My bike came with 6 degree positively raised stem. When I did my fitting my current position was dialed in ( comfortable and more wattage produced as per the computrainer scan) without changing the stem. I still have about 1.5" of spacers underneath the stem. Would changing the stem to a 0 degree raise (same exact one) will requiere theorically adjusting the rest of the fit? in other words, maintaining the same position but going from positively raised to 0 degree could be ridden maintaining watt output in the same exact position. I know its trial an error but wanted to know if there is any specific numerical correlation I should be adjusting somewhere else.
I might have to slide forward a little on the seat which doesnt bother me at all but want to try this before removing spacers so I start from a straight plane.
If you have a 100mm +6deg stem going to a 100mm 0deg stem will drop the height by 9.9mm and increase the reach by 3.5mm.
I don’t see what you gain by getting a 0deg stem though, if you want a flat to the ground stem you need -17deg. It is possible that you would not need to shift the saddle at all and your body will adapt fairly easily. Or you could shift it forward a touch and maybe up a little too.
Hey, thanks for your response and the numbers… I do have a 100mm stem.
My final intent is trying to get the front lower (although I am not on the l"ower is always better " bandwagon). I feel I am more flexible than a year ago. My current options for getting the front lower are the stem and the spacers and I just thought I will start with the stem since its raised. I want to make individual small adjustments and not affect power output if possible.
Your cheapest and easiest option is to shift a 5mm spacer from under the stem to over - easy to reverse if you dont like it. If it works and you want to go a step further shift another 5mm. Then another 5mm.
Once you have 20mm on top of the stem, flip the stem and put all the spacers under it again then start the shifting process again.
A -6deg 100mm stem is 20mm lower and 6mm longer than a +6
No need to buy another stem until it’s sitting on the HT and you need a -17. Not that many 0deg stems around either.