Most riders are best served by a single mirror on the wearer's-left side of the lens — the side overtaking traffic comes from in right-hand-drive countries, and the setup most cyclists choose. A dual mirror (one on each side of the same lens) gives balanced coverage on both shoulders and suits scullers, busy two-way paths, and anyone who likes symmetry. You choose your side — or both — when you buy, but you're not locked in: TriEye lenses swap easily, so you can change your setup or mirror size later.
Here's a question we get more than almost any other: one mirror or two? It sounds like a small decision, and in a way it is — there's no wrong answer. But it shapes how the glasses feel on every ride, so it's worth thirty seconds before you check out. We'll tell you which way most riders go, when the other way is smarter, and the one thing about TriEye mirrors that's easy to misunderstand.
What's the difference between a single and a dual mirror?
On a TriEye, the rear-view mirror is a small optical mirror integrated into the lens itself — not clipped to the temple, not bolted to your helmet. It sits at the edge of your field of view, so a flick of the eye shows you the road behind without turning your head.
One thing to clear up first: The View has a single, one-piece shield lens — not two separate lenses. A single-mirror setup places the mirror on one side of that lens (your left or your right). A dual-mirror setup puts a mirror on both sides of the same lens, so you can check either shoulder with a glance. Same shield, same fit, same forward view — just one rear window or two.
For more on how the optics actually work, our deep-dive on how TriEye's integrated mirror works walks through it lens-first.
Which side should a single mirror be on?
For a single mirror, the wearer's-left side of the lens is the default — and it's the one most cyclists pick. The reasoning is simple: if you ride on the right-hand side of the road, as you do across the US and most of mainland Europe, faster traffic overtakes you on your left. A left-side mirror points straight at the lane that matters.
Flip the country and you flip the logic. Ride in the UK, Ireland, Australia or anywhere else that drives on the left, and overtaking traffic comes up on your right — so a right-side mirror earns its place. The right-side option exists for exactly that reason, and for riders who simply find one eye more natural than the other.
A quick note on how we describe sides: "left" and "right" always mean the wearer's left and right — the side of the lens in front of your own left or right eye when you're wearing the glasses. The TriEye logo sits on the right arm, a handy way to orient a pair in your hands.
Who should choose a single mirror?
If you're a road or commuter cyclist riding with traffic on one consistent side, a single mirror does almost everything you need. One clear rear window, slightly lighter on information, and the rest of the lens stays completely clear. It's the no-overthinking choice — and it's why single-left is our most popular setup.
Single makes the most sense if you:
- Ride mostly on roads where traffic passes on one predictable side.
- Are new to riding with a mirror and want the simplest introduction.
- Prefer the rest of the lens kept totally clear.
- Want the most affordable, most common configuration.
New to the idea of a mirror at all? Start with our cycling pillar, do you need a rear-view mirror for cycling?, then come back to choose your setup.
When does a dual mirror make sense?
Two mirrors aren't overkill — they're the right tool for specific situations. The clearest case is rowing. A sculler faces the stern and travels toward the bow, so "ahead" is behind your head, and a mirror on each side lets you track your line and watch for other boats on either hand without breaking the stroke. If that's you, our guide to rear-view mirrors for scullers goes deeper — and on the water, dual is the setup we'd point you to first.
On the bike, dual earns its keep when traffic isn't politely one-sided: two-way cycle paths where someone can pass on either hand, dense urban riding with bikes and scooters filtering on both sides, or group rides where you're reading riders to your left and right. Some people also simply prefer the symmetry of a balanced view.
Choose dual if you:
- Row or scull, and need to see what's coming on both sides.
- Ride two-way paths or busy city streets where passing happens on either side.
- Travel often between drive-on-the-right and drive-on-the-left countries.
- Like the balance of a mirror on each side (and the larger out-of-the-box mirror).
Single vs dual: a side-by-side
| Single mirror | Dual mirror | |
|---|---|---|
| Rear coverage | One side (your chosen side) | Both sides |
| Mirror size (out of the box) | Smaller | Larger |
| Best for | Road & commuter cycling, running | Rowing, two-way paths, busy city riding |
| Forward view | Rest of the lens unobstructed | A mirror on each side |
| Popularity | Most common (single-left) | A deliberate, situational choice |
| Change it later? | Yes — lenses swap easily, and you can move a single up to a larger mirror | |
Can you change your setup later?
Yes — and this is the part worth getting right, because it's the thing people most often misunderstand. The mirror is built into the lens, so single and dual are different lens setups rather than a switch you flip in software. But TriEye lenses are easy to swap, so you're not locked into your first decision — you can move between setups, and change your mirror size, as your riding changes.
It helps to keep two ideas in view, and both point the same way — flexible:
- Tints swap freely. Buy a View Spare Lens ($29) to change the tint for different light and conditions.
- Mirror setup and size aren't fixed. Single ships with the smaller mirror and dual with the larger one — and because the lenses are interchangeable, you can change configuration or add a larger mirror to a single later.
Not sure yet? Single-left is the safe default. It covers the most common riding situation, it's the most popular choice, and it's the easiest place to start if you've never ridden with a mirror. You can always move to dual — or a bigger mirror — once you know how you ride with one.
Single and dual across The View, The Classic, and The Clip
The View ($89) is our dedicated sport frame and the one with the full range of choices — a single mirror on your chosen side, or dual. If you want two mirrors, The View is the place to look.
The Classic ($99) is an everyday frame with the mirror built in, made to wear off the bike as easily as on it — a single-mirror design for people who want the awareness without the sport look.
The Clip — our clip-on mirror — is the flexible option: a single mirror module you attach to glasses you already own, including your prescription pair, and you choose which side it sits on. A great way to try riding with a mirror on kit you already love.
Still weighing the bigger picture of mirror styles? Our comparison of helmet, handlebar and glasses-mounted mirrors puts the integrated-lens approach in context.
FAQ
Is a single or dual mirror better for cycling?
For most cyclists, a single mirror on the wearer's-left side is the better everyday choice — it watches the side overtaking traffic comes from in right-hand-drive countries and keeps things simple. A dual mirror is better for two-way cycle paths, busy city riding, or balanced coverage on both sides.
Which side is the TriEye mirror on by default?
The default single-mirror setup places the mirror on the wearer's-left side of the lens — the side in front of your left eye. A right-side option is available for left-hand-drive countries or personal preference. You choose the side when you buy, and because the lenses swap easily you can change it later.
Can I switch from a single to a dual mirror later?
Yes. The mirror is built into the lens, so single and dual are different lens setups — but TriEye lenses are interchangeable and easy to swap, so you're not locked in. You can also move from the smaller single mirror to a larger one. If you know you want both sides from the start, choose a dual View.
Do rowers need a single or dual mirror?
Scullers are best served by a dual mirror. Because rowers face backward and travel toward the bow, a mirror on each side lets you watch your line and check for other boats on either hand without twisting around and breaking your stroke.
Is the dual mirror bigger than the single?
Out of the box, yes — dual ships with a larger mirror and single with a smaller one. It's not fixed, though: because the lenses swap easily, you can add a larger mirror to a single later if you want more to look at.
