Hello, wondering whether anyone has installed a working alternative to the giant integrated aero stem and handlebar system that runs the cables over the top of the stem and then behind the steerer on a giant propel (circa MY18-20)?
Seems like the design of the cable routing is going to make alternatives difficult to find.
Does yours have the oversize 1 1/4” steerer tube too? That will further complicate things
Yup. It has ALL the things. Annoyingly, I’m coming to the conclusion that the best option is most likely try to find the same components, but in the desired sizes, assuming they are still available.
Yeah, Either that or you’ll be able to fit a “standard” 1 1/4 stem and any bar, accepting that the cable routing will look… interesting. Judicious application of zip ties may help rein in the resultant spaghetti monster, but won’t do much for the looks.
Last time I looked (about 6 months ago, while I was still working at a Giant dealer) the Giant handlebars with the flattened clamp section were out of stock in the UK in useful sizes, but you may have better luck elsewhere. Maybe contact a dealer in NL who might have easy access to Giant Europe stock. You’re unlikely to see them online, but that doesn’t necessarily mean they won’t be available to order.
I can’t remember if the last-gen Defy stem was compatible - that may open up more options as it has a standard round handlebar clamp, so you could at least fit your choice of bar. The cable routing system was very similar, so it may work, though I dont know if there were some differences in the spacers, or the frame/headset interface
Appreciate the comprehensive answer. Thanks James. 
James is on the money here. I have a 2019 Defy with the same setup. The stem is pretty much the same setup in terms of hiding the cables, but has a round centre of the bar. Can’t remember what model it changed away from this abomination.
There were some lower spec Defys that had the cables showing so if you search around that model, you will get an idea what it looks like with a “normal” stem - eg https://99spokes.com/en-AU/bikes/giant/2019/defy-advanced-1
Interesting. It’s a different look for sure.
A bit more context, my customer has brought the bike in along with an aliexpress one piece bar that he was hoping to have installed. Unfortunately the bar appears more suited to a later model propel. From memory, the older defy had the little cable stopper plate in it (memory might be off here) and I’m a bit worried that if I try running the cables in this fashion there will be water ingress to the headset bearings and also frame due to the large hole that will remain behind between the steerer and the frame.
Was hoping to give him some options, this might be one.
If it’s not the one he already has, maybe look at a Yoeleo H9.
I have one on my bike (with external cable routing) and it’s been great. Comes in 1.25” steerer version.
For the Giant, you may be able to run the cables out of the underside (there are two sets of holes, under the stem and under the bar), either might work?
that underside image may be out of date… there’s also this as possibly the current version:
