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milesenoell
Dec 8, 2009, 8:54 PM
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I am curious if there is any good reference for the affect of temperature on the various climbing shoe rubbers on the market currently. I have read some of the threads on the subject and seen that people seem to think that colder weather (40-55 degrees F) is optimal for a few of the most popular rubbers, but I'd like to find a bit more info if it is available.
For instance, are we talking about air temp or rock temp (I'm assuming it's not shoe temp, but maybe)?
Does it matter if you just put your shoes on and they are basically air temp or if you they have had a chance to warm up on your feet?
Does the friction deteriorate more rapidly as temps drop below or rise above optimal?
Any feedback would be great.
(My own experience with climbing on a 34 degree F morning after a 14 degree F night on rocks that don't get sun until mid-day, suggests that that is cold enough to have moved out of the optimal range and into the crappy friction range.)
(This post was edited by milesenoell on Dec 8, 2009, 8:59 PM)
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subantz
Dec 8, 2009, 9:03 PM
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Its a sticky situation any way you step on it...
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lena_chita
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Dec 9, 2009, 3:35 PM
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Must bite my tongue...
I don't know the exact range for different types of rubber.
But I can report from recent first-hand experience that at 23F friction is not the best... 45F seems really good.
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milesenoell
Dec 9, 2009, 8:20 PM
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I was hoping for some official-ish reference if it existed, but I expect that it probably just doesn't. In the absence of hard data I appreciate any personal experience, so thanks for offering up yours Lena. No need to bite tongues around here. Well, at least not on this subject.
I figured that there was a good chance this one would never actually have any on topic responses, but that the off topic responses would be more entertaining.
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curt
Dec 9, 2009, 8:28 PM
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5.10 once published that their rubber had maximum friction around 50 F, and I think that's probably typical of most climbing shoe rubbers. When Mad Rock first came out with their shoes, they used to have a tag on them saying that their rubber worked best at around 75 F. That's about all I can contribute--for whatever it's worth.
Curt
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milesenoell
Dec 9, 2009, 8:37 PM
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Thanks for the info Curt. That is definitely the kind of info I was looking for.
(This post was edited by milesenoell on Dec 9, 2009, 8:38 PM)
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seatbeltpants
Dec 9, 2009, 9:01 PM
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good questions - I'm intersted in this as well.
i have a follow up questions too. if the optimum temperature for 5.10 rubber is 75F but many people climb when it's either much cooler or significantly warmer, why don't shoe companies offer hot and cold weather options for their rubber? i'm pretty sure that'd be a popular idea - i know i'd prefer to have a winter pair of shoes that worked best in the cold if it meant i could have a summer pair which worked equally well in the heat...
steve
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minorclimber
Dec 9, 2009, 9:16 PM
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This is really interesting, but are we talking air temp. or rock temp.?
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milesenoell
Dec 9, 2009, 10:09 PM
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Hey now, no poaching my question.
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tomcat_ct
Dec 9, 2009, 10:36 PM
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I personally don't fell that there is a lot of difference in the higher temp range but in the low temperature range(0-5C, I can't really climb if it's colder than that) I feel that the rubber starts to become stiff and I loose a lot of grip.It starts to feel like some sort of cheap plastic but it may also have something to do with loosing some of the sensation in my feet bellow 5C if I'm wearing climbing shoes with no socks.
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milesenoell
Dec 9, 2009, 11:02 PM
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tomcat_ct wrote: I personally don't fell that there is a lot of difference in the higher temp range but in the low temperature range(0-5C, I can't really climb if it's colder than that) I feel that the rubber starts to become stiff and I loose a lot of grip.
That was my experience, and prompted my post.
In reply to: It starts to feel like some sort of cheap plastic but it may also have something to do with loosing some of the sensation in my feet bellow 5C if I'm wearing climbing shoes with no socks.
No doubt. I was very aware that numb fingers don't have the same grip.
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skiclimb
Dec 10, 2009, 2:32 AM
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OMFG
just freaking climb pussies.
i can climb 11.a at 54F but only 10d at 85f
those bastard rubber manufacturers are trying to keep da man dowwn
I dont give a crap how it climbs till it's -30f
the rest is all PRACTICE!
PRACTICE! we're talkin bout PRACTICE!!!!
BTW chalk dosnt work very fucking well when on GLOVES
(This post was edited by skiclimb on Dec 10, 2009, 2:40 AM)
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milesenoell
Dec 10, 2009, 3:16 AM
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I should probably have titled this thread "at what temperature does friction start to suck". I'm not really as concerned with optimal performance, but was definitely struck by the crappy performance of the rubber at low temp. To be honest though, I just switched from friction-y face climbs to jamming up cracks and it ceased to matter.
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tomcat_ct
Dec 10, 2009, 10:16 AM
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Well most of the climbing I do is on limestone so the majority of the routes are face climbs so I definitely fell the cold having an impact on how hard I can climb.The main problem I have is that the rock quickly drains heat from my hand and they start to get numb so I can't fell how hard I am gripping the holds so I tend to overgrip everything, even those huge jugs.The fact that my shoes feel like plastic just adds to the frustration.
I'm not saying that one shouldn't climb when it's cold and I definitely believe that if you climb enough in cold temps you can learn how to control yourself and get used to the limitations the shoes have and adapt to the new environment.
But since where I live off season is December-March, I tend to only climb in a gym during this time and go mountaineering when I want to go outside.It's much more fun to play with snow, ice and easier rock than have my rear end freeze at the crag.
Anyway, if you look at it from a different perspective, you have a lot more to wait for those 3 months of snow and ice than you have to wait for those other 9 months of rock.
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Bats
Dec 10, 2009, 1:17 PM
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That's a good one USNavy...
I find that if I put hand warmers in my shoes before I climb, it seems that my feet are sticking to the rock a lot better. I am not worry about the rubber, I am worry about numb toes where I can't feel the rock. That is the only friction issue I ever had with cold weather.
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airscape
Dec 10, 2009, 1:37 PM
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I think this topic is in need of some random graphs.
You know, for science.
Random Graphs of stuff:
This is an interesting one.
And so is this:
I hope this answers your question.
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joeforte
Dec 10, 2009, 2:16 PM
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That first graph is good, but the second graph is total crap! Whoever plotted that thing has NO IDEA how friction and temp are related.
On a more serious note, I believe that rubber-on-rock friction increases with temp.
Take it with a grain of salt, this is my non-technical opinion:
Colder temps make the rubber harder, and warmer temps make it softer. This is similar to why drag-racers do burnouts to warm up their tires. If not, why wouldn't they just design a tire rubber that had maximum friction at ambient temperature?
Can anyone cite a source that shows the coefficient of friction of a rubber going down with an increase in temp? I'd be interested in knowing if and why this can happen.
I think the major difference in friction, when climbing at lower temps (40-50s) is SKIN to ROCK friction. Slopey problems are much easier at these temps, most likely due to less perspiration on your hands. I've never felt limited by shoe friction in warm weather (unless it was super humid), however I always feel limited by skin friction in warmer weather.
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dynosore
Dec 10, 2009, 2:27 PM
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Rubber and most other elastomers have a "glass transition" (Tg) point, at which they go from flexible to brittle. I've climbed at below freezing, and my Moccasyms were noticeably less useful.
I could formulate a compound that has a low Tg and max friction at low temp, but it would have low strength. The most common way to lower glass transition temp is to use oils and extenders in the rubber compound, but these compromise the physical properties significantly. There's always a balance between properties, cost, processibility, and a host of other factors.
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curt
Dec 10, 2009, 3:05 PM
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joeforte wrote: On a more serious note, I believe that rubber-on-rock friction increases with temp. Take it with a grain of salt, this is my non-technical opinion: Colder temps make the rubber harder, and warmer temps make it softer. This is similar to why drag-racers do burnouts to warm up their tires. If not, why wouldn't they just design a tire rubber that had maximum friction at ambient temperature? Can anyone cite a source that shows the coefficient of friction of a rubber going down with an increase in temp? I'd be interested in knowing if and why this can happen...
You're not looking at it correctly. If you start with climbing shoe rubber at zero degrees F (for example) and begin increasing the temperature, the coefficient of friction will indeed go up. But, for each rubber, there is some temperature at which the coefficient of friction peaks--and then decreases with a further increase in temperature. By the way, this is actually because the rubber is getting softer. After a point, softening of the rubber no longer enhances the ability of the shoe rubber to "stick" to the rock--it actually does exactly the opposite.
Curt
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blueeyedclimber
Dec 10, 2009, 3:21 PM
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USnavy wrote: seatbeltpants wrote: why don't shoe companies offer hot and cold weather options for their rubber? Because its not that important. Working on your technique and strength will do a hell of a lot more for you then figuring out the optimal shoe temp. When Sharma wakes up do you think he says, "fuck, its not the optimal temperature for maximum friction today, I am going back to bed"? 
YES. That's EXACTLY what I think he says.
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villageidiot
Dec 10, 2009, 4:40 PM
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curt wrote: You're not looking at it correctly. If you start with climbing shoe rubber at zero degrees F (for example) and begin increasing the temperature, the coefficient of friction will indeed go up. But, for each rubber, there is some temperature at which the coefficient of friction peaks--and then decreases with a further increase in temperature. By the way, this is actually because the rubber is getting softer. After a point, softening of the rubber no longer enhances the ability of the shoe rubber to "stick" to the rock--it actually does exactly the opposite. Curt
From statistical mechanics you can derive a relationship showing that th elastic modulus of a crosslinked network, like that found in show rubber, is proportional to the temperature. Meaning that the elastic modulus increases with temperature. While I am not sure exactly what you mean by "softer" I doubt that climbing shoe rubber actually gets softer at higher temperatures.
I am also pretty suspicious of you first claim that there is a maximum of the friction coefficient with respect to temperature. In "Viscoelastic Properties of Polymers" there is a master curve for the friction coefficient versus velocity. This curve was formed by time-temperature superpositioning according to the WLF equation. I believe this would imply that the friction coeffiecnt incerease monomtonically in a rubber.
Edited:
Your description is consistent with the material undergoing a glass transition. I just find it unlikely that many climbers climb in temperatures were that type of behavior is relevant. I was climbing in 35F a couple weeks ago and the soles of my shoes still did not seem glassy.
(This post was edited by villageidiot on Dec 10, 2009, 5:22 PM)
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seatbeltpants
Dec 10, 2009, 7:06 PM
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USnavy wrote: seatbeltpants wrote: why don't shoe companies offer hot and cold weather options for their rubber? Because its not that important. Working on your technique and strength will do a hell of a lot more for you then figuring out the optimal shoe temp. When Sharma wakes up do you think he says, "fuck, its not the optimal temperature for maximum friction today, I am going back to bed"?
what a fucking retarded statement. seriously.
if you're on a slab, standing on a shit hold that has enough surface area and texture to generate enough friction with your shoe to just manage to hold 70kg, but need to put 71kg of weight on it to step up, you will slip off. if another rubber - be it another company's rubber, or perhaps one designed to work best at the current temperature - can generate enough friction against the hold to hold 71kg then you may be able to complete the move.
all things being equal, why the hell would a different rubber not make a difference? are you stating that all rubbers are the same? you must know that's bullshit - try climbing in a pair of mad rocks and tell me that. i don't have any data to quantify the difference temperature makes to friction but even if it's 1% that'll still mean the difference between slipping or not in some instances - if you can use different rubbers to maximise friction at different temps why not do it?
In reply to: When Sharma wakes up do you think he says, "fuck, its not the optimal temperature for maximum friction today, I am going back to bed"?
honestly, wtf? climbers - particularly on slabs - say that all the fucking time.
are you on crack?
steve
edited to apologise for getting a bit excited. frustrating morning at work - no excuse, though. sorry!
(This post was edited by seatbeltpants on Dec 11, 2009, 1:25 AM)
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curt
Dec 10, 2009, 11:31 PM
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villageidiot wrote: curt wrote: You're not looking at it correctly. If you start with climbing shoe rubber at zero degrees F (for example) and begin increasing the temperature, the coefficient of friction will indeed go up. But, for each rubber, there is some temperature at which the coefficient of friction peaks--and then decreases with a further increase in temperature. By the way, this is actually because the rubber is getting softer. After a point, softening of the rubber no longer enhances the ability of the shoe rubber to "stick" to the rock--it actually does exactly the opposite. Curt From statistical mechanics you can derive a relationship showing that th elastic modulus of a crosslinked network, like that found in show rubber, is proportional to the temperature. Meaning that the elastic modulus increases with temperature. While I am not sure exactly what you mean by "softer" I doubt that climbing shoe rubber actually gets softer at higher temperatures. I am also pretty suspicious of you first claim that there is a maximum of the friction coefficient with respect to temperature. In "Viscoelastic Properties of Polymers" there is a master curve for the friction coefficient versus velocity. This curve was formed by time-temperature superpositioning according to the WLF equation. I believe this would imply that the friction coeffiecnt incerease monomtonically in a rubber. Edited: Your description is consistent with the material undergoing a glass transition. I just find it unlikely that many climbers climb in temperatures were that type of behavior is relevant. I was climbing in 35F a couple weeks ago and the soles of my shoes still did not seem glassy.
All you need to do is stand on a very tenuous friction foothold (for example, one that you can just barely stand on at 55 degrees F) and then go back at, say, 90 degrees F with the same pair of shoes on and just try to stand on the same hold. I guarantee you will not be able to do so.
So, if you want to claim that what you are experiencing is not a decrease in the coefficient of friction, that's fine (and I might even agree with you) but the effect is the same.
Curt
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milesenoell
Dec 10, 2009, 11:32 PM
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USnavy wrote: seatbeltpants wrote: why don't shoe companies offer hot and cold weather options for their rubber? Because its not that important. Working on your technique and strength will do a hell of a lot more for you then figuring out the optimal shoe temp. When Sharma wakes up do you think he says, "fuck, its not the optimal temperature for maximum friction today, I am going back to bed"?
I think that it would be ridiculous to think that top climbers don't factor for temperature, especially if they are considering pushing their limits on friction intensive climbs. That isn't to say that they would not climb, or even choose not to climb slabby stuff, but I would expect it to be part of their mental calculus.
I find it a little funny that someone from a place that doesn't get cold is trying to say that cold doesn't matter. Especially after climbers from cold climates have all chimed in to describe their experiences of bad friction on especially cold days.
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