Hmm, there is no reason at all not to use that hook.
Pla should have been strong enough.
For strong parts, though, you need a lot more shells and layers - also more infill.
basically you have bugger all skin and sod all infill in that model.
Print that with 6 shells and layers at 0.3mm layer height and 50% infill and it shouldn't have any problem at all holding a bike.
The print orientation is correct. It needs to be lying flat.
Speedwise - print at about 50mms.
The temperature is a little high, I suually go to about 215 max for pla.
You also want your infill combined every layer - ie: it needs to form a solid internal matrix.
You could invest in some stronger pla for this kind of model. polymaker, polyplus and polymax are probably your best bet:
http://www.polymaker.com/shop/polymax/
You should be able to print with pet-g on blue tape or pva.
Obviously a heated print bed is best - only things I print on a cold bed are flexible filaments on pva.
But as you don't have that option - you can play with different filaments.
Would be worth getting a sample of pet-g and testing:
http://www.globalfsdusa.com/?target=main
trying samples is a great way to work out just what you can and can't print.
It will print on a cold bed, thibk they recommedn blue tape - but I'd try pva (gluestick) as well
One thing you absolutely cannot use is abs - that not only requires a very hot build plate, but a lack of smell and an enclosed printer as well :-)
You could print that hook in polyflex of ninjatek semiflex - both are super strong and pretty stiff if printed as a largish model.
I'd expect to be able to hang off a polyflex hook and I'm around 90kg.
It would probably bend but never break - polyflef is virtually unbreakable. Short of using powertools I'd defy anyone to break a decent polyflex print with their bare hands.
But as far as your failed hook goes - you just printed it incorrectly. Needed lots of shells and layers and at least 50% infill. Triangular pattern I find best, if you've got the option.
Pla is a very strong material - as long as you use it correctly.