Why is this a thing?

[ravdg316]

Yesterday, I rode my bike w my wife at her pace (slower). Felt miserable — aching wrists, brooks c13 seat too hard, handlebars too low, achy back.

Today, I rode around this morning at my pace: (faster, in the drops) and it was like everything fell into place again. Felt perfect. Seat felt Just right. Handlebars felt right. No pain anywhere.

What’s going on here?

[clyde the point]

*it's in your head*

[BdaGhisallo]

Your position on the bike is probably dialed in to the effort you normally put in. Pedaling harder means you put out more force into the pedals and that can help support your upper body over the front of the bike, for instance, taking some weight off your hands. Pedal easier for an extended time and that support isn’t there, causing more effort to be extended by your support muscles.

Also, going slower you were probably sitting up much more, putting more weight on your sit bones for a longer period than you normally would.

I don’t know that a slow ride should cripple you, but a much lower or higher intensity ride than normal can have effects.

[Turkle]

I'm 41 years old. Part of being this age is some days you wake up and feel like butt. Gotta roll with it sometimes!

Fortunately, we're all getting younger...

[callmeishmael]

Originally Posted by ravdg316

Yesterday, I rode my bike w my wife at her pace (slower). Felt miserable — aching wrists, brooks c13 seat too hard, handlebars too low, achy back.

Today, I rode around this morning at my pace: (faster, in the drops) and it was like everything fell into place again. Felt perfect. Seat felt Just right. Handlebars felt right. No pain anywhere.

What’s going on here?

Basically, your front end position on the bike, as well as saddle setback, is substantially affected not only by your flexibility, but by your power output. As someone else pointed out, force through the pedals supports the weight of your upper body. One of the reason pros have very long and low positions, and often not much setback is they can ride at 4w/kg all day. For a club rider that might be a 10 min max effort.

If you're producing less power, then everything else being equal, you'll have less counterbalancing upward force. That'll lead to more force through your hands and sitbones. Hence the sore hands and backside. You're also probably not engaging your glutes at the lower power output either, which loads up the lower back to stabilise the pelvis. It doesn't like doing this, as a rule, hence the back pain.

[Seramount]

James Taylor summed it up succinctly in 'Traffic Jam'...

'...it hurts my motor to go so slow...'