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Road Cycling “It is by riding a bicycle that you learn the contours of a country best, since you have to sweat up the hills and coast down them. Thus you remember them as they actually are, while in a motor car only a high hill impresses you, and you have no such accurate remembrance of country you have driven through as you gain by riding a bicycle.” -- Ernest Hemingway

Coasting down hill

Old 05-26-22, 09:56 AM
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LarrySellerz
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Coasting down hill

Is putting out consistent power faster than attacking climbs and coasting down descents? Constant power and pedaling down hill are common tips for doing endurance rides. Personally I don't often pedal when im going ~26+ mph
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Old 05-26-22, 10:25 AM
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my legs love me when i give them a well deserved respite, even if only for the brief duration of a downhill
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Old 05-26-22, 10:29 AM
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If you wear a shirt and let it fly behind you like a cape, it will generate lift. The result will be less tire to road contact and reduced friction, enabling you to go faster downhill without pedaling. YMMV
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Old 05-26-22, 10:48 AM
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Take up running; problem solved.
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Old 05-26-22, 11:03 AM
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Originally Posted by LarrySellerz View Post
Is putting out consistent power faster than attacking climbs and coasting down descents? Constant power and pedaling down hill are common tips for doing endurance rides. Personally I don't often pedal when im going ~26+ mph
I'm not sure how much more speed you can gain by pushing harder on the descents. Mostly, I spin up to 25 or so and then coast, on the straight ones. The technical ones, I'm braking WAY more than I'm pedaling. I think you'd lose more by going less hard up the hills than you'd gain pushing more on the descents. And, geez - you say you weigh 260. How much more speed do you need than what that gives you? You could probably get more speed by rebuilding your hubs with new grease and bearings.
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Old 05-26-22, 11:24 AM
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Originally Posted by Bah Humbug View Post
Take up running; problem solved.
He said he wants to be faster!
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Old 05-26-22, 11:41 AM
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Depends on how hilly and long the ride is, and what type of physiology you have / want to train to have.

Mathematically it's faster to go harder uphill and into a headwind, go easier downhill and with a tailwind. However attacking and going over threshold takes longer to recover and eventually you'll blow. Some riders are much better at putting out bursts of power and recovering, others are diesels that can't go into the red much at all.
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Old 05-26-22, 11:42 AM
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Originally Posted by Seattle Forrest View Post
He said he wants to be faster!
Oh I'm sorry; did I derail the thread?
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Old 05-26-22, 12:17 PM
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Originally Posted by LarrySellerz View Post
Is putting out consistent power faster than attacking climbs and coasting down descents? Constant power and pedaling down hill are common tips for doing endurance rides. Personally I don't often pedal when im going ~26+ mph
You'll probably find it pretty difficult to maintain a consistent power both up and down the other side. Not unless you climb with very little power and therefor will be slower overall.

If you are coasting at 26 mph, you might need a bigger chain ring or develop a faster cadence.
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Old 05-26-22, 12:24 PM
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On anything more than a moderately steep descent, your pedaling effort will be wasted. This is because aerodynamic drag (and therefore power required to increase speed) goes up by the square of your speed increase.

Going up a hill, obviously you must pedal to keep moving. It's okay, because at speeds below 10 or 15 mph, air drag is by far the smallest component of the total formula you have to overcome to maintain or increase speed. In other words, your effort is not wasted, because increasing power by 20% will bring an increase in speed of nearly 20%

On flat ground, pedaling is again required, obviously. At speeds of 15 to 20 or 22 mph, air drag starts to take over as the major component. Within this range, any increase in speed will require a progressively greater effort--actually, this is always the case, but in this range it becomes a significant factor.

When you're coasting downhill at 25, 30, 35 mph or higher, you might as well rest and enjoy the free propulsion from gravity (technically, withdrawing potential energy you put in the bank while climbing earlier on your route, or if your descent is at the beginning of the route, going in debt by using energy you haven't banked yet). To increase your speed, you'll have to exert a disproportionately greater effort. Spending any energy here does little to increase speed, therefore it's better saved for a time when it will make a bigger difference.
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Old 05-26-22, 12:29 PM
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Old 05-26-22, 12:35 PM
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Originally Posted by prj71 View Post
If you ever drop your keys into a river of molten lava, let 'em go, because man, they're gone.
Worse than trying to catch a falling knife?
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Old 05-26-22, 12:39 PM
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I am in the flatland of Delmarva. The only "hill" for many miles is the Indian River Inlet Bridge, guessing about 50 feet above sea level, each side is about 1/4 mile long. I believe the grade is about 4%. So, this likely does not relate a whole lot to the descents the OP has in mind. Anyway, it's about half and half in regards to getting as much speed as I can, or just coasting. I would have to go over and back on the bridge about 55 times to reach 1 mile of elevation gain. On days the wind is out of the north or south at a good clip, I like to go uphill into the wind riding hard, then coast the downhill, then do the reverse coming back across. I once hit 42 mph in the downwind, downhill 1/4 mile. Recent memory is more like 32 max.
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Old 05-26-22, 01:16 PM
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Originally Posted by Broctoon View Post
On anything more than a moderately steep descent, your pedaling effort will be wasted. This is because aerodynamic drag (and therefore power required to increase speed) goes up by the square of your speed increase.

Going up a hill, obviously you must pedal to keep moving. It's okay, because at speeds below 10 or 15 mph, air drag is by far the smallest component of the total formula you have to overcome to maintain or increase speed. In other words, your effort is not wasted, because increasing power by 20% will bring an increase in speed of nearly 20%

On flat ground, pedaling is again required, obviously. At speeds of 15 to 20 or 22 mph, air drag starts to take over as the major component. Within this range, any increase in speed will require a progressively greater effort--actually, this is always the case, but in this range it becomes a significant factor.

When you're coasting downhill at 25, 30, 35 mph or higher, you might as well rest and enjoy the free propulsion from gravity (technically, withdrawing potential energy you put in the bank while climbing earlier on your route, or if your descent is at the beginning of the route, going in debt by using energy you haven't banked yet). To increase your speed, you'll have to exert a disproportionately greater effort. Spending any energy here does little to increase speed, therefore it's better saved for a time when it will make a bigger difference.
The one point I'd make here, though, is that if you come over the top of the hill at 10 mph, and then start the descent by spinning up to a decent speed, like 25 or 30, if that's less than your terminal velocity on that hill.
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Old 05-26-22, 01:39 PM
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1. It's not just a physics problem, but a physiology one also.
2. In time trial, if you're not pedalling within 10% of your target power during the event there better be a sharp corner, insufficient gearing, or you've already passed the finish line.

If confused about #2, refer to the part after the "," in #1.
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Old 05-26-22, 03:53 PM
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Originally Posted by burnthesheep View Post
1. It's not just a physics problem, but a physiology one also.
2. In time trial, if you're not pedalling within 10% of your target power during the event there better be a sharp corner, insufficient gearing, or you've already passed the finish line.

If confused about #2, refer to the part after the "," in #1.
If it's a hilly TT, your target power on the climbs will be higher than it is on the descents or flat. At least if you want to win. It's simple physics/maths. Any pacing algorithm (eg. Best Bike Splits) will always set higher power targets on the climbs (obviously taking account of your personal limits).
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Old 05-26-22, 04:26 PM
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Last time I did a 20 minute MMP test, I was pretty done at 18 minutes, then the road went uphill at about 18:30 and my power went up with it. I don't know if hills just keep us honest, if the different position recruits more muscles, or if somebody shot me with a tranquilizer dart but filled it will speed instead. But I've heard a lot of people say hills draw more power out of them at the same feeling of effort.
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Old 05-26-22, 04:43 PM
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Originally Posted by burnthesheep View Post
2. In time trial, if you're not pedalling within 10% of your target power during the event there better be a sharp corner, insufficient gearing, or you've already passed the finish line.
.
so ive heard stuff like this but it seems to contradict the idea that its more efficient to work hard when going slow because of drag. Ive also heard people talking almost derisively about riders going hard on hills and coasting on the decents, as if they are training ineffectively or are inexperienced. It also seems like people drop massive watt bombs on punchy climbs, but maybe people just like doing that? I dont really know what to think tbh
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Old 05-26-22, 04:45 PM
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Stupid question. If you can pedal you can go faster.
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Old 05-26-22, 05:03 PM
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Originally Posted by cxwrench View Post
Stupid question. If you can pedal you can go faster.
Once your cadence gets high enough soft pedaling can take hundreds of watts, gassing yourself for little gain
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Old 05-26-22, 05:28 PM
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Originally Posted by LarrySellerz View Post
Once your cadence gets high enough soft pedaling can take hundreds of watts, gassing yourself for little gain
Hence, gears.
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Old 05-26-22, 05:32 PM
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Originally Posted by LarrySellerz View Post
so ive heard stuff like this but it seems to contradict the idea that its more efficient to work hard when going slow because of drag. Ive also heard people talking almost derisively about riders going hard on hills and coasting on the decents, as if they are training ineffectively or are inexperienced. It also seems like people drop massive watt bombs on punchy climbs, but maybe people just like doing that? I dont really know what to think tbh
There's a whole range of power output between on the one hand pushing the same wattage as on the flat, and on the other, charging up the hill with everything you've got. It does you no good to be the first to the top of a climb if you have nothing left when you get there.

(I confess, I do the latter for fun, where you turn off of Page Mill onto Arastradero right by 280. Charge up the hill like my life depends on it then gasp like a fish on a dock for the next 100 yards. Why? Why not?)
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Old 05-26-22, 06:13 PM
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It's kinda a fun question. Pretend you have a course that's 20 miles long. 5 miles of flat, 5 miles up a 5% gradient; turnaround and do the 5 miles back down and the final 5 miles on the flat. If you have eg. a 200 watt FTP.. do you go out at 200 watts, and gear appropriately to keep that all the way through the ride, or do something else, and what would it look like?
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Old 05-26-22, 06:15 PM
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Originally Posted by Bah Humbug View Post
Oh I'm sorry; did I derail the thread?
Reported
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Old 05-26-22, 06:54 PM
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Originally Posted by genejockey View Post
Hence, gears.
Not sure he understands what soft pedaling means.
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