Double sided tape
 

I just need some help on this...
I recently installed my roof spoiler (nothing big.. its CF too so its light)
with double sided tape they sell in Canadian Tire (red ones). I've noticed that one side is stuck on real good but the other isn't... In fact the other side kinda lifts... Do I have to take it off and retape it again? Or is there another solution?

make sure the surface in clean.

make sure the spoiler itself is the same curve as ur roof. if not, ur gonna have to compensate by adding a bit more tape to make certain areas higher than others.

and buy real automotive tape, from places like lordco. if u can afford it, real 3M automotive tape is what u want (red plastic backing, dark gray double sided tape)

yeah, if you can, wash, then claybar the area that you going to apply it to, and make sure its Dry as well, then stick it down. if you can i would go looking for some Automotive Double-sided tape as mentioned above, its a whole lot stronger.

Even the 3M tape isn't the greatest solution, especially if your spoiler doesn't sit absolutely flat against the surface (ie it will pull itself away over time). I ended up gluing my roof spoiler on with construction adhesive.

even wipe down the areas that contact the tape with a mild solvent like wax and grease remover

Thx guys!

Easiest way is to use rubbing alcohol to clean the surface first to remove any grease/wax. But in your case I'd say u gotta take it out & retape it