Prologo Nago R4 Road Bike Saddle

Name: Prologo Nago R4 Road Bike Saddle
Brand: Prologo
Price: 48200.0 JPY
Availability: InStock

¥48,200 JPY

The Prologo Nago R4 is a compact, lightweight performance road saddle developed with professional riders, combining a movement-friendly T-shape, semi-round profile, carbon-fibre base and multiple width, pressure-relief and rail options for Australian cyclists seeking greater comfort, support and pedalling efficiency.

Key Prologo Nago R4 Features

Compact 245mm length and T-shaped profile provide freedom to shift position during climbing, racing and sustained high-power efforts.
Available in 137mm and 147mm widths to accommodate different sit-bone measurements, body types and support preferences.
Choice of closed Active Base or open PAS pressure-relief designs allows riders to select the support style that suits their anatomy.
Nack carbon-composite or TiroX alloy-steel rails provide a choice between minimum weight and improved vibration absorption.
Carbon-fibre base and variable-density foam balance efficient power transfer with comfort during long road rides.

(more product details...)

Saddle rail material

Saddle Width (mm)

Model

loading inventory data..

At Pedal Passion we aim to provide great value to our fellow riders. Listed prices and availability are updated regularly. Chat to us about latest price updates, special deals, shipping cost and ETA or any other product details and advice.

We want You to fuel your cycling passion now, not later, so with the help of our partners, we offer flexible payments terms including 4 interest-free installments (Afterpay or Paypal) or over 6, 12 or even up to 24 month repayments (Afterpay, Shop Instalments or ZIP).
Eligibility, T&Cs and minimum order value conditions may apply.

More Product Details:

Saddle profile: Semi-round

Saddle shape: T-shaped
Saddle length: 245mm

Available widths:

137mm
147mm

Available pressure-relief formats:

Prologo Nago R4 closed version with Active Base
Prologo Nago R4 PAS with an open central pressure-relief channel

Available rail options:

Nack carbon-composite rails
TiroX light-alloy steel rails

Base material:

Long-fibre carbon or carbon-fibre-injected base, depending on the version

Cover material:

Durable microfibre on standard foam models
Model-specific printed polymer construction on 3DMSS versions

Padding:

Variable-density foam on conventional models
Multi-zone 3D-printed structure on 3DMSS models

Standard colour:

Hard Black

Additional finishes:

White and special-edition colours may be offered according to model, distributor and production year

Prologo Nago R4 137mm

The 137mm model is the narrower option in the Prologo Nago R4 family. It is designed primarily for cyclists with a narrower sit-bone measurement or riders who prefer a compact race saddle with minimal interference around the upper thighs.

Dimensions: 245x137mm

Typical closed-version weights:

Nack rails: Approximately 142g
TiroX rails: Approximately 194g

Typical PAS-version weight:

Approximately 138g to 143g with Nack rails, depending on the published specification and production variation

Best suited to:

Riders with relatively narrow sit-bone spacing
Cyclists using an aggressive road position
Riders who move regularly along the saddle
Weight-conscious custom bike builds
Racers wanting a compact, supportive platform

Prologo Nago R4 147mm

The 147mm model provides a broader support platform and additional padding compared with the narrower version.

Dimensions: 245x147mm

Additional padding compared with the 137mm version:

Approximately 10mm more padding towards the sides
Approximately 3mm more padding across the upper surface

Typical published weights:

Nack rails: Approximately 153g
TiroX rails: Approximately 203g to 212g, depending on PAS or closed construction

Best suited to:

Riders with wider sit-bone spacing
Cyclists who benefit from a broader weight-bearing surface
Riders with a higher body mass
Endurance cyclists seeking additional support
Cyclists who prefer a more planted seated position

Prologo Nago R4 Closed Version

The closed version uses three independently developed padded sections across the saddle surface.

Beneath the central cover section is Prologo’s Active Base system. The base remains perforated internally even though the upper cover is closed.

This arrangement is designed to combine:

A continuous seating surface
Broad central support
Improved pressure distribution
A degree of base flexibility
Reduced concentration of pressure through the saddle centre

The closed version may suit riders who dislike the edges of a large anatomical cut-out or prefer a continuous upper surface.

Prologo Nago R4 PAS

The Prologo Nago R4 PAS uses a large open central channel combined with a perforated base.

PAS stands for Perineal Area System. It is designed to reduce concentrated pressure through sensitive areas while maintaining support along the two independent side sections.

The PAS version may be particularly suitable for riders who:

Experience central pressure or numbness
Maintain a low and rotated road position
Spend extended periods seated
Prefer a clearly defined anatomical cut-out
Have been fitted successfully to pressure-relief saddles

The PAS channel should not be considered automatically more comfortable for every rider. Saddle width, pelvic rotation, fore-aft position, tilt, handlebar drop and riding posture all affect pressure distribution.

Prologo Nago R4 3DMSS

Selected Prologo Nago R4 PAS models are available with Multi Sector System 3D-printed padding.
This construction replaces conventional foam with separately tuned printed zones. Different areas can be engineered to provide specific levels of support, compression and rebound.
The 3DMSS version is positioned as the flagship comfort and performance model, but its higher price makes professional saddle assessment particularly valuable before purchase.

Professional Rider Development

The Prologo Nago R4 was developed in consultation with professional cycling teams and refined through Prologo’s Pressure Map MyOwn testing system.

Pressure mapping records how force is distributed across a saddle while a cyclist pedals. This allows the manufacturer or bike fitter to identify concentrated pressure, insufficient sit-bone support and differences between riding positions.

The Prologo Nago R4 uses this information to balance support, freedom of movement and pressure management rather than relying solely on additional padding.

Compact 245mm Shape

The Prologo Nago R4 measures 245mm in length, placing it within the compact road saddle category.

A compact saddle can offer:

Reduced material and weight
Greater clearance when moving forward
Easier adoption of an aggressive riding position
Less unnecessary nose length
A clearly defined usable seating area
Improved compatibility with modern race-bike positions

The saddle is not excessively short or locked into one riding position. Its T-shaped plan allows riders to move along the available length as effort and terrain change.

T-Shaped Profile

The T-shaped design combines a broad rear support section with a relatively narrow transition towards the nose.

This shape is intended to provide:

Stable sit-bone support
Clearance around the inner thighs
Freedom to move forward during hard efforts
Reduced interference during high-cadence pedalling
Easier movement between climbing and aerodynamic positions

Riders who prefer to remain firmly positioned in one location may favour a more V-shaped alternative. The Prologo Nago R4 is better suited to cyclists who naturally move across the saddle during a ride.

Semi-Round Ergonomic Profile

The semi-round profile sits between Prologo’s flatter and more rounded saddle shapes.

It is particularly suited to cyclists with moderate pelvic-rotation flexibility. The shape supports forward pelvic rotation without forcing the rider into an extremely fixed position.

Potential benefits include:

Easier movement into the drops
Support during forward pelvic rotation
Stable seated climbing
Smooth transitions between riding positions
Balanced pressure distribution

A rider’s flexibility should be assessed as part of an overall bike fit. Saddle shape cannot compensate fully for excessive handlebar reach, an overly low cockpit or incorrect saddle height.

Anatomical Centre

The saddle’s anatomical centre is marked on the cover to support accurate installation and measurement.

Using the anatomical centre rather than the saddle nose helps a fitter compare different saddle models whose total lengths and nose shapes may vary.

This is valuable when transferring:

Saddle setback
Effective seated reach
Bike-fit measurements
Position between multiple bicycles
A known successful setup to a replacement saddle

The marking also makes it easier to record adjustments and restore the previous position when servicing the bike.

Variable-Density Foam

Conventional Prologo Nago R4 models use modern variable-density foam rather than one uniform block of padding.

Different sections can therefore provide different levels of support and compression.

Firmer zones help stabilise the pelvis and prevent the rider from sinking excessively into the saddle. More compliant sections can reduce pressure and improve comfort where additional movement is beneficial.

Excessively soft padding can feel comfortable initially but concentrate pressure during longer rides as the rider compresses through it. The Prologo Nago R4 instead uses shaped support and controlled foam density to promote sustainable comfort.

Prologo Active Base System

The closed Prologo Nago R4 uses Active Base technology.

Although the upper cover is continuous, the base beneath the central section is perforated. This allows the saddle to retain a broad seating surface while providing additional flexibility and reduced central pressure.

Potential benefits include:

Continuous upper support
Less exposed cut-out edge
Improved pressure distribution
Controlled central flex
Greater support than a completely open channel for selected riders

The Active Base version can be a useful alternative for cyclists who want pressure management but do not enjoy a full anatomical cut-out.

Prologo PAS System

The Prologo Nago R4 PAS uses a broad central channel that passes through the cover and base.

The channel is intended to reduce pressure peaks during:

Aggressive road riding
Long seated climbs
Sustained aerodynamic positions
High-power seated efforts
Extended endurance rides

The two padded side sections operate independently, helping each side respond to the rider’s pedalling movement.

The correct saddle angle remains essential. Excessive nose-down tilt can cause the rider to slide forward and place additional load through the hands, while excessive nose-up tilt can increase central pressure.

Carbon-Fibre Base

Every Prologo Nago R4 uses a carbon-based shell construction.

Depending on the model, this may be described as:

Long-fibre carbon
Carbon-fibre injection
Full carbon base construction

The shell is engineered to provide enough stiffness for effective pedalling while retaining carefully controlled flex for comfort.

A saddle base that is too flexible can feel unstable under hard efforts. A base that is excessively rigid can transmit more vibration and increase sensitivity to imperfect setup.

Nack Rails

Nack stands for Nano Carbon Fiber.

The rails combine carbon fibre with Kevlar and aluminium filaments to create a lightweight and stiff support structure.

Benefits include:

Minimum saddle weight
High structural rigidity
Responsive race-oriented feel
Premium appearance
Suitability for lightweight road builds

Nack rails use an oval profile rather than a standard round metal-rail shape. The seatpost clamp must be designed for the rail dimensions and must support the rails correctly.

A clamp intended only for 7mm round rails must not be forced onto Nack rails.

TiroX Rails

TiroX rails are manufactured from a light-alloy steel.

They are heavier than Nack rails but offer:

Greater vibration absorption
Strong durability
Conventional round-rail compatibility
Lower purchase price
A more forgiving ride character
Easier integration with common seatpost clamps

For many Australian road cyclists, the TiroX version provides a strong balance of performance, comfort and value.

Nack rails are most compelling when minimum weight and maximum stiffness are priorities.

3DMSS Printed Padding

The 3DMSS construction uses a three-dimensional printed matrix divided into functional support zones.

The structure can be tuned according to the force applied in each area, allowing selected regions to compress differently under load.

Potential benefits include:

Zoned support
Improved pressure distribution
Reduced material in low-load areas
Controlled compression
High ventilation
Low overall weight
Distinctive premium construction

Independent testing of the Prologo Nago R4 PAS 3DMSS has praised its all-day comfort and lack of concentrated pressure points, although its premium price remains its most obvious drawback.

Saddle length: 245mm

Available widths:

137mm
147mm

Published height for selected 147mm models: Approximately 58mm from the lower rail edge to the top of the saddle

Rail adjustment range: Approximately 65mm on selected TiroX versions

Nack rail dimensions: Approximately 7x9.3mm oval

TiroX rail diameter: Approximately 7mm round

Product diameter: Not applicable

Saddle profile: Semi-round

Plan shape: T-shaped

Pressure-relief options:

Closed Active Base
Open PAS channel

Rail options:

Nack carbon composite
TiroX alloy steel

Prologo Nago R4 137mm Fit

The 137mm width is best considered when:

Sit-bone spacing is relatively narrow.
The rider has moderate pelvic flexibility.
A compact race position is used.
Additional thigh clearance is required.
The current saddle feels too broad.
The rider prefers a precise and supportive platform.

Prologo Nago R4 147mm Fit

The 147mm width is best considered when:

Sit-bone spacing is wider.
The rider needs a broader support platform.
A narrow saddle produces pressure or instability.
Additional padding is preferred.
Body mass requires improved pressure distribution.
Long-distance comfort is a priority.

Additional width should not be selected simply because a rider wants more comfort. A saddle that is too wide can interfere with thigh movement, create rubbing or cause the rider to shift forward.

Saddle Width Selection

Correct width should be assessed using:

Sit-bone measurement
Pelvic rotation
Riding position
Handlebar drop
Saddle-to-handlebar reach
Rider mobility
Current pressure symptoms
Pedalling movement
Previous saddle experience

Sit-bone width alone does not determine the ideal saddle. A rider rotates the pelvis differently on an upright endurance bike than on a low race bike, changing which surfaces contact the saddle.

Saddle Installation

Initial installation should reproduce a known successful position where possible.

Setup should include:

Saddle height
Saddle setback
Saddle tilt
Anatomical-centre position
Rail-clamp compatibility
Rail torque
Left-to-right alignment
Knee tracking
Weight distribution between saddle and handlebars

Small adjustments can have a significant effect. Changes of only 2mm to 3mm in height or fore-aft position can alter pressure and pedalling mechanics.

A near-level starting angle is generally sensible, followed by small adjustments based on the rider’s movement and pressure distribution.

The Prologo Nago R4 is best suited to road racers, fast club cyclists, gran fondo riders and performance-focused recreational cyclists who use an assertive riding position but still require sustainable support during long hours in the saddle.

Professional Saddle Fitting

Professional fitting is recommended before selecting the saddle width and pressure-relief format.

A proper assessment should consider:

Sit-bone spacing
Pelvic rotation
Rider flexibility
Saddle height
Saddle setback
Saddle tilt
Handlebar reach
Handlebar drop
Leg-length difference
Current pressure symptoms
Pedalling movement
Typical ride duration

A fitter may use pressure mapping or dynamic observation to determine whether the rider is supported correctly.

Installation

Confirm that the seatpost clamp is compatible with the selected rails.

TiroX rails:

Approximately 7mm round
Compatible with many conventional saddle clamps

Nack rails:

Approximately 7x9.3mm oval
Require an oval-rail-compatible clamp

Apply the seatpost manufacturer’s stated torque rather than tightening by feel.

The clamp should remain within the rail’s marked adjustment area. Clamping outside this range can damage the rail and invalidate warranty coverage.

Cleaning

Clean the saddle with:

Mild soapy water
A soft cloth
A soft brush around seams and channel edges
Clean water for rinsing

Avoid:

Aggressive solvents
Petroleum-based cleaners
High-pressure washing
Abrasive brushes
Silicone dressing
Prolonged soaking
Excessive heat

Allow the saddle to dry naturally after wet rides.

Routine Inspection

Inspect regularly for:

Cracked rails
Rail separation
Shell damage
Loose rail interfaces
Torn cover material
Damaged PAS edges
Deformation
Unusual movement
Creaking
Loose seatpost hardware

Stop riding if a rail is cracked, deeply scratched or separating from the saddle base.

Carbon-Rail Care

Nack rails should be inspected carefully following:

Crashes
Bike-transport incidents
Overtightening
Saddle-bag clamp installation
Seatpost failure
Significant impact

Road.cc published an independent review of the Prologo Nago R4 PAS 3DMSS Nack 137 on 5 November 2024 after using the saddle across criterium racing, ordinary road riding and a demanding 220km gravel ride.

The saddle received an overall score of 8 out of 10. Its strongest qualities were all-day comfort, lack of concentrated pressure points, low weight and a useful adjustment range.
The reviewer found the 3D-printed zonal construction supportive across different riding positions rather than excessively soft. The PAS channel also provided effective central pressure relief during extended rides.
The review’s primary criticism was cost. The 3DMSS Nack version sits at the premium end of the saddle market, making correct fit particularly important before purchase.
Although the reviewed model uses 3D-printed padding rather than the standard variable-density foam, it shares the same 245x137mm platform, T-shape, semi-round profile and PAS pressure-relief concept found throughout the Prologo Nago R4 family.

The 147mm version receives favourable comments from riders who previously found the 137mm model too narrow. Its additional padding and broader base can distribute weight more effectively during longer rides.

The main considerations are personal fit and rail compatibility. A saddle that works exceptionally well for one cyclist may not suit another rider with different pelvic rotation, sit-bone spacing or riding posture.

Prologo Dimension R2

Best for: Riders wanting a flatter, more locked-in performance saddle.

Advantages:

Compact race-oriented design
Flat profile
Wide nose
Strong support in an aggressive position
PAS and closed options
Multiple rail choices

Considerations:

Less freedom to move than the T-shaped Prologo Nago R4
Flatter profile may not suit riders with moderate pelvic rotation
More fixed seated position
Shape can feel broad through the front

The Prologo Dimension R2 suits riders who prefer a stable and fixed position. The Prologo Nago R4 is more appropriate for cyclists who move along the saddle during changing efforts.

Specialized Power Pro

Best for: Riders wanting a widely supported short-nose saddle with broad pressure relief.

Advantages:

Established short-nose design
Large central cut-out
Multiple widths
Broad dealer availability
Extensive bike-fitting familiarity
Numerous rail and padding levels

Considerations:

More locked-in seating position
Wider nose may not suit every rider
Less rearward movement
Shape differs substantially from the Prologo Nago R4
Premium carbon versions can be expensive

The Specialized Power Pro offers broad market support and a stable short-nose position. The Prologo Nago R4 provides more freedom to change position through its T-shaped profile.

Fizik Vento Argo R1

Best for: Road racers wanting a short saddle with a stable central seating position.

Advantages:

Carbon-reinforced shell
Carbon rails
Pressure-relief channel
Multiple widths
Strong racing reputation
Supportive short-nose design

Considerations:

More fixed seating concept
Less movement along the saddle
Wider central platform may not suit narrow riders
Carbon rails require compatible seatpost clamps

The Fizik Vento Argo R1 encourages riders to remain in a defined position. The Prologo Nago R4 provides greater fore-aft movement and a more traditional T-shaped transition.

Selle Italia SLR Boost

Best for: Riders wanting a lightweight compact saddle with a classic performance feel.

Advantages:

Low weight
Compact proportions
Multiple width and rail options
Cut-out and closed versions
Strong professional-racing history
Broad model selection

Considerations:

Flatter and firmer feel on certain versions
Model selection can be confusing
Narrower padding may feel less forgiving
Premium carbon versions are expensive

The Selle Italia SLR Boost is a natural lightweight alternative. The Prologo Nago R4 differentiates itself with its semi-round profile, variable-density support and width-specific padding strategy.