Drilling into a Cromoly frame and steerer?
 

My idea for getting a custom frame built seems to be too difficult for frame builders to attempt. So instead I am thinking of modifying a Cromoly frame (Kona Sutra) I am wanting to know if the modifications are safe as it involves drilling into the frame.

I would need to enlarge 2 of the gas vent holes, one on the fork, and another on the chain stay, these two holes would need to be enlarged to 5mm (0.2in)

In addition to those two holes, a completely new hole would have to be drilled into the lower half of the steerer tube, again it would be 5mm (0.2in)

All of this is so I can internally route a dual strand 18 AWG cable from a SON28 hub to the front and rear lights, although 22 AWG is recommended for 6V 3W dynamos, with 18 AWG I will have less than <1% power loss through the cables.

I have attached a picture to help explain what I mean, aswell as some pictures from some one elses Di2 install.

From the SON28 Hub > Into the drilled out gas vent hole > through the fork leg > coming out of the crown (a hole for this already exists) > attaching to the front light.

From the front light > back into the crown and up the steerer tube > through a new drilled hole in the lower half of the steerer tube > excess wire will be looped in the empty space between the headtube and steerer tube (to allow the forks to turn) > through a hole in the head tube that goes into the down tube (this hole also already exists) > through the bottom bracket > into the chainstay > and out an enlarged gas vent hole, that I would need to drill out in the chainstay > up the rear rack to the rear light.

I propose looking at electric motors 2 rings the conductors around the of steerer tube

and 2 "Brushes", of another conductor spring loaded to press against those rings, so there is your rotary connector...





BTW hub dynamo wires go up the right side of forks, not the Left.



./.

Don't know about the drilling but two points I see:

• Have you checked to see if you can route the wiring past the bottom bracket from the rear dropout.

• Will the constant flexing of the wiring inside the steerer/head tube cause a fault in the wiring.

I don't know the answer to those btw. People drill frames all the time to add riv nuts but that is in the larger diameter tubing. In the chain stay the tubing/vent hole may bear stresses that will fail if it is enlarged to 5mm (?). I also thought you wanted to route your cables as well?



An interesting project. Post pics if you do it.

Drill the steerer tube? What could go wrong? Your current plan will lead to broken wires. Why not run the wire on the inside edge of the fork. Zip ties. Then run it up and through the steerer tube and out by the top cap. You are not talking to the correct frame builders, this id not a new idea.

Not to dissuade you but, if you want a cleaner look and find you can't drill, what about using a narrow SS tube brazed along the frame and bondo/filleted to form a neat appearance. I've seen similar tubing in the automotive shops for brakes or hydraulic lines (can't remember which).

A disk fork is going to be stressed pretty highly, and wouldn't be a place where removing material would be recommended. If I were drilling a 0.2" hole into my fork, I'd try to make sure it was a place that could easily be inspected, because I'd want to check it carefully before every ride. Inside the fork next to the disk doesn't fit that criteria. But it's your teeth!

You'll have racks and bags, H2O cages, etc and a little bit of wire and zip ties doesn't look right? I wouldn't bother with the risk.

Why anyone would want to complicate maintenance or troubleshooting on a bicycle that ostensibly could be 100 miles or more from a LBS or a good box of tools is beyond me. No custom builder will do it as you wish because they know they will end up eating it and getting trashed on a forum somewhere.

That rant out of the way, In the olden days before wireless cycle computers you would occasionally see the computer wire routed through the fork blades by slightly enlarging the weep hole on the bottom of the fork blade and drilling a matching hole through the top of the fork crown and then routing the wire up the head tube to the computer.

With a uni-crown fork you can drill a hole through the steerer tube to the inside cavity of the fork blade then bring your wire up through the steerer. The stem won't be in your way but the star nut will need some slotting and you need to drill a hole through the stem cap. Wire to the head light. To the tail light you would need to braze in a internal cable setup through the top tube to route the wire back to a tail light. Again the likely hood you would find someone to do that for you is pretty slim.

Since this will probably be another "virtual" bike, just use Photoshop and have it any way you like!

That is a bloody brilliant idea, that might alleviate wear and tear on the cable in the head tube, thanks, I might use that, when I come upto it.

Yes, I can route past to bottom bracket.
Over time the constant flexing of the cable will probably cause it to snap, but I don’t mind changing a power cable every 6 months or so.
I did want to also route the brake/gear cables, but a couple of frame builders I contacted said it was too risky to make a frame with disc brakes with an internally routed front brake cable through the fork, they also said it’s too difficult to alter and existing frame to have internal cable routing tubes. So now I’m just hoping the get the dynamo cables internal at least.
Absolutely I will post pics of the whole bike build, same as I did with my Di2 Carbon bike build last year http://www.bikeforums.net/touring/10...ike-story.html
Although this bike may take me until the end of the year to build, since the group set (Shimano T8000) I am going to use doesn’t get released until September.

I know wear and tear will cause broken wires eventually, but I should get decent mileage out of them. With fietsbob’s idea of the brushes that shouldn’t be a problem though.
I haven’t completely ruled out just running it up the side of the fork, but that will be my last resort, I would try 22 AWG cable first.
The frame builders had no problem with me wanting to internally route the dynamo cables, they took issue with internally routing the brake cable through the front fork. I have only ever seen it done on carbon bikes so maybe it’s a carbon only thing.

I do agree with you it’s a tiny little thing, but my mind is weird enough to still want it.

It would only be the cable for the rear light that would go through the headtube, and the rear light isn’t a tour stopper.

The frame builders had no problem with me wanting to internally route the dynamo cables, they took issue with internally routing the brake cable through the front fork. I have accepted this and given up on brake and gear cables being internally routed but if I can I would still like to have the dynamo cable internal.

If you want to be a wanker, go be a wanker on your own posts.

To everyone else who provided advice, ideas or insight, either for or against my hair brained idea, thank you.

fork wiring has been done.....buy an awol to customize, or source a fork:

The New 2016 Specialized AWOL Touring Bikes - CyclingAbout CyclingAbout

"...The AWOL Evo comes with a few features that make this bike totally awesome. My favourite feature without doubt is the dynamo light-to-USB-charger switch, which is integrated into the barend plug (image by Cycling-Ex.com). That is a collaboration piece made by Supernova for their E3 lights and The Plug III USB charger – it’s unfortunately not available aftermarket. All dynamo cable wiring is internal in the fork which is super clean...."

"....If you’re thinking of doing a custom build with an internal geared hub, this could be a great frameset option given how versatile the swinger dropouts make the bike. At US $700, it’s a bit of a steal for a Rohloff/belt compatible touring frame with all the braze-ons....."

modifiying existing frame? should be possible within limits.
internal smaller tube not always essential. some builders
(as when i bought my mercian) just have in/out nozzles
brazed onto the tubing for cable housing to pass through.

any reason you don't want the rear light wire to exit
the frame higher up the seatstay?

I have several thousand miles on my mountain bike with a somewhat similar setup -- Didn't have to drill my fork vent to route the wire through the fork, drilled the steerer tube 1/8", and drilled my stem 1/8" to have the wire exit at the handlebar where the headlamp is mounted. It's a nice clean install and I keep extra wire for repairs inside the stem. My setup is simpler than your proposal because I use a battery-powered taillight so it all turns together.

I would be really nervous about drilling the steerer anywhere near the bottom headset and am not quite sure what to think about the middle. It might depend on how long your head tube is.

Good luck and be sure to post results/pics if you do it.

PS. Actually mine is a bit more complicated than indicated above because I also split a connection off for a Reactor USB charger but that's not relevant to the conversation.

I just figured the chainstay was the cleanest place for it to come out, but the seat stay chould also work, but the seat stays are much smaller tubes than the chain stays.

Do you have any idea where on the AWOL the internal cable routing exits in the rear, the only one I can find in photos is on the downtube right next to the BB

competent frame builder should be able to place the
wire outlet just about anywhere you desire, braise on
an exit nipple/nozzle/whatchamathingie.

if me, i'd rather not have a loose, thin wire where it
could potentially get snagged.

so then your only problem will be dealing with the
wire rattling inside the frame.

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isn't there a framebuilders subforum?
might get better results if post moved

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I chould heat shrink the brake cable and dynamo cables together, I wonder if the heat would ruin the brake cable housing.

I used the external FD cable running inside a plastic liner tube, and spiral wrapped the wire to the tail light

around the plastic tube ,

then hot melt glued the wire under the mudguard, until i was near the mudguard mounted tail light.

later removed it all when battery LED head & tail light power improved,
enough to make any short time of a trip extending into dusk in Higher latitude summers OK,
I'm fine with that ..

My Rohloff trekking bike, i use the shift cable housing to the external shift box,
then run the wire up the rack strut to the wired top, rack, mount tail light.

There isn't enough power to justify 18 gauge wire. 24 would probably do fine.

When drilling wood structural members, it's always recommended to stay away from the load points. So if you go ahead with drilling, keep as far away from the dropouts as you reasonably can. And of course keep the holes as small as possible.

I agree with not routing a wire through the steerer tube as originally diagrammed.

Does not meet K.I.S.S. principles for touring.....

I don't see any reason why you can't if you wish.....

Just think how much fun you'll have in the middle of nowhere when the wire in your head tube takes a crap,you know it will......

The flip side of this argument is that I don't give my headlamp wiring a second thought as I brush bushes on the trail but have seen external wiring destroyed by same.

I say go for it and prove them wrong or right!

BTW: How was the tour on your carbon-tourer? I don't remember hearing how that worked out.

Ditto; after trying to route an internal rear brake cable through a frame - I will NEVER work on or have a bike with internally routed cables or wiring. Just not worth the effort.

:thumb: :roflmao:

This is probably the most critical factor of all. Every reference I have read about internal wiring and/or cabling is about the difficulty of getting it through the holes at either end.

Now, heat shrinking to the existing outers of the shifter or brake cables seems like a logical conclusion that I might even consider myself. Especially if there is a constant run of outer cable or hydrualic tube. The heat to shrink the wrap is not at all enough to disturb the plastic coating on the cable outers.

Makes sense to me. I appreciate the innovative impulse but it seems like much work/little payoff to route wires-only internally. OTOH if one is a lighter rider perhaps 5-mm holes in frame would work OK.

I'm a bit surprised the custom builders wussed out. Swiss Hi-Lite company makes super-custom Ti touring frames w/Ti stems/handlebars/steerers as options; if anyone has the expertise to do internal cable/wire stuff I'd guess they do. Only problem is they're super-expensive too.