Flounce

In theory at least, does shortening the stem by 10-20mm require other changes to the fit (e.g. saddle height and fore/aft) ?

The story: I've worked with a pro bike fit to get to my current position. It's taken a while to get a fit where there is no achilles pain or anterior knee pain. I can ride around 200 miles (so far) without much issue other than a bit of back soreness. I think I'm a bit too stretched out.

I have noticed that on long rides I find myself holding the tops and the ramps/shoulders in order to give my core/back a rest and achieve a more upright position.

When I'm holding on the hoods or hooks, I'm in an optimal "regular" fit position, i.e. looking down I'll see the bar tops superimposed over front hub. But when I'm riding on the tops or ramps, I see the front hub closer to me.

My current stem is 130mm. I'd like to try a 120mm or even a 110mm to see if this more upright position lets me spend more time on the hoods or hooks: it is nice to be able to reach the brakes when riding

I want to know - at least in theory -will I need adjustments made to saddle height and fore/aft if I am shortening my stem.

I ask because I want to know if I should pay for another fit along with the stem change.

thank you.

IK_biker

Shortening the stem does not require any other changes.
Saddle height and fore/aft is a separate deal, and the first step to the correct fit. If yours feels comfortable where it is, don't foock with its position.

In your case, there are 3 things you may want to try:
1. shorter stem;
2. handlebar with a shorter reach;
3. raise the stem a bit (by adding a spacer underneath or by using a stem with a different angle).

Whether or not your line of sight places the front hub in front or behind of the handlebar is entirely irrelevant, although this contradicts the "old wives" approach to stem length I recall applied back in the mid-60s. The proportion between your torso length, arm length, and neck length is unique, which is ignored by the above "rule of thumb".

Secret Squirrel

I am going to ask the obvious, does your current fitter allow you to ask their advice after the fit? Bike fit is an on going process that requires follow up. They shouldn't need to charge you for the inquiry. If you change your stem, it absolutely effects your other contact points. It might be a simple adjustment like flipping a stem over to shorten your reach and give you more elevation. In any case, a pro fit cost should allow for continued correction advice.

Flounce

I am in an unusual position: It has been over a year from my initial fit, and I have gone back to my bike fitter several times, maybe 10 times, over the course of 12 months to make changes to get rid of Achilles tendinitis, and then anterior patellofemoral pain. He has never charged me anything extra. He is sawesome.

I can go to him for this, but 1) I don't want to bother him yet again if I can trial this small change in stem length without messing with saddle height/fore aft, and 2) he is a little dogmatic - naturally, given his experience - and I am a little pig-headed, so if I tell him that I want to try a change in the fit he might say, "no, that (changing crank arm length, stem length etc) isn't the problem, you need to (strengthen your core, move saddle slightly aft, etc), and I'll think to myself"yes you know tons more than me, but I know my body and I want to try my solution first."

Hope that makes sense

Secret Squirrel

Ok. I had an accountant like that.
You will probably end like us, with a box of stems of various sizes.
I would then recommend aquiring an adjustable angle stem in the length that approximates your final lenght. performance bike might be a good source. Play with various angles. Look at an online stem angle calculator that relates stem angle to total reach. After trying different angles, buy the stem that best reflects the final position.

Carbonfiberboy 

Rather than sit more upright, my advice is always to get stronger and thus remain in the lower and faster position. Just takes some core work, which does not mean crunches! This is a very good book which I've used:
https://www.velopress.com/books/tom-...ore-advantage/

I worked my way though all the programs in the course of a year. It helped. Takes about 20 minutes to do a set of exercises.

There's also flattening your back:
https://www.bikeforums.net/road-cycli...discovery.html