jyl

Just curious.

At what percent grade does it become faster to run up versus to cycle up? Assume a smooth paved road and a medium distance, like a mile EDIT: or as little as a few hundred meters, and equally fit/fast competitors.

I ask this after watching spectators running alongside bike racers on some of the Giro's steeper climbs. Of course those are random spectators vs the best cyclists in the world, but then again the spectators haven't previously ridden 100 miles.

FBinNY 

This, and not the grade is the key. It's not as much the last 100 miles as the last 1,000 yards of grade and the 1,000 yards to go. Lower gearing might give riders more torque and make some extra speed possible in the short term, but there's a big difference between running 50 yards up the side of a mountain, and climbing to the top.

BTW- cycle tourists often see something similar, they'll be climbing a long grade in farm country, and 4 kids on 20" bikes will whip out from someplace and fly past them then turn off.

It's Classic tortoise vs. hare.

Zinger

I personally think it's probably most likely going to be some of those very steep climbs in Europe, that aren't even very auto friendly, and slows the cyclist down to their speed.

02Giant 

When you have a flat...

Little Darwin

There would seem to be some point where running is faster, since I understand that cyclocross racers run up the steepest climbs on their races... Even if it means the hill is too steep to ride at all.

Also, from personal experience, for me, a consistent relatively steep grade will be faster to walk than ride, because I can't ride them at all.

jyl

Just to be clearer about what I'm asking - suppose you have a runner and a cyclist of high and equal fitness at their sport, and a mile-long climb of X percent grade. Paved (not a muddy cyclocross track).

At 0% grade: figure a fast (high level racer) runner can run 15 mph for a mile (that is a 4 minute mile). Obviously a fast (also a high level racer) cyclist can go far faster.

At 5% grade: according to the "Daniels Running Formula" (see How hills will impact your race times : Runners Connect ) each +1 percent grade slows a runner by 12-15 seconds per mile, so in theory on a 5% grade our four minute miler becomes a 5.125 minute miler, or 11.7 mph. A fast cyclist can go up a 5% grade faster than 12 mph. According to a standard calculator, 400 watt power will propel a racing cyclist up a 5% grade at 16-17 mph (see Kruezotter calculator at Bicycle Speed (Velocity) And Power Calculator )

At 10% grade: still using the formula above, our fast runner is now a 6.25 minute miler or 9.6 mph - if the Daniels formula still works at this sort of grade, which I doubt - I suspect the runner's speed slows more rapidly (non-linear) as the grade increases. A fast cyclist can go up a 10% grade at about 10 mph - per Kruezotter calculator, 400 w at 10% grade -> 10.2 mph.

At 15% grade: I really have no idea how fast our fast runner can do a mile now - I'm quite sure the Daniels formula doesn't work by now, even though it would spit out 7.4 mph. The bike calculator says the fast cyclist is now doing 400 w at 15% grade -> 7.1 mph. I'm thinking that requires granny gearing, if even a high level racer is going to ride that speed for a mile of 15%.

At 20% grade: Is the fast runner still "running"? Or are we more at jogging speed? Remember, we're talking a mile distance. For the fast cyclist, the Kruezotter calculator says 400 w at 20% grade -> 5.5 mph - I'm not sure I believe that. Maybe if you give him gearing not found on most bikes so that he can spin 90 rpm?

I'm speculating that with any sort of standard roadbike gearing, the cross-over point (where the runner goes faster than the cyclist) is somewhere around 10% grade.

I'm further speculating that if you equip the bike with ever-lower and lower gearing, there might not be a cross-over point (the runner and the cyclist's speeds converge with the cyclist always a bit faster) at least until you reach a grade so steep that the tires lose traction and/or the rider goes over backwards, while the runner can keep "running" up.

The thing is, the above is just my speculation. I don't have any real world comparisons. I know how fast I can climb 5%, 10% and 15% grades on a bike, but only short ones, and I'm not the hypothetical high level racer. I don't run at all.

So - what do you think? Anyone here both run and bike? Or have an evenly matched runner buddy who wants to race?

EDIT: Maybe we should use a shorter distance, to make real world testing easier. I don't know of any mile long 15% grades around here, and who the heck wants to hurt themselves that much. Maybe say a few hundred meters instead?

John E

Having been passed by joggers on climbs in the hills above Malibu, I definitely believe there is a grade, possibly around 10-12%, but definitely cyclist-, runner-, and possibly gearing-dependent, at which being on a bicycle slows one down.

FBinNY 

What your forgetting is that a bicyclist can use gearing to optimize torque and speed for any grade, even down to where the effort at the pedals, (both force and speed) match the conditions of running or walking.

rm -rf

The famous 38% grade on Canton Avenue, in Pittsburgh. Every fall, it's part of the "Dirty Dozen" hill climbing race.

Canton Ave. It's a great photo.


I think runners would match the rider speeds. But the riders do get a boost from the fast approach.
On the other hand, "not falling over" is a runner advantage!

FBinNY 

Curious.

Do mtn bikers fare better on that climb?

Dudelsack 

You'd have to think mountain bike gearing would be better, like 30X34 on 26" wheels. If I ever do that ride that's what I'd use.

rm -rf

It's so steep that a low mountain bike gear, like 22-34, (17.4 gear inches) would be all about balancing at a very slow pace. Like this guy on 33% Fargo Street (youtube at 6:00 mark), with his 8.6 gear inch custom hill climbing bike. He's spinning the cranks, but the less than walking speed pace requires excellent balance.

The Dirty Dozen race attracts road bike riders, even though their gears are mostly way too high for all the climbing.

An entertaining local TV documentary on the Dirty Dozen. (My back is sore just watching it!)
At the 19:50 mark, the hill winner just muscles up in a fairly high gear. I don't think a runner could keep up.

FBinNY 

That's why I asked.

Lower gearing would address the running out of torque and stalling problem, but gearing too low, combined with inability to maintain cadence would bring the speed so low that balance is an issue.

For my part, I can balance a bike at speeds as low as 1-2mph, but I suspect I might run out of gas before the top.

jyl

Maybe the cross over point (where running is faster than cycling) with "unlimited gearing" lies somewhere south of 33% . . . If we're now talking about cycling up at "less than walking speed".

350htrr

JMO But I suspect 12%+ is where the break even point is... That's assuming both parties are fresh out of the block at the beginning of the hill... Now I have been up some 2+ mile 14% hills where I suspect people could have walked passed me at some parts of the hill, but on average, I would probably get up the hill faster than anyone (average person) running... Again JMO...

big john

I've been on steep trails with my mtb and it seems to be above 15%, maybe close to 20% when the strong runners pass me. I don't remember a similar experience on the road but one time climbing Balcom Canyon before the ToC came through a strong friend (on foot) pushed me for what seems like 20 seconds or more at a speed I could not acheive without the help.

jyl

There is a climbing ride like that in Portland every winter. The Ronde de PDX or Ronde de Portland. The steepest climbs are 23% and 20%. Those climbs are a good deal longer than the Fargo climb shown above, but less steep. The total ride is 47 miles and 8000 feet climbing. I've never done it - I'm just never in good enough shape in April or that's my excuse (and I have others as backup). People mostly do it on roadbikes, that's just who it attracts. A friend did it, using 34 x 28, and said it was tough but doable.

big john

I have been to the Fargo street event and 25 years ago people would climb it on road bikes and touring bikes. Now people actually build funny bikes just for the event, like gearing waay lower than you would ever see on a mountain bike. Even saw some guys go up on a stand-up type of scooter.
Fastest guy the last time was a well trained junior racer on his road bike, he just went straight up like it was no big deal.

gregf83 

The answer is largely a function of traction. Provided the cyclist has decent traction he will generally be faster than a runner of the same weight and power because a bicycle is more efficient.

When the road surface becomes loose, i.e. gravel or sand, then it depends on the type of tires and bike used. A 130 lb rider using a 30 lb bike with soft, fat, knobby tires would have trouble against a runner due to the lower power/weight ratio.

Cyclocross riders carry their bike when traction is poor and the ground is soft.

Gnosis

Rm–rf, thanks for providing that enticing video!

Though it’s surely a brutal ride, it sure looks fun to try! I wish I was located closer, as I’d love to give it my best via my road bike geared down a bit further (perhaps 24/32 hence 20.25 gear inches or even 24/34 hence 19.0588 gear inches). As steep and long as some of those hills are, I honestly can’t imagine being able to climb every one of them to the top though, with fresh legs, I could likely conquer several of them. It would be gratifying to be able to climb the absolute steepest of those hills even if it was the only hill being attacked.

I give every one of those bicyclists credit for their valiant efforts on those 13 ascents of utter misery!

fietsbob

on a fairly short out and back around a Pylon , as seen on the Nat Geo TV show 'None of the Above'
https://channel.nationalgeographic.co...-of-the-above/

A runner crossed the line first of the 4 contestants,
because of the inertia that the other 3 had to overcome just to accelerate from a stop, and .. regain momentum
after the turn around .


Then again, commonly, Slippery, steep sections in Cyclocross Race courses

are often faster to shoulder the bike and run up them .. every Lap..

Rudebob

I enjoy trail running as much as I do cycling. Some of the trails I run are shared with MTB's. I usually pass most MTB's, except the elite cyclists, on the steeper ascents. Of course they will quickly get me back on the flats or downhill, but it sure is fun to see the expressions on some of the noob's faces when they are passed by someone on foot (or maybe that is just the pain of the grade on their face). I am not sure what the grade threshold is where the runner gets the advantage but it is probably the only scenario where running is more efficient than rolling inertia powered by the same human body. While trail surface, switchbacks, etc. all play into the runners advantage, IMO the weight of the bike becomes the biggest disadvantage on ascents as the cyclist is now carrying more of this weight on an incline. Gearing can only go so low before you are essentially going nowhere. I have often thought to myself while passing a MTB on some pretty steep grades that I was sure glad that I was not carrying an extra 20+ pounds at that moment. Runners don't have gears and may slow down on grades, but they just work different muscle groups (calves and ankles) and usually can usually move at some kind of respectable pace. MTB's can only keeps their legs going at a sewing machine pace for so long (barely going anywhere in those low gears) until a hike-a-bike is their ultimate future.

'bob

wphamilton

This is an interesting question, partly because there's no real answer here yet. At what grade - let's say paved surface - would it be faster on foot, and why?

It's related to the other question, why can we go so much faster on a bike? If you could pin down all of the reasons why, put a formula and numbers to them, then you could figure out the grade. I did a brief search on the internet and this is the other interesting thing about it: almost all of the answers (guesses) are completely wrong! (Mostly it has to do with bouncing up and down. Although leg muscles are partially elastic only a fraction of our running energy propels us forward).

Maybe it's as simple as comparing metabolic power expended. I am familiar with formulas related to cycling and we could write it as a function of grade and speed for a given weight. But I don't have a clue about the same thing with running. It seems to me that running uphill, at least the vertical bounce is more useful - it moves you uphill. Does anyone know of such a formula?

crazyb

How long did it take you to get to the hill in the first place?