I was looking on this forum :rolleyes: http://forums.bicycling.com/thread.jspa?threadID=155426&tstart=0 and it came up that 40mph in a solo sprint is a "RARE breed," especially for amateur road racers.

Uh, are they serious? I did some sprints a couple weeks ago and I wanted to do a top speed run on flat ground for my first one just for shits and giggles. I hit 41mph, accoring to my Garmin Edge 305 - winds at that time were East with a max of 16mph, I was riding West-obviously there had to have been no headwind at the time of my sprint. I only held it for about 6 seconds before trailing back down to ~30mph.

So does that mean I should quit trying to become the next Lance :p and instead go into track racing? Racing in a circle is kinda boring to me though...

BTW, I got my road bike and seriously started riding (very limited schedule) about a month ago.

From http://www.kreuzotter.de/english/espeed.htm : for a 160 lbs person

going at 41mph with a 16mph tailwind: 505watts
going at 41mph with no wind: 1204watts

I would think you're somewhere in between...:)

That's what livin' on nitro will do to a G.

Yeah, dude, 41 mph is extremely fast on flat ground. Like Robbie/Tom/AleJet/Thor fast. With a tailwind more feasible, with a tailwind downhill, somewhat likely.

It'd be interesting to see the power numbers from that effort.

Are you frequently winning county line sprints on the club rides?

yeah, I don't have the numbers on me, but REALLY going 40mph on totally flat ground with no wind help at all is very, very hard. If you can do it, you'll win nearly every amateur race you enter.

To make sure it's not calibration, subtle lack of road flatness, etc, the best way would be, as you said, a track. Even if you're not into the track racing scene, a couple of flying 200's would quickly tell you your real speed.

There's no way mine would be 40mph.

41 mph is VERY fast for any ameteur sprinter. The thread is correct.

Remember that EASTERLY winds blow WEST. I could probably hit 41mph w/ a 16mph tail wind.

41mph with no wind: 1204watts

Either that's low, or I've got a headwind that follows me around. In a flat (i.e. crit) sprint, even with a phenomenal leadout, I've never seen more than 38 at 1300+ W. The difference between 38 and 41 is huge.

That's what livin' on nitro will do to a G.

Yeah, dude, 41 mph is extremely fast on flat ground. Like Robbie/Tom/AleJet/Thor fast. With a tailwind more feasible, with a tailwind downhill, somewhat likely.

It'd be interesting to see the power numbers from that effort.

Are you frequently winning county line sprints on the club rides?
I've never done a club ride. At one point on my last ride I tacked onto the end of a pelo of ~15-17 riders who all looked like they were fast (lean/muscular). There was a sprint uphill (4 or 5% grade, can't remember) just for kicks (allez allez allez!) and I don't remember seeing anyone next to me after about 10 seconds - then I proceeded to die from the effort i exerted so i took it slow for a long while.

I don't know anyone with a power meter, but I wouldn't mind meeting up with someone so I could try it. All I remember from this group of sprints i did was one time around 30mph a gust of wind blew from the front/side and it felt like a brick wall-and i was pulling up on the bars/pushing down on the pedals hard enough to get my front wheel up and have it slide over - scared me half to death.

I used to be a weight lifter and at my peak (i didnt know what protein powder or anything was) I was 145lbs and squatting 315lbs-i can still rep 225, so I know my power/force:weight ratio could probably pull it off. My theighs are unfortunately big :(

please don't take this the wrong way:

....im 120-125lbs and i can max squat 350. I rep 250. My legs aren't that, big either.i used to alpine ski race, and thats where im getting that info from (pre-season weight training)

there is no way i could do 40mph in a sprint. I could hit 40 going downhill drafting behind a few people with a tailwind. The fastest ive ever sprinted was like 30-32 for a few brief seconds, and i don't even think thats accurate.

Either that's low, or I've got a headwind that follows me around. In a flat (i.e. crit) sprint, even with a phenomenal leadout, I've never seen more than 38 at 1300+ W. The difference between 38 and 41 is huge.

Don't forget that a sprint is a constant acceleration. If you could constantly hold 1300watts until you reach max speed, your top speed would be higher.

Woah -- how tall are you?

I'm used to being one of the light guys on my team, but I'm carrying 6 kilos more than you!

argentius im assuming that was directed at me?

im around 5'8. not quite 5'9 but well over 5'7.

fastest for me is 38 with no wind, at 205lbs, man i wish i could get some more weight off

I've gotten 38.5 ONCE on a flat smoothly paved road while doing sprint workouts.I can get over 35 pretty consistently.

However,41 is FAST.:eek:

Err doesn't the Garmin Edge 305 use GPS to measure speed? Something tells me that doesn't yield the most accurate results in the world...

It's more accurate than just a wheel senor is. On top of that, it has a wheel sensor to record speed as a second measure.

It registers position and time and records the velocity - i would trust it more than any wheel sensor.

Speaking of which, I just lost my cadence magnet, anyone know if I can rig a regular powerful magnet to my crankarm instead of buying another garmin-specific one? Any recommendations?

I remember from watching older Giro/ TDF videos in the sprints, The Lion King (Mario Cipollini) himself reaches about 38--40 MPH which analiates everyone else in the competition.

when you hit 41?

Unless my math is off, were you in the neighborhood of 53-11 or 53-12?

http://www.hostelshoppe.com/tech_gearcalc.php

It's more accurate than just a wheel senor is. On top of that, it has a wheel sensor to record speed as a second measure.

It registers position and time and records the velocity - i would trust it more than any wheel sensor.



Why? How is that relevent? It must always be receiving conflicting information. Even my Polar and FlighDeck provide slightly different speed data due to their sampling rates. GPS simply is not accurate enough to measure speed to the level of 6 seconds duration. It is fine for measuring overall avg. speed, but take a look at the positioning error. Being off by a few hundred feet can have a huge overall impact on speed during very short time intervals.

when you hit 41?

Unless my math is off, were you in the neighborhood of 53-11 or 53-12?

http://www.hostelshoppe.com/tech_gearcalc.php

The gearing is irrelevant without the knowing the max attainable rpm in the gear. I can usually reach 35-38 mph on the velodrome with only a 48x16 gear. Later in the season I use only a slightly taller gear to go faster still.

Why? How is that relevent? It must always be receiving conflicting information. Even my Polar and FlighDeck provide slightly different speed data due to their sampling rates. GPS simply is not accurate enough to measure speed to the level of 6 seconds duration. It is fine for measuring overall avg. speed, but take a look at the positioning error. Being off by a few hundred feet can have a huge overall impact on speed during very short time intervals.

I had great reception on about 9 or 10, maybe more different satellites - it was accurate to +- 14-16ft that day - easily able to measure 41mph for 6 seconds accurately.

Gearing was at 50/11--stock gearing on a Felt F75. My max cadence was at 132rpm. That should give a theoretical top speed of 49mph, right? Factor in wind resistance and I guess 41 isn't far out of the equation?

Any ideas about replacing my now lost cadence magnet?

The gearing is irrelevant without the knowing the max attainable rpm in the gear. I can usually reach 35-38 mph on the velodrome with only a 48x16 gear. Later in the season I use only a slightly taller gear to go faster still.

To reach 40+ most riders who can go that fast are in the 53-11 or so range. That's why I provided the link in my prior post. To reach 40+ with about 110 rpm, the rider would have to be in the 53-11 range.

It won't give you an accurate measurement for a 6 second sprint. Forget about comparing top speeds on the internet, that's what racing is for.

A strong magnet and some electrical tape will do. You could file a slot in the magnet and lock it down with a zipp tie.

Any ideas about replacing my now lost cadence magnet?

Radio Shack has all kinds of magnets. I lost my magnet sensor for my trucks aftermarket cruise control. Went to Radio Shack and zipped tied that sucker on the drive shaft and it works fine!

I had great reception on about 9 or 10, maybe more different satellites - it was accurate to +- 14-16ft that day - easily able to measure 41mph for 6 seconds accurately.

Gearing was at 50/11--stock gearing on a Felt F75. My max cadence was at 132rpm. That should give a theoretical top speed of 49mph, right? Factor in wind resistance and I guess 41 isn't far out of the equation?

Any ideas about replacing my now lost cadence magnet?

Basic physics tells you that wind resistence has nothing to do with the relationship between cadence and gear inches... so if your math is correct (which I won't bother checking), you were actually hitting 49mph!

someone is channelling the ghost of Aarontoy here (http://archive.roadbikereview.com/04/0EFD45F5.php) and it is creeping me out!

Philippe

Basic physics tells you that wind resistence has nothing to do with the relationship between cadence and gear inches... so if your math is correct (which I won't bother checking), you were actually hitting 49mph!

You're right, I see your idea. That's weird.

...I regraphed it and zoomed in, this time with cadence vs speed - my cadence of 132 was a few seconds BEFORE my max speed (before I shifted), my cadence at max speed was actually 121. I think that's what, 43mph? I doubt I could ever hit that, the exponential for power to get there is too high...

Thanks for the magnet ideas guys.

I enjoy sprinting, and I can hit 38 on the flat in solo drills. I can't do 41, but I will race you for money!

www.bikereg.com (http://www.bikereg.com)

One thing that struck me in your original post is the fact that you stated that you've only been training seriously for a month. That tells me this could be 1 of 3 things. 1) You're the second coming of Mario Cipollini 2) You need to check your calibration 3) You're trolling and full of s$!t. My money is on #2 or #3. My fastest ever sprint after a leadout of 3 beasts of racers with a tailwind in a crit was 39.8 mph and I'm considered an above average sprinter. But trust me, the difference between 39.8 and 41 mph is huge and I haven't even sniffed 40 mph since then. So if you can truly hit 41 solo with no leadout....you need to contact someone at usa cycling pronto and they will have you on the next flight to Boulder.

Notice that the up spike in speed is followed a few seconds later by a severe down spike. That's a clear GPS anomaly: the GPS sensor first read you as mistakenly further down the road than you were (making the first up-spike in speed), then corrected itself a few seconds later (making the down-spike).

If the speeds were real, you'd have to have:
- started in on a normal sprint, plateuing at about 35mph like your other sprints
- suddenly gotten a huge burst of power, pushing you to 41mph
- immediately braked, bringing your speed down again to around 33mph
- coasted for a few seconds
- braked HARD, bringing your speed down to only 17
- done a second mondo-sprint, accelerating to 30mph in only a second or two

You said the sensor claimed accuracy to +-16 feet. 5 seconds at 41mph is 300 feet. Subtract 16 from each end gives 268 feet, which works out to 36.6mph, a far more reasonable speed. I'd say you're a fair sprinter for having only ridden a month, but you're far from world-class.

someone is channelling the ghost of Aarontoy here (http://archive.roadbikereview.com/04/0EFD45F5.php) and it is creeping me out!

Philippe

.....zoom zoom

GPS is not a good tool to measure instantaneous speed. Like the other guy pointed out, the +/- 15 ft makes a huge difference when the speed is measured at small time increments, like 6 seconds. GPS is used more for averaging your speed over your trip and plotting your route. Even the claimed error, +/- xx feet, has a margin of error.

...in top shape last summer I hit 38.2 mph in a flat sprint with a tail wind and two guys to draft off (almost ran straight into the back of the second guy). i barely hit 32 last week in the same situation...
41 for any amateur is strong...might be possible...but not on a regular basis...

I've hit 39.8 mph on my cx bike on flats with no wind before. It was fun seeing the look on peoples faces as a bike passed them.

Notice that the up spike in speed is followed a few seconds later by a severe down spike. That's a clear GPS anomaly: the GPS sensor first read you as mistakenly further down the road than you were (making the first up-spike in speed), then corrected itself a few seconds later (making the down-spike).

If the speeds were real, you'd have to have:
- started in on a normal sprint, plateuing at about 35mph like your other sprints
- suddenly gotten a huge burst of power, pushing you to 41mph
- immediately braked, bringing your speed down again to around 33mph
- coasted for a few seconds
- braked HARD, bringing your speed down to only 17
- done a second mondo-sprint, accelerating to 30mph in only a second or two

You said the sensor claimed accuracy to +-16 feet. 5 seconds at 41mph is 300 feet. Subtract 16 from each end gives 268 feet, which works out to 36.6mph, a far more reasonable speed. I'd say you're a fair sprinter for having only ridden a month, but you're far from world-class.

I like this explaination best.Those of you that have gone this fast,you know that as soon as you stop pedaling you will coast at 35+ for a LONG ways.Even if you sit up your speed will not decrease quickly.

It's more accurate than just a wheel senor is. On top of that, it has a wheel sensor to record speed as a second measure.

It registers position and time and records the velocity - i would trust it more than any wheel sensor.

Speaking of which, I just lost my cadence magnet, anyone know if I can rig a regular powerful magnet to my crankarm instead of buying another garmin-specific one? Any recommendations?
GPS is better than a wheel sensor for average speed, but instantaneous speed can be seriously screwed up by all sorts of things, ranging from atmospheric disturbances to multipath interference to local radiofrequency noise sources.

When I go for long rides with a Garmin Foretrex 201 GPS and a Polar (wheelsensor) computer, the two agree on total distance and average speed within a few tenths of a percent, but the Garmin typically tells me that my maximum instantaneous speed was 10-20 miles per hour faster than the Polar. I know my real speed and I will tell you that I'm never hitting the speeds the Garmin says (60 mph going downhill, 45 on level ground). One time I was using the GPS in my car and it told me that I had a maximum speed of over 100 mph on residential streets in a 17 year old station wagon :)

When I look at the detailed GPS record, I see discrete glitches where it seems that the GPS position jumped instantaneously.

I haven't used the Edge, but I'd guess that because Garmin has very smart engineers, the wheel sensor is there to correct the instantaneous speed from these known glitches.

About cadence sensors, any decent magnet would work. Just stick it on the crank arm with epoxy and/or a zip-tie.

The street I was doing my trials on ended into a busy street, so I braked decently hard after every run.


wavylines-
I was wondering when someone would give an arguement like that ;) I knew that I couldn't have hit 41 - and the reason I didn't give a full screen shot of my training program with the charted exact values of my training is because my actual speed, calculated with numbers and not just a potential graph, showed that I hit a max speed of 37.4mph. I knew the graph was wrong and I was just wondering when someone would pick it up and do the calculations.

37.4 isn't too bad though, right??

To reach 40+ most riders who can go that fast are in the 53-11 or so range. That's why I provided the link in my prior post. To reach 40+ with about 110 rpm, the rider would have to be in the 53-11 range.
That's not right. That's not even wrong (apologies to Wolfgang Pauli). Any competent track rider can hit 40 mph in an 88" gear. My max RPM on a bike on the road or velodrome is 200 RPM and 110 RPM is just a warmup spinning exercise...

argentius im assuming that was directed at me?

im around 5'8. not quite 5'9 but well over 5'7.
that's scary, man.
145, 5'8.
wow.
and you can see my ribs.
are you emaciated? or really narrow?
what's your inseam/waist/chest?
wow i sound like a stalker, it's just that I calculated that I'd be dangerously underweight if I personally was to drop below 139.

That's not right. That's not even wrong (apologies to Wolfgang Pauli). Any competent track rider can hit 40 mph in an 88" gear. My max RPM on a bike on the road or velodrome is 200 RPM and 110 RPM is just a warmup spinning exercise...


I don't know squat about track.I have been told and have read that the key is high cadence.I just can't imagine hitting 200rpm on my roadbike.Is it "easier" to do in a fixed gear bike?(by easier I mean assisted by it being fixed)

I don't know squat about track.I have been told and have read that the key is high cadence.I just can't imagine hitting 200rpm on my roadbike.Is it "easier" to do in a fixed gear bike?(by easier I mean assisted by it being fixed)
It's slightly easier on the track bike due to the typically shorter crank length, which is conducive to spinning - but it is a matter of physiology; fast twitch folks excel at sprinting but tend to suck at climbing. Life is full of compromises. As I mentioned earlier, gearing is irrelevent to speed unless you know what RPM you can hit at the specified gearing...

It'd be interesting to see the power numbers from that effort.

Are you frequently winning county line sprints on the club rides?

And in the interest of contradicting my own skepticism, I actually hit 40.9 today on a slightly downhill sprint with a bit of a tailwind on a mere 1000 watts. I was in my 53-12 and did not feel overgeared.

But... this was on a club ride with a big fat leadout (though I'm not sure whether the leader-outers knew that's what they were doing).

Here ya go:
http://www.indigo.com/magnets/neodymium-magnets.html

GPS is better than a wheel sensor for average speed, but instantaneous speed can be seriously screwed up by all sorts of things, ranging from atmospheric disturbances to multipath interference to local radiofrequency noise sources.

I agree that GPS can be better than a wheel sensor for measuring the straight line distance between two distant point - but bikes don't travel in a straight line. Bikes frequently take very winding paths. To measure the distance (and therefore speed) on a winding path, you have to take many closely spaced measurements and add them up. If a measurement device can have large instantaneous errors, while some of those errors will tend to average yout, you still can't expect to be able to get a very accurate cumulative measurement. This is even more true with speed measurements - speed is change of position with respect to time, so instantaneous errors tend to create spikes in measured speed, and therefore a higher estimation of average speed.

So yeah, I'd trust GPS more to measure the straight line distance between points - but I'd trust the wheel sensor more for distance traveled and average speed.

Its hard to compare our best tested sprint speed with the world class boys. Be fair to them, they raced 100 miles before they uncorked a 40 mph sprint...

I really don't trust these top speed ratings at all, and they really don't mean much because of varying conditiions. If you really want to compare maximum speeds, the only real legitimate measurements are 200m and kilo times on a track, and even these vary from track to track. On the road, the only real average speed times should be on a measured 20 or 40k out and back course on relatively flat ground.

As I mentioned earlier, gearing is irrelevent to speed unless you know what RPM you can hit at the specified gearing...

By your logic, someone can hit 40mph at 22x34 (the typical granny gear on a mtb drivetrain) IF they spin fast enough.

I would love to see that. Hell - I'd pay money to see that.

The lucky few who can hit that 40 or faster on a road bike are usually in the 53 (or as the poster - a 50) ring.

My original question (asking the poster what gear he was in) was to determine the gear/cadence it takes to hit that speed.

Your blanket statements about the gear being irrelevant implies to spin at 200 rpms or faster and the magic 40 will be ours.

The reality is, at some point, most road riders (not track riders) will need to increase the gear size. When was the last time you saw someone win the green jersey by sprinting in his 39 ring...?

The street I was doing my trials on ended into a busy street, so I braked decently hard after every run.


wavylines-
I was wondering when someone would give an arguement like that ;) I knew that I couldn't have hit 41 - and the reason I didn't give a full screen shot of my training program with the charted exact values of my training is because my actual speed, calculated with numbers and not just a potential graph, showed that I hit a max speed of 37.4mph. I knew the graph was wrong and I was just wondering when someone would pick it up and do the calculations.

37.4 isn't too bad though, right??

That is excellent. Start racing now! Good luck.

fastest I've done on the flats without much wind is about 36.5 or so. It is flat everywhere where I live unless I venture out a good 45 miles from my apartment, so I always train on the flats. Last week I was riding in a 30+ mph headwind. I wanted to quit so many times, but pushed myself. Going 12mph on the flats is just depressing. Then again, when I turned around I kept up 30+ mph for a good 7 miles with the tail wind I had. That was pretty sweet.

Ha, ha, ha! I know what you mean, but I myself am also a stick- 5'8" and about 123 soaking wet. I can climb like a goat (as you might imagine), but get smoked solo on most straights. I felt a little better when I read that Michael Rasmussen is about 5'9" and 125 (race weight). But then I've seen pictures of him w/o a shirt and he does look like he came from a concentration camp (no disrespect).

I'm a clyde and I can only recall hitting 33 or so on a solo "sprint." I use the term "sprint" loosely as i've never raced and have to plans to. I did that just messing around trying to beat a car to a stoplight.

fastest I've done on the flats without much wind is about 36.5 or so. It is flat everywhere where I live unless I venture out a good 45 miles from my apartment, so I always train on the flats. Last week I was riding in a 30+ mph headwind. I wanted to quit so many times, but pushed myself. Going 12mph on the flats is just depressing. Then again, when I turned around I kept up 30+ mph for a good 7 miles with the tail wind I had. That was pretty sweet.
Oh yeah, I know what you mean, I went out for a ride the other day and did 12, 13mph into the wind, and my knees were screaming. Turn around, start pedaling and go to adjust my helmet, look down at the cyclocomp, ohmygod 24mph no hands adjusting my helmet and eating a powerbar.
Though it's no fun having gear restrictions when that tailwind hits you, you're toast... I counted my cadence for a minute at one point, and was doing 120. Try 120 for 40 minutes, it's killer... Got home, toast.
But hey, the winds actually make pretty good virtual hills - those 25mph gusts are right up there with a 6, 8% grade, it seems.
-estone2

On todays ride I hit 44 in the flats, riding solo.


























feet per second.

On todays ride I hit 44 in the flats, riding solo.
...feet per second.

On my commute into work this morning, my average speed was 43 kfpf.


(kfpf = kilo-furlongs per fortnight)

On my commute into work this morning, my average speed was 43 kfpf.


(kfpf = kilo-furlongs per fortnight)


ahaha, embarassed to say (as a professional scientist) that I actually had to look this one up

http://en.wikipedia.org/wiki/Fortnight

It's time to measure by attoparsec per microfortnight (~1 inch per second). Curtosey of the Wikipedia link above.

To measure the distance (and therefore speed) on a winding path, you have to take many closely spaced measurements and add them up. ... So yeah, I'd trust GPS more to measure the straight line distance between points - but I'd trust the wheel sensor more for distance traveled and average speed.
If you take each point GPS measurement literally and in isolation, you can come up with serious deviations from the actual distance, but the engineers who design GPS units are pretty smart and manage to come up with good filtering algorithms to manage glitches.

What I've found from a couple of years of riding with a cheap portable GPS is that the GPS and the wheel sensor agree within less than one percent on cumulative distance over 100 miles of real-world winding roads up and down hills etc.

The only place I"ve consistently seen problems with the GPS displaying nonsense numbers is in instantaneous and maximum speed measurements.