Since the M3 is not a hatch back, I try to think how to carry objects on the roof, such as bicycles. I noticed that the glass roof doesn't provides any roof gutters, so it seems difficult to install a roof rack. I wonder if the M3 glass roof could handle this type of bike rack with suction cups?
I think an accessory hitch with a rear rack will be your best bet. Your aerodynamics will still suffer, but at least your Model 3 will be uninjured.
Currently the Model S requires the panoramic roof option to be chosen to allow for Whisbar roof rack mounting. I'm REALLY hoping that roof rack mounts are available on all configurations of the Model 3. Yes, the rear accessory hitch is better for aerodynamics, but a roof rack is the only good way to carry boats.
The GPS mount in my car eventually falls off the windshield, shelves/hooks/etc in the shower eventually fall down. The GPS lands in the car, the shelves/etc end up in the tub - the expensive bike could end up on the road, potentially causing a serious accident that you'd be liable for.
But Elon guaranteed it, so it shouldn't be a worry. These are very different than a shower hook - it took be a lot of work to take off the suction cup for a radar detector.
I wouldn't even consider it around here. All I see in those pictures is sand and grit being ground in to the paint under those cups. Sand can still scratch glass, plus the 3"s roof isn't entirely glass unless you pay extra for the option. Also it wouldn't help visibility. I also wouldn't trust it enough to not fail and slam my bike in to my car. It may not look as "cool" but I'd go with the hitch like everyone else says. I put a class one hitch on my mustang specifically for carrying my bike and you can barely notice it.
Has anyone ever known a suction cup that didn't fail at one time or another?? Go with the rack in the back...get the trailer hitch.
