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Dynamo headlight mounting on bike without fork crown hole?

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Dynamo headlight mounting on bike without fork crown hole?

Old 05-31-22, 03:54 PM
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Yan 
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Dynamo headlight mounting on bike without fork crown hole?

As you can see on the below pictures, the fork crown hole on the bike does not extend through the front of the fork. Does anyone know of an alternative way to mount a dynamo headlight to this fork? I'd like to avoid a handlebar mount as that will interfere with bar bag use.



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Old 05-31-22, 06:41 PM
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You can use the rack mount point half way down the fork.

Or you can drill the front of the fork.
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Old 05-31-22, 07:09 PM
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Drill press and then carefully tap in the correct threads?
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Old 06-01-22, 06:02 AM
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My fork crown hole was already in use for a cable hanger, so I used some threaded rod instead of the bolt for more length in my canti brake mount.

I pasted this text from a previous post I made:
The headlight is mounted on a brake cantilever mount. It would have been easier to mount the light on the fork crown, but that is already used for the canti brake cable hanger, that is why I mounted the light in an alternative place. The brake mounting bolt was not long enough to be safely used, I used galvanized threaded rod and several nuts and washers instead. The light mount is an extra tall Edelux light mount, slightly straightened to get the light up higher above the fender and also move the rear of the light further above any tire spray on wet days. Used blue (removable) threadlocker and made sure that these nuts are all very tight, I do not want this to loosen since my front brake uses the same mount as the light.



More detail here, this is where I copied the text that I pasted above:
https://www.bikeforums.net/electroni...b-charger.html

As I noted above, I used the extra tall mount, the mount I used was an Edelux mount but that might be the same as the extra long B&M mount.
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Old 06-01-22, 10:04 AM
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If you don't care how it looks, you can use my technique.

I just used a T bracket, covered it in tape, put some old inner tube around the fork blade for protection, and used hose clamps to secure the bracket to the fork blade. This is on a recumbent, and there weren't many options. While it's ugly as sin, it worked quite nicely!



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Old 06-01-22, 11:34 AM
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Note to self: make sure any custom bike I order has a through-hole on the fork crown for my dyno light.

steelbikeguy, that setup looks like the light is mounted kind of low. Aren't the German dyno lights designed to be around fork height for "standard" wheel sizes, e.g. 26", 650B, or 700C?
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Old 06-01-22, 11:56 AM
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Originally Posted by pdlamb View Post
Note to self: make sure any custom bike I order has a through-hole on the fork crown for my dyno light.

steelbikeguy, that setup looks like the light is mounted kind of low. Aren't the German dyno lights designed to be around fork height for "standard" wheel sizes, e.g. 26", 650B, or 700C?
I am not Steelbikeguy, but I will comment anyway.

I have mounted a dyno powered light that low, and any debris or tree leaves in the road left big shadows behind it, so that was a problem. And a pot hole was harder to see too. I picked up a used donated dynohub wheel from a bike charity for cheap, had a spare vintage light on the shelf so put them together. But in my case, this was on my errand bike, only ridden on well lit city streets to grocery store or other places near home. For that purpose, the low height is not that bad.



Simplest wiring job I have ever done, the hub and light were both grounded to the frame so only one wire needed.

Regarding the German rules, I am clueless on that.
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Old 06-03-22, 01:04 PM
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I assumed that there would be more ideas, but looks like there are none. So, I will throw out one more idea.

You can buy plates that are called Cantilever Brake Boosters that attach to the canti brake mounts, you could put a light on one of those plates. They are intended for bikes where the canti mounts flex too much. That said, I have no clue how much clearance you have below your bar bag.

The shipping time looks like it is shipped from asia.
https://www.amazon.com/Aluminium-Bic...dp/B08THVNXF8/

I bought one of those plates to use on another fork that I have, but have not used that plate yet.
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Old 06-06-22, 02:24 AM
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If youíre going to put a front rack on just put it there.
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Old 06-06-22, 06:26 AM
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Originally Posted by pdlamb View Post
Note to self: make sure any custom bike I order has a through-hole on the fork crown for my dyno light.

steelbikeguy, that setup looks like the light is mounted kind of low. Aren't the German dyno lights designed to be around fork height for "standard" wheel sizes, e.g. 26", 650B, or 700C?
It's definitely low, but with the "high racer" style of recumbent, I need it to be that low to avoid having it hit by my foot.
The light I'm using is home built, so the impact on the beam isn't too bad.

When I had my conventional touring/commuting bike frame made, I specified a threaded boss brazed onto the fork blade to permit the mounting of a headlight. I got used to this position for the headlight a long time ago when I used a fork mounted "block" dynamo. Over the 22 years that I've had it, it's worked fine.



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Old 06-06-22, 10:07 AM
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Originally Posted by steelbikeguy View Post
It's definitely low, but with the "high racer" style of recumbent, I need it to be that low to avoid having it hit by my foot.
...
I suspect that with a recumbent, your eyes are so close to the ground that having a light up higher might not help much anyway.
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Old 06-06-22, 11:05 AM
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Originally Posted by Tourist in MSN View Post
I suspect that with a recumbent, your eyes are so close to the ground that having a light up higher might not help much anyway.
it depends on the style of recumbent. On my Bacchetta Giro 26, my head wasn't too low. Still, recumbents do require some creativity to do some otherwise routine things.

A lot of 'bent riders will mount a light to the frame near the front. The potential disadvantage is that it might throw enough light to the side to light up your feet and be distracting. Having the light attached to the frame also means that it won't light the way when you are making a turn, which was my main motivation for mounting my light to the fork blade.

To their credit, Bacchetta did provide bottle mounting bosses under the frame tube near the cranks which made a handy spot for attaching a light. I made a bracket so I could mount a little Cateye Micro II, which I used as a back-up light (just in case I had a wiring problem with the dynamo, etc.)



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Old 06-07-22, 08:37 PM
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Originally Posted by Yan View Post
As you can see on the below pictures, the fork crown hole on the bike does not extend through the front of the fork. Does anyone know of an alternative way to mount a dynamo headlight to this fork?
I have the exact same problem on my Airborne, which has a Co-Motion front fork. I currently have my dyno-hub-powered light mounted on the left-side brake post.
I considered drilling a hole through the front of the fork, but the metal there is not really thick enough to tap threads in. I suppose I could use a bolt long enough to engage the threads at the back to hold the light on, and then use a locknut to hold the fender on. For the present I've decided to leave things as they are.

Moderately acceptable light mounting.
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Old 06-08-22, 06:12 AM
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Originally Posted by sweeks View Post
I have the exact same problem on my Airborne, which has a Co-Motion front fork. I currently have my dyno-hub-powered light mounted on the left-side brake post.
I considered drilling a hole through the front of the fork, but the metal there is not really thick enough to tap threads in. I suppose I could use a bolt long enough to engage the threads at the back to hold the light on, and then use a locknut to hold the fender on. For the present I've decided to leave things as they are.
....
As noted above, I put my light on the right side, not left on my rando bike. I did that because I did not want shadow from the tire to block the light on the right side of the road where you could have curbing or edge of pavement, etc. Since my light is above the fender, opposing traffic can still see my light just as well as if I had it on the left.

If you have the tools to drill the steerer tube, that is what I would do. Then cover up the metal where you drilled it with finger nail polish to prevent rust.

Different bike in photo below, if a long bolt is impractical, use threaded rod. In the photo below, I used a threaded rod for extra length, as I also had a fender mount to deal with. And my headtube was so big that I needed to move the light mount further forward from the fork. This is a touring bike and I do not carry lots of open end wrenches, so one of the nuts was one of those allen wrench type nuts that are used on rim brake blocks so I can use an allen wrench on it if I needed to remove the fender. This fork hole was not threaded, so the nuts on the threaded rod are torqued tight enough that it should not move.



The light mount is similar to a standard B&M, but that is not what I used, I bent a different mount to fit my needs. So, you will not see an identical one for sale anywhere, but there are similar ones.

If you drill it, if you have a drill press, that would be best. You want to make sure that the hole is directly ahead and not off to one side. My first dyno powered headlight went on a fork where the hole was not exactly straight ahead, the light beam was clearly in the wrong place. My light mount was plastic so I could not bend it for aim. Eventually I realized that I could use some of those weird spherical shaped washers like on rim brake blocks to allow me to aim it. But it is best if you do not need to resort to that, so getting the hole straight is better.

This placement of course assumes you have enough clearance for a light under your handlebar bag.
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Old 09-08-22, 11:26 AM
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I'm facing a similar puzzle at the moment on my gravel bike, with the added wrinkle that the fork is carbon, and has no crown hole that goes through. There's a rivnut in the back to mount a fender, but I have yet to find a bracket that would reach under the crown, and I don't have a machine shop to try and make one. The fork has three rivnuts on each blade for mounting bottles or racks, and I think a long m5 bolt with a nylock nut against the fork and another holding the lamp against the head of the bolt might do the trick.

Wire routing is the real conundrum, though. I want the lamp on the left, but the hub connector is on the right. I'd like to minimize the use of zip ties, both for aesthetic reasons, and to avoid abrasion against the carbon. I'm thinking I might splice the wire with 2.8mm spade connectors, right below the lamp, staggered along the wire, so they're not directly adjacent, then run the wire through the 6mm openings of the hollow thru-axle (I thought about Schmidt's coax connectors, but they're 6.2mm in diameter). If I need to take off the wheel, I disconnect it on the lamp side, pull the wire back out and use my 6mm Allen key to remove the axle.

Any obvious flaws to this plan?
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Old 09-08-22, 01:49 PM
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I should also add that my backup plan is a 28.6mm rack-mount-adapter seat clamp in place of one of my headset spacers. I've ordered the Axiom Gear Trekk version. I'm hoping that it does actually have a uniform thickness, as it appears. My fork bung is 90mm long and extends into the headset, so it will be safe to clamp the steerer tube.

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Old 09-08-22, 04:16 PM
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Originally Posted by hankamania View Post
....
Wire routing is the real conundrum, though. I want the lamp on the left, but the hub connector is on the right. I'd like to minimize the use of zip ties, both for aesthetic reasons, and to avoid abrasion against the carbon. I'm thinking I might splice the wire with 2.8mm spade connectors, right below the lamp, staggered along the wire, so they're not directly adjacent, then run the wire through the 6mm openings of the hollow thru-axle (I thought about Schmidt's coax connectors, but they're 6.2mm in diameter). If I need to take off the wheel, I disconnect it on the lamp side, pull the wire back out and use my 6mm Allen key to remove the axle.

Any obvious flaws to this plan?
I'm not familiar with the through-axles, so I don't see a problem. This seems easy enough to put together and try out, so let us know what problems you run into.

I've got a Schmidt disc brake hub dynamo, circa 2008, and it also requires putting the connectors on the right. The wiring has to run up the right fork blade and down the left, and it's not the best looking arrangement. It would probably look a bit stealthier if I had used black wire for both conductors.. oh well.

The only practical issues with the proposed scheme might just be that extra connectors introduces more opportunities for wire and connector failures.


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Old 09-08-22, 04:55 PM
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I discovered the big flaw to my plan... The rivnuts on the side of the fork aren't square with the plane of the wheel (they're all sloping in towards the wheel - it's symmetrical, and intentional). So... Headset spacer bracket it is!
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Old 09-08-22, 05:25 PM
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Did you look at Peter White's page? There is also the traditional style like here on Ebay.

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Old 09-12-22, 03:28 PM
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Originally Posted by 2_i View Post
Did you look at Peter White's page? There is also the traditional style like here on Ebay.
That metal one is for 1" threaded, and I wouldn't want metal that thin anywhere near my carbon steerer. I've pored over Peter White's site, as well as BUMM.DE looking at the various brackets. The B&M 471B/1 looks possible, but it doesn't appear to have a way to lock in place on the steerer tube. It's keyed for a threaded tube.

I received the Axiom clamp, and I think it's going to work. It had a lip on the edge to keep it from falling down the seat tube, but that ground off easily enough with my Dremel, The black paint on it was helpful to spot if any part of the lip was left - I'd hate for that to be a point of stress when clamped.
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