Introduction: Internal Cable on Any Bike Frame
I bought this bike for 40 bucks, which is next to nothing, so I decided to personalize it:
1. Reproduction of the spoke lock key, which I described here: Reproduce spoke lock key
2. Replacement of the front hub because the flange was broken. The new flange has a smaller diameter, so I had to lace it 2 cross.
and 3. Some of the cable mounts were broken off so I decided to lay the cables into the frame.
Which I will show you in the next steps.
Frame material and durability:
My frame is an old steel frame.
A friend told me that he is doing the same with a real cheap aluminium frame and with bigger holes for cable stops, and his frame is still in good conditions.
The holes could be weak spotsbut there haven´t been any problems this far, even on bikes with a lot more holes drilled into.
Step 1: What You Need
I used a vernier caliper to measure the diameter of the cable housing.
The drill for the holes and the dremel to round off the edges and to grind off the old cable mounts.
And the safety goggles for SAFETY.
Step 2: The Frame
Here you can see how the cables were layed before.
Doesn't look pretty...
Step 3: Measure Your Cable Housings
Measure your cable housings so you know which drill diameter you will end with.
Step 4: Mark the In- and Outlets
The position is completely your choice.
But remember some points:
1. a short look on the internet gives you an idea of the different in-, outlet positions and could save you from drilling wrong holes (like I did with the rear break cable).
2. You can't go through your steering & head tube and seatpost
(seatpost: eventually you could make a slotted hole so that it's possible to adjust your seat height while the cable is running trough. But think about the stability!!!)
3. the cable bends shouldn´t be too tight or too wide..
(too tight causes friction while too wide doesn't cause too many problems but we want a clean look)
If you want to know more about cables, cable routing and anything about bicycles then have a look at
sheldon brown's website: LINK
Step 5: Drill the Holes
A drill press would be the best tool to prevent from slipping when you drill the first holes.
I used the dremel to get the "punch"-marks.
Start with a small drill, I used 4 different drill sizes to widen the hole up step by step.
When the hole was widened up with drill Nr.3, I slowly turned it sideways to get the hole into the right shape.
*Your drill gives you a very good preview of the entry/exit angle.
*this way you can adjust whether the cable should go slightly up or down OR if the cable should touch the frame.
*For instance the rear brake cable on the steering side could stay away from the frame to prevent paint scratches.
The same with the last drill which should be slightly bigger than the cable housing.
If the cable housing is slightly bigger than the closest drill size or the housing doesn´t fit easily just (carefully) wiggle the hole bigger with your drill.
Step 6: Round Off Sharp Edges
Round off all sharp edges, it will prevent cutting into your cable housing and it looks way better.
Step 7: How to Thread the Cable Through the Out Hole
After your finished drilling the holes it is time to get the cables through the frame.
How to get the cable out of the frame?- I think the easiest way is to get a piece of pliable wire, I used fence- and garden-wire.
Bend one side into a "U" shape.
Step 8: Details
My front derailleur and my rear brake cable are laid through the bottom bracket.
I rode my bike around 150 miles since I laid the cables through the BB, without any problems.
Step 9: The Whole Bike
I think it looks very clean.
Fin.

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25 Comments
Question 3 years ago
could you explain a bit more about routing through the bottom bracket? i want to do this for my rear derailleur cable entering the downtube near the head and coming out the chainstay bu the dropout but i have a sealed bottom bracket and im not sure thee will be room for the cable in there
3 years ago
Awesome project. Make sure you think about the strength of the frame and water that can sneek in the inner side of the tubes. Corrosion is a steel bike's worst enemy!
8 years ago on Introduction
Am I the only one concerned by frame resistance? I mean you can do it but then you should reinforce it with a grommet. Otherwise, if your frame is made of steel, you'll make it weaker (like yours in this case). If alu this is worse, if carbon you can as well throw it away (especially carbon).
Reply 8 years ago on Introduction
You are not the only one, I said it in the intro.
Especially old steel frames are stronger as needed...
I made around 800km, with tons of curbs, cobblestones and drag race events since I drilled the holes, without any problems!
10 years ago some friends of mine drilled really big holes in there BMX frames for weight reduces (okay 4130 CrMo steel is another class) but I saw only one broken.
Reply 8 years ago on Introduction
I understand that it might seem okay on steel, which is the best material for bikes btw, but why take the chance and not use grommet? It's safer, not so hard, and looks like the same. Besides it avoids wires to but cut if pulled too hard. (I make a few bikes a week fyi! ;)
Reply 8 years ago on Introduction
This bike is a no/low budget project because
over 10.000 bicycle in my city are stolen every year....
And the holes have to be much bigger, you know what this mean...
Reply 8 years ago on Introduction
Then I strongly suggest than the cable goes through front brake, under/through the speed levers collar, then under bottom bracket and so on. Safe and invisible.
Especially since, taking a closer look at step 7, if it might be okay to drill the main tubes (in the meaning ''not so dangerous''), it is definitely dangerous to drill the little rear tubes, wich are very sensitive (especially on cheap frame like yours), and where are weld the rear pattes. It will eventually break while riding, and might cause serious injuries to you and to the rear wheel while breaking.
I witnessed myself many times the rear patte breaking itself (most of the time the freewheel sided one), whithout any drilling performed. So, just don't.
Reply 8 years ago on Introduction
The chainstay is pressed into a flat piece, the weld is far away from the hole. And there is also a hole for the rear light cable, I don't think the manufacture make dangerous weak spots just for that cable...
Like I said before, I informed about weak spots and I have no problems so far...
84kg+8kg backpack and average speed about 30km/h.
And your suggest has some cons:
*very long cable, which results in
*more friction
*many curves -> friction
*new brake cable
*many many cable mounts all over the frame
*doesn't look clean
*how would you connect the side pull brake (tight curve) (might be okay on V-brakes)
And the instructable is about internal cable and not about alternative cable laying...
But I will send you a message when the frame is broken ;)
Reply 8 years ago on Introduction
Okay so it seems you're not understanding what I'm saying. The little hole you've seen made by the manufacturer is actually made to weld the rear patte, not to install electricity... So first thing first, you're right onto the weld.
Then friction can only result in movement, which is absolutely none for electric wire. ''Many many cables'' just one for electricity, which you can hide so easily, and one for brake, which is better outside since you're damaging the sheath since you're hole have no profiling at all or no grommet.
And no friction for brake cable, if you're able to install the sheath properly, it was even made for that purpose and have teflon in it so it will stay lubricated.
As of the remark concerning general presentation of the bike, maybe you can try to make a How To hide the wheels next time. A bicycle is a bicycle.
And if the purpose of your topic was internal cable, then I suggest that you learn how to do it properly before to try teaching others, or just buy a frame where it was designed that way by the manufacturer.
So I get you want a free mountain bike as a prize for your How To (Kill Yourself?), but please don't give away dangerous advice. I'm a do it yourself enthusiast, but you should be careful about what you do.
8 years ago on Introduction
Where did you get that dremel bits box at? :) Look great btw
Reply 8 years ago on Introduction
I see it in every hardware store, it's my second box which I bought for 5 bucks in a car parts store
8 years ago on Introduction
What holes did you drill that were wrong? Adding an explanation could help prevent others from repeating the mistake. From my experience working on older steel bikes like this, they seem to be adequately overbuilt (i.e. strong enough) to accommodate the holes you added. The final product looks great.
Reply 8 years ago on Introduction
next time I would drill the rear hole on the top of the top tube and the front hole on the left side. I mounted a flat handlebar and now the cable bend doesn't look good, it's okay but could be nicer....
8 years ago on Introduction
Otherwise Dremel is a great tool, if you know what to use it for.
8 years ago
my bike's got internal routing and one of the disadvantages I've found is that the cables rattle within the frame - very irritating
Reply 8 years ago
I wonder if you sprayed in a teeny bit of expanding foam. Would be a pain if you had to replace the cable but it might put an end to the rattling without adding any real weight.
Reply 8 years ago on Introduction
Although expanding foam might work to stop the noise temporarily, you'll be in real trouble once it comes time to replace your cables and housing.
Reply 8 years ago
You could add a foam spacer to fill the gap between the cable and the frame hole. Assuming your cable is the exact length you need, that will stop rattles. I don't really hear many rattles - could be your frame hole is too big or not angled.
8 years ago on Introduction
Very well done! I had this very idea back in the summer when I got tired of my cables getting stuck on things getting it in and out of my apartment. I had no idea how to make this happen, and now this shows up!
8 years ago on Introduction
the final result is worth everything. looks neat indeed.