Alpinestars Nucleon KR-1i Back Protector Insert
- CE certified Level 2 (EN1621-2:2014)
- Fusing together a lightweight perforated hard shell and energy absorbing foam for excellent impact resistance
- Anatomically contoured
- Perforated for breathability and comfort
- Channel ventilation system for optimized airflow
Choose the back protector size based upon the size of your jacket as follows:
For Men’s Alpha Sized Jackets: Choose size Medium to fit jacket sizes Medium and below. Choose size Large to fit jacket sizes Large or above.
For Men’s Euro Sized Jackets: Choose size Medium to fit jacket sizes 50 and below. Choose size Large to fit jacket sizes 52 or above.
For Women’s Alpha Sized Jackets Choose size Small to fit jacket sizes Small and below. Choose size Medium to fit jacket sizes Medium and above
For Women’s Euro Size Jackets Choose size Small to fit jacket sizes 40 and below. Choose size Medium to fit jacket sizes 42 and above.
We have “yardstick” photos of each size of these back protectors in the KR-2i version, so if you want to see physical measurements take the link below and have a look at the photo gallery.
Our Two Cents
There are two versions of the new Nucleon back protectors for Alpinestars jackets. The Nucleon KR-2i is the standard impact foam version, and the Nucleon KR-1i is a “beefed” up version that has an additional plastic stiffener added down the spine area (the white part).
The base material in this back protector is a dense memory foam… the kind that is pliable but then under impact becomes momentarily hard to disperse impact over a wide area of the body. The material feels very similar to other back protector upgrades available these days from D3O and SAS-TEC.
I asked our Alpinestars rep to tell me why a person would choose the KR-1i or the KR-2i. He said the intention was that the 1i is more stiff and will feel more secure for those wearing a leather sport race jacket. And the 2i, being without the stiffening piece (the white part), would be best suited for a mesh or textile jacket or a street rider in leather (all non-racers). But it is perfectly OK to use either back protector in any jacket.
Note: These Nucleon back protectors are the replacement for the Bio Armor back protector that is now discontinued. The Bio Armor was a similar shape but of different construction and was level 1 protection where both these new back protectors offer level 2.