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Alpinestars Nucleon KR-2i Back Protector Insert

Item: P279619

The Alpinestars Nucleon KR-2i brings CE Level 2 protection and airflow to both men's and women's Alpinestars jackets. Read More

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Product Details

Alpinestars Nucleon KR-2i Back Protector Insert

The Alpinestars Nucleon KR-2i Back Protector Insert fits all Alpinestars jackets and race suits and delivers CE Level 2 impact protection.


  • CE Certified Level 2 (EN1621-2:2014)
  • Lightweight, flexible PU injected impact foam
  • Contoured for anatomical and adaptive fit
  • Perforated for breath-ability and comfort
  • Channel ventilation system for optimized airflow

Note: Size MD is recommended for Men's jackets size 50 and smaller and XS-MD. Size LG is recommended for Men's jackets size 52 and larger and LG-4XL. See specific Women's jackets for sizing recommendations.

Sizing Info:

Waist to Shoulder (in) Height (in)  Protector Size
15 - 17 56.75 - 64.25 SM
17 - 19 64.25 - 71.75 MD
19 - 20 71.75 - 76.5 LG

Product Style RevZilla Item # MFR. Product # Availability
Product Style SM RevZilla Item #973533 MFR. Product #6501615-10-S AvailabilityIn Stock: Ships within 24 hours
Product Style MD RevZilla Item #973534 MFR. Product #6501615-10-M AvailabilityIn Stock: Ships within 24 hours
Product Style LG RevZilla Item #973535 MFR. Product #6501615-10-L AvailabilityIn Stock: Ships within 24 hours


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Product Description
Part Numbers
Shipping & Returns
Product Description
The Alpinestars Nucleon KR-2i brings CE Level 2 protection and airflow to both men's and women's Alpinestars jackets. Read More
Part Numbers
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Shipping & Returns
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Reviews & Questions

Start typing your question and we'll check if it was already asked and answered. Learn More
Browse 37 questions Browse 37 questions and 111 answers
Why did you choose this?
RevZilla Store
Alpinestars quality and design.
Daniel J on Oct 15, 2017
Improve back protection in my tour master air draft jacket.
Jeremy B on Sep 18, 2017
Alpinestars quality and design.
Daniel J on Oct 15, 2017
I ALWAYS upgrade my armor to CE level 2!
Louis G on Sep 20, 2017
Improve back protection in my tour master air draft jacket.
Jeremy B on Sep 18, 2017
fits perfect in the back of my Reload leather jacket
Mike M on Sep 6, 2017
High reviews from actual riders that have crashed while wearing one and posting experiences.
B A on Sep 2, 2017
CE 2 rating and more flexible
James E on Sep 1, 2017
More protection
U R on Aug 5, 2017
Robert T on Jul 31, 2017
love this back protector. It flows a ton of air and is decently flexible. The only time I know its there is when I'm wearing a backpack.
Hodari S on Jul 29, 2017
Son wanted
CJ W on Jul 28, 2017
I like my spine intact
Easton P on Jul 19, 2017
Add this to an Alpinestars T-GP R Air Jacket for the little extra protection. It's quite malleable and comfortable.
Charles L on Jul 19, 2017
I purchased this back protector to replace the foam in my Scorpion and/or Dianese jacket.
Douglas D on Jul 18, 2017
Upgrade for T-GP Plus R v2 jacket, Flexible, comfortable, CE L2, A* quality.
Trishul R on Jul 11, 2017
astars gear is quality with protection to match.
james r on Jul 10, 2017
to improve protection
bruno s on Jul 5, 2017
Safety for my super cool Brera jacket.
Brad L on Jul 3, 2017
I wanted the extra protection.
Marc M on Jul 1, 2017
Super easy addition to my T-GP Pro jacket. More protection without sacrificing comfort or style? That's a no brainer.
Thomas D on Jun 29, 2017
Just bought the Alpine Stars Bogota jacket, wanted to complete the purchase with the back protector
michael m on Jun 22, 2017
CE protection
Francesco B on Jun 18, 2017
To protect my spine, fits jacket.
Paul J on Jun 12, 2017
Wanted a CE back protector for use in my Jaws Jacket
Sean R on Jun 10, 2017
It's the logical choice if you have an Alpinestars jacket without back protection
NorcalNoob on Jun 9, 2017
Wanted extra protection.
Calvin C on Jun 9, 2017
My girlfriend.
Mark G on Jun 4, 2017
You can't put a price on your safety.
Matt F on Jun 1, 2017
Hoping for high air flow along with high level protection in summer.
Harold H on May 30, 2017
To protect my back and fit perfect with my Astars jackets
Michael P on May 17, 2017
I have a jacket but it doesn't has chest protections. That item easily fits my ALPINESTARS HOWLER jacket
Alexandr U on May 9, 2017
Mario G on Apr 26, 2017
Love how light and flexible it is, how well it still ventilates, fits in my A* and Dainese jackets perfectly. Highly recommended..
Scott P on Apr 20, 2017
brand, airflow, CE protection
R S on Apr 14, 2017
CE level 2 and lots of air flow.
Richard Q on Apr 11, 2017
Very good fits perfectly
Arunas J on Apr 8, 2017
Need it
Floro R on Apr 7, 2017
Because I want better protection and it has good reviews.
Skyrider on Mar 23, 2017
Great price for a good piece of armor, fits well in all my alpine star jackets , and does allow noticeable breath ability.
Thom Q on Mar 17, 2017
Good reviews, price. Been using it for a year now and I don't even know it's there.
Louis O on Mar 16, 2017
No brainer - you wear a helmet for your head, a back protector is the helmet for your spine!
Jonathan C on Feb 14, 2017
really foamy. i dont think it will offer that great of a protection compared to others but it is the only one that will fit my jacket
Alan T on Feb 10, 2017
Peace of mind, God forbid.
Matt L on Feb 10, 2017
Compatible with Alpinestars Jacket for the track
Madeline M on Feb 8, 2017
Didnt want to break my spine. Fits my jacket
Mitchell C on Dec 3, 2016
Stanislav D on Dec 1, 2016
built for the jacket I chose, Valparaiso 2
Cory N on Nov 17, 2016
More safety = more peace of mind
joshua g on Nov 15, 2016
added turtle insert for a lil more protection
chris c on Nov 4, 2016
very cool so cool
DAN S on Oct 20, 2016
Because it would fit my new AStars Jaws leather jacket . I have others to use but wanted to try this "lighter" one and see how it works . Supposed latest iteration of back protection from AStars raises protection to a level 2 C rating. You can never have too much protection. Calling Astars out , ALL leather jackets in this price point should come with at LEAST level 3 C3 Back protectors. Point of purchase could be absorbed up to abut fifty bucks in my view..... seriously..
Ray E on Oct 10, 2016
I ALWAYS upgrade my armor to CE level 2!
Louis G on Sep 20, 2017
fits perfect in the back of my Reload leather jacket
Mike M on Sep 6, 2017
What are the dimensions of this protector? Small, Medium, and Large, Length, width
Michael B on Nov 2, 2015
BEST ANSWER: Medium is 16.4"long, 9.5" at widest
What is the difference between KR-1 and KR-2 ?
A shopper on Aug 19, 2015
BEST ANSWER: the kr2 is only foam, the kr1 is newer and has plastic and foam, more protection, more money
Would this fit in a Icon jacket equipped with a back protector pocket?
R X on Mar 10, 2016
Will it fit Alpinestars Motegi 1 pc race suit?
Adil A on Jun 15, 2016
BEST ANSWER: Sorry, I bought this for an Alpinestars T-GP Pro Air Jacket. It fits this perfect though
Which size d I need to get for my alpinestars small TGPR texture jack ?
I'm confused Your video says Dont get small size?

katsuhide y on Feb 1, 2015
BEST ANSWER: I believe the larger is for size 52 and above. The smaller one is made to fit jackets small to medium.
I have a Alpinestars GP Plus R Perforated Leather Jacket which back protectors recomend?
Eduardo M on Mar 14, 2016
BEST ANSWER: I have 2 textile jackets and one whit the núcleon back protection and ita moré confortable and breathable, i think this is a good chioce for your leather jacket
How would you compare the Nucleon to the Klim D30 Viper regarding flexibility, w

How does this back protector compare to the Klim D30 Viper? Is it as flexible and have as good airflow?
Robert C on Nov 12, 2016
BEST ANSWER: Regarding flexibility, from least to most: seesoft from rev it < Nucleon < D30.
Which size d I get for my alpine stars gtr air texture jacket small?
I'm confused that Your YouTube ads say don't buy small size.
A shopper on Feb 1, 2015
BEST ANSWER: The small should be fine.
I have an Alpinestars GP Tech Air Jacket in size 48. I'm unsure on which size back protector to get. I'm roughly 5'6", 150 pounds. Which size is right for me?
A shopper on Dec 29, 2014
BEST ANSWER: Probably Medium. I'm 5'7" 162 and have a Medium in my M Bogota. Feels great. Ironically, I don't even notice it's there, which I guess means that it "feels" great! Good luck.
I am purchasing the Alpinestars Stella Gunner WP textile jacket in a size small. Should I purchase the Alpinestars Nucleon Back Protector in small or medium? I am 5'2" and weigh 110 lbs. I am also considering purchasing the Alpinestars Bionic Chest Pad, although I'm not sure how much protection the pads really offer.

I'm a new rider on a 2004 Honda Rebel 250CMX

Any suggestions are welcomed!
A shopper on Oct 29, 2014
BEST ANSWER: Hi - I am also a new rider (2014 Honda CB500f). I am 5'7" and 175 pounds and where a Large Jacket because of chest size. The protector is light and semi-flexible. I got a Medium and it fit fine. I think Revzilla has a return policy so I would go for a medium if you where a Medium jacket. If you where a small jacket, then I would get a small. That is purely my guess. You should contact Revzilla; they have been great about answering questions for me.
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