[the other Anne]

I understand why we need lights mounted on our bikes, rather than our helmets, when we are riding on the road: we need the car about to turn left into us to see us, even when we are looking to the side, so we need a light pointing forward.

But what is the benefit to having a bike-mounted light on the trail? When I'm riding on the trail, there are no cars to hit me, and all I care about is lighting up where I'm looking. So why would I want a light on my bike instead of my helmet?

 

[znomit]

It illuminates the bits in front of your wheel all the time.
You need two lights for redundancy so it makes sense to have one on the bars.
You get better depth perception from a bar light.

 

[the other Anne]

Why do you need the bits in front of your wheel (or any other place) illuminated when you are not looking there?

 

[znomit]

Peripheral vision.

 

[the other Anne]

Good point.

 

[Vancbiker]

While many like a bar light with a pretty wide beam to light up the "bits in front of your wheel", I prefer a spot on the bars. I like it to light up the distance on the faster, straighter parts of a trail. If I'm in a tighter techy section, I'm looking close in and the helmet light shows everything I need. I find that a flood type bar light creates weird shadows to the sides of the trail that catches my peripheral vision and is distracting. Light where I want to go is my preference.

 

[Cat-man-do]

Why do you need the bits in front of your wheel (or any other place) illuminated when you are not looking there?

The need for helmet AND bar lights becomes more apparent once you encounter the sharp turns and hazardous terrain associated with MTB'ing. The bar light will always point in the direction that the handlebars are pointing. This will NOT necessarily be where the bike needs to go in the next couple seconds That is why you need two lights so you don't find yourself turning into a dark void and hitting unknown objects.

The same principle applies when using just a helmet light. When you need to look around that sharp turn to see what's coming up you will still need light directly in front of the bike to help avoid those obstacles that the bike has yet to encounter.

You can ride with just one light but it won't as safe ( or as fun ) because you will have moments when the light you do have won't be able to illuminate everything you will need to see. With bike lights as inexpensive as they are now there is really no reason not to use two lights. ( not to mention if one goes out you still have the other )

 

[eatdrinkride]

For me when combined with a helmet mounted light it helps with depth perception.

 

[pharmaboy]

Helmet lights are perched on your head, just waiting to be taken out by a tree branch over the trail.

Helmet lights are heavy and require a battery to be on your person instead of on the bike which means wearing a roadie jersey

I race with both, but ride socially with just the bar light - heaps easier to manage

 

[Cat-man-do]

Helmet lights are perched on your head, just waiting to be taken out by a tree branch over the trail.

Helmet lights are heavy and require a battery to be on your person instead of on the bike which means wearing a roadie jersey

I race with both, but ride socially with just the bar light - heaps easier to manage

Depends on what you have as a helmet light. I'm lucky enough to have a helmet that will accommodate a very low-profile / light-weight single cell ( 18650 ) torch. It set-ups in less than a minute with just a velcro strap. For casual rides it works very well. For longer rides I either carry a second battery cell or opt for a dedicated bike helmet light. BTW, changing batteries in a torch takes 20 seconds. That said I rarely need to change batteries when doing a two hour ride.

 

[grandsalmon]

I learned early on I needed at least the bar light. I get a better sense of depth/contour of the ground, especially when I am not paying full attention straight forward w the head lamp. Picking up the light strike and shadows made by the bar lamp, I make better steer & line decisions accordingly.
I ride occasionally w just the head light, but I don't get the same type of trail information.

 

[Reelchef67]

Helmet lights don't have to be heavy, and common sense says put the battery in your hydration pack. Bar light allow you to open up speed on faster straighter sections of trail. Plus what if your helmet light goes out suddenly , then you riding in dark instantly. Which is how lithium powered lights behave. It is complete insanity to trail ride with only one light.

 

[kjlued]

I see people with just a helmet light, just a bike mounted light and with both.

My preference is to have both.
Wide angled/flood light on bike and spot on helmet.

Once you do it this way, you won't want to do it any other way for the trail.

For the road bike I find just a handle bar mount is best.
It is sufficient light and lets you be seen.
You also don't risk accidentally blinding drivers when turning your head.

 

[Vancbiker]

Helmet lights are perched on your head, just waiting to be taken out by a tree branch over the trail.

Depends on the light and how one chooses to mount it. Mine mount just a bit above the visor on my helmet. If one is riding in pretty wide open terrain, a high mounted light works fine. In the areas I ride it is a branch catcher.

Helmet lights are heavy and require a battery to be on your person instead of on the bike which means wearing a roadie jersey

I have a couple ~600 lumen lights that weigh just over 20 grams each and an ~1800 Lumen one at just over 60 grams for the light heads. Neither is noticeable on the helmet. My night rides are usually in chilly to cold temps so the battery goes in the windbreaker or jacket pocket. Hydration pack for the battery is a PITA IMO.

 

[androgen]

I'm a big advocate of helmet light as the main light, but i still like to have a smaller bar light. My preferred scenario would be 4,000 Lumen helmet + 1,500 Lumen bar.

the optimum brightness of bar light is heavily dependent on beam pattern, more so than helmet light which you simply point where necessary.

My system design process is as follows:

step 1: put as much light on helmet as your neck will support.
step 2: put as much light on the bar as you can without the bar light becoming brighter than your helmet light.

because the bar light is 2 - 3 times closer to ground than helmet light it can easily become brighter than helmet light at less than half the lumen output of helmet light, so that must be taken into account.

given today's technology, as i said, we're looking at about 4,000 helmet + 1,500 bar.

 

[TiGeo]

Because I like a light that always points where the bike is going as well as a light that always points where my head is going. This most-closely gives you the same light needed to ride during the day. When you are looking around the corner/up the trail you still use your peripheral vision to look in front of the bike and without a light on the bike..you aren't going to see much!

 

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...depth perception. critical to know if that is a flat rock or tombstone up ahead
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