The CL-15 is a huge downgrade from the FS-10. It uses a lower-grade shell, lower quality materials, and essentially lower-end everything. Right now HJC offers 4 different trim levels:
FS series (which includes the Sy-Max II, FS-10, and FS-15), which is made from the highest-end race grade materials HJC offers. It is the best in safety and features among the HJC line. Prior to the Introduction of the FS-10 the FS series was the AC series.
Next step down we have the IS-series, which offers many of the high-end features of the FS-series and all have retractable sun shields, but use lower-end build materials found on the CL series to cut costs. Because the design of the sun shield mechanism prevents the helmet from passing SNELL tests, these helmets are DOT approved only, but are still fine helmets.
Third on the list is the CL series, which includes the CL-Max, CL-SP, and CL-15. These are budget helmets that are still Snell approved but barely. They use respectable quality materials but that’s what you get at this spot in the budget.
Finally we have the lowest-end helmets they make, the CS-series, which use absolute bottom of the line materials and are only DOT approved, but not SNELL.
Also, in case you guys weren’t aware, the Joe Rocket RKT101 helmets are actually rebadged CL-SP helmets just with their own paint work and a different liner.
My first helmet was an HJC CL-15 and I can honestly say that after I upgraded from that to my Shark RSR2, i will never be able to go back down to a low-end helmet like that again. The FS-series, however, is worth considering…
By the way, you should look up stuff on the SHARP helmet safety board. They rate how helmets perform in safety tests. As of right now the only brands that can consistently make at least 4/5 star ratings in their tests are Shark, AGV (even their lowest end Stealth and S4 models rate a 5 star rating), and Bell.