Review on 🚲 ROCKBROS Suction Cup Bike Rack: Quick Release Aluminium Alloy Carrier for 1 Bike by Kirk Womack

Before trying it on a car I decided to test it on a granite countertop. Of the 4 cups, only one works on the rear wheel and the middle one on the front wheel mount. The other two don't suck at all. He took out the pistons, made sure there was no dirt in them, the pistons were lubricated - no luck. I've tried swapping pistons between working and non-working cups, cleaning rubber and granite surfaces - same result. Returned it and bought a similar stand from imt/zuos - works perfectly, looks much better, comes with all adapters and costs even less.