Kryptonite Series 2 Standard

Lockreviewer’s Take: This mid range U-lock is suitable for use in low crime areas. At the end of the day Kryptonite is not a lock company and complaints regarding the locks used as well as physical integrity of this shackle should not be overlooked.

Kryptonite says:

  • 13mm hardened Performance steel shackle resists cutting and leverage attacks
  • High security Bent Foot(TM) design for serious protection and great value
  • High security, pick and drill resistant disc-style cylinder
  • 2 keys – “I” style for easier usage
  • Includes Transit FlexFrame Bracket for easy mounting to frame tubing 25mm to 80mm wheter round, oval, triangular, or square. Also features 360° rotation providing the ability to better fit and align with a bike frame’s specific geometry.

Additionally, I note that the Series 2 is 2.85 pounds. Kryptonite ranks the lock as 6/10 on their security rating. Of course, these company given ratings should mean little to you. Sold Secure ranks the Series 2 as a “Silver” level lock. This means that they recognize weaknesses in the lock, but feel it is a compromise between security and cost. In comparison, the “Bronze” level means that the lock being rated is effective against opportunist thieves. I like to this of this as the security theater level.

Regardless, this lock has gotten high praise from the biking community at large, likely due to price point for security level. It is generally agreed upon that a U-lock is preferred over a cable for purposes of security when considering that a 13mm shackle requires much more force to break than a cable or basic chain.

However, there have been several reports that the shackle, while resistant to bolt cutters, is still able to be cut open by them. Furthermore, the internal components for the lock itself have left many wondering whether purchasing the lock is worth it compared to similarly situated competitors or slightly more expensive locks.

One of the primary complaints I have heard in regard to the lock itself is that the key requires a bit of work to turn the plug. My theory was that the discs were seizing after repeated exposure to humidity over time. Another Amazon user who had his bike stolen shows clear indications of rust which would lend a bit of credence to that thought. However, the lock is made from hardened steel so rusting seems unlikely. Furthermore, Kryptonite is insistent that users insert the key completely into the key way. Admittedly, the key is not a great fit. The reason for this is that the very tip of the key drives the final disc which also provides the tension to open the lock.


Obviously, these issues have generated complaints from cyclists who have taken to the internet after their have been stolen as well as users who have become frustrated with the functionality of the disc lock. However, with security comes sacrificing convenience in the lock world. The vulnerability here is not the lock, but rather the shackle. I note that it would take an expensive pair of bolt cutters to get through one half inch of hardened steel. For the price point, it does not seem like the Series 2 has much competition at this point.

VERDICT: The Series 2 is a solid choice for a mid-level U-lock; however, if your bike is worth over $500, you may want to consider a thicker shackle such as that offered by Kryptonite’s Fahgettaboutit, or New York Standard, which offer 18mm and 16mm thick shackles respectively. 

Kryptonite Series 2 Standard






Bypass Rating




Build Quality



  • Affordable for Level of Security
  • Disc Lock Difficult to Pick for Novices
  • Deterrent Factor


  • Vulnerable to Bolt Cutting
  • Ease of Use Issues

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