Towing a trailer changes your vehicle’s width and blind spots. Proper mirror setup is not just a convenience, it is a safety requirement. This guide explains how to position your tow mirrors, what to check before each trip, and how to stay legal on the road.
Why Tow Mirrors Are Necessary
Your stock side mirrors are designed for the width of your vehicle alone. When you attach a trailer, especially a wide one like a camper or boat, those mirrors no longer cover the area beside and behind you. Without proper mirrors, you have large blind spots that can hide cars, cyclists, and pedestrians.
Tow mirrors extend your field of view outward and downward. They let you see the trailer wheels, the sides of the trailer, and the lane next to you. This visibility is critical for changing lanes, merging, reversing, and making tight turns.
Legal Width and Mirror Requirements
Federal and state laws regulate how wide your vehicle plus mirrors can be. Most states allow mirrors to extend beyond the vehicle’s body, but there are limits. The general rule is that mirrors must not extend more than a certain distance, often 12 to 14 inches beyond the widest part of the vehicle, including the trailer.
Some states require that if your trailer is wider than your tow vehicle, you must have mirrors that allow you to see at least 200 feet behind you. Other states have specific rules about mirror size and convex lenses. Check your state’s Department of Motor Vehicles website for exact numbers.
Also, many states require a minimum of two mirrors, one on each side. Some require that the driver can see the rear wheels of the trailer. To be safe, always aim for a clear view of the trailer’s sides and the road behind.
Step-by-Step Mirror Setup
Before setting your mirrors, park your rig on a level surface with the trailer attached. Have a helper stand at the rear corners of the trailer while you adjust.
- Start by adjusting your existing side mirrors as you normally would, so you see a sliver of your own vehicle’s side.
- If you have clip-on or extendable mirrors, mount them securely. They should be rigid and not shake at highway speeds.
- Adjust the driver’s side mirror outward until you can see the far edge of your trailer, not just the side of your truck or SUV.
- Do the same for the passenger side, tilting the mirror slightly downward to see the trailer’s wheels.
- Check that you can see the rear bumper or tailgate of the trailer in each mirror.
- If you have a convex or spotter mirror, position it to cover the blind spot right behind the trailer.
Take your time. A proper setup takes a few minutes. Once you think it’s right, do a slow test drive in a safe area and adjust again if needed.
Blind Spot Checks You Should Perform
Even with well-adjusted mirrors, you still have blind spots. Use a combination of mirrors and shoulder checks before every lane change.
- Check your rearview mirror (if you have one) for close traffic.
- Look at your side mirrors, then turn your head to glance over your shoulder toward the lane you want to enter.
- Pay extra attention to the passenger side, where blind spots are larger.
- Remember that your trailer’s rear swings wide when you turn, so leave extra space on the inside of corners.
Some drivers install additional blind spot mirrors or camera systems, but even with high-tech aids, a physical mirror check is the most reliable method.
Adjusting Mirrors for Different Trailers
If you tow different trailers, you need to adjust your mirrors each time. A tall box trailer requires a different angle than a low flatbed. Always reset your mirrors after hitching up a new trailer.
When your trailer is narrow, you might be tempted to leave the mirrors stock. But remember, the trailer still hides the lane behind you. Keep your tow mirrors extended even for small trailers.
If you tow occasionally, consider removable mirrors. They give you the same safety benefit but allow you to remove them when not towing, so you don’t damage them in tight parking spots.
Common Mistakes to Avoid
One mistake is setting mirrors too far inward. You need to see the trailer, not just your own vehicle. Another is forgetting to adjust the passenger side mirror, which is often the hardest to reach but essential.
Some drivers set mirrors too high, showing the sky. The mirrors should show the road and the side of the trailer. Also, avoid using dimmed or tinted mirrors that reduce visibility at night.
Finally, don’t rely solely on mirrors when reversing. Use a spotter if possible. Mirrors give you a view, but a person outside can see the entire trailer and obstacles that are still hidden.
Proper mirror setup is a simple step that prevents accidents. Take the time to do it right, and you’ll have a safer towing experience.
Frequently Asked Questions
How often should I adjust my tow mirrors?
Adjust your tow mirrors every time you change trailers or alter the load. Even slight variations in trailer width or height change what you can see. Make a habit of checking mirrors before every trip and after you hitch up.
Can I use my stock mirrors for towing a small trailer?
If your stock mirrors let you see the full width of the trailer and the lane behind, they may be sufficient. But for most trailers, especially anything wider than your vehicle, you should use tow mirrors to eliminate blind spots. Safety is more important than convenience.
What is the legal mirror requirement for towing in most states?
Most states require at least two mirrors, one on each side, that give the driver a view of the road behind. Some states require that you see the rear of the trailer or a certain distance (like 200 feet). Always check your state's specific law to ensure compliance.
