i tried. i wanted to love this ski boot. it sounds perfect and has some amazing reviews. i only ski the backcountry and after the first day i had the worst shin bang of my life in these.. as well as inner ankle rub from another planet! i don't think they have much padding on the inner ankle bone area and i suffered EVERY time i wore these. on two ocassions i took two weeks off from skiing in hopes my wounds would heal but these boots just don't fit me right. they ski well and they are stiff for sure. i was pushing k2 coombas around in them with ease. but the fit hurt me very quickly in a alpine tour. the ski to walk mode was easy enough for me to flip with gloves, no issues there once you figure out how it works. also the buckle latches sometimes prevent the buckles from falling into the actual slot. they are there for a reason but it sometimes makes it harder than necessary to get the buckle on without a lot of tension. also at 14 degree lean i felt a tad in the back seat with these. i need more forward lean options! anyway they just aren't the boot for me.

i went into pro ski in seattle thinking i'd be trying on and eventually buying the dynafit zzero cf. i tried them on side by side, one on each foot. i had been warned by tetonat.com's steve romeo about the boot liner in the dynafits. wearing them on different feet this was obvious. the dynafit zzero boot just wasn't as comfortable as the garmont radium. also the radium feels like more boot because it comes up higher. it's a full alpine length boot which can only translate to better ski performance. now knew which one felt better on my foot it was time to weigh them. in size 25 the garmont radium was 5 ounces heavier per boot. for a race geak that is considerable. but for me that wasn't enough to tip the scale. i just ordered the radiums and can't wait to ski it!

These boots are light, ski well, and seem very durable. My major complaint is that they are a little narrow and rub my "6th" toe. I am going to try and have them punched or ground for additional width. The material of the shell is great. I was up Death Canyon in Grand Teton National Park last week on an ice/mixed climb that I skied in on these boots, changed into my climbing boots and left these in the pack. When I returned several hours later (no sun) I was able to get my foot in without too much work. The strong pull tabs on the tongue and back of the liner really helped with this! These boots ski really well...can lock them down well and they feel tight. As apposed to another reviewer, I feel the walk/ski modes are markedly different with the walk mode flowing nicely and the ski mode locked down nicely.

In short: these boots are light and ski well. If you have a wide forefoot, you might have some work to do to accommodate your big foot, like me!

This is my 4th Garmont boot. The lasts that Garmont uses fit my feet better than any other brand out there. I have a narrow boney foot and have always used race plug boots to get a good fit - with the resulting problem of a very stiff boot. When I started to ski more off piste, I discovered Garmont. I wear a size 10 1/2 shoe. In the Adrenalin I skied a 26.5 - the boot was never long enough and I moved into a 27 - this needed some fitting to get the boot snug enough though. The Radium size 27 fit like a glove right out of the box - perfect length (toes wiggle and stay warm) and snug and the fit remains excellent after 1 full season on them. Awesome boot though a bit soft for stiff skis in-bounds. This boot is a definite improvement in design over the Adrenalin. I also purchased the Endorphin. The size 27 was too snug in the toes. The 27.5 Endorphine fits as well as the Radium and is stiffer (but not Dynafit compatible). If you plan to spend a significant amount of time inbounds, I'd recommend looking at a stiffer Garmont model than the Radium (e.g. the Axon). Finally, I have a pair of Garmont SynerG telemark boots - soft, used to drive a pair of Karhu Guides around logging roads mostly. Size 27 gives me the same perfect fit. So, if you have a thin foot and are looking for a performance fit for AT, Garmont is definitely your boot.

Paul Parker here. I'm the Garmont ski boot Product Manager. Of course I give the Radium 5 Stars! More seriously, I wanted to reply to Spike's review and fit concerns.
Spike--Sorry that you aren't happy with your Radiums. I'd like to suggest a couple of things that might help out.The foam used in the liners of the Radium is the same foam composition as used in your Endorphin liners, just an improved design with a separate Strobel-stitched sole, new inner and outer skin, plastic-reinforced tongue for shin protection, and more cuff reinforcement, to name a few details. The fact that you find them uncomfortable and "hard" makes me wonder if there is an issue with the thermforming or fit, as feedback on fit has been consistently positive. You might get a shell fit from a boot fitter to be sure that you are in the right size. And, another thermoforming could be in order as well. Regarding walkability, these boots have more cuff travel in walk mode than any boot we've ever built. Be sure that you loosen the power strap, flip the walk mechanism's lever up to open it, open the cuff buckles completely, and use the Easy-Lock cuff catches in the biggest notch to give you the best range of motion. Following this routine, I think that you'll find that they walk very well. Spike, I hope that these suggestions are of some help and that you have better luck iwth your new boots--
Regarding flex index--Flag nailed it that flex index is random. There is no science in it. That said, Radiums are comparable to a 120-130 flex index, depending on the brand. We call it a 120 AT since it's not fair to compare alpine and AT boots. Radiums are quite stiff and handle big skis with ease. The High Overlap makes them especially quick and supportive in forward flex.
I hope these details are of some help--

Lightest perfromance 4 buckle mountaineering boot I've tried on. Great fit. Tight around instep and heel. Liner is light and warm. Best when thermofit by bootfitter. Skiing performance is phenomenal. Skiing on Coombas with dynafit bindings and it's plenty stiff for a 100mm+ waisted alpine board. Bottomless feel to the flex. Walk mode easy to open and lots of mobility in the cuff. Full strides save steps and energy on the up.

I own the Endorphin and it has been a great boot. I am 220 pounds and like a stiff boot to drive fat skis. The Endorphin was just the ticket. I was in a shop looking at the Axon for dynafit compatibility. One of the gear heads suggested the Radium and offered to let me try them. I have skied them a couple full days at the resort. All i can say is, these are an amazing out of this world boot. They are stiff but not like the Endorphin which is like skiing against a wall. The Radium flex the with you keeping you one with the boot. If you hit a hole and are thrown forward the boot flexes just the right amount to maintain perfect balance and control. I couldn't over flex the boot either, like i could in the Megarides. Did i mention light, Wow! A very simple walk/ski mode switch unlike the Endorphin where you have to pay close attention to which ski mode degree you are in, or you might be skiing 25 degreeProxy-Connection: keep-alive

These boots rock. Like others below, I had to some work on the liners. Once dialed in, however, they're great. By no means are they as stiff as a racing alpine shell, but they're burly enough for my K2 Hellbent + Marker Duke setup. I tried on a pair of Tecnica Agent AT boots, which were a lot roomier, but noticeably softer.

I used to tour in my alpine boots, but after painfully scrambling up a scree-field on a 14er in Colorado, I made the decision to get some AT boots. I talked to a good friend who manages the Surefoot store in Beaver Creek and he said the Radiums were the best AT boot out there.

When I first put them on, my toes felt pretty pinched. I have some serious foot problems (bunions), but have heard from others that they have the same issue. Regardless, after a bunion-punch and the heated liner fit, they felt great. By no means are they as stiff as an alpine race boot, but they felt solid enough for my hefty touring setup (K2 Hellbents + Marker Dukes).

I tried on the Tecnica Agent AT boots, which were extremely comfortable and roomy, but too soft.

I have skiied these two days so far, so it's possible my opinion could change if they break in, but I doubt they will change that much. The liners are very uncomfortable; cooking them a second time made no difference. They seem to be made of hard plastic coated with a thin layer of cloth. I'm getting numerous hot spots plus shin bang; not what I expect from a thermomoldable liner. The boots look great on paper but I'm very disappointed so far.

Another more minor criticism is the walk mode, which is barely discernable from the ski mode.

PS-I have owned a pair of Endorphins for a couple of years and they fit me quite well; I did not have to do any custom fitting beyond heat-molding. Unfotunately that will not be the case with these boots. I'd wait a year on these, hopefully Garmont will put a decent liner in them next year.

Had these for a few weeks now and probably have 10 solid days on them. Performance and weight are great... A few considerations... The buckle bail holders on the upper 2 buckles are nice and I haven't had problems with icing up or sticking, but it sure would be nice if the third buckle down had them, too. That's always the buckle that's dangling off to the side after a hard ride. Super easy to get my feet in and out, and the liner slides in and out easily, too. Lots of people I know have said these boots are a no-no if your forefoot or toes are wider than average. Indeed, my little toe is the most cramped spot on either foot.

I have always used Garmont boots and to me going w Radiums was really not a choice, but a certainty. In addition the features are very attractive and most reviews are great. Unfortunately, my first week long backcountry experience was not that great and the limiting factor was the boots.
They have a real narrow toe box, and large foot makes you want to upsize your shoes. I might have had therefore to big of boots (usually 27.5, i ended up with the 28), but here are the problems: toe box too small, liner's tongue doesnt really stop boot from hurting on your tibia and the heel seams actually create friction spots. Never had blisters or loose a toe nail in Garmonts before. So disappointed. Thanks to a great return policy, i might be looking at something else. So 5 stars for return policy, but only 3 for boots for me cause maybe I am dumbass you didn't get the right size.

Really like the shells, overlap, walk/tour mode, the little buckle catches on the top 2 buckles,etc.

Like others, I had initial problems with the fit of the G-fit liners -- just too tight in the width of the forefoot, even after heat molding. This basically prevented me from putting in full days in the backcountry due to foot pain.

A second heat molding has made all the difference! 10 minutes at 280 did the trick, much softer than the initial molding, and now I'm loving these boots. Just got back from a week of hut skiing in Canadian Rockies without a single hot spot or other bit of foot pain (wish I could say the same for my knees!)

Also, as others have commented, the liners started showing wear after about 5 days. For me, it was caused by the inner cuff rivet -- fixed with a little duct tape on the shells.

For reference, I've been skiing Scarpa tele boots with Intuition liners for many years now. For various reasons switched to AT for this season -- pushing Manaslu's with Vertical ST binders

This the best fitting AT Boot I ever used so far and finally a Dynafit compatible one which easily controls big mountain skis (using it on an Armada ARV 185 with the Dynafit Vertical ST). It might be true that the liner it comes with is slightly too hard on the upper part and could fit better at the heels. But I took my G-fit liners out from my Garmont Megalites and even though they're a bit shorter they perform great inside the Radiums - perfect toe-control - perfect heel fit - great comfort even when closed tight. A big YES for this boot!

Ok, I have been skiing the Radium since last spring, probably over 60 days in them now, and I can honestly say this is the best performance ski mountaineering boot on the market/ I say this for two reasons: first, the overlap construction provides excellent power and control in the cuff, and combined with the very light weight, gives an ideal power to weight ratio, which for A/T I think is paramount. Secondly, the Pebax material used in the shell is far more responsive to energy input, and also isn't as easily affected by warm or cold temps, meaning it doesn't get all soft when it's warm out or crazy stiff when it's cold.

Another bonus is the G-Fit thermofit liners are incredibly comfortable, and wrap snugly around the ankle, which adds to your power and control of the boot. The thin yet ultra durable rubber sole climbs like a champ on rocks, and mine are barely chipped or worn, and that is after a good beating in the California 14ers, the Alps, Colorado 14ers, and Antarctica. Also the boot buckle locks keep the buckles from flying around when they are open, and are nicely designed.

Also, the Raduim just well may be the first and only A/T boot featured in a Matchstick Productions film. I wore them skiing the Matterhorn, Eiger, Mt. Blanc, and Monte Rosa in "Claim"- check it out if you need more convincing.

The shell seems great but the liner does stink. The plastic reinforcement on the upper part of the tounge is in the wrong place - making the flex not very progressive. The BD Factor has a more progressive flex but is too heavy. The first part of the boot to make contact is at the top of the shin = shinbang and an "all or nothing" feel to controlling the ski. I put my liners from my G-rides in the Radiums and it helped a fair amount. Any suggestions for decent replacement liners?