Old 12-14-18, 12:06 PM
  #30  
Koyote
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Originally Posted by Spoonrobot
No, I meant what I typed. On flat, smooth, gravel; rides are like a group ride or road race. Weight matters much more since there is a smaller window for staying in the draft, rejoining the pack if dropped and responding to gaps where short bursts of acceleration are important. A few pounds makes a difference where being dropped can be caused by not being able to close a 2 meter gap while the pack charges along at 28 miles an hour.


To expand: On chunkier gravel or very hilly gravel weight matters much less than technical ability. It still matters, just much less. Being able to pick a good line, and being able to pick a good line consistently when tired or under stress, can lower the amount of power you have to put out by 15-60% (not a typo) easily. Chunk and hills can instantly spread out the pack due to queuing problem, there are a finite amount of "good lines" for a given section and riders will(eventually) by pure reaction, sort themselves into a queue for the good line and delay themselves and each other. Being able to recognize where the good lines are before hand or having course knowledge allows a good rider to situate themselves ahead of time and save both literal time and effort getting through a section. Having a bike that's X pounds heavier doesn't matter if you're always hitting the smoothest flattest parts of the road. The difference in wattage required to push a heavy bike is outweighed by the wattage required to ride over the roughest surfaces, repeatedly.

Especially where there are ruts or embedded rocks in the road that can be like riding over a speedbump on an already steep incline. The amount of additional power required to boost over a speedbump like obstacle on a 10% gravel grade is considerable, more so if you do it dozens of times a ride.

This is illustrative of the issue: https://janheine.wordpress.com/2016/...ses-confirmed/

https://janheine.files.wordpress.com...q8-1_chart.jpg

What's telling is that early in a gravel race often the pack will be together taking up the whole road. When there are rough sections or hills everyone will charge ahead and try to keep the same pace, there is little room for lateral movement and no one is going to voluntarily drop back to find a better line. Riders will burn all their matches staying in the same relative position as the bounce and clunk over the roughest sections of the road. Soon they will have exhausted themselves and been dropped. As the main group stays together and the numbers lessen, very rough sections are often approached benignly. Riders will sort into a single file line and all hit the same smooth section, often moving significantly left or right and winding around the section. This does not always happen and is indicative of individual rider knowledge forcing group behavior as many riders are happy to ride as if on pavement, taking no consideration for road surface.

Tail-gunning can be a much more effective strategy than it is in a road race. Often finding the good line as the last rider in the pack allows you to save enough energy to move past other riders as they exhaust themselves and eventually integrate into the main pack as the strongest racers survive.

There is also a wrinkle wherein a heavier bike may actually be helpful on certain courses or even just sections of courses. Inertia is always a factor and it's something I think about quite a bit with no conclusion. It's another one of those things where 5 pounds may only be 2.5% of the total system but hey I lost my race by less than 1% so does it matter or not?
I skimmed the above but will not read all of it, because I understand enough about physics to know that you are wrong.

It takes more power to move more mass when fighting inertia and/or gravity; translation: heaver bikes will be slower on climbs. Sure, a heavier bike makes it harder to close a gap, but that's a minimal and solvable problem: don't allow gaps to open. But a heavier bike requires more power on EVERY climb, for the WHOLE climb. And a heavier bike is generally harder to maneuver, which makes it even harder to choose the best line.
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