K2 Renin boot review

K2 Renin featured image

A premium soft-flexing boot from K2.

After using the K2 TT snowsurfer boots last year and loving them, I thought I’d try out another K2 boot from the ‘soft yet high end’ category. Breaking in new boots sucks so if I could get another pair of quality boots that fit great out of the box (and stayed that way) life would be great. With the ad copy stating the Renin were “team driven” I was looking forward to trying them out.

Fit & Durability

At first, the Renin felt good but a little boxy. I didn’t have time to go get them heat molded so I thought I’d see how the natural heat molding system worked. Yep, if you just ride them, the Intuition Pro Foam 3D liners will mold to your foot. I think it was about three days before I completely lost the boxiness feeling completely and they just felt like 30-day old boots in their prime (in other words, awesome). I think trying on these boots in store will give you an accurate feel for how they will ride as they don’t pack out significantly. The new boxy feeling will disappear completely after a few days, but other than that, there won’t be any significant changes.

K2 Renin insole
Hooray for ankle bone cutouts!

The K2 Renin slides in one notch higher than the TT in K2’s stiffness ranking scale (a 3 out of 5) but in real life useage, I didn’t notice much of a difference. They feel like a medium to medium-soft boot with plenty of support from the Endo 2.0 tech in the outer shell.

K2 Renin Endo construction
Endo 2.0 construction shown on a display model

As for durability, after 40 days, similar to the TT Snowsurfer boots, the only wear is cosmetic from the BOA cables rubbing on the tongue. The Renin have not packed out very much and I haven’t noticed any increase in flex or looseness. The outer shell has flex zones on each side of the cuff and these really help to reduce wear and tear. I can see myself getting quite a few seasons out of these boots.

K2 Renin cuff
Flex zones on the cuff means less boot break down

Boa system

The Renin features a double BOA system, but not the usual upper and lower zone coilers like on the TT snowsurfer boot. On the Renin, there is just the one H3 BOA Coiler for the outer boot, and a BOA Mobility Conda inner boa for ankle hold on the liner. Only one outer BOA had me hesitating when choosing this boot, as the ability to independently adjust the lower and upper boot is quite important to fit. However, when that one outer BOA is combined with the inner ankle BOA I have to admit, it does make for a smooth fit. I was expecting performance loss and general sloppiness, but nope, it fits great with no heel-lift issues. While I think that a separate upper and lower zone BOA system might be better to dial in a ‘perfect’ fit, in reality these boots fit great as they are, so I’m not sure I should ask for more tech just for the sake of more tech. In addition, having a third boa knob sticking out of the boot would probably be too much.

To be honest, I don’t think the inner boa brings much to the table over a traditional lace pull system, apart from being able to adjust liner tightness on the fly, and with gloves on. Sounds good, but I don’t remember having to adjust my old liners ever. I will concede the convenience factor though and after using the double BOA system all season, I’m going to give it a thumbs up.

K2 Renin inner Boa
The inner Boa Conda, as seen on a cut out display model

The first day, I had top of the foot pain from the inner boa plastic plate (the teal-coloured bit in the picture above) being located right under my binding’s ankle strap. Being annoyed enough by the pain, I stopped and took a close look at the system. I realized the plate was held in place with Velcro, and it could be adjusted – so I moved it up as high as it would go and the pain went away. I haven’t touched it since and have been getting a great fit every day.

With every new boot you have to find the best way to get the right fit. With the Renin, I find that doing the inner boa first and getting a snug fit while I’m bending my knee forward (to make my instep expand), followed by the outer boa brings me the best results.


The outsole is the new Vibram RollSole, which K2 says is, “ergonomically shaped and allows riders additional maneuverability for next-level heelside carves and surf-style vibes.” Practically speaking, I have not noticed myself doing next-level anything but I do appreciate a sole that won’t break down before the rest of the boot will.

K2 Renin sole
This sole is supposed to help you with your tweaks

Final thoughts

It was honestly tough to review these boots – I kept forgetting I had new boots on! From day one, the K2 Renin were comfy and the break in process merely consisted of going from ‘a little boxy’ to ‘perfect fit’ thanks to the Intuition liners. Heat molding them upon purchase would get you that custom fit even quicker. After my initial reservations about only one outer BOA to tighten the boots, I have quickly grown to like the system. Getting them on and tight, or loosened and off is fast and easy, without any compromise in fit, response or comfort. The build quality is excellent, and these are the best fitting (and pain-free) boots I have ever had. Personally, the medium-soft flex is perfect and provides adequate support. I’m going to have to stock up on these!

Get more information on K2 Snowboarding at their official site.

Disclosure: The K2 Renin boots were provided by K2 Snowboarding.