We just bought a new Ford Escape diesel.   I strapped our old mirrors on and found the plastic mirror surrounds flex and bend allowing the strap ons to wobble all over the place.   I'm pretty sure the wind created by oncoming trucks may cause the plastic to fracture.   Any Escape owners on here who can suggest a mirror type that works with the Escape.   BTW, just because a strap on works on you Territory or whatever you have doesn't make it ideal for an Escort.   The issue is the flexibility of the plastic on the mirror surrounds.

If you go further down the page Tony mirrors were discussed there. Maybe page two now. I know yours is a different tug but you might get some info to look at. Maybe even do a search in the thick blue line above.