SHIMANO ULTREAD Gravity is a family of mountain bike outsole technologies developed for aggressive trail, enduro, and downhill riding. It combines discipline-specific rubber compounds with tread patterns designed around how gravity riders interact with both the pedals and the ground.
The Gravity family includes two distinct versions: ULTREAD GF for flat-pedal shoes and ULTREAD GE for SPD-compatible Gravity Enduro shoes.
ULTREAD Gravity at a glance:
- ULTREAD GF: Soft, slow-rebounding rubber designed around flat-pedal grip.
- ULTREAD GE: Enduro-focused outsole with SPD compatibility and an expanded pedal channel.
- Terrain: Trail, enduro, downhill, and technical off-road riding.
- Tread: Gravity-specific hexagonal patterns for pedal and ground contact.
- Goal: Provide dependable grip and durability both on and off the bike.
What Is SHIMANO ULTREAD Gravity?
ULTREAD is SHIMANO's family of discipline-specific off-road outsole technologies. Rather than using the same rubber and tread pattern across every mountain bike shoe, SHIMANO tunes each version around the needs of a particular riding style.
ULTREAD Gravity is the branch developed for aggressive trail, enduro, and downhill riding.
Within that family:
- ULTREAD GF is designed for flat pedals.
- ULTREAD GE is designed for SPD clip-in pedals.
Both use gravity-specific tread concepts, but the rubber characteristics and pedal interfaces are optimized differently.
Learn more about the complete SHIMANO ULTREAD family.
How Is ULTREAD GF Different From ULTREAD GE?
ULTREAD GF:
- Designed for flat pedals.
- Uses soft, slow-rebounding rubber.
- Hexagonal tread is shaped around flat-pedal pin interaction.
- Prioritizes pedal grip while preserving off-bike traction.
ULTREAD GE:
- Designed around SHIMANO SPD.
- Uses an expanded pedal channel.
- Includes enduro-specific toe and heel tread patterns.
- Balances clip-in compatibility with traction when walking or riding temporarily unclipped.
The distinction is important because flat-pedal and clip-in riders interact with the pedal differently. ULTREAD GF relies heavily on rubber-to-pedal-pin contact, while ULTREAD GE works around the SPD cleat and pedal interface.
How Does ULTREAD GF Work With Flat Pedals?
ULTREAD GF combines a soft, durable, slow-rebounding rubber compound with a hexagonal tread pattern designed around flat-pedal pins.
The tread provides multiple contact areas where pedal pins can engage the outsole, helping create a stable connection between the shoe and platform pedal.
Slow-rebounding rubber is particularly useful for flat-pedal riding because the compound can deform around pedal pins rather than immediately springing away from them.
This gives the outsole the grip characteristics needed for rough trail and gravity riding while preserving the freedom of movement that flat pedals provide.
Why Does ULTREAD GF Use a Hexagonal Tread Pattern?
The hexagonal tread pattern creates multiple edges and recesses that interact with flat-pedal pins.
SHIMANO also uses tapered grooves within the outsole to help manage mud and debris that can collect between the shoe and pedal.
Keeping the contact area relatively clear helps the rubber and pedal pins continue to interact as intended in dirty trail conditions.
Actual grip still depends on the pedal, pin configuration, terrain, weather, and rider technique.
How Does ULTREAD GF Work Off the Bike?
Gravity riding often includes steep hike-a-bike sections, track walks, lift lines, and scrambling over rocks or roots.
ULTREAD GF uses stepped tread blocks toward the front of the outsole to create additional ground contact when walking on uneven terrain.
The tread is also shaped to help channel mud and water away from the sole.
These features make the same outsole useful both on the pedal and during short off-bike sections.
Which SHIMANO Shoes Use ULTREAD GF?
ULTREAD GF is used across SHIMANO's Gravity Flat footwear range, including models such as:
- GF800
- GF600
- GF400
These shoes share ULTREAD GF technology but differ in upper construction, closure systems, protection, fit, and overall intended use.
Explore SHIMANO Gravity footwear.
How Does ULTREAD GE Work With SPD?
ULTREAD GE is designed specifically around SHIMANO's two-bolt SPD pedal system.
The outsole incorporates a molded, expanded pedal channel surrounding the recessed SPD cleat. This channel provides space for pedal engagement while also creating ground and pedal contact around the cleat area.
When clipped in, the SPD cleat and pedal mechanism provide the primary connection between rider and bike.
When the rider is temporarily unclipped, the surrounding ULTREAD GE outsole can still contact the pedal platform, which can be useful in technical situations before the cleat is fully re-engaged.
Learn more about SHIMANO SPD.
Why Does ULTREAD GE Use an Expanded Pedal Channel?
The pedal channel is one of the primary differences between ULTREAD GE and an XC-style SPD outsole.
Gravity and enduro riders may repeatedly clip in, unclip, dab a foot, and re-engage while riding technical terrain.
The expanded channel gives the pedal additional room around the cleat area and allows the outsole to interact with the pedal platform when the rider has not yet fully clipped back in.
This design is tuned around the stop-and-start pedal interaction common in aggressive trail and enduro riding.
How Is ULTREAD GE Designed for Walking and Hike-a-Bike Sections?
ULTREAD GE uses gravity-specific tread patterns at the toe and heel to provide ground contact away from the bike.
This is particularly useful on steep trail sections, rocky surfaces, muddy terrain, and race-course walks where an SPD rider may need traction without changing footwear.
The recessed SPD cleat allows the surrounding rubber tread to contact the ground rather than forcing the metal cleat to take the full load while walking.
Which SHIMANO Shoes Use ULTREAD GE?
ULTREAD GE is used throughout SHIMANO's Gravity Enduro SPD footwear range, including models such as:
- GE900HS
- GE900
- GE900GTX
- GE700
- GE500
These models use the same underlying ULTREAD GE concept but vary in protection, closure systems, weather resistance, upper construction, and intended riding level.
Is ULTREAD Gravity Responsible for Shoe Stiffness?
Not by itself.
ULTREAD refers primarily to the rubber outsole compound and tread design. The shoe's midsole construction plays a major role in determining overall stiffness and flexibility.
For example, SHIMANO Gravity footwear may pair ULTREAD with technologies such as TORBAL 2.0 or different midsole constructions depending on the model.
This is why two shoes using the same ULTREAD family can still feel different when pedaling or walking.
Learn more about SHIMANO's Footwear Stiffness Index.
ULTREAD GF vs. GE: Which Is Right for You?
Choose ULTREAD GF if:
- You ride flat pedals.
- You want direct rubber-to-pedal-pin grip.
- You prefer the freedom to reposition your foot easily.
- You ride trail, enduro, downhill, or bike-park terrain.
Choose ULTREAD GE if:
- You use SPD clip-in pedals.
- You want a recessed two-bolt cleat.
- You want an expanded pedal channel around the cleat.
- You ride aggressive trail, enduro, or downhill terrain.
How Is ULTREAD Gravity Different From ULTREAD XC?
ULTREAD Gravity and ULTREAD XC are designed around different riding priorities.
- ULTREAD XC: Lightweight, durable outsole design for cross-country and cyclocross riding.
- ULTREAD GE: SPD-compatible gravity outsole with an expanded pedal channel and enduro-specific tread.
- ULTREAD GF: Flat-pedal outsole using soft, slow-rebounding rubber and hexagonal tread.
Each version follows the same ULTREAD philosophy: combine a discipline-specific rubber compound with a tread pattern engineered for how and where the shoe will be used.
Who Is ULTREAD Gravity For?
ULTREAD Gravity is designed for mountain bikers who ride technical terrain and need footwear that works both on the pedals and during off-bike sections.
Flat-pedal riders can choose ULTREAD GF for a rubber compound and tread pattern tuned around pedal pins, while SPD riders can choose ULTREAD GE for a clip-in system designed around aggressive trail and enduro riding.
The result is not one universal gravity outsole, but two purpose-built systems designed around the different ways flat-pedal and SPD riders connect to their bikes.
