As I've been getting more fit and more limber, I've been finding that I can ride in the drops comfortably for quite a while - up to a half hour so far, and that was limited by the ride rather than comfort. I've started to lower my position already, and am down to one 5mm spacer on my Look 585 Optimum. To go lower, I'd need to switch stems or flip the one I have. I have in the back of my mind that one needs to go to a longer stem as one gets lower. Is this correct, and if so, what's the formula for figuring out how much longer one needs to go when going lower?

Thanks!

There's two parts to your question:
1. If I lower the bars, I'll be leaning forward more, so do I need a longer stem to compensate? But I'm also increasing the seat to bar distance, so does that offset the difference?
2. If I change to a different length or angle stem (or flip it), how will that affect the handlebar position?

I can't help on part 1. Maybe someone that knows bike fitting will comment.

For part 2:
This stem angle chart from Habanero can show you the effect on the handlebar distance of changing to a different stem or flipping your stem.

(To go below horizontal, just read the upwards angle off the chart, and treat it like a downwards angle.)

You should experiment with longer stems. Even Hinault, just before winning the Tour of Lombardia (at the end of his career) put a 1 cm longer stem on his bike. He ended up soloing for a good amount of time to win solo.

One way of doing this is to go to your local friendly shop and see if they have take-off stems in appropriate lengths. If things work out you may be able to borrow a few of them to test and then return the ones you don't want (and pay for the ones you keep).

Technically, if you put a tape measure from say the nose of the saddle to the hook of the drops, when you drop your bar you end up with a longer position. If that "length/reach" is right then you should actually be using a shorter stem to maintain reach. However many people find a longer stem works better.

You can also experiment when riding the trainer (if you have one). I set up stuff next to my bike so it is about how high my hands are when I'm holding the drops; the object sits to the side of the bars so my hands are basically just a touch wider than if I was holding the bars. Then I slide my hands forward or back on that surface. I used plastic totes. Typing here away from the trainer I realize that one of our shorter bookshelves in the living room would work also. You can make very coarse, very radical adjustments in position without changing anything on the bike. This will give you some idea of what an extreme position would do.

this tool is also cool

https://yojimg.net/bike/web_tools/stem.php

This one's better than those other two.

https://www.brightspoke.com/t/bike-stem-calculator.html

I would recommend you experiment with moving your saddle forward a bit too. If you have a good position that works for you, lowering your stem will tighten up your hip angle, which can mess up your fit (same effect as moving your saddle back). If you move your saddle forward a bit (and raise it a smaller bit), then you're rotating position forward around the BB spindle.

That said, I think it helped me to tighten my hip angle a bit, but I still have a fairly forward saddle position. I've gotten pretty low now. I did a lot of stretching to get started on this position, to where I can get my forehead on my knees with straight legs.

Buy used stems so you can change them with very little cost when you re-sell as you work on your position.

Low can be good but don't sacrifice comfort. My last fitter raised my handlebars a spacer and I was much more comfortable.

I also recently changed seats and the new one is slightly taller and with just that tiny little change, gave me a little decrease in perceived effort and my powermeter shows that I am making more power.

looigi - Thanks! That's exactly what I needed.

But were you faster?

Lower is generally faster unless you are sacrificing more power than is offset by the aero improvement. But both power in the lower position, and comfort in the lower position, can be gained by adapting to it.

IMO, Waterrockets is spot on. I recently moved my saddle back a touch, both to gain a tiny bit of height (can't extend the seat post cap any further) and to rotate my pelvis a little more to lock myself more firmly into the saddle and stretch my position a touch. It gave me a lower position in the drops, without lowering the stem, which is slammed. I already use a 140mm stem, so extending it isn't an option. I could use a shorter headset cap, or a stem with more angle, but I think the drop is about right now...

Comfort isn't an issue - if I'm comfortable now in the drops for extended periods, I should have some room to go down farther.

Flip it.

<--- can't believe it took 11 posts for "flip it" to appear.

Lower has worked better for me comfort wise. Tops of my bars are 10 cm below the top of the saddle. My lower back is much happier than when the bars were higher. My wife also found happiness with lower bars. She had pains in her upper back and tried moving the bars higher and closer by a lot and finally found that going lower and longer was what she needed. Obviously this doesn't/won't work for everybody.

One think to be aware of. As you lower your bars your torso pivots forward, so you may want to go longer on the stem an amount similar to decrease in height.

Kiss it.

That's because this isn't the 41!

Actually, that's the plan. I'm going to move a 10mm spacer under the stem as well. That should result in about a 16mm decrease in height and about a 5mm increase in reach.

If the 16mm thing works, a 10mm longer stem would put me about there.

My main comfort concern is my shoulders and the back of my neck. I think my back will be fine.

I'm currently using 6cm seat-bar drop. This would put me at about 7.5cm.

You will gradually adapt and the shoulders and neck issues should resolve themselves. You can help the shoulder issues by exercising them in addition to your cycling. Anything that strengthens them helps.

I started out 3 years ago with the saddle almost level with the bars - my drop is now 4.75 inches. I can't touch my toes, but I have decent hamstring flexibility and I guess we tall guys have backs like giraffe necks.

Agreed 100%. I went from a 110mm -6* stem to a 120* -17* stem about a year ago. I felt like I was pedaling into sand for a week before a friend told me I needed to adjust my saddle position slightly. I pushed it forward just under 1 full mark on the rails (on an arione, it looks like 1cm but I haven't measured) and raised the seatpost about 4mm. At first, tempo riding felt awkward, but I got used to it. Hammering on group rides/races or doing interval/tt training feels way more effective now.

Don't forget you can also bend your elbows, so you can lower your torso position without lowering your bars.

+2

i had a comfort type bike fit for endurance riding. Got bored with all that, plus more flexible now, so got a new fit that was described as more speed orientated. The result was a 30mm drop in the bars, 30mm longer stem, and seat forward by 10mm. Cleat position was also changed, can't remember details. Took a bit of getting used to, around 600kms into it and am loving it. Am faster, feels like I can put more power down, and legs/back are fine. Rode it for 300 or so kms to make sure fit was okay then had steerer cut.

Well, it's flipped on the Look. Last hard pre-race workout tonight on my Allez, I'll take the Look out tomorrow on the recovery ride and see how it feels.

Dredging this back up for another question...

I've done a 50 mile ride with the new position - my fastest 50 mile solo to date, but I'm not claiming cause-and-effect - and I'm completely comfortable. Time to move it again, but would like input on which direction to move...down or forward? I've got a 10mm longer stem I can use, and 15mm worth of spacers I can remove. Recommendations?

I always start with the spacers. One change at a time.

I would concur.

Guys - Thanks, that's what I was thinking, but wanted confirmation from more experienced folks. Now I'm getting to the point of thinking about moving the new frameset idea from "want" to "need"...and I was once afraid the HT on the Look would be too short!

With the spacer vs length thing you should consider your arm extension. If your arms are dropping straight down (as mine do) then going forward may be better than lowering the bars even more. For me I ended up going forward a lot, down not so much, meaning forward 6 cm and down maybe 1 cm max. On the resurrected now-Red Tsunami I'll be about 1 cm higher and closer in the drops than before, but the tops will be 2 cm further out. 14 cm stem instead of 12 cm, compact bars so -3 cm reach and -2 cm drop, "track" stem so -0.5 cm height, shorter cranks so +0.5 cm saddle relative to bars. Net result -1 cm reach in drops, -1 cm height in drops, +2 cm reach in tops.

I position the drops for sprinting out of the saddle. I prefer the drops to be a certain distance from the cranks in height and reach so I can reach down with my arms instead of forward (going against that "if your arms drop straight down" tip, but this is different). If my compact bar experiment fails then I'll be reverting to my old bar/stem set up.

I don't know. I respect the learned opinions in here and find them interesting. But to me it sounds like you need a new bike.