73 MPH, now that's FAST

[keno]

"On one particularly treacherous descent during Stage 7, one rider for the Saxo Bank team was clocked at nearly 73 m.p.h. Stage 8’s finish also came shortly after a steep, fast descent."

From an article in today's NYT on yesterday's work stoppage. http://www.nytimes.com/2009/05/18/sports/cycling/18cycling.html?ref=sports

keno

[Onno]

I'm going to take this with a grain of salt, since the reporter also says that a pace of 20 mph is "about half the usual speed." Perhaps she doesn't know the difference between mph and kph?

[tylercheung]

that's probably it.


OTOH, my iphone clocked me at 60 mph as I was lackadaisically pedalling up the cape cod rail trail last weekend...it's probably equipment error but heck, i'll take what i can get :banana:

[toaster]

Usually a confusion between kilometers and miles per hour. 73 kph is about 45 mph.

[BumbleBeeDave]

I think a 73mph speed would take a heck of a long rollout on a heck of a steep descent. I imagine there's also a point at which wind drag would simply not let him go any faster, but I don't know how to calculate it.

BBD

[toaster]

According to this article, 70 kph is terminal velocity for a cyclist:

http://www.sportsci.org/jour/9804/dps.html

Sheldon Brown's gear calculator shows 120 rpm in the 53/11 is about 45 mph (72 kph) and nobody pedals that fast downhill for very long.

I once pedaled downhill as fast as I could on a fairly steep descent and got 56 mph.

So, is 73 mph possible with 53/11 gearing on a standard road bike?

NO.

[Tom]

And I mean a hell of a tailwind.

The other weekend I was rolling the top part of a favorite downhill, the part that isn't the steep part where I usually can get about 35 if I drill it and I was floating above 40... I knew the steep part was going to be some serious fun.

The best part was the driver's expression when I came around the corner going somewhere around 48-49. Since the speed limit's 35, it definitely was a case of "Where's a cop when you need one?"

[goonster]

So, is 73 mph possible with 53/11 gearing on a standard road bike?

Gearing has nothing to do with it. At those speeds, pedaling slows you down.

The terminal velocity will vary from rider to rider, and I doubt that it can be calculated to any significant accuracy even for a specific rider. Even a loose, flapping jersey will make a big difference.

73 mph does not sound right. I keep hearing that 60 mph is about the max, and footage from Tour descents seem inline with this, where the motos can barely keep up and the speedo is not quite up to 100 kph (62 mph). For the really high speeds you need steep grades and long, straight roads. The latter don't really exist in the Alps.

[Ken R]

Tailwinds usually aren't very effective when going downhill. You're in the wind shadow of the hill on which you're descending.

I've seen 60mph on a steep downhill in the Texas Hill Country. (15% grade, road straight as an arrow going towards Medina or on the back side going away from Medina) I don't think 70mph is possible.

[dookie]

So, is 73 mph possible with 53/11 gearing on a standard road bike?

off a cliff?

[goonster]

Tailwinds usually aren't very effective when going downhill.
That's right. The main problem there is that at high speeds, airflow becomes turbulent.

[RPS]

I've seen 60mph on a steep downhill in the Texas Hill Country. (15% grade, road straight as an arrow going towards Medina or on the back side going away from Medina) I don't think 70mph is possible.Much the same for just west of there on the same road (FM 337) going east – descending down to Vanderpool store at corner of FM 337 and Ranch Road 187. Nice slope and distance but no 70 MPH on a single. Heavy couples on tandems should come close though.

[Climb01742]

Heavy couples on tandems should come close though.

but then a heavy couple on a tandem going 70mph would create their own set of problems, no? as in, look out below! :beer:

[RPS]

That's right. The main problem there is that at high speeds, airflow becomes turbulent.I'm not following what you mean. Turbulent versus what, laminar? :confused:

Or are you suggesting different amount of turbulence which affects speed?

[fiamme red]

"On one particularly treacherous descent..."Such an incredible speed would be highly unlikely on a treacherous descent (i.e., one with turns). If it were possible, it would have to happen on a very steep straightaway road.

As Jobst Brandt would say, "I've read this sort of hyperbole for years and am not impressed." ;)

It's true that even faster speeds are possible, if we're talking about ski slopes, not roads: http://www.adventureblog.org/entry/markus-stoeckl-sets-a-new-downhill-biking-record/

[bironi]

Glad Keno brought this up. I saw the over 70mph reference the other day, and it made me scratch my head also. I've hit 58 sucking a tandem wheel, and a larger buddy says he hit 62, but 70 and beyond seems hard to believe.

[goonster]

Or are you suggesting different amount of turbulence which affects speed?
I'm suggesting that more turbulence will add drag.

[RPS]

but then a heavy couple on a tandem going 70mph would create their own set of problems, no? as in, look out below! :beer:I some times ride with a couple in the Texas Hill Country that descend so fast that I can’t even hold on to their wheel. When I get to the top of a climb first and start down ahead of them I get passed by what seems like a margin of 15 to 20 MPH. I’m doing 45 to 50 MPH and they blow by me like I’m standing still. They do 60s on a regular basis.

[zap]

"On one particularly treacherous descent during Stage 7, one rider for the Saxo Bank team was clocked at nearly 73 m.p.h. Stage 8’s finish also came shortly after a steep, fast descent."

From an article in today's NYT on yesterday's work stoppage. http://www.nytimes.com/2009/05/18/sports/cycling/18cycling.html?ref=sports

keno

keno keno keno..........nyt? ;)


:D


:banana:


:beer:

[Climb01742]

keno keno keno..........nyt? ;)


:D


:banana:


:beer:

it's his yearly dose of reality. :D

[zap]

WSJ had some great articles about cycling and the giro last week.

The bit about tumbling and learning how to fall was a good reminder.

[Geoff]

I believe S Kelly said on Euro Sport that he maxed out at about 120 kph (~73mph). Personally I have maxed out at just under 60 mph (Hogpen, GA decent) and could have gone faster if I had more nerve.

G

[C5 Snowboarder]

FYI- record speed on a skateboard is 63 mph and record speed on a snowboard is a wopping 125 mph.. so I have to believe a bike could go within that range.

interesting reads

http://www.canosoarus.com/08LSRbicycle/LSR%20Bike01.htm

http://www.exploratorium.edu/cycling/timeline.html

[Kevan]

Pasta fazool!

I mean...Fasta fazool!

[Nathanrtaylor]

I came up with these figures using the terminal velocity calculator on http://analyticcycling.com

Assumptions - 90 kg rider and bike weight, calcs run at 1500 meters above sea level

2% slope = terminal velocity of ~32 mph
4% slope = terminal velocity of ~41 mph
6% slope = terminal velocity of ~49 mph
8% slope = terminal velocity of ~54 mph
10% slope = terminal velocity of ~60 mph

According to this, you would need to bomb down a slope of close to 18% for at least 100 seconds in order to reach 73 mph.

So 73 mph is absolutely possible, I just know I would white-knuckle-brake my way down the road needed to do it.

[djg]

According to this article, 70 kph is terminal velocity for a cyclist:

http://www.sportsci.org/jour/9804/dps.html

Sheldon Brown's gear calculator shows 120 rpm in the 53/11 is about 45 mph (72 kph) and nobody pedals that fast downhill for very long.

I once pedaled downhill as fast as I could on a fairly steep descent and got 56 mph.

So, is 73 mph possible with 53/11 gearing on a standard road bike?

NO.

70 kph seems ridiculously slow for terminal velocity -- I have no idea how to get my bike to go 73 mph and I'm not sure I want to find out, but I reckon we've all gone faster than 42 mph down hill. FWIW (maybe not much), the top end I've noticed on a computer for myself is the same as yours.

[Kingfisher]

I live in a valley in Central Pa...there is a hill midway up our valley that I DON't climb unless I have to...1 mile straight up, no stair steps, not sure about the grade, but local racers say it is the steepest they've climbed. I hit 59 mph VERY quickly (I weighed approx 210 lbs) 2 years ago and could have gone much faster had I not valued my life...so 73 is not out of the range of possibility.

BTW, my CSI was stable as a rock at that speed.

[tylercheung]

you could maybe do the crazy speed skiiing thing, where you find a big steep hill with nothing on it for miles, dress yourself and the bike up like darth vader, and let er rip? don't those ski nuts hit 120mph?

[BumbleBeeDave]

If it were possible, it would have to happen on a very steep straightaway road.

You might be able to do 73mph, but it would have to be a dead straight road--or else you may just end up dead.

I've done 54 and change before, so I know my own terminal velocity is at least that fast . . . :eek:

BBD

[tuscanyswe]

you could maybe do the crazy speed skiiing thing, where you find a big steep hill with nothing on it for miles, dress yourself and the bike up like darth vader, and let er rip? don't those ski nuts hit 120mph?

http://www.youtube.com/watch?v=4do2PfFmD6g&feature=related

[C5 Snowboarder]

this is good

http://www.youtube.com/watch?v=5V2FgwN_re4&feature=related

[mike p]

I've hit 63 down a very steep hill in upstate NY confirmed by cop and radar gun. My own avocet computer read 62.

Mike

[dogdriver]

My record is 67mph. A tailwind that day decreased terminal velocity issues-- normally mid 50's is max on this stretch. Don't know the grade, but the center mile (the steep part) of the 2 mile road is a b@tch with a 34/26...the big boys probably climb it in the big ring...

Slow but heavy, Chris

[rustychisel]

My record is 67mph. A tailwind that day decreased terminal velocity issues-- normally mid 50's is max on this stretch. Don't know the grade, but the center mile (the steep part) of the 2 mile road is a b@tch with a 34/26...the big boys probably climb it in the big ring...

Slow but heavy, Chris

oh hello.

Alright, I wasn't there, but pleeeez.

Two things: anything above 78kmh is pretty difficult - but not an impossibility - due to aerodynamic drag and that's just the way it is.

and, if this thread goes on long enough, as is the way with all such threads on the internet, someone will claim 85, no wait 90, no wait, I topped 100 as the law of increased improbability kicks in.

[keno]

climb and Zap, the section of the NYT with the article was on the floor of a stall in a public restroom I was using. I had nothing else to read. I used rubber gloves, of course, not for sanitary reasons but because it is the NYT after all.

keno

[Lincoln]

oh hello.

Alright, I wasn't there, but pleeeez.

Two things: anything above 78kmh is pretty difficult - but not an impossibility - due to aerodynamic drag and that's just the way it is.

and, if this thread goes on long enough, as is the way with all such threads on the internet, someone will claim 85, no wait 90, no wait, I topped 100 as the law of increased improbability kicks in.

Sorry, you're the one who get's the "puh-leeez."

78 KPH is nothing. Unless I'm riding in the flats I break it most every ride. Now I do enjoy my descents, plan my routes to maximize the downhill fun and like to look for ways to go fast but it's not that hard. I did cobble together an 11-25 cassette to get a little higher gearing and still be able to get up the hill. Even with that I stop pedaling in the low to mid 40's (MPH), the fast stuff is after you stop pedaling and gravity is competing against drag.

Next, you don't know Chris but I do.
He is as straight a shooter as you will find. Take him at his word.
Unless you are an aeronautical engineer he knows more about aerodynamics than you do. Trust me.

I don't know which hill he did that on but my first guess would be Ontario Canyon (aka "the mine road"). When I lived there, I did about 60 on that road without trying. Got curious so I grabbed my disc rear, deep dish front and speed suit and got into the mid 60's (don't remember the exact speed, it was over a decade ago). Pretty sure it was over 65.

Low 50s is easy if you have any decent hills, 60 not too hard with a good hill without turns, 70s would be tough but I could envision it. Not saying the guys in the Giro did it but as they say on Mythbusters: "Plausible."

Cheers :beer:

[dogdriver]

FWIW, same road, similar tailwind. Straight, steep stretch of road with a visible runout. Anyone reading this could do it...

Remember, its airspeed, not speed over the ground that is the major determinant in terminal velocity. F'rinstance-- think of a grade on which you could roll 40mph in still air. Add a 20mph tailwind, and you're going 60mph down the road with the same speed through the air mass, assuming your hubs don't explode...

But I digress, Chris

PS-- Lincoln would have gone 72.

[Lincoln]

Oh, that's totally fake. I can tell you photoshopped it :).

Actually It would have taken you longer than a week to figure out how to do that :beer: (3.2% for you).

[rustychisel]

okay, I withdraw the objection in the face of good photographic evidence.

[frenk]

Savoldelli said he once reached 115 km/h in the Dolomites.
I am just an average non-pro rider, I'm a fairly good descender and spend a lot of riding time going up and down mountains, the max I've reached is ~98 km/h.
So I can easily believe that a good descender in the pro peloton could reach those speeds.
However even if pros routinely hit 100km/h down the alps, 115 is a bit of an extreme (Savoldelli is one of the best descenders ever), more than 115-120 becomes difficult to believe IMO.

The hardest part is finding the right conditions: a long straight section steep enough, no cars, preferably tailwind.

[Flat Out]

climb and Zap, the section of the NYT with the article was on the floor of a stall in a public restroom I was using. I had nothing else to read. I used rubber gloves, of course, not for sanitary reasons but because it is the NYT after all.

If it was the Post you would have needed a hazmat suit.

[Your_Friend!]

Friends!

Watch_This!

http://www.youtube.com/watch?v=4do2PfFmD6g


Love,
Your_Friend!

[BumbleBeeDave]

. . . he's BACK! :banana: :banana: :banana:

BBD

[Louis]

. . . he's BACK!


He? Do you know something you're not sharing?

[BumbleBeeDave]

He? Do you know something you're not sharing?

I'd never even considered that possibility!

Hey . . . Do you know something YOU'RE not sharing? ;)

BBD