Using a flashlight as a bike headlight?
 

So I understand you can simply secure a flashlight mount on the handlebar, and put a flashlight on there as your bike head light.

What are your guys thought on doing this as a lighting option? Pros/cons...?

You will blind motorists and oncoming cyclists unless you have optics that can diffuse or redirect the beam to the ground

I place it under the "better then nothing" category. It will meet minimum standards for being seen.

You can use cloth tape on the handlebar to increase friction so the mount is more likely to hold still. A good-sized roll is $2 at the pharmacy/general store. You can magic-marker it black to match your bars or if it stands out too much.

One nice thing about bike-specific headlights is the beam pattern that spreads the light out to the sides and, on some, keeps the beam shining toward the ground and out of people's eyes. In my opinion the spread beam is really nice, you do want to see what's off to the sides.

I rode for a while (a short while) with a round flashlight beam and it was hard to make tight turns, like within the width of a neighborhood street, because I lost orientation information from the sides and it blew my balance. The bright light made everything else seem darker, practically invisible. It really cut me off from everything around me. I felt more connected to the world with lower levels of lighting, without the bright flashlight. There are diffuser lenses you attach to the flashlight to spread the light around, and I have a couple on order to try out, but I don't know how well they work yet.

Here's a cheap way to keep from blinding other people: https://www.bikeforums.net/20657904-post8.html

Here's a guy who made a flashlight handlebar mount out of a soft drink bottle. I don't know though, that looks like a lot of work, and the TwoFish one looks more sturdy.

I tried using a 2 AA cell Maglight held onto my bike with a P clip once. But only once. And that was half a decade ago.

There are so many good LED headlights at a good price out there now compared to years ago, there really is no reason to not use a bike light.

I did it, and I was satisfied for a while. Some flashlights provide shocking amounts of light for very little money, but I decided output level was not the important thing for me. Most of those mounts aren't very quick, and I had to take the cell out to charge it, adding steps to the process. Aiming the light and keeping it aimed right is also tricky. A lot of the lights have hot spots in the beams, which is terrible for me. My eyes go to the hot spot rather than where I want to look. I can't help it. I found that paying the extra -- and it's a lot -- for a bike-specific light is worth it for me.

My main commuting bike has a hub dynamo wired to bolted-on lights. This is the most convenient, and the beam is shaped like a car headlight's. I like this best, but the cost is high, and it doesn't move from bike to bike. The dynamo hub is also heavy.

I have a Cygolite Streak which mounts with a bolt I can operate with my fingers. It's very intelligent.

I also have a Busch & Muller Ixon Core with a German-style shaped beam. Great light.

I just got this Xanes light, and it's pretty good, too, especially the $9 or $10 price. I haven't used it much yet, so I can't give it a long-term review.

Tried it.
 

two fish . biz for AA battery flashlights , can offer a secure, be seen quick mount light option.

you can also strap on your helmet; if you use one. Have mounted flashlights(torch to you Brits);
on my handle bars and helmet. This was a long time ago when bike specific lights weren't powerful
and as cheap as they are now.
But current bike specific lights are just as powerful and more convenient.
Specific mounts, no need to remove battery for charging, etc.

Fenix sells a bike flashlight mount for around $15:
https://www.fenix-store.com/fenix-al...se-bike-mount/

Drawbacks are:
- Having to remove the batteries from the light and recharge them every time you ride with the light. Most bike lights you just plug into the charger. Not a big deal if you only ride 3 times/year in the dark but if you ride often it becomes annoying. I personally try to store my bike next to a charger so I can charge the lights without removing them from the bike at all so they're always charged and always with the bike.
- Sometimes the beam pattern that's good for a flashlight is bad for riding. It really depends though, and some bike lights have bad beam patterns as well.
- More work to attach and detach from the bike. Better bike lights you just slide on and off the mount.

Last night a security guard in my Safeway parking lot shined his flashlight at my face as I sat in the car waiting for my wife. It actually caused pain in my good eye from mabout 50-60 feet away. I was a guard and used a high lumen light, too, for pitch black surroundings. This was in a lighted parking lot.

Watch how powerful your flashlight or bike light is in the high setting. Adequate is good. High lumens are bad, depending. Be considerate of victims when using the high setting like high beams on a car. Thats why you see very low lumen lights in Target and other stores. High lumens are to light things, not people's faces.

Distance of the light depends on lumens and size and depth of the refector. So, a low lumen flashlight with a big diameter deep refector can out distance one with high lumens and small reflector. Always look for distance ratings on the package, if power and distance are your forte. Look for battery saving technology.

True in most cases since flashlights are spot lights with a narrow (hot spot) beam. They also don't offer the high, medium, low or flash modes or tilt/angle flexibility of a bona fide bike light.

I mentioned above that years ago I once tried a 2 AA Maglight on my bike. Some flashlights like my Maglight had an adjustment for beam width. That might be a good thing to have if you are that opposed to getting a bike light.

I did that back when I was a poor student watching my pennies. The road shocks/vibrations are hell on a flashlight's contact points, so eventually either the switch or the battery contacts (or both) will fail, plus the beam pattern sucks. Sure you may be able to get around both sets of problems by using a fancier flashlight, but at that point you're probably spending as much or more for it than for a decent bike headlight.

Flashlights are false economy.

Beam patterns and mounting/retention are inferior to purpose made bike headlights.

Every group ride I've been on where one or more riders used flashlights and makeshift rubber band mounts, someone's light fell off and endangered other riders. Every ride. No exceptions. I usually ride at the back to encourage stragglers and keep track of folks who voluntarily drop off partway through rides. Every group ride I've retrieved flashlights that popped off or inadequately secured tailights. Every damned ride.

Those rubber bands and aftermarket stretchy mounts will break. I've used them for various accessories and they all eventually break. Recently one of two I used to mount a video camera to my helmet broke. That's why I double and triple up on retention with those things. At a minimum, two rubber bands and a zip tie backup. I'll often use velcro or other mounts as backups too.

Those makeshift mounts are such hazards I'd ban them from group rides if I was ride leader. Either that or require backup retention using zip ties.

If you do go with a flashlight and makeshift rubber band mount -- I don't care how fancy the mount is -- do yourself a favor and use a zip tie as a backup retention.

Or just get a proper headlight. They aren't that expensive. In particular Serfas discontinued lights tend to be heavily discounted and are often outstanding values.

Even purpose made headlight mounts can break. My first Serfas mount broke after two years -- Serfas replaced it free. My Light & Motion Urban 500 headlight strap just developed a crack tonight. So I've backed it up with a zip tie until I can replace the strap.

I must be doing it wrong. I've used a variety of different flashlights secured with the 2 fish products for over 10 years and haven't lost one yet. I've also used the wrist straps as a backup instead of zipties, and I think that worked once to keep me from losing a light.

And the removable batteries may take more effort to recharge, but they're a lot easier to change midride than the USB powered batteries in the dedicated bike lights. I'd rather carry around some spare batteries than a spare light when I go for longer rides.

A flashlight-for-headlamp is my preferred set-up for cycletouring, since I don't plan to ride at night but want to be able to make myself visible in bad weather, the common AA batteries frees me from dealing with recharging, and I'll want a flashlight anyway for camping. For commuting/errands/club rides, I use a purpose-designed bicycle headlamp.

I have been using a Fexix LD10 and LD20 flashlight for perhaps a decade. Mounted on bike with a twofish linked above.
It works for seeing the road in total darkness even on winding hilly roads when racing friends.
I put in a fresh charged NiMH A or 2xAA before ever ride and if the ride is over 3hrs I carry a 2nd set of batteries.
I can aim it level to slightly down for use on road or tilted down more for rare use on MUP.
Flash mode during the day.

The last group ride I was on a week ago I noticed a regular from our group with a new bike and a flashlight in a TwoFish lockblock. Usually I'd consider those better than the rubber band straps. Nope. Her light popped off on a moderately rough road.

Reminds me, next group ride I plan to ask cyclists using those things to please use backup retention -- a zip tie or something.

I don't disagree with the reasons for preferring a flashlight, despite issues about beam patterns -- that can be fixed with a decent hood, even a homemade hood like I use on my L&M Urban.

My only concern is with the farm rigged methods for mounting flashlights.

Any bicycle headlamp or tail light that is fastened to the bar mount with a clip can fall off. I had to back track in car traffic to retrieve batteries when I hit a pothole.

Now they are secured with additional elastic bands that have their own hooks.

As for flashlights, mount them on your helmet. Your body makes for an excellent shock absorber and the beam will point to wherever you're head is turned (instead of where your handlebar is turned).

I second the two fish lock blocks . Solid reliable design. Never had a light fall out or any part of the clamp slip or move at all on the bars even when wet. Quick removal. Commuted to work with them for a year and continue to use them. The rechargeable AW liion cells I've been using in my now vintage incandescent surefire flashlights since 2008 are beginning to not hold a charge. The lights worked OK .. I upgraded one with a brighter LED lumensfactory drop in lamp module but I'm looking into a purpose made bike light for my next setup. https://cimg1.ibsrv.net/gimg/bikefor...a1f73be560.jpg
https://cimg9.ibsrv.net/gimg/bikefor...6e0016d9b0.jpg

You can buy proper torch mounts for less than the price of a loaf of bread, on ebay here.

https://i.imgur.com/ygcQe5k.png

Sure you could use a flashlight on bicycles. After all, you could hang a lantern from your handlebars, if you wanted to.

Personally, I'd consider them something to be used on an ah hoc basis due to their design limitations. But as long as I can see you coming that's up to you.

Why even going through all this trouble when there is a bunch of inexpensive designated bike lights? Looks like an additional mount isn't a concern here. If it were - there are bike lights with strap mounts, really quick and easy to install and remove the entire unit (e.g. Niterider Swift series).
Remember, just because you can make a mount out of a soft drink bottle, doesn't mean you should (that was fun to watch though).

To answer the original question:

Pros: you'll still be probably seen, potential savings of $20.
Cons: time loss, lower quality light for the purpose (difference in optics), a headache of the potential do-it-all-over-again.