They don't cover tires.

If you have a flat tire - excluded.

If the rental car company accuses you of damaging the tire upon return of the car - excluded

Amex will only pay for tires if there is also additional damage to the car but not if the only damage is the tire.

Beware. Thinking I was "covered", on a foreign trip, I declined Avis roadside coverage (cost me $150) and declined LDW (cost me $600).

It actually would have been free for me, if I had just taken the car and purposely smashed it into a wall, which would of course be a perverse outcome of their cost-cutting exclusions. I'm pretty annoyed. Pay very close attention to the fine print - the Amex coverage is really not broad enough to decline the LDW and so then you have to wonder, why bother having the feature.

ALSO - beware - Amex does not cover OTHER CARS in case you are in an accident. If you do not carry your own car insurance, do not own a personal vehicle etc....you may be very dangerously exposed to accident liability risk when renting a car.

(Since I don't own a car at home and don't have regular car insurance -- I have been looking for rental car accident liability coverage from third parties and so far not found anything good for my situation but if anyone has recommendations please advise.)