Alpinestars Nucleon Flex Proi back protector

Technical sheet

Alpinestars Nucleon Flex Proi back protector

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4 Reviews

19 Questions

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Long

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Features of Alpinestars Nucleon Flex Proi

Product description of Alpinestars Nucleon Flex Proi back protector

Description summary

The extremely lightweight Level 2 CE and UKCA certified Nucleon Flex Pro Back Protector Insert features a highly ventilated hybrid of Nucleon Cell and Nucleon Flex protectors for the optimum balance of force dispersion and flexibility, with a soft-touch 3D mesh liner for enhanced rider comfort.

Features:

- The super lightweight back protector insert is developed in three waist-to-shoulder dimensions in order to cover all body sizes.
- High performance polymeric material Cell and Nucleon Flex structures for optimized flexibility and excellent weight saving properties.
- The back protector’s design changes from the centre towards the outside providing the perfect balance between energy absorption and flexibility.
- Soft comfortable 3d mesh on the body side of the protector offers breathability and rider comfort.
- Snap button compatibility for quick and easy use with Alpinestars suits and jackets.
- Rigorously tested and certified to T+ & T for proven performance in extreme temperatures.

Protection:
- Back Protector: EN 1621-2:2014 Level 2 (T+ & T-)
- CE Level 2 – Back

Specifications

Manual

Technical specifications of Alpinestars Nucleon Flex Proi

Protection level

Level 2
Temperature testing

T+ & T-
Coverage type

Back Only
Ventilation system

Yes
Color

Grey
Product Type

Back protectors
Location

Back

Features of Alpinestars Nucleon Flex Proi

Color Grey

Color

Grey

Product Type Back protectors

Product Type

Back protectors

Location Back

Location

Back

Key differentiators

Constructed from a hybrid of Nucleon Cell and Nucleon Flex structures for a balance of flexibility and energy absorption.

Engineered with a highly ventilated design and a soft-touch 3D mesh liner to enhance breathability and rider comfort.

Features CE Level 2 (EN 1621-2:2014) certified protection, tested for performance in both high and low temperatures (T+ & T-).

Includes snap button compatibility for simple integration with compatible Alpinestars suits and jackets.

Technology in Alpinestars Nucleon Flex Proi back protector

Energy rating

Warnings

5 / 5

4 Reviews

What our customers are saying about Alpinestars Nucleon Flex Proi back protector

This high-quality Alpinestars back protector is praised for being super light, practical, and offering perfect protection at a great value. Buyers frequently inquire about compatibility and correct sizing for various Alpinestars jackets, including the Bogota, T-SP S, and GP Plus models. The flexible design and quality construction make it an excellent purchase for riders seeking a lightweight yet robust protective insert for their motorcycle gear

Excellent product

2025/05/14

Aldo

It fits exactly like the Bogota model jacket

Unparalleled quality and protection

2025/03/15

tiago

Super light and practical. And maximum quality. Perfect protection and at a value well below the quality presented. Excellent purchase

Back protection

2024/04/28

Yriy

Quality product

Back protect

2023/05/24

Roland

Good quality product. Can only recommend

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Include AI Generated questions and answers

2023-10-23

Khalid

i need to know is it compatibility with this jacket " Alpinestars T-SP S Jacket " https://www.tradeinn.com/motardinn/en/alpinestars-t-sp-s-jacket/137451139/p and if it compatibility what is the correct size of the back protector, knowing that the jacket size is L.

Answer of Richard

So I got the Alpinestars Nucleon Flex Proi back protector in the Alpinestars Viper V3 Air jacket. Try it out, if it doesn´t fit in the other jacket, you can send the jacket back

* Generated by AI based on customer and product data

2024-05-07

Ferhat

I have the “Alpinestars T SP X Superair jacket (XXL)”. Is this protection suitable for my jacket? If yes, which size should I buy?

Answer of Yuri Nikolaevich

I have another jacket size XL, for it I took the back protector size L

Answer of Roland

You have to check the inside of your jacket, I have a missile V2, which has a small pocket, which also fits this lengthy one , from the upper side, but not the lower. You should either but this long version with its own straps or tweek it into your jackets small pocket. having ,,the short version is worthless.

* Generated by AI based on customer and product data

2024-11-13

Mahendaraj

What is the measurements of this item as i need to know if it will fit my jacket

Answer of Sven

Size L for jacket sizes L and XL

* Generated by AI based on customer and product data

2024-12-08

Dino

Its Will fit to my Mirage Drystar jacket? Which hand of protector will fit a size L in a jacket?

Answer of Roland

these all have the same default protector pocket , i dont see why it would not

* Generated by AI based on customer and product data

2026-09-25

Generated by AI and verified

What are the main features of the Alpinestars Nucleon Flex Proi?

Answer of Generated by AI and verified

The Nucleon Flex Proi is an extremely lightweight back protector insert that is CE Level 2 certified. It features a highly ventilated, flexible design using Nucleon Cell and Nucleon Flex structures, a soft 3D mesh liner for comfort, and snap button compatibility with Alpinestars gear.

* Generated by AI based on customer and product data

2026-09-25

Generated by AI and verified

Is the Alpinestars Nucleon Flex Proi Back Protector worth the investment?

Answer of Generated by AI and verified

The Alpinestars Nucleon Flex Proi Back Protector offers Level 2 CE and UKCA certification, ensuring high protection standards. Its lightweight design and ventilation system enhance comfort, making it a valuable choice for motorcycle riders seeking reliable protection.

* Generated by AI based on customer and product data

2026-09-25

Generated by AI and verified

What level of protection does the Alpinestars Nucleon Flex Proi offer?

Answer of Generated by AI and verified

This back protector is certified to EN 1621-2:2014 Level 2, providing a high level of impact protection for motorcycle riders. It has also been rigorously tested for performance in extreme temperatures (T+ & T-).

* Generated by AI based on customer and product data

2026-09-25

Generated by AI and verified

Is the Nucleon Flex Proi back protector ventilated?

Answer of Generated by AI and verified

Yes, it features a highly ventilated design to optimize airflow. It also includes a soft, comfortable 3D mesh on the body side of the protector to enhance breathability and rider comfort.

* Generated by AI based on customer and product data

2026-09-25

Generated by AI and verified

What materials are used in the construction of this back protector?

Answer of Generated by AI and verified

The Alpinestars Nucleon Flex Proi is constructed from a high-performance polymeric material, utilizing a hybrid of Nucleon Cell and Nucleon Flex structures. This design provides an optimal balance of flexibility and force dispersion.

* Generated by AI based on customer and product data

2026-09-25

Generated by AI and verified

How flexible is the Nucleon Flex Proi back protector?

Answer of Generated by AI and verified

This back protector is designed for optimized flexibility. Its construction uses Nucleon Cell and Nucleon Flex structures, and the design changes from the center outwards to provide a balance between energy absorption and flexibility during movement.

* Generated by AI based on customer and product data

2026-09-25

Generated by AI and verified

What certifications does the Alpinestars Nucleon Flex Proi Back Protector have?

Answer of Generated by AI and verified

The Alpinestars Nucleon Flex Proi Back Protector is certified to CE EN 1621-2:2014 Level 2 standards, ensuring high levels of protection.

* Generated by AI based on customer and product data

2026-09-25

Generated by AI and verified

Can this back protector be used in very hot or cold weather?

Answer of Generated by AI and verified

Yes, the Nucleon Flex Proi has been rigorously tested and certified to T+ & T- standards, which confirms its proven performance in extreme temperature conditions.

* Generated by AI based on customer and product data

2026-09-25

Generated by AI and verified

Is the Alpinestars Nucleon Flex Proi suitable for long-distance rides?

Answer of Generated by AI and verified

Yes, the Alpinestars Nucleon Flex Proi Back Protector is designed for comfort and flexibility, making it suitable for long-distance motorcycle rides.

* Generated by AI based on customer and product data

2026-09-25

Generated by AI and verified

Is the Nucleon Flex Proi compatible with Alpinestars jackets?

Answer of Generated by AI and verified

Yes, this back protector insert features snap button compatibility for quick and easy use with compatible Alpinestars suits and jackets.

* Generated by AI based on customer and product data

2026-09-25

Generated by AI and verified

Can the Alpinestars Nucleon Flex Proi be used with other brands of motorcycle jackets?

Answer of Generated by AI and verified

The Alpinestars Nucleon Flex Proi Back Protector features snap button compatibility, allowing it to be easily integrated with various motorcycle jackets, including those from other brands.

* Generated by AI based on customer and product data

2026-09-25

Generated by AI and verified

How does the Alpinestars Nucleon Flex Proi compare to the Alpinestars Nucleon Kr Celli Protector?

Answer of Generated by AI and verified

The Alpinestars Nucleon Flex Proi features a highly ventilated design with Level 2 protection, while specific details about the Nucleon Kr Celli Protector are not available. Both are designed to offer excellent protection for motorcycle riders.

* Generated by AI based on customer and product data

2025-03-19

Thomas

What size should I choose for a GP Plus RV4 Rideknit jacket, size EUR 56?

Answer of Yuri Nikolaevich

the protection fits well with the ALPINESTARS Bogota´ Pro Drystar Jacket Vetiver Military Olive XL, because the protection is very soft, it can be trimmed

* Generated by AI based on customer and product data

2023-10-07

Mauro Meirelles Costa

This is the NÚCLEON FLEX PROi FULL…??

Answer of Richard

Yes, that is the Alpinestars Nucleon Flex Pro-I, back protector.

* Generated by AI based on customer and product data

2025-05-07

Jon

Is it compatible with Alpinestars suits with the button strip? Thanks in advance

Answer of Janez

Yes, it is compatible. I bought the ALPINESTARS T-GP R V3 Drystar® jacket and it fits perfectly.

* Generated by AI based on customer and product data

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Frequently bought together

Best sellers

Use cases

Touring and Long-Distance Riding 90% Fit

This back protector is a reliable upgrade for touring riders who spend long hours on the road. Its certified Level 2 protection offers peace of mind, while the ventilation system and flexible design ensure comfort over extended periods, making it a great all-rounder for varied conditions.

CE EN 1621-2:2014 Level 2 certification,Ventilation system for breathability,Flexible construction,Performance tested in both high and low temperatures (T+ & T-)

Street Riding and Daily Commuting 90% Fit

For daily commuters and street riders, this protector offers a balanced combination of safety and comfort. The flexible polymeric material and soft-touch liner allow for easy movement in stop-and-go traffic, while the high level of impact protection provides confidence for urban environments.

Flexible design,Ventilation system,Soft-touch 3D mesh liner,Level 2 impact protection

Spirited Canyon or Sport Riding 80% Fit

This protector is a solid performance choice for spirited sport or canyon riding.

Level 2 impact protection,Temperature tested (T+ & T-),High-performance polymeric material,Ventilated for active riding

Upgrading Jacket-Integrated Armor 100% Fit

As a versatile insert, this is an ideal upgrade for riders looking to enhance the safety of their existing gear. Its compatibility with specific jackets via a snap-button system and its high Level 2 certification provide a significant and straightforward improvement over standard foam pads.

Snap-button compatibility,CE EN 1621-2:2014 Level 2 certification,Flexible and lightweight design,Back Only coverage type

Best for

Best for Safety-Conscious Riders

This protector meets the stringent CE EN 1621-2:2014 Level 2 certification, offering a high standard of impact resistance for the back.

Based on: certifications: CE_EN_1621-2 (Back Protector: EN 1621-2:2014 Level 2), Protection level: level_2 (Protection level: Level 2)

Ideal for Regular Commuters & Weekend Riders

Its flexible design, ventilation system, and soft-touch liner provide all-day comfort, making it a great all-rounder for frequent use.

Based on: flexibility: flexible, Ventilation system: Yes, Liner material: soft-touch 3D mesh liner

A Solid Upgrade for Performance Riders

Based on: impact_protection: level_2, Temperature testing: T+ & T-

Great for Alpinestars Gear Integration

Featuring snap-button compatibility, this back protector is designed to seamlessly integrate with compatible Alpinestars jackets.

Based on: snap_button_compatibility: yes, Compatibility: specific_brands

Benefits

FunctionalRide with Confidence Thanks to Certified Level 2 Protection

This back protector is engineered to provide a high standard of safety, meeting rigorous certification standards. It is certified as EN 1621-2:2014 Level 2, offering you peace of mind by safeguarding your spine against impacts during a fall.

Certifications: CE_EN_1621-2 (Back Protector: EN 1621-2:2014 Level 2)

Impact protection: level_2

FunctionalConsistent Protection Across a Range of Temperatures

This back protector is tested and certified for performance in both high (T+) and low (T-) temperature conditions. This ensures its protective qualities remain consistent and reliable, whether you're riding on a hot summer day or in cooler weather.

Temperature testing: T+ & T-

Temperature certification: T+ & T

Ideal buyer profiles

The Safety-First Rider

This rider prioritizes maximum protection above all else. They seek out gear that meets or exceeds the highest safety standards, understanding that proper protection is a critical investment for every ride, whether commuting or on the track.

This product is ideal for the safety-conscious rider because it offers CE EN 1621-2:2014 Level 2 protection, the highest standard for back protectors. The high-performance polymeric material is engineered for impact resistance, and its certification for both high and low temperatures (T+ & T-) ensures consistent performance in various conditions.

The Performance-Focused Rider

This individual is dedicated to optimizing their riding experience. They look for gear that offers high levels of protection without compromising comfort, flexibility, or integration with their existing setup, allowing them to focus on the road or track ahead.

With its flexible construction and Nucleon Flex structures, this back protector moves with the rider, ensuring it doesn't hinder performance. The integrated ventilation system and soft-touch 3D mesh liner enhance comfort during demanding rides, while the snap-button compatibility allows for seamless integration with Alpinestars jackets.

The Weekend Warrior

This rider enjoys spirited weekend rides on twisty roads or occasional track days. They want reliable, certified protection that is comfortable for several hours at a time and easy to use with their favorite riding jacket.

The Nucleon Flex Proi provides the confidence of Level 2 protection for weekend adventures. Its flexible design and effective ventilation system prevent overheating and discomfort on longer rides. The simple snap-button system makes it easy to attach to a compatible jacket and forget it's there, providing hassle-free safety.

Competitive features

When evaluating back protectors, key factors include certification level, comfort, and integration with your existing gear. The Alpinestars Nucleon Flex Proi Back Protector is an extremely lightweight, Level 2 CE and UKCA certified insert. It utilizes a hybrid construction of Nucleon Cell and Nucleon Flex protectors designed for an optimal balance of force dispersion and flexibility. It stands out with its focus on ventilation and a soft 3D mesh liner for rider comfort. In our comparison, it is positioned as a highly accessible option against competitors like the Zandona Shield Evo series and the Forcefield Freelite L2.

Where it excels

The Alpinestars Nucleon Flex Proi is explicitly described as 'extremely lightweight' and features a 'highly ventilated' design, combining Nucleon Cell and Nucleon Flex structures for flexibility and weight savings. It offers seamless integration with Alpinestars suits and jackets via snap button compatibility, a specific feature not detailed for the other protectors in this comparison. This protector provides Level 2 CE and UKCA certification, ensuring a high standard of protection, while being the most budget-friendly option among the compared models.

Consider alternatives if...

Verdict

The Alpinestars Nucleon Flex Proi Back Protector is an excellent choice for riders seeking a lightweight, flexible, and highly ventilated Level 2 certified insert. Its design prioritizes comfort through a soft mesh liner and optimized flexibility. The built-in snap button compatibility makes it a convenient upgrade for those already using Alpinestars jackets or suits. Given its competitive price point and strong feature set focused on comfort and certified protection, it represents a compelling value in its category.

Specs comparison

	Alpinestars Nucleon Flex Proi back protector	Alpinestars Nucleon Kr Cell Back Protector	Alpinestars Nucleon Kr Celli Protector Back Protector	Alpinestars Nucleon Kr 1 Celli Back Protector	Alpinestars Nucleon Plasma Back Protector	Alpinestars Nucleon Plasma Full Back Protector
Material	polymeric material	polymeric	polymeric material blend	high-performance polymeric material blend	bio-based materials and high performance polyurethane	bio-based materials and high performance polyurethane
Ventilation	Yes	Yes	Yes	Yes	Yes	Yes
Flexibility	flexible	flexible	flexible	flexible	flexible	flexible
Impact Protection	Level 2	-	Level 1	Level 2	Level 2	Level 2
Compatibility	specific_brands	specific_brands	-	specific_brands	-	-
Used For	motorcycles	motorcycles	motorcycles	motorcycles	motorcycles	motorcycles
Ventilation System	Yes	Highly perforated shell design for maximum airflow and breathability	high	Yes	-	Yes
Protection Level	Level 2	advanced	Level 1	-	Level 2	Level 2
Coverage Type	Back Only	Back Only	Back Only	Back Only	Back Protector Insert	Full Back Protector Insert

Specs vs competitors

	Alpinestars Nucleon Flex Proi back protector	Zandona Netcube Back Pro X6 Back Protector	Zandona Netcubepro X7 Back Protector	Zandona Netcubepro X8 Back Protector	Forcefield Freelite L2 Back Protector
Material	polymeric material	nitrile anti-shock rubber	nitrile anti-shock rubber	nitrile anti-shock rubber	state-of-the-art materials
Ventilation	Yes	Yes	Yes	Yes	-
Flexibility	flexible	flexible	flexible	flexible	flexible
Impact Protection	Level 2	Level 2	Level 2	Level 2	Level 2
Used For	motorcycles	motorcycles	motorcycles	motorcycles	motorcycles
Ventilation System	Yes	S.R.T. Technology (Sweat Removing Textile)	Breathable 3D Textile	S.R.T. Technology	-
Protection Level	Level 2	Level 2	Level 2	Level 2	Level 2
Coverage Type	Back Only	Back Protector	Full Back	Back Only	-