Well, damn. I tried so hard to make it obvious that there were advantages and disadvantages to every way to carry gear... and that I was
only answering the question about "why not use a hitch?"
I suppose it would have been better to mention up-front that I prototype and custom-build hitches and bike racks? And I have a web page on the pros and cons of every way to carry bikes on a car? I also "steal" bikes every week (condoned by my city's police department as a public benefit)–I've "stolen" at least 500 bikes by now. Tomorrow I'll add 20 more to the total.
You install the hitch once. Then every time you put the rack on it's an easy process. Unlike a roof rack, which is always a pain to remove and reinstall.
If you install roof rack anchors correctly, roof racks are not a pain to install and remove. Proper roof racks (cross-bars) take about as much time to install as buckling a seatbelt. And the installation of the anchors is much less involved, and much cheaper than installing a hitch on a model 3.
Don't even know how to respond to that one. (in reference to the damage that can happen to a bike on a hitch-mount)
If you haven't seen the result of a rear-end collision when the front car had a bike on a hitch rack, then I can see how it would be difficult to respond.
Untrue. (in reference to a bike in a roof rack being more difficult to steal than one on a hitch rack)
I do not know what you base your response on, but I base my comment on direct experience of stealing bikes, and on having had bikes stolen. Everything is easier to accomplish when hidden between cars, at waist-level, than reaching over your shoulders with whatever tools you plan to use for cutting a lock. I'm happy to hear of your contrary experience.
Can't drive under low clearance with items on your roof.
Correct. And this has nothing to do with the disadvantages of hitch-mounts.
True, but access to your items on the roof are a pain.
Correct. And this also has nothing to do with the disadvantages of hitch-mounts.
No sensor will tell you that your bike is on your roof rack when you drive into a garage. Ask me how I know.
1. I don't need to ask. There are obvious disadvantages to roof-mounts, and I have broken bikes and bike carriers here as proof.
2. The sensors I'm talking about are the factory ones that Tesla needs to function for future Full Self Driving, and proper Advance Auto Pilot functionality. I'm not talking about any sensors that tell you where your bike is, nor how to keep the bike safe.
I have contemplated roof racks and hitch racks many times. In the end I have chosen roof racks, because they served my needs. But that doesn't mean they don't have plenty of disadvantages of their own.
I have extensively studied and used all methods of carrying bikes in, on, and behind cars that I'm aware of. They all have advantages and disadvantages. There is no one best option. Everything depends on circumstances and desires. Several of the commercial options available to purchase have my input baked into them.
Having said all of that, I have struggled for years with the disadvantages of both, and I recently tried out what I believe to be a great compromise (for my needs, anyway).
SeaSucker
Check 'em out. Pretty cool. They can be installed on practically any car in two minutes, and removed in less time. They can be carried in your trunk. They'll work on the glass roof of the Model 3 without any brackets or modifications.
I am familiar with SeaSuckers, and I see many advantages on cars that do not have anchors. Cross-bars with proper anchors bolted to the car are still faster to mount (after the anchors are installed), more secure, and never leak vacuum. There is currently a kick-starter campaign trying to build a new version of the suction concept. They claim (of course) better functionality and lower cost.