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How fast have you gone on a downhill descent

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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

How fast have you gone on a downhill descent

Old 08-13-14, 01:16 PM
  #26  
joeyduck
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Originally Posted by UnfilteredDregs View Post
For the folks referencing Strava... It's quite inaccurate regarding top speeds.
I have noticed and agree with that. I have hit speeds according to it that baffle me. I wonder why top speeds are so bad but the average always matches my computer.
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Old 08-13-14, 01:17 PM
  #27  
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Originally Posted by UnfilteredDregs View Post
For the folks referencing Strava... It's quite inaccurate regarding top speeds.
Strava does nothing but import the data from your device. There are a variety of characteristics recorded in the file that's uploaded to Strava, depending on your device and it's capabilities. So if there are inaccuracies, it's the device that causes them not Strava.

iPhones are notoriously inaccurate at both speed and elevation because they're not using a dedicated sensor to track speed. But Garmins do --at least for those who have a cadence/speed sensor, so their speed data is very accurate. Garmins are more accurate using that sensor than satellite data.
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Old 08-13-14, 01:20 PM
  #28  
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Fastest I've gone is about 80ish riding the hill as I accelerated up to terminal velocity at settle in to a nice 120MPH freefall. Oh wait...you meant on a bike on a downhill section of road! I was having a flashback to my skydiving days.
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Old 08-13-14, 01:23 PM
  #29  
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I can't vouch for it's accuracy, but straight down hill on mini aerobars. Terrible idea.

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Old 08-13-14, 01:37 PM
  #30  
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It's pretty hard to break 45. To break 50, it takes some very specific conditions (at least three of the following: triathlon bike, 6000+ ft elevation, good tailwind, long 12%+ grade, or 30+ lbs of excess fat).
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Old 08-13-14, 01:44 PM
  #31  
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Originally Posted by hamster View Post
It's pretty hard to break 45. To break 50, it takes some very specific conditions (at least three of the following: triathlon bike, 6000+ ft elevation, good tailwind, long 12%+ grade, or 30+ lbs of excess fat).
Or just strong-ish legs and enough gear inches. Certainly doesn't require ANY of the conditions you mention.
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Old 08-13-14, 01:49 PM
  #32  
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Originally Posted by UnfilteredDregs View Post
For the folks referencing Strava... It's quite inaccurate regarding top speeds.
It is. I've seen some ridiculous max speeds. I did reference my Cateye as well, which I tend to rely on more for such things.

I've seen Strava segments on particularly winding descents where some riders have higher average than max. Presumably because their racing line is more efficient than the line of whoever designed the segment in the first place.
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Old 08-13-14, 01:56 PM
  #33  
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Originally Posted by UnfilteredDregs View Post
For the folks referencing Strava... It's quite inaccurate regarding top speeds.
It can be. The top speed I referenced on Strava was not the highest top speed Strava has spit out, but the highest top speed that my Garmin agreed with Strava on.
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Old 08-13-14, 02:03 PM
  #34  
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Originally Posted by GhostSS View Post
I can't vouch for it's accuracy, but straight down hill on mini aerobars. Terrible idea.

OK, you win! BTW, 52mph as per Strava......inaccurate I guess from the info gathered from the knowledgeable folks here! Felt pretty fast to me....
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Old 08-13-14, 02:07 PM
  #35  
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Originally Posted by joeyduck View Post
I have noticed and agree with that. I have hit speeds according to it that baffle me. I wonder why top speeds are so bad but the average always matches my computer.

N.

A max speed is pulled from a single momentary data point (or rather, a quick calculation of the time taken to get between 2 location data points), whereas your average speed is calculated based on your time to travel through multiple location points. Your smartphone's gps will track your location pretty well on a 2-hour ride, and will estimate your moving time pretty closely as well. If it's out by 5-10m at any point in your ride, that's just noise that will get lost in the overall. If it's out by 5-10m at successive location points, it can make a significant difference to the instantaneous speed between those points, hence it thinking you're going 10mph faster than you actually are.
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Old 08-13-14, 02:08 PM
  #36  
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52 mph in Wisconsin. Yes, in Wisconsin. I hit 45mph and held an average speed of 40 for a Km last Saturday;



http://connect.garmin.com/activity/561876285
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Old 08-13-14, 02:11 PM
  #37  
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48.8 mph going south on route 79 in Missouri on one of the downhills
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Old 08-13-14, 02:13 PM
  #38  
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I have been over 40 mph several times but my record (as recorded by my cycling computer) was about 48 mph. This was on a long & straight descent with no side rides and no traffic.

I'll never forget the feeling, because as I was cruising at top speed I thought about the fact that this was my first ride on a new bike that was purchased from BikesDirect and assembled by me. I had very little bike mechanical experience (still don't) but fortunately everything stayed together and I survived.
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Old 08-13-14, 02:16 PM
  #39  
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41mph according to Garmin. Then I flatted. That was a tense moment.
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Old 08-13-14, 02:17 PM
  #40  
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51 mph while sitting on the top tube...I'm small so that's the only way I can break 50
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Old 08-13-14, 02:21 PM
  #41  
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Originally Posted by MattFoley View Post
Or just strong-ish legs and enough gear inches. Certainly doesn't require ANY of the conditions you mention.
In 53/11 gear at 50 mph, you have to spin at 132 rpm and spinning gives 2-3 mph at best compared to an aero tuck.

Most cases of 50+ mph are due to tailwind. Any grade that's sufficiently long and straight to hit 50 is bound to have wind in one or the other direction. You may not notice it if it's something mild like 3-5 mph, but it makes all the difference.

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Old 08-13-14, 02:32 PM
  #42  
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Since recording my rides ~5 years ago with a Garmin, myfastest legitimate (not a glitch) downhill descent was 49.5 mph. My uphill descents are all much slower.
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Old 08-13-14, 02:42 PM
  #43  
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I break 30 mph fairly regularly, 40mph rarely, and have never made 50 mph. Not a lot of long downhills around here and frankly, I get about all the adrenaline rush I need at around 35 mph. Strava has given me credit for some amazing bursts of speed 18 mph > 88 mph and back in about 200 yards one time. I don't think I could reach that riding off a cliff with a tail wind and pockets full of rocks
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Old 08-13-14, 02:43 PM
  #44  
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Iphone Strava says max is 38mph which does seem about right. There are few places that are long/straight and steep enough that I ride for me to get to that level but it seems more or less right given relative car speed. I am not fast descender in general and I need to know the road well enough to know where it is safe to let it run and where I need to be on the brakes...otherwise I'm going to be braking way early.

I want to have fun when I ride and ending up in a ditch or as a hood ornament isn't my idea of fun
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Old 08-13-14, 02:46 PM
  #45  
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Originally Posted by hamster View Post
In 53/11 gear at 50 mph, you have to spin at 132 rpm and spinning gives 2-3 mph at best compared to an aero tuck.

Most cases of 50+ mph are due to tailwind. Any grade that's sufficiently long and straight to hit 50 is bound to have wind in one or the other direction. You may not notice it if it's something mild like 3-5 mph, but it makes all the difference.
On double digit gradients with a straight-ish road, you can spin out, tuck, and keep accelerating, wind or no wind. How quickly you spin out contributes to how quickly you're going by the time you have to brake/you run out of gradient.
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Old 08-13-14, 03:14 PM
  #46  
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Originally Posted by GravelMN View Post
I break 30 mph fairly regularly, 40mph rarely, and have never made 50 mph. Not a lot of long downhills around here and frankly, I get about all the adrenaline rush I need at around 35 mph. Strava has given me credit for some amazing bursts of speed 18 mph > 88 mph and back in about 200 yards one time. I don't think I could reach that riding off a cliff with a tail wind and pockets full of rocks
But it could take you back to the future.
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Old 08-13-14, 03:20 PM
  #47  
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54mph 2 years ago / tailwind, coming off a plateau in New Mexico - scariest ride yet...
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Old 08-13-14, 03:57 PM
  #48  
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Originally Posted by hamster View Post
It's pretty hard to break 45. To break 50, it takes some very specific conditions (at least three of the following: triathlon bike, 6000+ ft elevation, good tailwind, long 12%+ grade, or 30+ lbs of excess fat).
Or the right recumbent. I don't need as much slope as the rest of you guys to bust 50 on this rig

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Old 08-13-14, 04:08 PM
  #49  
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Heading down Carson Pass in the Eastern Sierra Nevadas. 15 miles, 2700' elevation loss, averaged 32 mph and topped out at 51 mph. You didn't even need to pedal, just tuck.
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Old 08-13-14, 04:55 PM
  #50  
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42.7 mph.
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