Can you drill holes in a steel bike frame?

[majornelson]

I have a steel framed cruiser and I would like to be able to run some of the cables through the frame. Most likely through the top tube.

I think I would need 1/4 inch - 3/8 inch (6 - 9 mm) diameter holes near both ends. I would somehow paint/seal the exposed metal from the cut and use a rubber grommet to help with water penetration and cable management.

Any thoughts, precautions, horror stories to share on this?

 

[mlt34]

Can it be done?
Yes.

Should it be done?
Depends.

First of all, you should know that drilling a hole in a steel frame means you'll let water into the frame, causing rust on the inside. The rate at which this would be a problem depends on where you live. If you lived in Phoenix, you'd probably be fine forever. Maryland, I'm not so sure. Do you guys get some pretty salty roads during the winter? That could be a problem.

Next you'll need to think about where you want to put the holes. The bigger the holes, the more they'll weaken the frame (obviously) but what is less obvious is how the placement of the holes will affect the frame strength. The most stress on the top and down tubes will be on the top and bottom surfaces right where they meet the vertical tubes. You'll probably want to be putting your holes near the ends of the tubes, which is pretty close to where they meet the vertical tubes, and where the most strength is required. For that reason, you'll want to drill on the sides of the tubes, and not the top or bottom.

You can put rubber grommet, but that requires even bigger holes which weaken the frame even more. I'd do without the grommets. Just drill the holes as big as needed, and file as best you can to avoid sharp edges that cut the wires. Then use some silicone window sealing caulk to try and seal up the hole as best you can. Use it liberally. This will both help protect against water and keep the wires from moving around and getting all cut up on the sharp inside edge.

Or you can just use cable ties to hold the wires to the frame, forgoing drilling. That's what most of us do.

 

[majornelson]

by mlt34 » Sat Aug 31, 2013 10:00 am
Can it be done?
Yes.

Should it be done?
Depends.

Good advice. I probably shouldn't do it. I did a little more reading on the 'net and the two issues you brought - frame strength and rust - were pretty consistent concerns.

This bike actually has two top tubes so it's pretty strong but I think I'm better off with the zip ties and that black mesh cable management flex stuff. I used it on my other bike.

It was all about vanity anyway. I love the clean top tubes on this bike.

 

[mlt34]

Depending on how many accessories you have and where the cables come from, you might be able to get away with putting the controller up front either in a handle bar bag or right under the down tube above the front wheel, thereby minimizing the number of cables you have running from the handlebars and messing up your bikes pretty lines.

 

[wesnewell]

I don't care much about looks, but there's all kinds of flex tubing you could use for cable management. Maybe painted thin walled pvc to make a second top tube either above or below. You can also find a lot of the high temp tubing in different colors that is very flexible. Home Depot has some.

 

[majornelson]

That's a great idea. I'll check it out...

 

[majornelson]

That's a great idea. I'll check it out...

 

[mlt34]

I'm a big fan of black spiral wire wrap, personally. It turns a bunch of messy cables into one neat, professional looking package. I get mine from BMSbattery but you can also get it on ebay: http://www.ebay.com/bhp/spiral-wire-wrap

Here's an example I made from my book:

 

[veloman]

I've drilled 1/4" holes in both steel and alum frames with no issues. I try to avoid it and use clamps. The alum frames are thick (early 90s built) I wouldn't drill larger holes

 

[-dg]

I have a steel framed cruiser and I would like to be able to run some of the cables through the frame. Most likely through the top tube.

I think I would need 1/4 inch - 3/8 inch (6 - 9 mm) diameter holes near both ends. I would somehow paint/seal the exposed metal from the cut and use a rubber grommet to help with water penetration and cable management.

My favorite grocery getter bike (93 steel Miyata Triple-Cross) had an internally routed routed brake cable with holes in the top tube for the cable exits. Eventually it cracked around the top tube starting at the cable exit hole a couple inches in front of the seat tube and I had to toss it. I still miss that bike. So my vote is for no large holes near the ends of tubes.

 

[wannesd]

I'm a big fan of black spiral wire wrap, personally. It turns a bunch of messy cables into one neat, professional looking package. I get mine from BMSbattery but you can also get it on ebay: http://www.ebay.com/bhp/spiral-wire-wrap

Here's an example I made from my book:

Tbh, that looks cheap to me. I prefer the braided sleeves. More labor intensive, but worth it

 

[dogman dan]

I tend to agree, I wouldn't do it just for looks.

I just route wiring along the same route as brake or shift cables, and it looks good enough for me.

Love that spiral wrap stuff, but haven't got enough of it to do all my bikes. I just use the smallest black zip ties to bundle wires to cable housings.

 

[mlt34]

I agree the spiral wrap isn't the single most beautiful way to do it, but it's up there. For someone who doesn't want to take the time or money to make their wires look like the inside of a show car's engine compartment, then the spiral wrap is the best way to quickly neaten things up. The other great thing is that it is really easy to remove, in case you ever want to swap a throttle or something.

I usually throw another 10m bag into my order whenever I get stuff from BMSbattery. Dogman, if you want I'd be happy to send you a few fistfuls of the stuff. I have more than enough of it laying around. I'm flying to Florida later this month for the filming of a video series and I'll have a pile of parts coming in so I'm sure I'll have some extra spiral wrap too.

 

[RoadWrinkle]

If you must drill holes in any frame, a steel frame would be a better candidate than aluminum. Steel is much less brittle and you would not generally risk compromising the frames structural integrity as would be the case if you poked holes in an Alum. Other than inherent strength, the workability and "weld-ability" of steel frames makes them popular for DIY eBike builds. Hard to find new cromo steel frames, but they are out there.

I would add that steel fails gradually with "advanced notice", whereas aluminum tends to fail instantly...and catastrophically.

 

[majornelson]

Thanks to all.

I didn't drill any holes in my frame although I'm convinced I'd have an even cleaner look if I did... Zip Ties Forever!!

Here is a link of the build that I completed:

http://endless-sphere.com/forums/viewtopic.php?f=6&t=52559&p=794191#p794191

Thanks again for all of the advice and guidance.