On Your Right

Saturday I went for a 58 mile ride with my frequent riding buddy Mike. We probably have ridden over 2000 miles together and we know each other's abilities well. Mike is quite a bit lighter than I am (I win by 230 to 180) and he always drops me on longer hills. I make it back up on the flats and downhills in typical Clydesdale fashion. This may be the first time we have ridden in windy conditions (Thanks Ike!) though.

Anyway, the first 30 miles of our ride was northbound with a nice 15 MPH tailwind. We rode together as always with him pulling me on the hills and me playing catch-up as required. We stopped at a Hardees for a breakfast and then turned into the teeth of the wind for the return trip.

I took the lead as we started and by then the wind was up around 20 MPH and gusty. I got in the drops and set a pace that I could comfortably keep. We were in fairly heavy traffic so I did not turn to check on Mike and the wind noise was so great I couldn't hear if he was behind me or not. At the first turn (about 4 miles), I checked and Mike was over 1/2 mile back!

I stopped and waited and we began again and within 5 miles I had once again dropped him by over 1/2 mile. This happened every 4 - 5 miles on the return trip and each time he said he felt fine. I really didn't feel that I was having an exceptional ride but I killed him on the return trip.

My question is: Does wind affect smaller or lighter riders more than it does us "Big Guys"? I have never been able to run off and leave Mike like that. I just wondered what the experience of others on here was concerning this. Maybe I have found another specialty. I was already a world class downhill rider with gravity and my 230 pound butt working together. Maybe I'm a "Wind Machine" too!!!

Flatballer

Theoretically, yes. It should affect lighter riders more. They have less momentum and energy built up, so the wind becomes a larger percentage of their power output. Your body is heavier and allows you to "power" through the wind with your bulk.

This is the same reason you win on the downhill sections too, you have a higher terminal velocity due to your greater mass.

Richard_Rides

I would guess that a heavier rider carries more inertia and would not be penalized by wind gusts as much as the lighter rider, yet the heavier rider has more surface area for the wind to act on. I'm gonna say it's a draw....

draxine

my training partner and i are in a similar situation, with him being the heavier guy (at 72kg compared to my 69kg). He'll usually drop me on the flats and vice versa in the hills.
It's not simply a matter of mass though, as part of that mass is muscle. A bigger guy may simply be able to produce a greater force as well as being less prone to deceleration by wind.

mattm

but what about surface-area of the larger rider? seems like they'll have more drag produced by a headwind than a smaller cyclist.

maybe your friend bonked on the way back, and wouldn't admit it?

johnny99

Depends a lot on how aerodynamic is your riding position. If a big guy and a small guy have a similarly low riding position, the wind will usually affect the big guy less in proportion to his power output.

Pedaleur

Drag goes like frontal area, which is (in a perfect world) proportional to height squared.

Muscle power goes like body mass, which is proportional to height cubed, again all else neglected.

There are a huge number of variables (muscle vs. fat, positioning, etc.), all of which are hugely important, but from a fundamental physics point of view, a larger rider will have a higher power to drag ratio.

EDIT: "All else neglected" with respect to muscle power would mean that the proportions of all the body parts would be the same. In fact, this isn't likely true, but power probably increases at a rate greater than height squared. In fact, since lighter riders typically have higher power/weight ratios, it must be less than height cubed.

On Your Right

I have a headache after reading this********** Can you put that in Layman's terms?

waterrockets 

As height goes up, power goes up faster than drag.

NYJayhawk

I'm 6'6" and weigh 230-235lbs. When I get to the top of a hill, people line up behind me like little ducks. Same thing on the flats as I punch a fairly big hole in the air.

There are a few things at work here, but in general terms, if you take a heavier object and get it going the same speed as a lighter object, the heavier object will go further because it has more momentum. So things like wind will have a bigger impact on the lighter object (throw a baseball as hard as you can and throw a similarly sized wad of paper the same way and see which one goes further).

Without getting into the fancy math of it, even at my extreme (for a cyclist) proportions, when I get tucked into the drops with my back flat, I'm not THAT much less inefficient than smaller dudes. So my considerable advantage in momentum more than outwieghs my relatively small areodynamic disadvantage.

Pedaleur

Heh. Sorry. Just got done giving BananaTugger the run around over in the HED thread..."goes like" is a nerdy expression that we use in scaling analysis. Assuming you're seriously interested in an answer and not just laughing at my geekitude, I'll try again:

Imagine you have two people, with exactly the same proportions, though one is taller than the other. That is, the taller one is taller, wider, and thicker _by the same percentages_ than the shorter person.

Now, since wind resistance is proportional to frontal area, we need to find the area ratio between the two riders. The area of the taller person will be proportional to height squared more than the shorter person because he is both taller AND wider (remember, by the same percentages).

But muscle mass would be proportional to height cubed in this perfect comparison. Each muscle would be longer, wider, and thicker. If muscle mass is proportional to height cubed, then one could argue power is also. Unfortunately for our taller friends, the energy delivery systems (blood vessles and such), don't "scale" the same way, so power is proportional to somewhere between height squared and height cubed.

So, what we see is as the height goes up, the drag goes up by height squared, but the power goes up by something more than height squared, and so a bigger rider can go faster in the wind.

In addition, weight goes up proportional to height cubed (more or less), and since power goes up by less than height cubed, the smaller rider has the advantage in climbing.

Is this better?

Caveat: Other factors make a BIG difference, but this is the fundamental underlying reason.

BikesAreCool123

This explains (read: gives me an excuse for) why I suck going into a headwind. Thanks guys.

johnny99

One advantage that small people have is that, with no belly to get in the way, small people can usually lower their back more and tuck their arms in more, thus gaining an aerodynamic advantage over chubby people.

Bobby Lex

Correct.

Uphill, the key is power-to-weight.

Into a strong headwind, the key is power-to-frontal area. The larger rider's marginally larger frontal area is surpassed by his substantially greater power.

A teammate of mine who is 45lbs. lighter than me kicks my *** on hills, but can't hold my wheel when riding into a stiff headwind on the flats.

Bob

umd

yes

jonestr

I didnt know there were so many cubic people walking around. I guess someone has to tend to all the spherical cows.

orcanova

When I was touring on a loaded down mtb (60lbs total, bike and gear) in the rolling farmland of southern PA, I was flying at my road bike speed, going up and down hills around 25 mph. Although it took me a lot longer to get up to speed, I could maintain it well both up and down the hills. I think the heavier weight punched through the air better and maintained my momentum better. I think the added width of the panniers was not really a handicap because of the extra weight, FWIW.

RoadToNowhere

Well, I feel better. I can't win in the wind no matter how hard I work.

5'5", 120 - I'm one of the little ducks who lines up behind you big guys on the descents and into the wind Thank you.

Beth

Pedaleur

For the record, on the flats, inertia and momentum aren't what's important. For a constant speed, acceleration is zero (by definition), and so you merely have to balance the propulsion and drag forces. The larger rider has more drag, but, as noted above, the larger rider tends to have even greater increase in power output.

The "larger rider has more momentum" rationale is incorrect because the ability of a heavy rider to "carry his momentum" is offset by the fact that it takes more energy to increase his speed through pedaling.

Up and down hills changes everything, of course, because changes in potential energy are proportional to mass.

umd

Inertia is important relative to a gust of wind. It's not about momentum, it's about the wind's ability to move the rider...

Reynolds 

That would be in a "perfect" steady wind.

+1

Pedaleur

Yes. I was using steady 'wind' (even though I quoted poorly).

Anything that creates a force imbalance (a gust of wind, for example) will affect the lighter rider more. But note that the converse is also true: when the wind lets up, it's easier for the lighter rider to speed back up.

valygrl

+1

Also, do any of the other smaller folks have trouble getting blown all over the road (sideways) by gusty winds? I just can't hold a line in the wind. A couple of weeks ago I was reduced to walking my 80# tour bike DOWN hill b/c I couldn't stay on the road. My 80-ish-pound-heavier companion had no trouble.

It was one of those winds where you pedal for all you're worth, and go 5.5 miles an hour down hill. Ugh.

RoadToNowhere

Not so much "blown all over the road", but occasionally slammed a couple feet off my line. Not fun.

Beth

bigtea

Of course it does, why do you think people hunker down behind big, heavy objects when a hurricanes passes? Wind is wind. Mass is mass. All things being equal, the greater the mass, the greater the likelihood of overcoming wind resistance.

A bit of evidence...we didn't see the Schleck brothers pulling the peloton for a hundred miles...that was Jens Voight.