Box Four 8 Speed Wide Rear Derailleur
The Box Four Rear Derailleur is the base of Prime 9 Technology that offers an affordable clutch based 1 by 8-speed derailleur that is simple and light; this makes it a perfect candidate for every entry-level bike that traditionally has a 3 by drive-train that is neither durable nor user friendly.
This is my second set. I bought it again because it works great. Easy to setup. Only issue it comes with a very strong clutch so it takes a pretty strong thumb to use it
Biggest upgrade ever to a kids bike
Installed on a Trek Roscoe 24in, no more chain slap. The tourney derailleurs that come on kids bikes are basically junk. The box derailleur with a clutch was a game changer for shifting on climbs and doing drops without the chain beating the heck out of the frame. Shifts are crisp. The kid won his first race right after I installed it. Sparkle watts are real.
Shifts like a dream
Running this on a 11-28t cassette and it works perfectly. Shifts great under load too.
Absolutely OUTSTANDING Product!
Im over-joyous about my purchase of this great Mech! My drive train has literally never rolled better or as quiet! Its a perfect combination for a 1x8 Drive train setup, Currently running this plus the matching shifter on my Downhill Bike! Zero issues and PERFECT SHIFTING! I HIGHLY recommend this for all your 1x8 needs!