I have found we as winter climbers tend to stick to the brands we know due to the potential financial loss and crippling pain an ill fitted pair of B3's can inflict on feet.I have been fortunate enough to have worn Aku's offerings before and they have fitted my feet well. When I saw the Serai’s previewed online I was very keen to try them.
Photo: Steve Dunne
Aku Technical Specification
- Upper: kevlar + nylon + mycrofiber
- Upper protection: liba smart pu
- Lining description: gore-tex® insulated comfort
- Outsole: vibram® nepal
- Midsole: double density pu exoskeleton
- Lasting board (stiffness): Carbon fiber lasting board + honey comb aluminum core + eva microporosa (xx stiff)
- Footbed: custom fit pro alum
- Weight (grams): 840
- Size range (uk): 5 - 13
When they arrived I was very surprised by how light they were. I had to double check they were B3 rated. Once I tried to flex them in my hand it was obvious, there was no movement as expected. There are the lugs front and back for C3 crampons you would expect. The Serai’s have some cool components, Gore Tex lining with some Primaloft insulation to boot. Also they look pretty cool.
In practice I have worn these on Scottish Winter trips, a not so Scottish Winter traverse of the Aonach Eagach ridge, a few trips to the ice wall and on this years trip to Switzerland where I participated in summiting the Monch via the south east ridge.
Photo: Alan McIntosh
As with my previous experience with Aku footwear my foot fitted well once they were tightened in. The mixture of runner style eyelets, lace locks and fabric lace loops allows the laces to be secured in stages meaning the tightness can be adjusted to suit the demands of the terrain. The way Aku sculpt the last and in turn the internals of the boot is amazing. I really hope they work for everyone because from their lifestyle shoes, through the trekking boot range, right up to these B3 Serai’s they have been spot on for fit!
For longer walk ins I'd keep them looser around the ankle, when it was time to kick in or going down hill then I cinched the boot in. At no point did I get blisters. That's not to say I didn't get some B3 pain on longer days. The velcro cuff that holds the laces and seals the top of the boot is simple but really effective. Most of the time I had salopettes with built in gaiters but it kept the laces in check.
The spec says that the Serai’s have Kevlar in the upper, honeycomb aluminum core with a carbon fibre lasting board. These components together make the boot sound strong, tough and light. When you look at the boot most of these elements can't be seen but knowing they're there gives you peace of mind. In practice these boots have taken a bit of a pounding from the different adventures they've been on. So how they sound lives up to how they perform.
The Serai’s are Gore-Tex and Primaloft lined. My experience of winter climbing boots is as soon as you stand about, whether it be on a food stop or especially at belay stance on a cold Scottish winter day, the sweat in your socks freezes within seconds, well minutes maybe but it doesn't take long. However Aku have set up the insulation in these boots I cannot remember a time I suffered from excessively cold feet. Don't get me wrong they got bit cold but nothing compared to what I'm used to in the boots and never uncomfortable!
Photo: Steve Dunne
The Vibram sole unit is fairly standard, it works well. Lets be honest it's only there to get you to the point where you don crampons. I was only able to test the with C2 crampons. They fit really well and I didn't have any issues with the crampons slipping or coming loose. The high rand has protected the boot well, you'd hardly know they had been out scratching about in desperate Scottish winter mixed conditions but I can assure you the have.
In summary, the Serai’s are strong, light, tough, comfortable, warm and they look bloody good too. Something pretty special is going to have to come around for these not be my preferred winter boot. Aku have hit the right balance between weight, durability and comfort. At £370 they are a good price too.