Rock Bros makes cheap crappy knockoffs of Spurcycle’s bells. James Huang at Cyclingtips said that his RockBros bell broke after 5 rides.

In principle, knockoffs can be acceptable or good quality. Magene appears to have knocked off the Wahoo Kickr. DCRainmaker thought the knockoff trainer was basically fine.

For Rock Bros, all I know is that they make crappy knockoffs of one product. The suction cups on a car rack are the things keeping your rack from flying off your car onto the Interstate. If the downside risk was less, then sure, in principle I could see myself considering Rock Bros.

I have a sea sucker for my Kia Stinger. Good roof rack!

I've got on of their gravel top tube bags. It works. It's also just a bag.

A bike rack isn't something I'd go with a knockoff brand for. Too much risk.

---

Strava

The suction cups are the most important part obviously. I had a Seasucker about 7 years ago, and it had marine grade suctions cups on it. They looked to be the same suction cups you could buy yourself from a marine supplier. Given that, as long as the knockoff is using the same grade suction cup, then you at least know the suction cup is going to let loose from your vehicle. You'll still have to worry about how they are actually attaching the rack to the suction cup though.

My Seasucker has been great. It took a bit to become convinced it was stable, but after using it for the past year I would highly recommend.

---

Human Person

Used a double Seasucker for RAAM. Worked as advertised. Highly would reccomend.

Yeah, I think I may have come across a Youtube review of their stuff that said the same thing. And anyway, failure modes for bags involve the stitching coming out or the closures failing, which could happen suddenly but you can frequently see them coming. Failure mode for a bell is that the thing stops ringing, in which case you at least still have your voice.

The failure mode for a suction cup that's holding your bikes on the car while driving down the Interstate is not something I'd care to think about, and since you are in your car and you're concentrating on traffic, that thing could start to fail and you might not catch it.

I have the rockbros Mount. I was skeptical at first but after driving with it for several hours (8+ at highway speed, some time above 95mph) I have some confidence in it.

I have a Ford Mustang and the roof suction cup was really the only solution. The rockbros seems to use the same cups and pumps as the seasucker one, likely sourced from the same factory. The suction cups are a thick heavy rubber. I’ve never had an issue with my rockbros mount after several trips to races, rides and vacations.