cemark

I have been using Merida Silex 7000, size XS for a while and even after the bike fitting I think I need something even more upright/comfortable. I already changed the stock stem to 25˚ 8cm stem. Reach is 379mm and stack is 588mm. Considering using a drop bar, my body position is pretty upright but thanks to my back pains, I have bulged disc, I am in need of a little bit more relaxed position.
Before buying the Silex I already wanted to buy Niner RLT but it wasn't in my budget. If I can sell my bike I will try to find a second hand Niner, which is already scarce thanks to pandemic.
Anyways, according to my bike fitting and my current setup, Niner RLT size 53 (reach 375, stack 579) is optimal for me. If I go with size 50 for short reach (367) I will have to sacrifice the stack height (568). Going with size 56 (reach 384, stack 597) with a really short stem and 44mm dropper looks like a good option.
I am also considering the flatbar conversion. Especially with the size 56 with high stack, and short reach thanks to lack of droppers seems the best option. I would like to get some help, opinions from someone that may have an experience with the similar issues I am having who may have found a good solution.

Paul Barnard

I hope someone can help you. I was horrible at high school geometry, so I am intimidated by all the numbers and geometry.

Kapusta

I got lost in all those numbers, but as someone who myself needs an unusually high stack to reach ratio, what I have ended up doing is going with smaller sizes frames (to get the shorter reach) and used a lot of spacers under the stem to get the stack.

If you go that route, the thing you need to keep in mind is that the more you raise the bars via spacers, the more you shorten the reach. There are calculators where you enter the stack, reach, and head tube angle of a frame, and as you add spacers it tells you what the new effective stack and reach are.

This is the one I used, and it has worked brilliantly for me.

bb2stem

Knowing the reach and stack I was looking for, this predicted within 10 mm the spacers I would need on any given frame to achieve it. Also predicted the stem very acurately. I just needed to know the stack, reach, and head angle of the frames I was looking at.

cemark

And what about handling. As I know shortening the reach with a shorter stem has a huge impact on handling. Its become very twitchy. That's my biggest concern. Going with the bigger frame with high stack will push me to use a really short stem. Going with the smaller size with a regular/long riser stem may cause to feel cramped from what i read from a lot of articles. How was it in your case? Do feel cramped with the shorter reach frame.

Also let me put the frame details in order to make it a little bit clear...

Merida Silex, size xs, reach 379mm , stack 588, with 8cm 25˚ stem . This is the bicycle i am using.

Option 1: Niner Rlt Steel, size 50, reach 367, stack 558. I can use this frame with 8-9 cm stem with high rise stem with a flat bar.
Option 2. Niner Rlt Steel, size 56, reach 384, stack 597, I can use this frame with really short stem and flatbar. Could be twitchy because of the short stem.
Option 3 Niner Rlt Steel, size 53, reach 375, stack 579, Almost the same geometry with my Silex, putting a flat bar could be the best solution, Its hard to find this size thanks to pandemice though.