Is anyone intentionally designing any of their frames around external dropper posts? I am working on the design of a hardtail for bikepacking and considering it.
I know internally routed droppers seem to be more in-fashion and offer more drop. Usually this means housing is routed internally down the DT or partially external, down the DT and then into a port on the ST.
I really don’t love external cable routing on the DT, and internal routing is a bit of a pain to work on. I already plan to run the r/d and rear brake under the TT with bolt on cable guides. It got me thinking, about running the dropper routing this way too and using an external dropper. I know the little loop of cable up to the post is maybe a bit unsightly, but no more unsightly than the same loop of cable going from the DT into the ST.
Then it also got me thinking:
I probably don’t need maximum amount of drop where I live and something like a PNW Pine would suffice
Could go with a lighter, more slender ST designed around 27.2 ID which would fit the many rigid posts I already own (If I decided to set it up at one point without a dropper)
Is this for a personal bike or a production one? On a personal bike you should do what makes you happy
It’s really hard to go back to 125mm drop after riding with 200mm or more for a while. The difference is getting the saddle a little out of the way vs making it really disappear. So on a production bike I think this would greatly reduce your customer base.
External droppers also usually can’t have their length fine tuned, which is nice if seatpost clearance is minimal. I ran into this when using one on my cargo bike (where I needed 145mm drop and had a 150mm post). I ended up drilling the frame and getting an internal dropper that I could adjust.
This bike is just for me. I like my dropper, but I guess I don’t find it as “I couldn’t ride a bike without one” as some others. East coast terrain where I live is very up and down, and sometimes I find having to thinking about operating it so frequently, a bit annoying (there are no situations where you are descending for extended periods). I know the merits of having one, but on this style of bike questioning if I need a full 180-200mm drop.
I did this on a couple of frames I made for myself for the very same reasons that you outline. I was using the Brand X type external droppers for a while and this routing worked well - short cable length, following the same path as the derailleur and brake lines. Many benefits imo.
I would likely still do it if options existed in longer drops. A lot of consumers are vocal about internal brake lines, I’d argue that internal droppers are worse. I’ve just switched to an AXS post and very happy about it.
I think I’d do external if I were building something a long the same lines as you describe. But perhaps build in an internal option if external droppers become harder to source.
It’s a totally fine approach, especially for a one off/custom bike. The big issue is the quality of external dropper posts avaliable. There really aren’t that many (any?) great ones on the market anymore. I would say PNW’s entry level posts are ok, not great. That’s compared to high quality posts like the BikeYoke revives I like to use. I would probably avoid a 27.2mm seatpost spec for the same reason. If you want to run a rigid/flexible post later a shim will be fine!
Also, not all DT/internally routed setups are the same. If you’re smart with your guide placement it might actually be easier to work on than an external/TT setup. I really like having my dropper cable on a seperate run of guides to my shifter/brakes as you need to slide the housing along when removing the post for a service. Getting post/lever that allows for cable termination/clamping at the lever end helps in regards to internal setup.
As a vehement external brake and gear cable guy… I vote for internal dropper cable. Mostly due to the reasons mentioned above. Most good droppers have the actuator on the bottom, so you gotta get the cable in there at some point anyway.
My preference is a full internal sleeve (stainless works nicely) entering at the top of the DT and running the length down and up into the ST, going over the BB at the DT and ST overlap. Keeping the internal diameter of the sleeve close the that of the cable outer diameter should keep the rattle at bay.