Alpinestars Nucleon Flex Proi back protector

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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

CE Level 2 certified protection (EN 1621-2:2014) for reliable impact absorption.

Features snap button compatibility for quick and easy integration with Alpinestars suits and jackets.

Highly ventilated design with a soft 3D mesh liner for enhanced breathability and rider comfort.

Hybrid construction using Nucleon Cell and Nucleon Flex structures for an optimal balance of flexibility and force dispersion.

Rigorously tested for proven performance in both high and low temperature conditions (T+ & T-).

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

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

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

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

2024-12-08

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

2026-09-10

Generated by AI and verified

Has the Nucleon Flex Proi been tested for performance in different temperatures?

Answer of Generated by AI and verified

Yes, this back protector has been rigorously tested and certified to T+ and T- standards, confirming its performance in extreme temperature conditions.

* Generated by AI based on customer and product data

2026-09-10

Generated by AI and verified

How does the Alpinestars Nucleon Flex Proi compare to the Zandona Netcubepro X8 Back Protector?

Answer of Generated by AI and verified

While specific specs for the Zandona Netcubepro X8 are not available, the Alpinestars Nucleon Flex Proi stands out with its Level 2 CE certification and ventilated design, ensuring both protection and comfort.

* Generated by AI based on customer and product data

2026-09-10

Generated by AI and verified

How does the Nucleon Flex Proi attach to Alpinestars jackets?

Answer of Generated by AI and verified

This back protector features snap button compatibility, allowing for quick and easy installation into compatible Alpinestars suits and jackets.

* Generated by AI based on customer and product data

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

2026-09-10

Generated by AI and verified

Is the Alpinestars Nucleon Flex Proi back protector suitable for both men and women?

Answer of Generated by AI and verified

Yes, this back protector is a unisex design, making it suitable for all adult riders.

* Generated by AI based on customer and product data

2026-09-10

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 protection with CE certification, making it a reliable choice for safety-conscious riders. Its lightweight and flexible design enhances comfort without compromising on protection.

* Generated by AI based on customer and product data

2026-09-10

Generated by AI and verified

Is this back protector flexible enough for active riding?

Answer of Generated by AI and verified

Yes, the protector is designed to be flexible. It uses Nucleon Cell and Nucleon Flex structures to optimize flexibility, allowing for a good range of motion while riding.

* Generated by AI based on customer and product data

2026-09-10

Generated by AI and verified

Is this back protector ventilated?

Answer of Generated by AI and verified

Yes, it features a ventilation system and a soft, comfortable 3D mesh on the body-facing side to offer breathability and enhance rider comfort.

* 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

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

2026-09-10

Generated by AI and verified

What is the intended use for the Alpinestars Nucleon Flex Proi?

Answer of Generated by AI and verified

This back protector is designed specifically for motorcycle riders to be inserted into compatible jackets and suits for enhanced back protection.

* Generated by AI based on customer and product data

2026-09-10

Generated by AI and verified

What level of protection does the 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 use.

* Generated by AI based on customer and product data

2026-09-10

Generated by AI and verified

What makes the Nucleon Flex Proi comfortable to wear?

Answer of Generated by AI and verified

The protector is designed for comfort with a flexible construction and a soft 3D mesh liner on the body side. This design enhances breathability and rider comfort during use.

* Generated by AI based on customer and product data

2026-09-10

Generated by AI and verified

What materials are used in the Nucleon Flex Proi back protector?

Answer of Generated by AI and verified

It is constructed from a high-performance polymeric material, utilizing Nucleon Cell and Nucleon Flex structures for an optimal balance of flexibility and weight savings.

* Generated by AI based on customer and product data

2026-09-10

Generated by AI and verified

Will this back protector fit in any motorcycle jacket?

Answer of Generated by AI and verified

The Nucleon Flex Proi is specifically designed with snap button compatibility for use with Alpinestars suits and jackets. While it may fit in other brands' protector pockets, the secure snap-in feature is intended for Alpinestars gear.

* Generated by AI based on customer and product data

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Frequently bought together

Best sellers

Use cases

Touring & Long-Distance Riding 90% Fit

This protector is a reliable upgrade for touring riders who spend long hours on the road. Its flexible design and effective ventilation system, featuring a soft 3D mesh, provide sustained comfort without compromising on certified Level 2 protection.

CE EN 1621-2:2014 Level 2 certification,Flexible construction,Ventilation system with 3D mesh,T+ & T- temperature testing

Street Riding & Daily Commuting 95% Fit

For daily street riding, this protector offers a great balance of safety and practicality. The flexible polymeric material construction and high performance design provide solid Level 2 impact resistance while remaining comfortable for regular use.

Protection Level: Level 2,Flexible construction,High performance polymeric material,Ventilation for rider comfort

Spirited Canyon & Weekend Rides 80% Fit

This is a solid performance choice for riders enjoying spirited weekend rides through canyons or on backroads. The CE Level 2 certification offers confidence-inspiring impact protection, while the flexible build allows for dynamic body movements on the motorcycle.

Impact Protection: Level 2,Flexible design,Nucleon Flex structure,Breathable 3D mesh

Light Off-Road & Riding 75% Fit

As a versatile option, this protector is suitable for light adventure and off-road use where mobility is key. Its certified Level 2 protection handles impacts, and the ventilation helps manage heat during more physically demanding riding, making it a great all-rounder.

CE EN 1621-2:2014 Level 2 certification,Ventilation system,Flexible construction,T+ & T- temperature testing

Best for

Best for the Rider

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

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

A Reliable Upgrade

It combines Level 2 protection with a flexible design and a ventilated mesh back for a balanced, comfortable, and high-performance experience on long rides.

Protection level: level_2, Flexibility: flexible, Ventilation: yes (Soft comfortable 3d mesh on the body side of the protector offers breathability and rider comfort.)

Ideal for Riders

Engineered with a high-performance polymeric material and Nucleon Flex structures, it provides certified protection that remains flexible and breathable for dynamic riding.

Material: polymeric material (High performance polymeric material Cell and Nucleon Flex structures), Flexibility: flexible, Ventilation system: Yes

Benefits

FunctionalCertified Level 2 Impact Protection

Ride with confidence knowing you're equipped with high-level spinal protection. This back protector is certified to EN 1621-2:2014 Level 2 standards, providing significant impact absorption in the event of a fall.

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

Impact protection: level_2

Ideal buyer profiles

The Rider

This rider prioritizes maximum protection above all else. They look for gear that meets or exceeds the highest safety standards and won't compromise on impact resistance for their daily commute or long-distance tours.

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

Ideal Buyer

This rider enjoys weekend trips and spirited rides, needing reliable protection that is comfortable for hours in the saddle. They want a 'fit and forget' solution that offers a great balance of safety, comfort, and practicality for various conditions.

The Nucleon Flex Proi is an excellent choice for the weekend warrior. Its flexible design and breathable mesh ensure comfort on longer rides, while the CE Level 2 certification provides peace of mind. Its proven performance across a range of temperatures (T+ & T-) makes it a versatile option for unpredictable weekend weather.

Competitive features

When selecting a back protector, key factors include certification level, comfort, and how it integrates with your existing gear. The Alpinestars Nucleon Flex Proi is a Level 2 certified insert known for its lightweight and flexible design. In our analysis, we're comparing it against several popular alternatives, including the Spidi Warrior Evo Inside and various models from Zandona's Shield Evo line. The provided comparison data shows all these protectors are positioned at a nearly identical price point, making other features the primary differentiators.

Where it excels

The Alpinestars Nucleon Flex Proi stands out with its explicit Level 2 CE and UKCA certification, a critical safety feature mentioned in the product details. This provides a clear benchmark for its protective capabilities. It is described as being extremely lightweight and flexible, featuring a hybrid of Nucleon Cell and Nucleon Flex protectors. This construction, combined with a soft 3D mesh liner, is designed to balance force dispersion with rider comfort. The protector is noted for being highly ventilated, which is a significant advantage for comfort during rides in various conditions.

Consider alternatives if...

While the Alpinestars protector is highly rated, the comparison data provided does not offer specific attribute differences in areas like abrasion resistance or adjustable fit systems between it and the Spidi or Zandona models. Riders looking for specific features not detailed here may need to research each model's full specifications.

Verdict

The Alpinestars Nucleon Flex Proi Back Protector is an excellent choice for riders seeking a lightweight, flexible, and highly ventilated insert with confirmed Level 2 protection. Its design focuses on providing comfort without compromising on safety standards. Given that it is priced competitively with the Spidi and Zandona alternatives, its combination of certified protection and comfort-oriented features like the hybrid construction and mesh liner makes it a strong contender 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	-	high-performance polymeric material blend	bio-based materials and high performance polyurethane	bio-based materials and high performance polyurethane
Ventilation	true	true	true	true	true	true
Flexibility	flexible	flexible	-	flexible	flexible	-
Impact Protection	Level 2	-	Level 1	Level 2	Level 2	Level 2
Used For	motorcycles	motorcycles	motorcycles	motorcycles	motorcycles	motorcycles
Protection Level	Level 2	-	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
Material	polymeric material	-	nitrile anti-shock rubber	nitrile anti-shock rubber
Ventilation	true	true	true	true
Flexibility	flexible	Semi Rigid	Semi Rigid	Semi Rigid
Impact Protection	Level 2	Level 2	Level 2	Level 2
Used For	motorcycles	motorcycles	motorcycles	motorcycles
Protection Level	Level 2	Level 2	Level 2	Level 2
Coverage Type	Back Only	Back Protector	Full Back	Back Only