Combat boot briefing
Here is a letter recently sent to an OS military who requested a Combat Boot Briefing. I think it gives you an insight into the depth of experience behind our boot designs.
Crossfire ( Aus ) P/L PeaceKeeper Combat Boots.
The PK +(PeaceKeeper +) is a bit unique in that it was designed from the very beginning to be worn by the only occupational group we know of which actually runs, on any terrain, carrying half again their body weight.
The biomechanics of that task go far beyond the shock and stress ablation abilities of most footwear construction methods and materials.
Which is why we went back to first principals to build the family of Goodyear Welted boots.
My previous firm, Wild Country P/L , was in the mountaineering and cross country ski trade in early 1980s.
We were importing boots from Europe . Beautifully made , but they hurt . It was almost accepted in those days that if you needed boots good enough to climb Mt. Aspiring you would be losing a few toenails.
Didn’t seem right to me , so I went to Europe and spent a lot of time in factories in France , Austria , Italy and Germany learning about last design and boot making .
Firstly I found that the low instep , narrow , rotated lasts were the fit problem . They were just the wrong shape for big wide , high instep ANZ feet .
So we invested in a full suite of lasts to our recipe . 27 years later we still use them .
Next I learned about the three main methods of boot construction .
- Welted . Goodyear or Norwegian .
A ribbed midsole board is the heart of the boot . Two main welted sewing lines engage the ribs and ‘ close the upper ‘ .
- Cemented .
Upper is made up over slip or curtain last . Bottom of it is buffed and glued to sole system .
- Injection moulded .
Molten rubber is injected into negative mould tool and cools onto upper .
The best of my visits was to an excellent firm in Germany. In 1984 I worked with them to make hiking and telemark boots of great quality . The Goodyear welt enabled us to include all the lining / Goretex / anti torsion shanks / shock absorbing foam etc needed to cope with the big stresses of skiing . And importantly it gave the midfoot flexibility for a long XC stride( this became vital for Combat Boot performance , more later ) .
The boot was a huge hit in the US and Australian markets . I still see some on the slopes .
However , like most European factories ours was looking at new technologies to reduce the use of highly trained craft workers and to speed up throughput . They went to unitised cement construction , and we learned a painful lesson . A platoon of Australian Defence mountaineers who experienced a batch failure of the sole glue at Annapurna . A very bad day in the field .
It became impossible to get the Goodyear Welted boots we wanted out of Europe so I got back on the road to investigate the US . After some years and a dozen factories of false starts we were delighted to find Dick Martens of Weinbrenner Shoe Co Wisconsin . The firm was a perfect fit with us . It is a century old and now employee owned . So the management has no interest in easing out highly trained workers , as they are the management . Consequently they have kept alive and thriving the Goodyear Welting skills , with capacity to do a half million or so pairs pa .
After the ADF climb of Everest in 1998 we shifted company work from Mountaineering to Military Gear .
In 2000 or so it was time for ADF to get new Combat Boots . Our early PK was in a trial of a dozen boots from worldwide, and did very well . However the tender was written only for injection moulding construction ( the Commonwealth had bought injection tooling already ) so our boot was excluded from consideration . For the next 20 years the issue boot has damaged feet , careers and combat capabilities . It has been defended by the system( see BRIG Nikolic interviews in the papers 2006 ) and hated by many troops ( thousands have told us so ).
Crossfire ( Aus ) P/L was placed in real bind .The system had no simple protocol for dealing with people who were hurt by the issue boot , or those who simply could not be fitted ( too big or two small ) . We became a defacto medical support Co . In the process we had acquired a good research cadre and priceless feedback .
So we made a non commercial decision to support the war effort by staying in production .
Some 1,000 people a year receive foot care help from Crossfire of a quality that the system cannot provide , but finally has formalised . People can now obtain medical approval to access non issue boots
When Afghanistan started the DMO reacted without thought and bought an inappropriate Mountaineering Boot with many problems . Which mean our workload of helping hurt individuals increased , as did our incentives to improve our boot and intensity of feedback .
20 years after the first models we now have a boot of a sound original concept , on a unique last , which has been continuously refined and includes materials developed specially for us .
Even better the Goodyear welt construction has made it easy to offer a family of boots , all built on the same last , with alternate materials for different tasks . Eg Navy boots , Flight boots , Cold weather , Jungle , Firefighter , Police etc .
The US Army has bought over 900,000 pairs of PK+ Steel Toe .
We wanted a boot to allow efficient ( and safe ) running , jumping , twisting , going to ground etc .
This required a last which promoted midfoot articulation for a ‘ strike and roll ” running gait . The boots underside is ‘ rockered ‘ like the foot wearing it . Not flat bottomed to ease popping out of injection tooling .
Note most work boots use a steel shank . Sole flex zone is just in front of the shank , well back from the midfoot . Promotes Plantar fasciitis , stresses the metatarsals and flattens arches .
PK+ has a doubled up synthetic athletic type shank which flexes progressively and in the right places . It allows big toe flexion for ‘ spring off ‘ . Each stride is longer but less energy demanding as the toe acts as a spring lever . In offhand stance the improvement in marksmanship is surprising . Better muzzle control when firing from the hip . Tendons and muscles from big toe to lower back can work as designed .
Ankle fore and aft flexibility is designed in by orientation of the fabric panels . Sideways and torsional stability is not compromised by this .
Shock Absorption .
In other construction techniques there is very little , or none , antishock material between foot sole and the road . In cemented types this is because of the difficulty of glue stabilising totally different materials to each other ( our Annapurna experience ) . In injected types it is because high quality foams would be melted by the process and thee is no room to fit them in .
Welting permits us to use the highest quality of preloaded foams which last the boots life without bottoming out .
Also , the space inside the welt rib is filled with cork compound which breaks in to the shape of the foot sole , dispersing load and eliminating ‘ hot spots ‘ .
Watch a soldier walking away from you . Nine times out of ten the boot heel will be breaking down sideways ( usually outwards ) , throwing out ankle / leg / spinal alignement . It is often an accelerating problem . As sole wears on one side the heel box breaks even more and injury becomes yet more likely .
PK+ Heel box is a water resistant styrene which is structurally sewn into the welt . No side collapse , no breakdown .
Once again , the simpler construction styles preclude use of the best quality linings .
Wet skin is more likely to blister . Skin comfort is determined by relative humidity at the surface . For foot comfort and health it is important to move water away from the skin as fast as possible . ” Walk Yourself Dry ” .
Flat non woven liners , low quality leather and coated nylon panels all slow breathing . PK+ uses a 3D free2air mesh to surround the foot surface with a moving layer of air to waft away humidity . Mesh is some 2.8mm thick which also gives over 5mm of size tolerance during break in .
We are ambivalent about waterproofing layers , using them in Alpine and Arctic boots . Sympatex , Goretex and eVENT are all good . In military use they can’t protect from water pouring off wet tussock and down the ankle , and actually slow down the drying process .
Liner socks made of stretch Lycra / Goretex are a very valid alternative . Sealed against the leg to resist water pouring from above , light , non blistering and super drying .
Decades of trials have taught us where the good materials come from . We are not constrained by the Berry Amendment .
Outsoles come mostly from Vibram . PK+ uses Sierra sole , Flight Boot -Matayur non FOD , Police boot -Polypillow etc .
Side Panels . We specify non coated Cordura for better breathability . We are experimenting with Nextec encapsulation .
Lacing . Tight woven laces to resist nasty corkscrew grass seed . Free running through quality hooks .
Anti intrusion Plates . Anti-nail plates of ceramic / Kevlar . No extra weight , protection right out to the welt line .
Toe boxes . PK+ is crush resistant vacuum moulded nylon . Safety toes steel or composite .
Haven’t met a soldier we can’t fit yet .
Sizes 3 – 16 . Half sizes up to 12 .
Two widths standard ( 85% Australians go W ) .
Custom fits to order .
FireFighters – we suggest the PK Fire ( NFPA or Euro) .
Airforce – the PK Flight .
We do an exception to our Welt only rule . That is a very lightweight Barracks / Day wear boot with cemented sole . Really an 8″ khaki running shoe .
Many thanks for your interest . Much enjoyed the visit ,
Crossfire ( Aus ) P/L
138 Wallace St