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How can boots be too stiff?

post #1 of 20
Thread Starter 

Hi,

I posted this question in ask the boot guys, but am also interested in what the general population has to say. 

 

Just thinking ahead to my next purchase.  Boots come in various flexes.  If everything else is done right, why not get the stiffest setting?  What would be wrong with normal weight skier skiing a boot with a very high flex index?  What would be wrong with a normal weight skier skiing a boot with a low flex index (say 100)?

How stiff is too stiff for a 175 lb skier who skis fast with good technique.

 

Thanks.

post #2 of 20

Ghost,

We are about the same size (173#) and I race.  My boots are "set" for 115 flex but then I crank the booster strap down so the top buckle loosens.  I'm not sure that increases the flex or not.  At most, they might be 120. Last year I tried my boots with the setting around 135.  The L2's and L3's I was working with noted that I wasn't as forward and it looked like my ankle wasn't closing.  At the time I was probably 165# and not skiing as well as this year.  I didn't increase the forward lean when I increased the flex.

 

My reason for dropping the flex back down was I lacked the force to flex the boot enough to bend the ski and it put me in the back seat.  Could a more talented person the same size use a stiffer boot; without a doubt.  I race with a friend that is very similar in size to me and has race boots that are 130's.  He's also been skiing over 50 years.  The forward lean in his boots is more forward than mine.  I also work with someone that is close to 30# lighter and has boots that are 130 flex.  Both skiers are very good racers, very technical skiers with a long skiing history.

 

I guess you can use any stiffness boot the allows you to pressure the front of the ski and doesn't push you into the backseat.

 

I think, especially with normal sized people like us wink.gif, if the flex is increased, something has to be done to shorten the dorsi-flexion angle (more forward lean or toe liftsth_dunno-1[1].gif).  Maybe its a matter of strengthening whatever muscle it is that helps you flex (I know body position is part of it).

 

I think height and not just weight play into this also (this gets into the whole argument on binding release settings and which is more important - height or weight).  Height of the boot is going to affect your ability to flex too.

 

"How stiff is too stiff for a 175 lb skier who skis fast with good technique."

 

From asking similar questions in the past, I received and answer along the lines of "you should be able to get your knees over your toes when you flex".

 

Maybe a way to check is don your current boots and skis, place a scale under the tip of your skis and see how much pressure (measured in weight) you put on the tip.  As long as a higher flex boot lets you do the same, you should be OK.

 

The boot also needs to be robust enough for the demands you are going to put on it.

 

I think boot flex, especially among men, is another way of bragging (Mines bigger!).  Think of the drills more experienced skiers do - ski with boots unbuckles.  You need to be well balanced to ski well with your boots unbuckled. 

 

3 weeks ago I had one of my scariest nastar runs.  Had trouble getting around a couple gates and just barely cleared a couple.  It was as if my skis weren't listening to me.  It was a fairly straight course too.  When I went inside I realized I never re-buckled my boots before I raced .  I had un-buckled them to set fencing at the start area.  Top and middle buckles (Kryptons) were wide open.  Re-buckled and ran the course - skis listened.

 

So the Goldy Locks rule applies.  Too soft isn't good, too stiff isn't good.  They need to be "just right."

 

Ken

post #3 of 20

 

^^^^ Thoughtful reply. I just starting running Dalbello Krypton Crosses. Quickly lost interest (and BSL appropriate bindings) in my old Falcon 10's, which are 110 flex. Oh, and am a truly mediocre rec racer on old Sollie Lab Plugs, said to be 130, but plastic doesn't seem to stiffen as much as my other boots (version of Pebax?). Anyway, my Crosses can be adjusted from 90 to 120. Initially had them at max. Then got Intuition Power Wrap ID's, which increase stiffness by I'd guess 10%. So dialed the shell flex back to 100, add in the Intuitions, and should be about 105-110. They feel about as stiff as my Falcons, although a very different forward flex pattern. 

 

What I found, rec skiing at 120+Intuitions, so say 130, was that even with the more linear flex of the cabrio design, my outcomes suffered. I wasn't as planted on ice because it was harder to pressure the front of the skis at normal non-racing speeds, so I ended up with my CM further back. 

 

Just as importantly for rec skiing, the stiffer boot didn't absorb shocks as well. So bumps, which are a cabrio's strength, became no easier than in my Falcons. 

 

Finally, am wondering if the whole front pressure bit is behind the curve of modern skiing. I take lessons from Level III's and racing coaches regularly. The mantra is "neutral stance, stay centered in your boots, concentrate on lateral movements." Isn't the lateral stiffness of any boot a lot more relevant than its forward flex number? 

 

Put another way, I think the flex needs to balance a skier's typical F, which is M x a. For racing, a stiffer flex balances higher F from a. And for heavier skiers, greater M needs more resistance to the F. Otherwise, you're just using more muscular pressure or doing weird things with your CM to flex the boot. Why?

 

So at 165 lbs, I think a 105-ish boot that's very supportive laterally is about my cuppa tea. Maybe 120 for racing, if that. Plan to try my Dalbellos in the gates, suspect they'll be great there too...

post #4 of 20

The simple answer to your question, as far I am concerned, is that it is indeed possible for boots to be too stiff.  I've been skiing in Tecnica Diablo Pros for the past 4 seasons and this season it has been confirmed by three L2 instructors and two L3 examiners that I cannot flex my boots.  The flex index for the boots is supposed to be 100.  My weight varies between about 146 and 150.  I have had a fair amount of work done on the boots to try to soften them but cutting a big "V" in the top of the inner cuff and removing the metal connector from the rear of the boot has only made it possible for me to flex them "some" inside when the plastic is at room temperature but I still cannot really flex them on the snow.  There are no boots in town of any flex index that are the right size, 98mm last and 25.5 or 26 mondo point, so I am stuck with these until next season and have to delay my L2 exam until then because two examiners have told me I will not pass since I cannot adequately flex and extend due to my boots.  I ski bumps more and more and the guy I often ski them with commented on Friday that he noticed I'm not able to flex properly in the bumps.  Next fall I will be looking principally at Dalbello Krypton Cross ID and Il Moro ID.  Full Tilt boots might also work if a 99mm last isn't too wide.  I have no trouble at all flexing my ankles outside the ski boots and my legs are in pretty good shape from cycling, running, backpacking and skiing.

post #5 of 20

There are different schools of thought on this. There are many examples of lightweight skiers in very stiff boots without problems. If you have to flex the boot very much to remain in a balanced position, then your boot angles are probably not right for you.

post #6 of 20

Yes, it is possible for boots to be too stiff.  As a racer and from working in a ski shop, if your boot is too stiff, then you will not be able to get forward.  Outside of a race setting, if a boot is too stiff, shin bang and similar is very common.  On the other hand, it is also possible to be too stiff.  I stepped up my flex from a 130 to a 150 this year mid year, and my race results got better very quickly.  On the other hand, the 150s are too stiff to be my first choice of boots when I charge the mountain.

post #7 of 20

My boots have a stiffness adjustment, which I used to leave most of the way stiff.  Then one day I was experimenting with it and discovered softer is sometimes better.  Here is what I do now:   for ice, I set them as stiff as they go (which is not that stiff compared to race boots).  It helps engage the front of the skis early.  For soft snow (including soft packed snow), I set them as soft as they will go.

 

Writing this reminds me I ought to do a controlled comparison of boot flex in the moguls.  Maybe a softer boot would help your bump skiing.

post #8 of 20
Quote:
How stiff is too stiff for a 175 lb skier who skis fast with good technique

Ghost,

 

I think a more appropriate question would be "is my fore-aft alignment dialed in?"  Poorly aligned boots aren't much good since no one likes to ski out of balance.  Soft boots handicap skiers by decoupling them from the snow, so they aren't much good either.  A stiff, well-aligned, well-fitted boot, on the other hand, is skiing nirvana.  There are lighter skiers than you who have upgraded to ultra-stiff carbon fibre boots, so stiffness per se isn't a problem.

 

As always, it boils down to finding that rare bootfitter you can really trust.  Explain your penchant for high speed and gs / sg skis, describe your technique, and do what the bootfitter tells you.  Spend several hours on snow with your bootfitter to dial in your fore-aft and lateral alignment.  In-shop alignment is always dicey and is simply not an option for a skier like you. 

post #9 of 20

a stiff boot is a great thing on smooth/hard snow it lets you adjust your fore and aft pressure faster than a soft boot.

 

In soft snow, bumps, trees, and powder though sometime you lose the ability to flex your ankles and you lose you ability to maintain for and aft balance. To be fair though its more the skier than the boot, last year I use to take my kryptons pros down to 120 on days I was all over the place, this year I just learned how to maintain fore and aft balance better and run them at 140 for everything. The cabrio design and low hinge point make off trail skiing much easier than the alternatives.

post #10 of 20

On a theoretical basis, you want it as stiff as possible while still giving you an adequate range of motion in your ankle joint.  'Stiffer' translates to being more responsive in terms of pressuring the front or back of the skis.  If you can't get any movement in your ankle (and I've seen students like this), your skiing is gonna suffer.  Being heavier, stronger, and faster will give you more ability to flex a stiff boot.

 

Your ankle has a smaller range of motion than your knee or hip/waist, especially in ski boots.  That generally establishes the limit on how far you can get your COM forward without overcompensating somewhere else.  If you can't close your ankle, the only way to try to shift your COM forward is to overflex at the waist and/or underflex at the knee.  That's slower and can compromise you in other ways (e.g. if you unflex your knees, you also push your COM *up*.)

 

Overly soft boots don't provide a lot of ankle support.  You can still ski well in them, but it works the muscles in your lower legs pretty hard if you're not perfectly balanced.  If you go real fast, you might not be able to resist the turn forces without some support from the boots.

post #11 of 20

Quote:

Originally Posted by Ghost View Post

Hi,

I posted this question in ask the boot guys, but am also interested in what the general population has to say. 

 

Just thinking ahead to my next purchase.  Boots come in various flexes.  If everything else is done right, why not get the stiffest setting?  What would be wrong with normal weight skier skiing a boot with a very high flex index?  What would be wrong with a normal weight skier skiing a boot with a low flex index (say 100)?

How stiff is too stiff for a 175 lb skier who skis fast with good technique.

 

Thanks.

how stiff is too stiff?

IMO (taking racing out of the equation)
if trying to pressure your boot causes you to drop your hips backward, as opposed to down, then you're prolly at the point where the boot is workin you instead of the other way around.

A consequence of too stiff a boot is the hips/ass drops back, the upperbody drops forward and down more - you become accordianed - consequent further progress over variable terrain means you have less ability/range to absorb those irregularities - with your hips back your quad strength to drive the ski while on edge is substantially reduced.

your skiin goes to hell.

for me I've found that free skiin in a boot which offers good progressive range of movement for my weight/force is key to skiin my best - that currently happens to be a Fischer HeatFire 105, which feels more like 110/120 when in temps of 10 - 30 degrees Fahr.

Most all modern boots of decent quality, if fit properly, have more than enough lateral stiffness for effective side to side work in any form of rec skiing.

The forward flex progression is what one needs to decide.

Quote:
Originally Posted by mtcyclist View Post

The simple answer to your question, as far I am concerned, is that it is indeed possible for boots to be too stiff.  I've been skiing in Tecnica Diablo Pros for the past 4 seasons and this season it has been confirmed by three L2 instructors and two L3 examiners that I cannot flex my boots.  The flex index for the boots is supposed to be 100.  My weight varies between about 146 and 150.  I have had a fair amount of work done on the boots to try to soften them but cutting a big "V" in the top of the inner cuff and removing the metal connector from the rear of the boot has only made it possible for me to flex them "some" inside when the plastic is at room temperature but I still cannot really flex them on the snow.  There are no boots in town of any flex index that are the right size, 98mm last and 25.5 or 26 mondo point, so I am stuck with these until next season and have to delay my L2 exam until then because two examiners have told me I will not pass since I cannot adequately flex and extend due to my boots.  I ski bumps more and more and the guy I often ski them with commented on Friday that he noticed I'm not able to flex properly in the bumps...

what has worked for me in the past...

 

3rd buckle/lower strap of the upper boot wrap - with a Dremel, starting as close to the inside hinge area, grind off about 1/8 inch of the 'lower' edge of the strap all the way to the end. important to make that grind very smoothly and cleanly. Very important to get the new strap edge real smooth - I use progress finer sand and emery paper up to 400 grit to get a smooth finish. 'Round' the lower edge a bit for very smooth progression.

That extra 1/8 makes the initial flex just a tad easier and smoother. The boot will eventually 'lock', but will allow a more progressive flex to that point. To get even a little more, you can also grind, in very small increments, the lower edge of the underflap (flap which the buckles are anchored to...)

The combination of working these really helps smooth the flex on stiff uppers.

There are 4 layers of boot shell at this area - the overlap of the 2 lower shell sides, over these is the overlap of the upper sides - Lotta Plastic - Stiff...

This is, of course, for 4 buckle PU shells...
 

 

post #12 of 20

In my opinion it is not stiffness but rather fit that determines responsiveness and performance. With modern skis you need to make lateral motions fast so forward flex is not necessarily as critical. Stiffness is primarily needed for tech racing events (SL, GS) where the skier is pulling a lot of Gs and also needs to bend a stiff race ski. Some racers even use a softer flex for speed events (SG and DH) since small scale bumpy terrain variations are absorbed better without throwing the racer off line. The same would be true for recreational skiers looking for for a boot for bump, tree, crud, or powder sking. For the speeds recreational skiers are likely to see on groomers there probably isn't a good argument for stiff boots there either. One should look for the precision fit of a race boot but not necessarily a stiff flex. I have a pair of Salomon plug boots reduced to a 110 flex (I'm 165lb) I use for Masters SG and DH that I have also found excellent for bump skiing due to the high level of responsiveness. The downside of a race boot is that they can be cold and uncomfortable when worn all day. I hope to find a new recreational boot next year with a precision fit that is warmer and more comfortable for all day skiing. I think some people look for stiffness due to ego rather than logic the same way people used to buy longer skis (I did that myself when I was younger) then they should have for the same reason.

Anyway this is just the opinion of a middle aged bump skier, racer, and engineer. Those of you with more expertise please correct me if my reasoning is faulty.

post #13 of 20

I would add to the discussion that the effective stiffness may be related to the diameter of the cuff on the leg and length of the tibia.  If you have a small diameter calf, then you have much more leverage to bend the cuff, but if you have a larger diameter calf, then you may have relatively less leverage, and the boot will feel stiffer.  Further, if your tibia is longer, you have more leverage to bend a given boot.  Thus two skiers at the same weight could get very different results.  A skier with long skinny legs will feel the boot as being far more flexible than a skier with short, bulky, legs.

post #14 of 20
Quote:
Originally Posted by FOG View Post

I would add to the discussion that the effective stiffness may be related to the diameter of the cuff on the leg and length of the tibia.  If you have a small diameter calf, then you have much more leverage to bend the cuff, but if you have a larger diameter calf, then you may have relatively less leverage, and the boot will feel stiffer.  Further, if your tibia is longer, you have more leverage to bend a given boot.  Thus two skiers at the same weight could get very different results.  A skier with long skinny legs will feel the boot as being far more flexible than a skier with short, bulky, legs.

 

Interesting point. In a completely different context, I've often noticed how skinny my lower leg is compared to other peoples', including how high up on the leg my calf muscle begins. I wonder if this is related at all to starting skiing at age 2 - that skiing has somewhat manipulated my body's development track.

post #15 of 20

The stiffness you need also depends on your musculature and the natural flexion of your ankles. If you have high dorsiflexion like me, weigh in around 210, and have rather massive quads and calves, a soft boot is not supporting your natural stance and you will end up off balance with burning quads. But a boot that is too stiff will not allow you to flex your ankles in softer snow.

 

But perhaps before looking at the stiffness of your boot, check to see what the angle your binding is doing to you. A high ramp angle might be forcing you into the cuff and flexing the boot before you are even skiing. There is an increasing consensus that for many people a neutral or even negative ramp might be better for getting you into an overall neutral and balanced position. The next time you see your bootfitter bring your skis too! All that good work on the boot and footbed may be messed up by the binding delta.

post #16 of 20

I want a stiff boot because it holds me in a correct balanced stance.  if I get out of balance, I have a strong platform from which to lever myself back in balance.  I weigh about 155 and I ski a 140 flex boot.

 

Personally, I have no interest in a soft boot.  Instead of holding me in balance, a soft boot allows me to easily move out of balance.  Why would I want that?  Aggressive, technical skiing requires a stiff boot.  If all you do is ski bumps, you could conceivably want a boot with some give in it.  However, if you go that route, you will be trading away some performance when you are not in the bumps.  The flip side is that a stiff boot can be made to work well in the bumps provided that you employ a carving-based technique. 

 

You do need to get forward at the top of the turn if you really want to bend the ski, but getting forward is not about flexing your boot.  Assuming you have your forward lean dialed, getting forward is accomplished by pulling your feet back and letting your boots hold you where you need to be.  Ironically, a softer boot will prevent you from getting forward because it will not be able to provide the level of support needed. 

 

All of that said, whether stiff boots actually work for any given person is highly dependent on two things.  First they must be set up correctly.  The stiffer the boot, the more critical getting fore-aft dialed becomes.  This can be a hard thing to get right and it usually requires at least some on-snow testing.  You either need to be able to figure this out yourself, or you need access to a coach who can help you. 

 

Second, the stiffer the boot, the better your technique must be.  This does not mean that you need to be a world-class skier, but it does mean that you must have the right movements.  Intermediate skiers can benefit immensely from a stiff boot, but only if they have solid fundamentals and only if they stay within the realm of their ability--which means gradually moving to more difficult terrain rather than skiing over their head most of the time.    

 

Stiff boots punish bad technique and reward the good.  Nowhere is this more evident than off-piste.  Smooth skiers who flow down the mountain will usually love a stiff boot.  OTOH, skiers who ski with foot-twisting, hard edge sets and slam the bumps will often find a stiff boot to be more than they can manage.  Even on easy, groomed terrain, some skiers may struggle with a stiff boot.  There has been at least one video posted within the last few months that demonstrates the disasterous combination of stiff boots and no skills.

 

The only real downside to going stiffer is that you usually pay a price with respect to getting in and out of the boot.  150 flex boots can be a nightmare to get in and out of. 

post #17 of 20
Thread Starter 

If there is no downside to going stiffer, why don't you have a 200 flex index instead of a 140 flex?

post #18 of 20

My rule of thumb is to go with a stiffer rather than a softer boot. Feeling an immediate 'connection' between my shins and calves and my skis improves my awareness of how well I'm balanced fore and aft, as well as helps me avoid face plants when my skis are punching through variable crud and powder. Stiffer also helps ensure a strong edge hold through the heavy turning pressures of a high performance turn. Notably, a stiffer boot reduces the amount my ankle can flex to help me absorb terrain changes---at 140 lbs, my 130 flex Lange boots let my knees travel little more than one inch ahead and back before I feel undue pressure on my shins and calves. For my skis to perform well I want my instantaneous weight acting through their midpoints (which happily coincides with me feeling my weight centered in my boots, where I can stay in balance and in a good posture while experiencing heavy turning forces). To accommodate the minimal ankle flex my boots allow, I use a specific technique: flexing primarily using my knees and hip joints to absorb changes in terrain (eg, moguls) or when transitioning from one turn to the next. Flexing as such avoids forcing my shins or calves against my boot cuffs, and the resulting challenge to my balance that doing so would cause. In brief, I find that stiffer boots go hand in hand (or should I say foot in boot) with better technique, provided my boot and ski setup allows me to flex my overall posture between tall and small while keeping my weight centered fore and aft, and the pressure on my shins and calves unchanging. I've described this topic carefully in my recent book "How I Ski: Expert Alpine Skiing Demystified!" and demonstrate the skill of flexing only, i.e. primarily, at the knees and hips on a brief video that you can find at www.skiwellsimply.com.

 

post #19 of 20
Quote:
Originally Posted by Ghost View Post

If there is no downside to going stiffer, why don't you have a 200 flex index instead of a 140 flex?



Well, I'm in a Dodge composite so there is just one choice (though you could probably soften it if you wanted).  Dodge doesn't actually advertise a flex rating, but there seems to be some consensus (which I agree with) that 140 is about right.   If I wasn't in a Dodge, I'd be in a Head Raptor 130 (which is what I came out of) because the 150 is just too hard to get on and off.  At the point in which the boot is stiff enough to hold you in balance and provide enough leverage to move out of extreme positions--given the forces that you generate when you ski--there are diminishing returns on increasing the stiffness.  In my case, the 130 is plenty stiff enough so any advantage offered by the 150 just isn't enough to make me want to deal with the extra effort required to get them on and off.

 

 

post #20 of 20
Quote:
Originally Posted by Ghost View Post

If there is no downside to going stiffer, why don't you have a 200 flex index instead of a 140 flex?



 You reduce your ability to flex the ankle, which in turn minimises your fore/aft balance ability since you only then have the waist to bend to work forward....and knees for working aft.  This causes major issues for any type of variable terrain like bumps, or ruts in a race course.

 

On my Raptor 150s I prefer just the bottom bolt in (140 flex) for all mountain skiing (read better ability to ski bumps), but notice the lack for high speed GS or racing, where I prefer 2 bolts in or (150 flex).

 

 

 

Keep in mind, you mentioned before the skiers weight...this is only 1 factor, the other is G-forces and the other is lateral balance.  A weak skier that say weights 200lbs, but cant hold an edge while skiing, and cant balance on the outside ski might only be able to generate 85lbs of force on 1 boot.  A good skier at 200lbs who can pull 2Gs in a turn, and balance 100% on the outside foot is applying 400lbs of force to one boot!  Hence the better skier has a much greater need for stiffness to support him!

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