Once you accept that arm length governs vibration, the remaining question is where the mount attaches. Each anchor point has a different set of trade-offs, and one of them is legal rather than practical.
Eyeline is the first consideration
The phone should sit low and close to your natural forward view, so glancing at navigation costs the smallest possible movement of your eyes away from the road.
That argues against high windscreen positions, which look convenient and require you to refocus between the phone and the distance, and against cupholder mounts, which pull your eyes right down into the footwell.
The best positions on most cars are in the lower centre of the dashboard or at the centre vents.
Vents
Strengths: the shortest arm available, a natural height, nothing adhered to the car, and easily moved between vehicles.
Weaknesses: the vent is blocked while in use, and the air passing over the phone is whatever the climate control is doing — cold air is helpful, hot air is actively harmful to a charging phone. Thin, vertical or delicate fins may not take the weight of a large handset, and some cars have vents that simply pivot under load.
Best for: most drivers, most cars, particularly with wireless charging in summer.
Dashboard
Strengths: an adhesive pad on a flat area is the stiffest mount available, and the height is close to ideal.
Weaknesses: adhesive and soft-touch dashboards are a bad combination — the coating often lifts with the pad. Weighted friction bases slide under hard braking. A sunlit dashboard is the hottest surface in the car.
Never mount over a passenger airbag deployment area. That is not a comfort issue.
Best for: cars with unsuitable vents and a genuinely flat, hard area low on the dash.
Windscreen
Strengths: works in any car, highly adjustable.
Weaknesses: the longest arm and therefore the most vibration; suction cups fail in heat and cold; it sits in your field of view; and many countries restrict what may be attached to a windscreen and where. That restriction is enforced, and it varies, so check the rules where you drive.
Also check for heating elements, rain sensors and driver-assistance camera apertures before sticking anything to the glass.
Best for: a fallback, mounted as low on the glass as the arm allows.
CD slot
Underrated where a slot still exists. The slot is rigid, the arm is short, the height is close to ideal and nothing is stuck to anything. If you never use the CD player, this is often the best mount in the car.
Cupholder
Very stable and completely out of the way, which is also the problem: it is low, requiring a long look downward. Reasonable for a passenger’s phone or for a phone that is charging rather than being read.
A short decision path
- Are the centre vents sturdy and not needed for airflow where the phone will sit? Use them.
- If not, is there a CD slot? Use it.
- If not, is there a flat, hard, shaded area low on the dash, clear of airbags? Adhesive mount there.
- Otherwise windscreen, as low as possible, and check local rules.
Two checks before you commit
Sit in the driving position and confirm the phone does not obscure any part of your view, including the mirrors and the area a pedestrian would occupy at a junction. Then drive a rough road and watch the screen. If it blurs, shorten the arm before changing anything else.
