Barrettscv 

The good news is that most roads are engineered to a 3% grade.

Climbing steeper hills is always a possibility, even in places like Ohio and Wisconsin.

However, human beings, even exceptional ones, are limited in power output. Most cyclists produce 100 to 150 watts while cycling.

Let’s look at a hypothetical cyclist who weights 175 pounds, rides a 28 pound touring bike, and carries 22 pounds of gear and can produce 200 watts of continuous power. These calculations ignore the aerodynamic drag of panniers.

How fast can this cyclist travel while producing 200 watts?

Flat & windless = 20 mph
3% climb & windless = 10.5 mph
6% climb & windless = 6.5 mph
9% climb & windless = 4.5 mph
12% climb & windless = 3.5 mph
15% climb & windless = 2.75 mph

Thulsadoom

Hey, as long as he/she gets over the mountain. Then they get to coast down the other side while singing "Clap for the wolfman".

mtnbud

I once bottomed out at 0.5mph (according to my bicycle computer) while climbing a 6% grade and hitting a killer headwind on a hairpin curve. Luckily, the turn continued around enough to get me out of the direct force of it's blast.

Thanks for the calculations Barrettscv. I feel better about my slow speed when climbing loaded. I might even be over that theoretical ave speed on many of my climbs.

Booger1

I must be on a 3% climb at all times....

Erick L

Barrettscv 

That would provide about 40 mph ;-)

fietsbob

Made it up a steep hill on the south side if Loch Ness, it was a get off and push hill ,
so that is what I did.

Did not calculate more than feeling my heart-rate top out,
hold the brake , wait, push some more, was on a multi month cyclo-camping trip.

operators of concession trailer at the top, gave me a nice Cuppa.
and a tenting spot that night.
nice View from up there.

Tourist in MSN

You got me beat, the steepest I have seen a sign is 14 percent. Part way up this hill, I decided that I did not see any cars so I created some of my own switchbacks back and forth using the full width of the road to get a breather for a short segment.



I calculated 3.0 mph at 15 percent and assumed no aerodynamic drag and no friction, all effort went into elevation gain. (I had already set up a spreadsheet to estimate how long it will take to climb a specific hill that has hour restrictions this summer when I cross the continental divide, thus I only had to plug in the numbers.) Where did you get a formula for aerodynamic drag?

Barrettscv 

There isn't much aero drag at these speeds, anyway.

raybo

How does this one factor in?

Doug64

Barrettscv,

Good job crunching the numbers. How hard would it be to run it with 150 watt output? It would give some of us another point of reference. I think that is more my output, because I'm about .5 to 1 m ph slower on the easier climbs.

The steepest sustained climb that I've knowingly rode up is 12%. Much steeper than that and my "watt meter" blows a fuse.

Not knowing what 200 watts meant to me as a cyclist, I found this article while looking for information. While still finding it hard to figure out my output, I can relate it to the ability I had when I was a Cat 4 rider, and what I hope is a "fit guy" today. Also this is the peak power for 2 hours. Some of the longer climbs on a tour could be quite a bit longer than 2 hours. From our home to the first major pass into the Cascade Mountains is 35 miles, climbing about 4000 feet. A portion of the distance averages 6%. It takes us about 4 hours to cover that distance on loaded bikes.

sstorkel

Sounds like they need to do some more training! I can average 170-180 watts over a 4-5 hour ride and that average includes time spent coasting. My functional threshold power is 240-250 watts and I can easily generate another 100-150 watts just by standing to pedal...

Barrettscv 

Deciding on a practical power level is not easy. Not only does power output vary on an individual basis, the rider’s weight is also a key factor. Climbing ability comes down to power to weight ratio. Secondly, the duration of the power output needs to match the duration of the climb.

My personal numbers, based on supervised Computrainer data after a one hour sustained 180 watt effort is as follows: 600 watts for 2 minutes and 225 watts for 20 minutes. I can also average 200 watts for one hour after a 15 minute warm-up. The issue for me is that at 200 pounds, I'm never going to be a great climber.

Here is the data for a 150 watt power output (rounded to the nearest 0.5 mph);

Flat & windless = 17 mph
3% climb & windless = 8.5 mph
6% climb & windless = 5.0 mph
9% climb & windless = 3.5 mph
12% climb & windless = 2.5 mph
15% climb & windless = 2.0 mph

pdlamb

If you leave the flat heartlands, you'll find many mountainous roads are now being engineered with a target grade of 6% or less. Older roads, from the Appalchians and Ozarks to the Sierras (the ones that developed from a game trail, to an Indian path, to a frontier road, to a paved road), often exceed that, often by a wide margin.

I usually found it easier to walk when the grade exceeded 15%. Don't know how slow I was going, as my speedometer decided I'd stopped.

DogBoy

I have hit 20% grade a/t my garmin, but only with a small bag. Gearing was 26/32 and I was going 3.5 mph. I also weigh in at 230 and have a 30 lb bike.

contango 

Just out of curiosity, a while back I was on a section of road that I measured as being somewhere between 18-23% incline (it was a tiny little back road so didn't have a handy sign to tell me). I made it to the top although my speed dropped to somewhere between 4-5mph through the steepest parts.

I weigh about 240, riding a bike that I guess is about 25 (specialized tricross sport). Just out of curiosity, what sort of power output would that equate to? I know we're talking a climb that was pretty short, I'm just curious.

jeffpoulin

I live in the Alps, and there is a pass nearby which is 18km long and averages over 8% (i.e. elevation gain is about 1500m or 5000 ft over 11 miles). On this climb, there are several sections which average 11% over 1 km. That's about as much as I can do on a loaded touring bike in my lowest gear. There are lots of 20% or steeper climbs around here, but as most are under 1km long, I can do them without getting completely exhausted. The long climbs can be grueling, though.

Dan The Man

Assuming that you can balance at 0 mph (track stand), then the only limit would be the slipping angle of the rubber/pavement interface which is about 100% grade or 45 degrees. Actually at that angle, the limiting factor would be your centre of gravity tipping the bicycle over backwards.

fietsbob

Run/Rise, like stairs,
You can make your own switch-backs, using the whole road width,
more run for the same rise.

jeffpoulin

Doesn't work so well if there are cars on the road.

Barrettscv 

513 watts @ 20% & 4.5 mph

contango 

500+ watts? Wow, I didn't know I could put that kind of power down. If only I could sustain it

Bekologist

Yep, you ride it or you push. There's hills out there.

The pretty roads are often steeper. Has anyone else noticed that?

contango 

I've always found the declines look prettiest to me.

Barrettscv 

not many can sustain 500 for more than a dozen minutes.