Dynamo carbon fork mounting options

[nomm]

Hi,

I have a full carbon fork on my bike. I also have a dynamo wheel and light I am transferring from my audax set up. And like most full carbon forks on 'gravel/allroad' bikes out there it has an eyelet at the back of the fork for mudguard mounting but not at the front.

Please can someone point me in the direction of mounting options? Some have suggested handlebar mounts or thru axle mounts but the light/beam spread always works best at the top of the fork above a mudguard IMO. A bit like this https://www.flickr.com/photos/34072799@N02/17190239952/

So far all I can think to do is buy this https://www.hebie.de/en/parking/stand-a ... r/bracket/

...and fit so it attaches to the rear of the fork, goes under the fork and then hammer it into a more vertical shape for light mounting at the front.

I would be grateful for any advice

[Jdsk]

The headlamps on our tourers are in a surprising range of places. And they can work well in positions other than the fork crown.

Please could you add some photos of the front end of the bike and the relevant areas so that we can see all of the options.

Jonathan

[cycle tramp]

Personally speaking running a headlamp from the crown of the fork is waaaaaaaay neater than any other option...

..however I've always found that I could generate a better pool of light from the handlebars.....

The issue with mounting anything to the rear of the forks and then running it between the front tyre and the underneath of the forks is two fold -

I) clearance- is it physically possible to do so
II) Safety - if the bolt works loose, what is going to stop the weight of the front lamp lowering the mount until it touches your (spinning) tyre - and in the worst cause scenario- this occurs at 35 mph down hill, on a slippery wet road....

At this point - whilst it's an offence against the eye- you might be better off living with some untidy wiring and mounting the headlamp to the stem or handlebars and then learning to live with it - in the knowledge you've got a lighting system on tap....

You also may be considering drilling a hole at the front of the forks- however
(A) your going to invalidate the warranty
(B) might make the forks weaker
(C) there is surprising evidence that if you breathe in any carbon fibre dust as you work - it goes into your lungs and behaves in the same way as asbestos does (so best not, eh?)

[Cyclothesist]

The bar mount in that first photo looks v neat and places the light high enough to project a good beam and still mostly out of the way. SJS have a good range of mounts including the one pictured.
https://www.sjscycles.co.uk/front-light-brackets/

I agree with cycle tramp's reasoning on not drilling the fork.

[deeferdonk]

Topeak bar xtender mounted on bar or stem would get the light closer to fork crown mount level?

[mattsccm]

I use something like that 60 quid Nitto thing from SJSC. However mine was a tenth of the price from Aliexpress which is probably the same ultimate source of the Nitto. It sits a bit higher than a fork crown light but is actually in a better position.

[nomm]

Topeak bar xtender mounted on bar or stem would get the light closer to fork crown mount level?
s-l1600.jpg

This is wild!

Yes, I agree that personal preference would be the fork crown due to my experiences of beam spread when located elsewhere

I will post some pictures

[Brucey]

I think you could easily make and fit a suitable bracket, provided the lamp isn't too heavy. My scheme would require just two materials; sticky tape and a couple of old spokes. Optionally some V-brake washers can be added. I think PVC insulation tape would be ideal. The procedure would be as follows. First cut the head and the threads from the old spokes so you are just left with bare wire. Next form a 360 degree loop about 4-5mm dia.near the mid-point of each wire. You can do this by simply winding the wire around something about 4-5mm diameter. Then reach into the loop using snipe-nosed pliers and form two 90 degree reverse bends so that the wire ends are no longer crossing over one another but instead sit side-by-side. If necessary, the thing can be made monoplanar by hitting it with a hammer against a flat surface. You should be left with two ~4-5mm loops, each on the end of two parallel and adjacent wire legs.

At this stage you can bolt the two halves of the new bracket to the headlight. It is best the threads are removed locally from an M5 bolt, using a file or the SG technique. The bolt will then be about 4.2mm dia. locally, and the same strength it ever was, because you have only removed the top parts of each thread. The wire parts will probably need to be opened up temporarily for them to be fitted over the bolt. They can be prevented from splaying by using some modified concave washers from a V-brake-block fixing. The modification required is very simple; just file a notch about 4mm wide into edge of the axial concave face, so that the loop can be trapped by the washer, but the legs are allowed free passage.

Now bend the legs to fit the fork and trim them to an appropriate length. I suspect that about 2" of each of the four legs needs to be beneath the tape, but a bit more won't hurt. First wind a base (protective) layer of tape onto the fork, then offer up the bracket. Secure the bracket in place using more tape. If the tape is stretched slightly as it is applied, it will (if you do enough turns) grip the legs very firmly, since the loadings are cumulative. The final few turns of tape should be applied overlapping but unstretched, since this way there will be less tendency for the tape to unravel, even if the adhesive on it is a bit suspect. If your bike ever sees much weather, it is probably best if the leg bends are below the tape ie. they are such that they leave an acute angle in each leg. This 'doubling back' of the legs will make the bracket slightly heavier (the legs have to be a bit longer), but the taped joint won't tend to fill with water in the same way. If weatherproofing the legs in this way, it will probably be more convenient to leave 90deg bends in the legs whilst the taping is being carried out, only completing the leg bends afterwards.

This schemeh has the great attraction of not requiring you to drill any holes into your CF. Nor will it permanently mar the CF finish, all whilst allowing the light to be inexpensively mounted exactly where you want it to be.

[nomm]

I appreciate the very creative idea you have suggested. But I'm not really a sticky tape finish kind of person.

Please see pics of fork/mount

https://photos.app.goo.gl/G6aCsWo8S35m7jQXA

[Mike Sales]

I would look into using epoxy resin to glue a lamp fitting to the fork.
Epoxy is the usual resin in the composite, and in any case adheres to most resins.
It is difficult to buy small quantities of epoxy, but Araldite is epoxy, usefully mixed with a filler.
I expect the idea wil strike many as outlandish, but the fork is made in exactly this way. The carbon fibre is stuck together with the resin to form a strong composite.
I have built several boats essentially out of plywood held together with epoxy, including an 8.5m. catamaran, which has crossed the North Sea, so I would have no hesitation in sticking a lamp bracket to a bicycle fork.

[Jdsk]

...
Please see pics of fork/mount

https://photos.app.goo.gl/G6aCsWo8S35m7jQXA

I can see two photos. The fork crown has no hole at the front and a presumably threaded hole at the rear.

But they don't show enough lower down the blades or higher up to the bars to tell if there any other options.

Jonathan

[nomm]

...
Please see pics of fork/mount

https://photos.app.goo.gl/G6aCsWo8S35m7jQXA

I can see two photos. The fork crown has no hole at the front and a presumably threaded hole at the rear.

But they don't show enough lower down the blades or higher up to the bars to tell if there any other options.

Jonathan

I am trying to avoid both of those as options for mounting

[Brucey]

it should be possible to create a wire bracket that mounts with an M5 bolt on the back of the fork crown.

My suggestion is that you make a four-legged bracket as per my previous post, but you make it so that two legs go under the fork crown, and two go over it. I think it would be best done with the two sides having one leg of each sort. Again, an additional modified 'V'-brake washer could be used, this time to secure the ends of the bracket legs. If the legs are fitted with a few of those protector 'o' rings as seen on many mtb top tube cable runs (or similar), it ought to be possible to make the bracket so that it is partially supported by the fork crown but the fork is not marred by it.

[backnotes]

In spite of the thread title, this one viewtopic.php?t=136985 turned out to be as much about mounting lights on the fork crown of carbon forks as about low rider racks. There were various suggestions about how to do this. I don't know what the final solution turned out to be in this case, but one option via Shand Cycles was to also consider the hole (if any) at the bottom of the steerer as another mounting option. Not sure how this would work with mudguards though.

[Brucey]

IIRC most CF forks have no hole at the base of the steerer.