There's no golden rule to match stem length as @Andrew Major said. Best possible solution is to CAD your cockpit from side. I'm taking dimensions from pictures (this has its problems) and trying to figure out X and Y distance from center of bar to 65mm from end (center of grips). SQlab 16-h has 51/47 and this soma bar most probably 87/66. So if you want to get same position as with SQlab 16-h and 50mm/0deg stem you need 75mm/0deg stem that is 30mm lower or 80mm/17deg stem that is about 5mm lower. To match SQlab 16-m it will be 70mm/0deg 45mm lower or 70mm/17deg 20mm lower. I'm using 65deg headtube angle.
This is quite possible to do. But take a look @ new ritchey kyote: [https://bikerumor.com/2019/04/05/ritchey-twists-new-mtb-drop-bars-aero-stem-break-away-refresh-more/](https://bikerumor.com/2019/04/05/ritchey-twists-new-mtb-drop-bars-aero-stem-break-away-refresh-more/) Forward sweep is so big, that to get proper headtube-grips alignment on longer frame you will require (currently) non-existent 20mm stem. And this is before shortening.
Aug. 13, 2019, 7:29 a.m. - Aleksander Pusz
There's no golden rule to match stem length as @Andrew Major said. Best possible solution is to CAD your cockpit from side. I'm taking dimensions from pictures (this has its problems) and trying to figure out X and Y distance from center of bar to 65mm from end (center of grips). SQlab 16-h has 51/47 and this soma bar most probably 87/66. So if you want to get same position as with SQlab 16-h and 50mm/0deg stem you need 75mm/0deg stem that is 30mm lower or 80mm/17deg stem that is about 5mm lower. To match SQlab 16-m it will be 70mm/0deg 45mm lower or 70mm/17deg 20mm lower. I'm using 65deg headtube angle. This is quite possible to do. But take a look @ new ritchey kyote: [https://bikerumor.com/2019/04/05/ritchey-twists-new-mtb-drop-bars-aero-stem-break-away-refresh-more/](https://bikerumor.com/2019/04/05/ritchey-twists-new-mtb-drop-bars-aero-stem-break-away-refresh-more/) Forward sweep is so big, that to get proper headtube-grips alignment on longer frame you will require (currently) non-existent 20mm stem. And this is before shortening.