Originally Posted by
Delmarva
I hope the parts are not made of cheap plastic because you will have problems in short order. Would not want you to be chasing a water bottle rolling down the path or have a rivet pull out of the fender. As with other bike components made of composite materials the manufacturer usually chooses something that is appropriate for the intended use. Composites can have long service lives.
I've ridden thousands of miles with these cheap bottle cages and they are just fine. One of them was an old cage that had been on a bike I bought on CL, and clearly had been on the bike for years. I have taken that bike apart, but put the cage on my new bike. I have at least 4000 miles with that cage without any sign of wear or stress. The other is a piece of plastic I picked up for $5 at Aldi. It's my go to cage on the down tube and I love it because it accepts all kinds of non-standard waterbottles, but it's as good a clip as I've ever had. I've been riding bikes on and off for about 50 years now, I can tell if the cage is going to work. I have never had a problem with a plastic cage, I have had several metal ones get bent out of shape, they're generally very finicky about what they'll accommodate.
My fenders don't have any rivets to detach. There's a bolt in the top of the rear fender that attaches to the frame by a hanger, The plastic on that is tough and there's no way it's going to spontaneousy tear off. The front fender is an SKS, and has no bolts attaching it to the bike whatsoever. $17, and I think it's a great piece of engineering. The plastic is quite tough.
I didn't just fall off the turnip trike, I wouldn't put anything on my bike that had a high chance of failure. I just don't think there's a correlation here between price and reliability.