In 2012 I climbed Innominata from Courmayeur and down to Chamonix in a single push. Since I belive that to do an activity we need to carry all the gear needed from the begining to the end and to be light one of the biggest concerns was the shoes. If I want the comfort and technical features for climbing boots will be the best, but then it will be a pain in the ass to run all the lower parts, and running shoes may be to cold and lack of rigidity for the climbing. That time I used my running shoes with a light gaiter to protect from snow and a pair of automatic aluminium crampons. It worked well but it was very painful on my toes and it wasn’t really possible to use the crampons very well on ice.
With that idea of cramponable running shoes I started to think about how to make it more technical and less painful. Looking to different running shoes and crampons. That year I did some more tests, and on some trainings with Jordi Tossas we comented what would be the next steeps to improve the system.
Jordi Tossas crossing a nevé under Dru’s 
Tosas dry tooling with running shoes
Basically the crampons were working fine on mixt climbing and on ice using the ice shapes but lacked rigidity on the crampon – boot connection to “hit” the ice. Another problem was the comfort, it was basically bery painfull on the hill and toes where the crampon slings were compressing the shoe – and bones-. Last problem was the temperature. Running shoes are normally thin and not impermeable, so in long cold climbs the feet became frozen.
In 2015 Simon Elias and I climbed Colton Mcintyre at Grandes Jorases, since we wanted to start from Chamonix and do in a push to Courmayeur I tought it would be a good way to test this system in a more alpine terrain. I used my x-alp shoes with a pair of dartwin crampons and a cross country ski overboot to protect from the cold. It worked well but on steep ice I wasn’t able to hit strongly the ice and the crampons had some mouvement.
One week after Jorasses I travel to Denali with Seb Montaz, Vivian Bruchez and Jordi Tosas. During the long hours in the tent I started to draw what it could be an improvement to this system.
Later this year I meet with dessigners at Salomon, with Patrick Leick and François Girard, and they make those ideas a reality:
I used this boots in my 15-16-17 expeditions in Himalaya and after some small improvements I think we got the right footwear to be able to run from low altitudes to everywere.
But this crampon overboot was too warm and too big for climbs in lower ranges. So symplifying the same idea, Patrick, François and Philippe Margolliet made a lighter overboot perfect for activities like the Peuterey, Grandes Murailles, Bruoillard ridge or 6000 m summits in Himalaya.
Didn’t you also use a carbon insole to stiffen the x-alp on the Jorases? I am currently using an insole to get the XA Alpine a bit stiffer than the x-alp for use with crampons while being nicer to run in without. But, especially with Irvis Hybrids, they are still a bit too soft. Not even just for kicking ice but also mixed scrambling when standing on the points. I was intrigued by the overboots for a while now and understand that Salomon is not planning to release them which is a total bummer. I can see the difficulties with production of many sizes for a very small market but do you think there is any possibility to get a pair somehow (size 44 ;-). Thanks for the insights and keep up the gear tinkering.
Not yet there, it was after that time I started using it.
Yes, I really wished they released the overboot, is one of the best mountain gear I have ever use. I use now a carbon plate with the x alpine and with a Irvis (slings system) it works well but the crampon is a bit bigger than the shoe so it moves a bit sometimes. ..