ditching the koflachs?

[DougPaul]

I would certainly agree that overtightening a boot or crampon will decrease bloodflow and cause colder feet, and in my experience this can happen rather quickly.

Straps and soft boots are pretty obvious, once you think about them. Some of the earlier comments suggested that some might not be aware of the problem, so better mentioned twice than not at all...

As for the impact of cold steel on one's feet - I've noticed this several times when climbing Washington in cold conditions. I've been able to climb this peak safely without crampons many times, but needed them on the way down. Under really cold conditions (subzero), I've noticed a big difference in foot comfort. I'm one of those people whose feet are warmer on the descent, so finding them colder is all the more noticable. But, whether I was wearing step-ins or strap-ons - I don't that - in and of itself - makes any difference.

OK. I don't doubt your percept. I don't recall feeling any difference myself, but then my boots (leather rigid double mountaineering) may be overkill for most situations (my feet were neutral to hot on a recent Lafayette hike and I can generally keep the boots on while camping).

The real experiment would be to put a real crampon on one shoe and a dummy on the other. And somehow, neither the expermenter nor the subject can know which is which (a proper double-blind experiment)...

The physics suggests the effect will not be very large: Assume the air temp is a bit below -10F, the average boot sole is 0F without crampons and -10F with. (Don't forget that the crampons only touch a very small fraction of the outside of the boot.) Then the temp diff between inside and outside of the boot sole would be about 100 deg without crampons and about 110 deg with. Thus there would be 10% more heat loss with crampons. (If the temp diff was the same, then there would be no difference in heat loss.) Of course these numbers are just my guesses, but that is the logic behind my opinion that the additional cooling would be present, but not large.

In the case of your uphill vs downhill, is it possible that the crampon straps shrink the toe of your boot only a small amount? Just enough to only become an issue when your foot is forced forward in your boot by the downhill? When I go downhill wearing crampons, my feet tend to get forced forward in my boot more strongly than without the crampons--is this the cause? Are there physiological or psychological factors operating behind the scenes that I am missing?

The piece of "wisdom" that crampons conduct heat away from one's feet has been around for a long time, but I've never seen good experimental evidence that the effect is really significant.

Obvsiouly, we can still hike without solving this issue. Just another "mystery" that probably will never get properly investigated...

Doug

 

[Kevin Rooney]

In the case of your uphill vs downhill, is it possible that the crampon straps shrink the toe of your boot only a small amount? Just enough to only become an issue when your foot is forced forward in your boot by the downhill?

I don't think so Doug, as it occurs whether I'm wearing crampons or not. In my experience, about 10% of people I've hiked with have this "problem", and it's not the simple problem of not enough gear (i.e., "if your feet are cold put on a hat"). My own theory is that is has to do with differences in circulatory systems and the efficiency of one's pulmonary & cardiovascular systems, because it's obvious that when you're cranking up a hill to the point of sweating yet your feet are cold that something else is happening. Specifically - I think for those of us in this situation our bodies are keeping more blood within the pulmonary circuit at the expense of our extremities. Then, once you head back downhill, requiring comparatively little effort, sufficient blood flow returns, and feet are toasty again.

And yes, I think it would be very tough to investigate this scientifically. Just finding a large enough sample size of very fit winter hikers who experience this problem would be a large obstacle.

 

[spider solo]

Highhorse... I love the Trangos'. They are a partial leather & material hybrid...very similar in apperance to the Asolo boot on the cover of the March Backpacker Gear Guide if you happen to see an issue.

They are not step in crampon compatable (though there maybe step ins' that I'm not familar with) as there is no set-up for a front bale. That is how I was reminded that cinching down the straps could make for chilly feet.

I see Doug Paul and others have already hashed things out about restricting circulation.
It's the same thing with your hands,for example, If you grab hiking poles to tight or snug the straps around your hands they will get colder quicker...on a mild day it may go unnoticed, on a cold day you would warm your hands by relaxing your grip or loosening the straps....Oppps.. I think that's a safe statement...it's just an analogy I'm not trying to go from boots to poles or any thing...just an analogy....

 

[jfb]

because it's obvious that when you're cranking up a hill to the point of sweating yet your feet are cold that something else is happening.

Then, once you head back downhill, requiring comparatively little effort, sufficient blood flow returns, and feet are toasty again.

I've also found that when I'm frontpointing up a trail with crampons or kicking steps without crampons my feet get colder than when going downhill. I think the pressure of my body weight on my toes is enough to restrict blood flow to the toes. Hiking downhill, my weight is distributed over a larger area and doesn't restrict circulation as much. A similar thing happens to my hands when ice climbing, blood flow stops when my hands are squeezing the ice axes and they get cold.

 

[DougPaul]

In the case of your uphill vs downhill, is it possible that the crampon straps shrink the toe of your boot only a small amount? Just enough to only become an issue when your foot is forced forward in your boot by the downhill?

I don't think so Doug, as it occurs whether I'm wearing crampons or not. In my experience, about 10% of people I've hiked with have this "problem", and it's not the simple problem of not enough gear (i.e., "if your feet are cold put on a hat"). My own theory is that is has to do with differences in circulatory systems and the efficiency of one's pulmonary & cardiovascular systems, because it's obvious that when you're cranking up a hill to the point of sweating yet your feet are cold that something else is happening. Specifically - I think for those of us in this situation our bodies are keeping more blood within the pulmonary circuit at the expense of our extremities. Then, once you head back downhill, requiring comparatively little effort, sufficient blood flow returns, and feet are toasty again.

OK, it was just a thought. Human systems under heavy load are complex beasts and different individuals might respond differently.

Another thought triggered by jfb's comment is that the different motions of uphill and downhill could affect the amount of blood circulated through one's feet.

And yes, I think it would be very tough to investigate this scientifically. Just finding a large enough sample size of very fit winter hikers who experience this problem would be a large obstacle.

Fortunately, it might be possible to compare feet with different rigs on them--people could be their own controls.

Anyhoo, when all is said and done, we all just adjust our gear based upon how we feel. And if ultimately each individual ends up doing something reasonable, that is the bottom line.

Doug

 

[HAMTERO]

Trangos

The red gore-tex ones take a newmatic crampon. They are great but wear faster than a full leather boot but way lighter. There are several other boots in the trango line. I have some ice evos also that have an insulated sole(same as nepal) and slightly insulated upper. They have a front bail for a step in. Pretty nice boot, wouldn't trade mine. So far my feet have not been cold in them. My feet stay way warmer than my hands though in general.

 

[HighHorse]

The red gore-tex ones take a newmatic crampon. They are great but wear faster than a full leather boot but way lighter.

that's precisely what i thought. good looking out. i have a couple pairs of la sportivas for climbing shoes, and i'm about to send them more biz.

 

[Chip]

My own theory is that is has to do with differences in circulatory systems and the efficiency of one's pulmonary & cardiovascular systems, because it's obvious that when you're cranking up a hill to the point of sweating yet your feet are cold that something else is happening. Specifically - I think for those of us in this situation our bodies are keeping more blood within the pulmonary circuit at the expense of our extremities. Then, once you head back downhill, requiring comparatively little effort, sufficient blood flow returns, and feet are toasty again.

I know you realize that's counter to standard. Blood flow to extremities should be restricted when the core is cold, but I'm no circulation authority. YRMV.
I just figure it's because I move slower, smaller steps, less movement in your feet to keep them warm, more time in contact with the ground hiking up hill. Going down you're moving faster, longer steps, more movement in your feet to help keep them warm. I'm going to cut a couple of "out-soles" from ensolite and put them between my boots and the crampons. Maybe I'll leave one out and see if that foot is colder.

 

[Kevin Rooney]

I'm going to cut a couple of "out-soles" from ensolite and put them between my boots and the crampons.

That can make a big difference, Chip. The trick is finding room in the boot to allow for this extra thickness.

Back when Sorels were one of the few winter boots, frequent wear meant the felt liners compressed. Rather than replace the entire liner, you could buy just the insole. The better ones had a coating of silver tin foil to reflect the heat/cold back. An additional insole made a huge difference.

 

[HighHorse]

Update

So I got the LaSportiva Nepal Evo's today. I haven't yet tried them in the field, but all I can say so far is wow. They feel like real shoes-not concrete casts with mushy stuff inside them. They are stiff in all the right places, and flexible in all the right places. Even after multiple adjustments with my koflachs, there was always a degree of heel-lift. Not so with these guys. Snug and great. I'm curious at how warm they will be, but I'm already 100% convinced that they are better to walk in than koflachs.
I will say that I have a thinner, low-volume foot, and I could see someone with wider feet or large-volume feet struggling to fit in these boots- but that's how la sportiva's generally fit.
One question for those that have these boots or have experience with them... What's the deal with the "additional tongue"? I'm done a little messing around with them, and they seem like they could optimize fit or insulation, but it hasn't fully clicked with me yet.
Again, I know there's a lot of Koflach lovers on this board, and I stress that I'm not knocking them. I just had a sub-optimal experience with them, and I'm reaching out to my brothers and sisters that never really clicked with these boots.

 

[bryan]

have koflach degrees, but have the same weight/clunkiness issues. needing a fair amount of volume in the front of the boot i have had no luck with la sportivas, though i wish i could. on a whim i just picked up a pair of raichle light weight gore tex mountaineering boots at rei on discount. i found the fit to be nice (a half size higher than normal) with minimal heel lift and some room up front. i can't imagine they will be too warm, but i plan on late winter and spring day hiking with them. we'll see. just a suggestion for people who have slightly higher volume feet and want something light weight. probably comparable in other ways to the trango that's been talked about. semi automatic crampon compatible as well. just can't take a toe bail.

bryan