Customer Services

Customer Services

IMS – INTERNAL MIDSOLE SYSTEM

A more stable, more comfortable underfoot platform — designed to reduce slippage and improve support.

IMS (Internal Midsole System) is an exclusive AKU construction used in the assembly/lasting build to improve the way your foot sits, loads, and stays in place during use. It combines a traditional nylon support structure with a microporous EVA layer positioned inside the upper. The result is a more secure, controlled footbed feel with uniform pressure distribution, reduced unwanted movement, and dependable comfort when you’re walking hard, carrying load, or working on uneven ground.

  • More stable feel: supportive structure helps keep the foot centred on uneven terrain.
  • Less slippage: designed to help limit lateral (side-to-side) and frontal (toe-bang) movement during intense use.
  • Comfort + shock absorption: integrated cushioning supports long-wear comfort and impact management.
What this means for you

A more locked-in, supported feel that stays comfortable over distance — especially useful on descents, under load, or on demanding mixed terrain.
IMS
AKU IMS (Internal Midsole System) internal support and cushioning concept
AKU internal support + cushioning construction technology.
What is IMS (Internal Midsole System)?
 

IMS is AKU’s internal footbed/lasting construction designed to help the footwear capture the anatomy of the foot more effectively than a simple “insole-only” approach. By integrating the supportive element (nylon structure) and the cushioning element (microporous EVA) inside the upper, IMS is designed to promote uniform pressure distribution, reduce unwanted internal movement, and improve comfort during prolonged, demanding use.
How it works (support + cushioning working together)
 
Support that keeps you centred

The nylon support structure helps stabilise the foot on uneven surfaces and during directional changes, improving control when you’re carrying load, moving over mixed terrain, or spending long hours on your feet.

Worth knowing

If you’re experiencing heel lift or toe bang, it’s often a fit/lacing issue rather than the midsole system alone. IMS is designed to help reduce unwanted movement, but correct sizing, socks and lacing still matter most.
Cushioning that stays consistent

The microporous EVA layer supports shock absorption and long-wear comfort. Because it’s integrated into the internal construction, the footbed feel is designed to remain stable and consistent through the step — not “squishy”, but supportive.

  • More even pressure: can reduce hot spots for many users over distance.
  • Better control: a more connected feel without harshness.
  • Comfort under load: particularly noticeable in trekking/backpacking and professional use.
Best use cases

Demanding hiking/trekking, backpacking, professional use, and any situation where you want support + comfort for long wear.
IMS versions (IMS1, IMS2, IMS3)
 
IMS1 — low-profile sensitivity + precision

IMS1 pairs the Internal Midsole System with a thin microporous EVA midsole. The lower-profile build is designed to deliver maximum ground sensitivity, precision and reliable response — ideal when you want confident foot placement and quick feedback from the terrain.

Exploded view key

1 = IMS (internal support + microporous EVA inside the upper)
2 = Slim microporous EVA midsole (low profile for sensitivity and precision)
IMS1 exploded view: low-profile build for sensitivity, precision and reliable response.
 
IMS2 — balanced control + shock absorption

IMS2 uses the same IMS internal concept, coupled with a thicker midsole in moulded EVA or moulded PU. This version is designed to find a strong balance between control, foot protection and shock absorption, while still maintaining a stable, supportive feel for long days on varied terrain.

Exploded view key

1 = IMS (internal support + microporous EVA inside the upper)
2 = Moulded EVA / moulded PU midsole (more cushioning + protection while staying controlled)
IMS2 exploded view: a thicker EVA/PU midsole for comfort and protection over distance.

 

IMS3 — stability + protection with PU exoskeleton support

IMS3 is used where AKU wants a more structured platform for demanding mountain use. This construction couples the IMS concept with a PU exoskeleton for stability and protection, and an ultra-light PU internal component to deliver cushioning, shock absorption and compressive strength.

Exploded view key

1 = Ultralight PU (cushioning + shock absorption + compressive strength)
2 = PU Exoskeleton (stability + protection at key points)
IMS3 exploded view: PU exoskeleton support combined with ultralight PU cushioning for demanding use.
Jargon buster (plain English)
 
Midsole
The layer between your foot and the outsole that affects comfort, support and shock absorption.
EVA
A lightweight foam used for cushioning. “Microporous” EVA refers to a structure designed for consistent comfort and shock absorption.
Nylon support
A supportive internal structure that helps stabilise the foot and improve control on uneven ground.
Toe bang
When toes hit the front on descents. Usually caused by fit, sock choice or lacing rather than the midsole itself.
Find IMS models on AKU UK
 

IMS appears on selected AKU models where stability, precision and long-wear comfort are priorities. Browse by category below.

Outdoor
Hunting
Tactical
Professional

Tip: if you tell us your terrain (mud/rock/mixed) and whether you carry load, we can recommend the best family for stability and comfort.
Care (keep comfort and control consistent)
 

IMS is internal and protected, but overall comfort depends on how the footwear is maintained. The biggest comfort wins come from correct drying, clean uppers, and a stable fit.

1
Dry correctly
Remove insoles (if removable), loosen laces, and dry naturally away from direct heat to protect materials and maintain comfort.
2
Keep the interior clean
Grit inside footwear can cause hot spots and wear socks faster. Shake out debris and keep the footbed area clean and dry.
3
Use lacing to prevent movement
If you notice heel lift or toe bang, re-check fit and lacing (especially before descents). A snug heel with toe room is the goal.
Insole swaps

If you use aftermarket insoles or orthotics, choose a thickness similar to the original to avoid changing volume and fit too drastically. If you’re unsure, tell us the model and insole/orthotic type and we’ll advise.
IMS FAQs
 
Is IMS an insole?
Not exactly. IMS is an internal construction system that forms part of the footbed/midsole build. Many models also include a removable insole on top, but IMS itself is built into the footwear structure.
Will IMS stop heel lift and toe bang?
IMS is designed to help reduce unwanted movement, but fit and lacing still matter most. If you’re getting heel lift or toe bang, check sizing, sock thickness, and lacing technique (especially on descents).
Does IMS make the boot feel stiffer?
It can feel more supportive rather than softer. Stiffness depends on the whole boot (sole unit, shank, upper build). IMS is designed to balance control and comfort in demanding use.
Can I use orthotics with IMS boots?
Usually yes. The main watch-out is volume: very thick orthotics can make the fit feel tighter and change heel hold. If you tell us your model and orthotic thickness/type, we can advise the best approach.
Is there a break-in period for IMS?
Any structured hiking boot benefits from a short break-in. Start with shorter walks to dial in lacing and let the materials settle. Most users notice the comfort benefit most on longer days, not just indoor try-ons.

Note: IMS terminology and versioning (IMS1 / IMS2 / IMS3) follows AKU’s global technology framework used across AKU Italy and international AKU platforms.