How do I pick a dash-cam mount for my windscreen?
Steps
- Identify the intended mount position. It should sit behind or immediately beside the rear-view mirror body, inside the swept area of the wipers, and above the horizontal line of the driver's normal forward gaze.
- Feel the glass at that position. A flat glass panel will feel level under your palm. A compound-curved screen has a visible curve in two directions and suction cups struggle to seal.
- Note how much direct sun the top of the windscreen gets. A car parked outside all summer in south-facing sun sees cabin temperatures above 60 degrees Celsius. Suction cups soften and release at those temperatures.
- Decide. Flat glass, indoor parking or car-swapping use points to suction. Curved glass, outdoor parking or a permanent install points to adhesive VHB.
- Before fitting, clean the glass with isopropyl alcohol and a lint-free cloth. Both mount types need a contaminant-free surface. Press the mount firmly for at least 30 seconds for VHB, or twist and lock the cam ring on a suction mount.
What you need
- Isopropyl alcohol wipes or a small bottle of IPA and a lint-free cloth.
- A plastic scraper for removing any previous adhesive residue.
- The rear-view mirror measurement, so the mount sits behind and not below it.
- The Highway Code (Rule 30) reference if in doubt about sight-line intrusion.
Common mistakes
- Mounting low on the passenger side of the screen. It keeps the camera out of the mirror shadow but places it directly in the driver's peripheral view, which the Highway Code treats as obstruction.
- Sticking VHB to a warm windscreen. VHB needs to be applied to glass at roughly 15 to 30 degrees Celsius and pressed firmly for the initial bond. Hot glass gives a weak bond that peels within a day.
- Reusing a suction cup that has been left compressed for months. The rubber takes a permanent set and no longer seals; a fresh cup or a new adhesive base is the reliable fix.
Frequently asked questions
Is it legal to mount a dash cam on the windscreen in the UK?
Yes, provided the camera does not obstruct the driver's view of the road, which the Highway Code Rule 30 covers under general obstruction rules. The Ministry of Transport interprets this as anything inside the swept area of the wipers that intrudes into the driver's forward field of view being an obstruction. Most drivers meet this by mounting the camera high, behind the rear-view mirror, so it sits in the shadow of the mirror body.
Suction or adhesive, which is more reliable?
Adhesive VHB is more reliable over the long term. A well-cleaned screen and a properly primed 3M VHB pad hold for years and survive cabin heat above 60 degrees Celsius that softens suction cups. Suction is easier to reposition and to move between cars, but the cup loses grip in summer heat and drops the camera onto the dash, often taking a piece of dash trim with it.
Will an adhesive mount damage the windscreen?
No, provided you use the correct 3M VHB or equivalent double-sided foam tape supplied with the camera. The adhesive bonds to glass and can be removed cleanly with a plastic scraper and a solvent such as isopropyl alcohol. It does not leach into the glass or leave permanent residue when removed carefully.
Does windscreen curvature affect the mount choice?
Yes for suction, less so for adhesive. Deeply curved windscreens on modern cars have a compound curve that a flat suction disc cannot seal against, so the cup pops off after a few days. Adhesive VHB pads follow shallow curves easily and conform to sharper ones after a firm 30-second press. If the windscreen curves visibly at the mounting point, adhesive is the safer choice.