I have a 2024 Giant Defy Advanced 1. It has a 100mm -10 stem that I would like to replace with a 90mm. I ordered a Contact SL Aerolite stem only to find that the 2024 Defy Advanced 1 came with a round steering tube; not the D shaped tube I expected. A 90mm Contact Aerolite stem for a round stem is non existent; out of stock everywhere. There is a Contact SL OD2 stem that I am wondering about. It is for a round steering tube, has 1 1/4" opening, but comes with a shim that reduces for a 1 1/8" steering tube. But I am wondering if this stem would be truly compatible. My brake lines go in a cutout under my current stem and disappear down the front of the head tube. Does anyone have any experience with this situation? Let me know what you think please.

i think completely internal routing of cables/hoses looks cool, but is a total hassle to deal with, in real life.

this thread should be moved to the "Mechanics" subForum.

Thread moved from General Cycling to Bike Mechanics forum.

So what's to prevent you from using any standard 1-1/8" stem, from, say Zipp, Ritchey, Pro, 3T, Bontrager, etc.? Does your Giant have some sort of oddball internal routing I don't know about?

It might work. There is a required spacer for the brake lines that goes under the stem. In all probability, the shape would not quite match a non giant stem, but maybe, as you point out, that is not a big deal.

https://www.giant-bicycles.com/ba/de...roductphotos-5

https://www.giant-bicycles.com/ba/defy-advanced-1-2024

to me, it looks like a regular stem will not have enough steerer tube exposed to clamp onto

the stock stem uses some of the area behind the cable routing insert to clamp the steerer...

possible route would be more compact bars, but they already look maxed out in that regard...

maybe have Morticia Addams stretch you on the rack for a day or two?

I see. Thanks.

Good news! I found a new 90mm stem on Ebay!! Got it on there. Fits perfectly.

A comment on Giant. If you are going to require proprietary stems, you should have a supply of stems available to be purchased.

and, from what i've seen.. they and other companies need to do the same with several proprietary "Aero" seat post designs too...