These are the same "plastic" pedals that probably came with your bike. The description says "composite", but they seem like nylon to me. The pedals themselves have 1/2" axles, the size used on childrens bikes and on (old) bikes with one-piece ("Ashtabula") cranks. A 1/2" to 5/16" adapter is included so that the pedals can also be used with modern 3-piece cranks. Schwinn seems to have done this with all its pedals. Clever, really - you can't buy the wrong size pedal, the pedals will be a bit narrower on kids' bikes than on most adult bikes, and Kmart can put something more interesting than more of the same pedals in another size on the shelf. However, the 1/2" shaft IS slightly weaker of course than a 5/16" shaft, not a concern for most of us, but if your pedal broke when you dropped off a 4' loading dock and landed all 200 lb of your weight on it, you may want the thicker shaft. (And major medical insurance.) Unfortunately, the adapters had been filched from almost every package of pedals at my local Kmart, making the pedals unusable with most adult bikes. (Grrr!)
good choice for reasonable replacement....
Package was may when it got to UPS station and no delivery was made. Tracking clearly showed UPS had updated it as such and said they would be contacting shipper. I waited a week for you folks to contact me but apparently that was asking to much. I finally contacted you, was given the run around, got annoyed and canceled order. Worse yet I just had to cancel an order for a Nordic track elliptical because of delivery issues(damaged) this week.