boot rocker?

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lilcliffy
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Location: Stanley, New Brunswick, Canada
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Favorite Skis: Asnes Ingstad, Combat Nato, Amundsen, Rabb 68; Altai Kom
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Re: boot rocker?

Post by lilcliffy » Sat Feb 09, 2019 6:27 pm

Leo Tasker wrote:I wonder if having a rocker sole and a flat binding would increase the likelihood of the toe section delaminating? Probably depends how stiff the sole flex is.
You know I think that this is a definite possibility of one was XC skiing on dense, consolidated snow most of the time...

BUT- on soft, fresh, backcountry snow?
Does the heel contact the binding when weighted?
Yes it certainly does. If I put the Alaska in the binding on a hard flat surface and then weight the heel, I can actually feel the front of the boot outsole flexing and putting pressure on the front of the boot and binding.
I imagine the Alaska may feel more natural to walk in...
I have no proof of this, but this is my assumption for why Alpina has designed the sole like this- copying a very effective design from modern hiking/backpacking boots?

Here are some thoughts and observations-
During the glide phase of the diagonal stride- the skier is fully weighted on the heel of the forward ski.
With the weight fully on the heel, that boot rocker- combined with a stiff sole- is bound to produce flex energy in the front sole of the boot and put pressure on the front of the binding.
On dense, consolidated snow- there is likely nowhere for this force to go, putting uneventful torque on the front of the sole.
BUT- on soft snow that force should actually transfer and produce a certain amount of tip rise...
Here's the thing- it may be only in my mind, but I think I can actually feel this when XC skiing with the Alaska on soft snow...
Cross-country AND down-hill skiing in the backcountry.
Unashamed to be a "cross-country type" and love skiing down-hill.

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lilcliffy
Posts: 4112
Joined: Thu Jan 01, 2015 6:20 pm
Location: Stanley, New Brunswick, Canada
Ski style: backcountry Nordic ski touring
Favorite Skis: Asnes Ingstad, Combat Nato, Amundsen, Rabb 68; Altai Kom
Favorite boots: Alpina Alaska BC; Lundhags Expedition; Alfa Skaget XP; Scarpa T4
Occupation: Forestry Professional
Instructor at Maritime College of Forest Technology
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Re: boot rocker?

Post by lilcliffy » Sat Feb 09, 2019 6:32 pm

phoenix wrote: I'm a little surprised they engage more quickly, I'd think it was the other way around.
The flexor on an NNN binding is engaged by the position of the toe of the boot- the flexor is not engaged until the boot is rotated far enough forward. The rocker on the Alaska boot means that- unweighted- the boot has a "head start" over the flat sole in terms of engaging the flexor.
Cross-country AND down-hill skiing in the backcountry.
Unashamed to be a "cross-country type" and love skiing down-hill.



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fisheater
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Re: boot rocker?

Post by fisheater » Sun Feb 10, 2019 9:48 am

The only thing I can offer is the Alaska seems to turn nicely. As a complete NNN newby, I was able to make Telemark turns going around the banked turns on my local trails. The boot offers easy ball of foot feel. As for striding, I have a long way to go, I'll keep my comments limited to turning.



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lilcliffy
Posts: 4112
Joined: Thu Jan 01, 2015 6:20 pm
Location: Stanley, New Brunswick, Canada
Ski style: backcountry Nordic ski touring
Favorite Skis: Asnes Ingstad, Combat Nato, Amundsen, Rabb 68; Altai Kom
Favorite boots: Alpina Alaska BC; Lundhags Expedition; Alfa Skaget XP; Scarpa T4
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Instructor at Maritime College of Forest Technology
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Re: boot rocker?

Post by lilcliffy » Sun Feb 10, 2019 11:41 am

When it comes to downhill skiing-
I am thinking that boot rocker on an NNNBC sole might be less of an issue than with 3-pin- because of the flexor?

A rockered boot in a flat-mounted 3-pin binding is a recipe for going over the handlebars isn't it?

I once had a miserable experience on my Annums were the flexor must have come loose- I lost one of them on some VERY hilly terrain- what a NIGHTMARE!
Cross-country AND down-hill skiing in the backcountry.
Unashamed to be a "cross-country type" and love skiing down-hill.



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STG
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Re: boot rocker?

Post by STG » Sun Feb 10, 2019 12:32 pm

I am wondering what the effects would be on joints, foot, knees? Would there be increased force or stress? More risk of plantar fasciitis with repetitive motion/compensation?



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Woodserson
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Re: boot rocker?

Post by Woodserson » Sun Feb 10, 2019 2:41 pm

I hate to be the buzzkill here, but I think this is just the boot flexing over use/time and staying in that position-- which of course could be unique to the Alaska than the other boots, but that Alfa is brand new... Here is my Alaska vs Wife Alaska-- One season (truncated since I got them late) vs 2 days of use. Thoughts?
20190210_143822.jpg



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lilcliffy
Posts: 4112
Joined: Thu Jan 01, 2015 6:20 pm
Location: Stanley, New Brunswick, Canada
Ski style: backcountry Nordic ski touring
Favorite Skis: Asnes Ingstad, Combat Nato, Amundsen, Rabb 68; Altai Kom
Favorite boots: Alpina Alaska BC; Lundhags Expedition; Alfa Skaget XP; Scarpa T4
Occupation: Forestry Professional
Instructor at Maritime College of Forest Technology
Husband, father, farmer and logger

Re: boot rocker?

Post by lilcliffy » Sun Feb 10, 2019 6:01 pm

Hmmm...
I have noticed the rockered sole on my Alaska BC since they were new...
Perhaps it has been toned down on the newer version?
I'm pretty sure that I have photos of my Alaskas when they were new- will have to look for one.
But- here are some photos of the same gen as mine:
alaska BC- boot rocker1.jpg
alaska BC- boot rocker2.jpg
I will have to check out my friend's new Alaskas again.
Regardless- certainly your wife's Alaska's have much less...

Also- my other NNNBC boots that have lots of miles on them (Rossi and Fischer BCX6) still have flat outsoles...
Cross-country AND down-hill skiing in the backcountry.
Unashamed to be a "cross-country type" and love skiing down-hill.



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paulzo
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Re: boot rocker?

Post by paulzo » Sun Feb 10, 2019 7:33 pm

This could conceivably be an artifact of the process that Alpina uses to put the rubber rand on there, or a result of the behavior of that material over time. Consider the other photos posted of cracking in the rand material after significant use, which suggests tension forces in it.
Given that teh boor maker do not make the soles, they just buy them and glue them on, it would have to be midsole or upper construction that is responsible, not outsole.
My suspicions lean heavily toward this being due to usege, not construction, or rather perhaps due to a combination of usage and a stiffer midsole.



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phoenix
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Re: boot rocker?

Post by phoenix » Tue Feb 12, 2019 4:43 pm

"Boot rocker is a liability when it comes to free-heel downhill skiing- exactly the reason why Voile risers have a backslope to them.
BUT- when it comes to XC skiing on soft snow?"

Can't say definitively, but I'd still rather do without the rocker, and probable dead spot that goes with it. For the down, it's a simple matter of adjusting technique accordingly, which is the case, regardless. And for all the other elements that get less attention, sidestepping, lifting over deadfall or other obstacles, etc... I'll take a flatter, more consistently predictable response.



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wabene
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Re: boot rocker?

Post by wabene » Mon Feb 20, 2023 9:58 am

Hello, I'm getting another ski mounted with 3pc for turns and my first non alpine plastic boot, the T4. The binding is being mounted flat. I've heard of boot rocker in plastic boots. A quick image search, since I still haven't seen a T4 in person, reveals zero rocker on this boot.
ipps_t4_ext_blk.jpg
Seems mounting flat would be just fine.



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