid climber. Each sample was placed on the marked portion of the granite. The screw (seen below the granite slab) was rotated, slowly raising the angle of the granite slab until the rubber sample failed. The height of a fixed point on the slab was measured (from the base) to determine the angle of the slab. Average Results in Degrees Granite Plastic Evolv TRAX XT-5 34.27 48.86 La Sportiva FriXion RS 33.94 45.61 Mad Rock Formula #5 28.40 43.80 Mad Rock FX5 32.77 46.21 Stealth C4 30.00 45.18 Stealth HF 28.16 46.68 Stealth Onyx 30.12 47.78 Vibram XS 30.87 48.79 Vibram XSV 29.59 49.48 Shoes from which the rubber samples were attained Evolv Trax XT-5 Evolv Defy La Sportiva FriXion RS La Sportiva Mojo Mad Rock Formula #5 Mad Rock (Old) Phoenix Mad Rock FX5 Mad Rock (New) Phoenix Stealth Onyx Five Ten Galileo Stealth HF Five Ten V10 Stealth C4 Five Ten Mojave Vibram XSV Mammut Goblin Vibram XS La Sportiva Nago Woman XS Grip Sage Details - All test samples were placed on the same location on the granite slab and climbing hold. Twenty slides (using an old climbing rubber) were run on each surface to avoid having the first holds have different results. - All samples were the same length and width (2 x 2 inches). - The weight (15 oz of steel) was used because it was low profile and would not flip during 45+ degree tests. Double sided duct tape was used to attach the top of the rubber samples to the weight. - The bottom (unpolished) portion of a granite counter top was used for the granite tests. - EGrip's Peabody Crimp Plate was used for the climbing hold tests because it had a large enough flat area. - All tests were completed in our lab which had a constant temperature of 68 degrees. - The chart on the back of the device is not used for measuring the angle (we measured the height of a fixed point on the ramp to the base). - A modified bell curve was used to convert degrees into the 0-10 format to make the data more readable. Physics behind the test The quantity we are trying to measure is called the "coefficient of friction," and it is a simple way to quantify the stickiness between two surfaces (in this case, the rubber and the granite or climbing hold). It is defined as the ratio between the normal force (defined as the force compressing two parallel surfaces together) and the frictional force, and is unique to each pair of surfaces. In this experiment, the normal force is being adjusted by changing the angle of the surface with respect to the ground. The advantage of this approach is that it eliminates possible systematic errors involving the weight or surface area of the rubber sample. Mathematically, the coefficient of friction works out to the tangent of the angle between the surface and the horizontal. mu (Granite) mu (Plastic) Evolv TRAX XT-5 0.68 1.14 La Sportiva FriXion RS 0.67 1.02 Mad Rock Formula #5 0.54 0.96 Mad Rock FX5 0.64 1.04 Stealth C4 0.58 1.01 Stealth HF 0.54 1.06 Stealth Onyx 0.58 1.10 Vibram XS 0.60 1.14 Vibram XSV 0.57 1.17 Steven Won is the Huang Fellow at Northwestern University's Department of Physics and Astronomy, and a member of the USCMS collaboration at CERN. He is also a climber. " _____________________________________________________________ Discuss Quote
rob Posted February 25, 2009 Posted February 25, 2009 Bill, I'm gonna kick your ass. Fisticuffs, yr place, tmmrw, 10 o'clock. I do all my ass whoopin' before lunch. Quote
pink Posted February 25, 2009 Posted February 25, 2009 might wanna wear the Evolv TRAX XT-5 boxing edition climbing gloves so u can really stick it to him. Quote
pink Posted February 25, 2009 Posted February 25, 2009 what was the cats name who developed the rubber for mad rock, didn't he design stealth as well or was that someone else. FUCK IT!!!!!!!! Quote
billcoe Posted February 25, 2009 Author Posted February 25, 2009 First ascent of Jolly Rodger ...and Stealth Rubber inventor. ...Charles Cole. ohoMG look, here he is CLIPPING BOLTS in JT (gasp) GASP: _________________________________________________________________ Rob: that was rock paper scissors with stealth rubber cups at 10 paces buddy! _________________________________________________________________ So...is everyone just sitting back quietly and accepting the testing methodology here? Quote
G-spotter Posted February 25, 2009 Posted February 25, 2009 Extensive testing by Boreal with Gullich, Bachar, Hill and Moffatt proved that for two shoes with same rubber, one purple and one green, the purple one climbed better tha the green one. Same thing here. Quote
Peter_Puget Posted February 25, 2009 Posted February 25, 2009 Bill – It would be nice to see the same test performed over a variety of temps.. Then we could compare coefficient profiles over a range of temps. Didn’t Cole’s personal testing indicate that the ability of the rubber not to tear off under loads was an even more significant determinant of real life performance than the coefficient of friction? Quote
tomtom Posted February 25, 2009 Posted February 25, 2009 The best shoe rubber is the one having the most fun. Quote
DavidHiers Posted February 25, 2009 Posted February 25, 2009 Coefficient of friction is just one important specification of rubber. What about ribbed, flavored, glow-in-the-dark, etc? Spadout's results are limited in value, as they don't usually list their assumptions, which for this case include: 1. mu is constant for every normal force 2. mu is constant for every relative humidity 3. mu is constant for every degree of surface roughness 4. mu is constant for every type and amount of surface contaminate (chalk, dust, organics (moss, lichen, etc), etc) 5. mu is constant for all phases of a shoe's life (new in box, broken-in, thrashed) Most of spadout's work seems to be a proof-of-concept for what a testing program might actually look like. The results are valid, but limited by the (usually omitted) assumptions. Quote
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