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Bootfitting FAQ and Glossary

post #1 of 7
Thread Starter 
Extracted from the Gear FAQ.


Boots are the single most important piece of ski equipment you can own, the first equipment you should purchase, and the ones that are most personal for you. The single most important characteristic of a ski boot is how well it fits your physiology; specifically, how well the boot's last and angles (forward lean and boot board ramp--called the zeppa angle) match you. You need to be in balance and in neutral when you are in cuff neutral with your skis parallel, so the boots need to get you into this position. Find the right specialist to get you into the right boot! This is critical to your skiing success.

Trained and experienced boot fitters tend to go beyond just stuffing your foot into a boot, but are able to adjust the boot to fit your foot exceedingly well. In addition, many are able to balance the boots to make sure that you are in perfect balance when standing on your skis--both fore/aft and lateral/medial.

This really is the best way to find boots.

Best by a wide margin.

If, however, you insist on doing it on your own or, heaven forbid, you are unable to access one of the accomplished bootfitters mentioned here. Then we have a little more advice...

Know the general performance level of ski boot that you seek. Many Bears will recommend that you purchase the highest-quality ski boot that you can. I recommend that high-level skiers seriously consider consumer or true race "plug boots" (see Jeff Bergeron's current answers thread for a lot on this)

The closest fit is best accomplished by getting a boot with a shell that most closely resembles the shape of your foot and leg. To discover this, shell fit the boot.

To shell fit a boot, first remove the liner. With the liner out of the shell, place your foot into the shell with your toes ever-so-slightly touching the front of the boot, look at the distance from your heel to the back of the boot.

This distance should be 1-2 finger-widths (approximately 1-2cm). Use the shorter end of the scale for more demanding performance, the longer end for a bit more comfort at the price of a bit lower performance.

Next, look at the shape of the shell. Is it wide where your foot is wide, narrow where your foot is narrow? You should ideally have a 1-2mm around your foot when it is centered in the shell. More than that in any area of the shell will indicate a spot that will likely be too lose. A bit less (including even touching) can be addressed by your boot specialist. It's easy to make the boot slightly bigger. It's very difficult to make it functionally smaller. Note that boots will pack out as much as a half size, so it is virtually always better to go smaller.

Does the cuff approximate the shape of your lower leg and calf muscle? It is often useful to remove the plastic spoiler from the back of the cuff so that the boot is a bit more upright and can accommodate a normal or low calf muscle. Skiers with thin calves may find the spoiler useful in reducing the size of the boot cuff.

After you find a shell that fits your foot pretty well, return the liner to the shell and put your foot in it. Make sure your heel is well-seated in the heel pocket (usually by pressing the heel down and back, flexing the ankle forward, and pulling up on the top of the liner). Then, stand in the boots in positions that approximate your skiing stance. Always wear thin socks (although thick socks can help make up for boots that have packed out).

The liner should wrap your feet much like a pair of hands holding your feet snugly. The footbed should support the length of your foot. Most stock footbeds are best removed for good. Most skiers will be more efficient with a skiing footbed that's either off-the-shelf or custom-built for them. The footbed can make a dramatic difference in getting your feet and legs aligned, so don't underestimate the value of an effective one!

Take advantage of any balance tests that you can, including standing on a cylinder to see where your balance point is in the boots

The bottom line in ski boots is this: unless you are pursuing FIS points (in which case, you're probably not reading this!), the fit of a ski boot is by far the most important aspect of it. You want it to be snug enough to hold your foot relatively immobile while you careen down a mountainside while also cushioning your feet enough that you can ski for the entire day (not to mention multiple days of a skiing) without pain.
post #2 of 7


This Glossary was put together by the Boot Pros to help explain some of the terminology used in responses in the Ask the Boot Guys forum. This glossary will be expanded as time and interest allows.

The platform inside the boot shell on which the liner rests; usually removable; also referred to by its Italian name, zeppa.

Campbell Balancer a device developed in the '80s by Harry Campbell that is used to determine the best position (fore and aft) of the boot on the ski for individual skiers.

DUROMETER A measure of the hardness of plastic. Boots using highdurometer plastic are stiffer-flexing.

CANT (1)The angle of boot bottom with ski viewed from the front. (2) The lateral angle of the boot in relation to the ski; often confused with cuff-alignment (the adjustment of cuff angle). Boots can be canted inward or outward, usually by grinding the sole at an angle, to give a skier better access to all four ski edges.

sagittal, transverse and frontal planes.

FOOTBED The removable platform inside the liner on which the foot rests. Custom footbeds are those molded by a bootfitter to conform to the shape of the skier’s sole for better fit and more precise energy transfer.

FRONTAL PLANE: A plane parallel to the long axis of the body and perpendicular to the sagittal plane that separates the body into front and back portions.

LAST The interior shape of a boot. “Last” is a cobbler’s term for the foot-like form around on which shoes were once crafted.

LINER The removable inner boot, usually made of foams, leather and textiles; provides padding for the foot to protect it from the rigid shell. (Note some liners are short compared to the shell volume and may make a boot feel too small when all that is needed is a stretch of the liner)

LIFTER Layer of plastic applied to the boot sole for extra height/leverage.

LUGS (TOE AND HEEL) The portions of the shell’s sole that interface with a ski binding; must meet industry standards for size; often replaceable in the event of wear.

ORTHOTICS is the field concerned with the application and manufacture of orthoses, devices which support or correct human function. The term is derived from the Greek "ortho", to straighten. Sciences such as materials engineering, gait analysis, anatomy and physiology, and psychology contribute to the work done by orthotists, the professionals engaged in the field of orthotics. A foot-supporting device or insole. In addition to providing relief for painful foot problems or an injury, those who may benefit from orthotics include people who must walk or stand excessively on the job. For those who are active in sports, orthotics will often increase endurance, performance and strength. For overweight individuals, orthotics can help to counteract the extra stress on the feet, as minor problems are often magnified due to the increased weight.

PEDORTHIST C.Ped.s select, make and/or modify footwear and foot control devices to help people maintain or regain as much mobility as possible or to optimize their lower extremity biomechanics. Their scope of practice is typically defined as the ankle and below in layperson's terms. Most often, it is Certified Pedorthists, not Podiatrists (or D.P.M.s), who create foot orthotics, whether custom-molded, or pre-molded. A Podiatrist will often take an image of the foot by means of a plaster cast, foam mold, or computer scanned image. He or she will then make recommendations for changes to that image, and send the mold to a lab where the Pedorthist produces the final product.

Q Angle: The quadriceps ('Q') angle is the angle between the quadriceps muscle (primarily the rectus femoris) and the patellar tendon.[1] When assessed correctly, it supplies useful information concerning the alignment of the pelvis, leg, and foot. It also provides useful information regarding the alignment of the knee in the frontal plane. Since large forces are transmitted through the patella during extension, misalignment will cause problems with knee function.

RAMP The angle (when viewed from the side) of the foot inside the boot. The angle created by a line connecting the bottom of the ball-of-the-foot and the bottom of the heel with a horizontal line. Positive is when the heel is higher than the ball and negative is with the heel lower than the ball.

SAGGITAL PLANE: vertically from the front to the back;parallel to the sagittal suture of the skull divides the body length wise front (anterior) to back (posterior).

SHAFT ALIGNMENT The lateral orientation of the cuff in relation to the lower shell; usually adjustable on at least one side of the cuff, so that the cuff can be angled to match the angle of the skier’s lower leg when standing.

SHELL The plastic exterior components of the boot, usually comprising two elements: the cuff (or upper) and lower.

SBS A dynamic pronation measuring system.

TEKSCAN Pressure measuring device and software from the medical community that in skiing is typically used to measure pressure under the boot with results being used to determine cuff alignment.

TRANSVERSE PLANE: horizontal to the body parallel to the horizon, divides the body upper from lower at the center of motion.

also called bootboard. It is the removable section (usually plastic or foam) inside the shell and under the liner on which the liner rests . It supports our weight when we stand.
post #3 of 7

Boot Fitting Basics (How Tight is Too Tight?)

This thread is the boot fitter's discussion of the fundamental principles of how a boot should fit. There have been several topics discussed behind the scenes, and this is one we wanted to share. I hope you enjoy and benefit from this conversation from the "shop" back room. Please read this fully and carefully to get all the opinions and nuances.


Boots should fit. You don't get extra bonus points for more than 2 sizes less than street shoe fit. Downsizing one U.S. is typical but that is because of inaccuracy in Mondo to U.S. conversion. For example size 27 mondo foot measures 10-10.5 U.S., not 9.5 as listed on boxes and most charts. Most skiers are not aware of this basic error in the mondo / U.S. size conversion tables. Here is some of the discussion the bootfitters have had in the back-room that is not visible except to the boot specialists.

Shell Fit: A boot may feel great right out of the box, but you need to account for compression of the liner that will always occur with use. A boot fitter will almost alway ask you to do a shell fit. This means pulling the liner out of the boot, inserting your foot into the plastic shell, and with the toes just brushing the end of the boot with weight on, checking how much room is left behind the heel. 5 to 10 millimeters is considered a good performance fit, while more than 15 millimeters is getting to where the boot will be too large after break-in. Always do a shell fit, and remember boot liners may be short-lasted - meaning shorter than the shell. Boot liners can be stretched, but you must get a shell that will contain the foot for best performance. Do not get a shell too large, get a boot that fits well, starting with the shell.

Originally Posted by Lou Rosenfeld View Post
I don't agree with the impression given that downsizing two sizes is done commonly. I find that down sizing even one size in Mondo is not that typical but does happen depending on boot shape. Downsizing one U.S. is typical but that is because of inaccuracy in Mondo to U.S. conversion. For example size 27 mondo foot measures 10-10.5 U.S., not 9.5 as listed on boxes.

I work with several national team members and have seen inside boots of others. Most I have seen are in proper size Mondo. There is no reason to downsize as the boot is narrow enough to begin with. If the boot is appropriately shaped and not overly wide where does necessity of downsizing come from?
Originally Posted by CEM View Post

this is really interesting, i had a racer in on friday, she arrived with a pair of tecnica diablo race 130 W/C [thick soles to be planed] having had a weeks racing in norway and going back in a day, she had lost both big toe nails..... fast forward to the shell check, toes touching the front she had 3mm :: behind her heel, options, well i would have put her up one size and all would have been great, but this is 6pm on friday and she sets off to ski again 10am saturday so no chance of that happening.... she measures 25.5+ but as she has a skinny foot she buys size UK5 shoes no amount of me telling her this was wrong was going to change this as her coach had told her the boots were the right size.

the problem really came after i had spent a couple of hours grinding the heel out , stretching and then grinding the toe box to gain her a couple of extra mm....... she now said that the boot felt great, well anything would feel better than it had been.....next request from said racer....can you do this to my new boots when i get them before next season::

there is just no telling some people

in general i would size dependent on the foot and the boot, almost forgetting what is written on the box and relying on the shell check one size down for a performance fit is fairly common but as you say two sizes???? either it is a boot which is really oversized or a foot which had not be measured correctly...
Originally Posted by JDoyal View Post
I agree also. I have not downsized 2 sizes in recent memory, even with a racer. I feel that to crush a foot to that degree will cause the skier to be put into a less than ideal stance. For 95% of the skiers out there mondo or one size down is the best way to size IMO. This all, of course, is predicated on the the shell being the right one (or as close as possible) for the skier.
Originally Posted by mntlion View Post
3mm is a VERY tight fit, I like that way of measuring the mm on the shell fit for downsize, not off a street shoe vs ski boot size.
lots of people have street shoes very large so they slip on and off easily.
different brands of shoes fit differently, so a 8 in one is a 9 in another
Originally Posted by bud heishman View Post
I agree too, for MOST skiers down one mondo size from US Branick sizing is good. Though I always shell size and go off that. In recent years I have found there are a few brands and models that can be downsized two mondo sizes because they have longer than average space inside shell.
Originally Posted by mosh View Post
Here here! the term downsize is such an oxymoron. There is no such thing as down sizing, it should be called what it is, "wrong sizing" Working with coach, Tim Lavallee the other day and we had similar conversation about how out of hand this has gotten.
Originally Posted by Cirquerider View Post
I don't think most of the public understands that the emphasis on downsizing of ski boots is because of the error in the sizing charts that incorrectly assigns US and UK sizes to the mondo point sizes. What we are really doing by "downsizing" is putting skiers in the right size. Makes you wonder, why not just change the charts?

Maybe we can post an EpicSki BootFitters Sizing Conversion Chart for proper fit. BTW, I'm sure you know this, but you have all done a great job in the forums.
Originally Posted by bud heishman View Post
Cirquerider, I agree and thanks to all bootfitters who have contributed regularly here and made this a nice forum for fielding boot related questions!

On this topic, I would say that the primary problem with the publics sizing choices is still by far, UP sizing not down sizing. I believe most people mistakenly try to judge their ski boot size by how they size/fit their street shoes, which is WRONG for ski boots. I regularly tell people when they put a boot on I selected for them, "you would never buy this size if it were a street shoe because your toes are touching the front of the liner."

So, in my mind downsizing is not a "fallacy" rather "proper sizing" many times involves downsizing from published sizes on boots. We should be careful how we title this public thread and how the information is communicated so we do not confuse or misinform!

We all know as we size smaller the amount of customization needed increases and the time to get everything comfortable takes a bit longer. Obviously if the foot is being contorted or is in pain, something is too tight!

For the racer the snugger the better provided there is a certain degree of comfort. For the novice a large degree of comfort is important not knowing the benefits of snugness yet! To the expert, something in between these two parameters is good. It is difficult to make this black and white for every skier.
Originally Posted by mntlion View Post
Another idea?
as different brands fit differently, and different shapes allow a smaller fit (or make a size larger necessary) why not just remove the size number all together and just have it as how to shell size a boot? My own boots are 299 to 287 (old Lange shape, to new Salomon/Garmont)
Plus the fact that some companies use US sizes, some use mondo, some use mens US size thru out the line, and some switch to ladies US for ladies boots, and who the hell knows what a JR boot will be. This might just confuse the public more (and more and more)

1) this is how to shell fit to length and a 5-10mm shell fit is a tight, performance fit, 10-15 = recreational, and 15+ too big.
2) width is light touching, 1-2mm, and 3+ = too wide
or not ....
Originally Posted by bud heishman View Post
That sounds better to me. Focus on how to properly size rather than talking about "downsizing".
Originally Posted by CEM View Post
i think saying that more than 15mm is too big and width more than 3mm being big is a bit on the neat side, a lot of the recreational skiers i see would not tolerate close to that..... 20mm might be a better reference point, however i will sometimes allow 22mm for a 1 week a year recreational skier as the size down being a 12mm shell check is tight for this level of skier,
the other issue is toe box shape which can affect how the client places their foot...but that is nothing to do with size more shell selection in the first place

this year [i think forf the first time] Salomon have taken all the crap off their shells and only put the mondo size instead of the mondo the us and the uk size
This thread will continue and hopefully a sizing chart will be published as part of it.
post #4 of 7
After some deliberation, we decided that Garmont was well ahead of the pack in publishing an accurate foot sizing chart. So, here is a US to Mondo Size conversion chart we think represents a better way to fit. Use the G-Fit size as Mondo, and you'll have it.
post #5 of 7
This chart is good. Don't know how Garmont got it right and everyone else gets it so wrong, but bravo. Again I've been away for awhile but things are slowing a little now. Has anything about this been started on the public site and if not how can I help. I can work on it today.

post #6 of 7
Perhaps a little explanation about Mondo sizing will help. Mondo size is the length of your foot in centimeters. So if you are Mondo size 27 your foot measures 27cm. if Mondo size 27.5 your foot is 27.5 cm.

This is standardized throughout ski industry but Mondo size is used elsewhere as well. A Mondo size 27 boot will be approximately 28.5 - 29.0 cm inside. This gives room for liner or when doing shell fit will give approximately 3/4" or 2cm between heel and shell heel pocket when the toes are gently touching the front of the shell.

Only infrequently or perhaps very infrequently do I need to sell someone a larger boot and only very infrequently do I need to sell someone a smalller boot. This applies to racers and recreational skiers.

Most people buy boots that are to big and it is unfortunate because it causes many problems not only with ski control and balance but also ultimately with comfort. It is caused by insistence that boots be comfortable out of the box. It does indeed happen when boots are correctly sized but not commonly so. I would say it is an unacceptably high expectation since boots are hard plastic and not soft accommodating leather.

Better is to find a boot that is correct length, width and instep height, accept that ankle pockets or room for your bunions is not exactly correct and have the boots modified. It is really the only way to get a comfortable correctly sized boot.

post #7 of 7
I thought I'd update this with a recent quote from one of Bud's replies.

Originally Posted by bud heishman View Post
So you are on the same page as the boot fitters here let's get some definitions straight.

Ramp angle is the angle created inside your boot by the boot board or zeppa. This angle affects ankle fore/aft balance as you suggest but it is most important to match ramp and forward lean to create a net forward lean to match your specific ROM needs taking into consideration dorsiflexion abilities.

Delta angle is the angle created by your bindings and the stand height differential they create which you have correctly identified above. This angle affects where your knee plumbs over your toes and your overall fore/aft body position.

Mounting position is another factor in the fore/aft senerio that affects where you are over the sweet spot of the skis and determines where your neutral stance has to be over the skis to turn most efficiently.

Forward lean is the fourth parameter that affects fore/aft balance is used in conjunction with ramp angle to create the "net" forward lean. If you have a hyper mobile ankle you will need more net forward lean and if you have minimal dorsiflexion you may need less net forward lean.

These four parameters are the ingredients which need to be blended together to find your optimal set up. I start with the foot and ankle checking the dorsiflexion range to help determine ramp and then net forward lean. Then I will click the skier into their bindings and look at the static neutral position created and make any delta angle adjustments needed to get a good static stance. Then it's out on the snow to test dynamically with some small shims in my pocket to change delta on the hill. You can do this with pieces of bontex insoles cut into 1 inch strips. They make both 1.5 mm and 3 mm thick insoles which is the maximum I would use between the boot and binding interface. You will notice as little as 1mm change in the delta which creates way less than a degree difference in delta angle, so it doesn't take much to feel a difference to a good skier.
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