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How easy/feasible is it to drill a steel frame to install a stealth routed dropper post?
My frame doesn't have internal routing for the remote cable and there isn't much choice in externally routed 27.2mm droppers.
I currently have a non-remote dropper operated by a lever under the saddle nose which is just about at the end of its life so it seems sensible to go for a remotely operated one next.
All my frame (2016 Kona Explosif) has is an oval hole in the seat tube, wouldn't take much to do the same, you can buy the rubber grommits to fit into the hole as well, buy a couple and you can then use one on the cable outer and the other as a blank if you need it.
It won't take much other than the correct drill bit and a dremel, or even a small round file.
Brand-X do a 27.2, 105 mm drop external. The cable mechanism is at the base of the post so nice and tidy. 2x lever options only though.
This is what the frame routing looks like, measured it, it's 6.5mm wide, 15mm long (from tip of semi circle both sides), and that fits the generic grommit that i bought.
My Starling just has a single hole with a rubber gromit at the base of the seat tube. Can't see any reason why it wouldn't be possible to reproduce pretty easily.
As I've said many times pull the cable through one of the bottle bosses. No drilling required.
If you have bottle bosses on the seat tube, i don't, the seat tube goes straight into the bottom bracket shell with the small hole only, no route to the downtube, same for a lot of steel frames i'd guess?
Fair enough, most steel and Ali framers I've had have two sets of bosses. My Onza doesn't but it has a port for a dropper, which is reinforced around the hole.
I have done it. Measured the hole similar to argee above. Put some masking tape over the rough location I wanted to drill, drew the shape of the hole in pencil. I then drilled out the ends of the oval and filed the middle bit out and tidied up the sharp bits. Bit scary, but I was pleased with the results.
Mine is very much like Argee. Drilling through at an angle or making a slot instead of a round hole is much better for cable routing, since of course the hose doesn't want to go through at right angles- it's how basically every bike company does it.
The other trick I learned from the first time I did it is a simple one- don't do it in the middle. Obvious once you've done it wrong once but if you offset it to one side you can get tools to it easily and put it exactly where you want it. If you put it in the middle, access is a problem. Mine is probably at about 45 degrees from the centre and that works really well.
And don't put it too close to the end as that's where there's most strain. But that's OK because the curve of the hose/cable probably means that a few inches up the tube is the best place anyway.
Oh yeah and since you want to have some sort of cover or ferrule or grommet, that has to be taken into account when making the hole- you're making it to fit that as much as you are making it to fit the hose. I use a plastic stick-on that doesn't go through the frame at all which means I can make a smaller hole but I need to be more careful of the edges to avoid damaging the hose. All other things being equal I'd prefer a pop-in rubber grommet, it'd be neater and have better sealing and I've occsaionally knocked the stick-on covers off my frame which is annoying. But not enough that I wanted to switch to having a hole twice the size.
I did it to my stooge mk3. 8mm hole if I remember correctly and a rubber grommet. No real need to ovalise the hole.