JungleCat

Three dudes blew by me in the park yesterday so I figured why not try drafting. I caught the wheel of the third guy. It was mostly flat and we moved somewhere in the 17-20mph range. I experimented by moving in and out of where the slipstream should be but did not notice a difference even though I was right on the guy's wheel. It got me to thinking, either we're not moving fast enough to make a difference or this drafting stuff is bs. Or maybe you don't feel the difference but it's there?

Really makes me wonder how, at the relatively slow speeds of a pro tour climb, any rider really needs a teammate pulling for him.

skinnyone

>12MPH seems to be a popular number...

MrCjolsen

I actually think drafting doesn't come into play until about 20+ mph. For example, when I'm going up a hill, and can only go 12 mph, it doesn't make a difference whether I have my hands on the drops or the hoods. But at 20 mph on flat ground, it makes a huge difference.

Wind resistance becomes a bigger factor at higher speeds.

Hipcycler

Higher the speed the more it helps.

Now, as for your pros being led up a mountain point, I think that's more about pace than drafting. There may be a little drafting factor there, but that's more about cadence, and clearing the path ahead to keep you safe on the climb and at a speed that's not too fast, not too slow.

peripatetic

But can you feel the benefit of drafting? Or only with a large group?

Hipcycler

I believe you can feel the benefit with only two riders! I've experienced it. What you feel is the fact that you aren't working as hard as you thought you would have to be while achieving a higher speed. In other words, you're drafting....you look down at your computer and think, "wow, I'm going 20 mph and it's not that hard..hmmmm"
That's feeling drafting.

And more people in the group, the more you feel.

mwilding

Drafting enables one to travel at a given speed for a longer period of time due to the reduced effort per stroke. An increase in speed increases the benefit. At 12-15 mph, many people can pedal indefinitely as it is, so the benefit is hard to perceive. Few people can sustain 25mph in the flats for too long and when you get into a paceline it suddenly becomes possibile to cruise long distances at that speed.

One way to "test" this is to pedal at a given speed behind another rider but out of his slip stream. Drop in behind him and coast and see how fast you drop back. The tide next to your partner and start coasting. You will notice that you drop back faster this time. At faster speeds, this is much more noticable.

For me, I start to "feel" a benefit at around 17mph even though the benefit exists at lower speeds.

CPcyclist

you may have had a tail wind which would mask the draft a bit. If you sit on the wheel then pull out of line you will feel the wind hit. Like Hip said you look down and go wow I'm doing 20+ and don't feel a thing.

cycleprincess

This is something I've been wondering about a lot. I have never been able to draft simply because I can't keep up!! How exactly do you draft? Do you have to be directly behind the person, slightly off to the side, right on the wheel (spitting distance) or can you be a little further behind? I'd like to learn before HHH just in case I can catch a paceline, doubtful but useful knowledge nonetheless.

popeye

What amazes me is how far back the draft extends when
your going fast 30-40+MPH.

mellonhead

Wind tunnel tests have shown that the benefit of drafting occurs at all speeds... you just do not notice the effect at lower speeds.

If you ride in single file, you will experience about a 20% reduction in wind resistance, depending on the size and position of the rider in front. This stays the same regardless if there are 8, or only 2 of you. Because the drafting benefit is a percentage, the faster you go the more perceived difference there will be between drafting and being up front.

Now, if you place three riders up front riding in a triangle formation (2 behind 1), and then you ride behind them, you will experiance up to a 40% reduction in wind resistance. This explains how a 'peleton' can ride at 45kph for hours at a time (though I wouldn't like to be the guy out front!).

mellonhead

If you have never ridden a 'paceline' before, here are a couple tips:

- You need to be close. Ideally, no more than 12 inches behind the wheel ahead.
- Never draft someone without telling them.
- Dont draft on roads where you frequently have to hit the brakes suddenly.
- If your group is just trying it out, increase the space between bikes.
- Most important. The leader must ride smoothly! No swerving, no sudden braking without calling out first. Arrange a common word, or gesture, to signal your braking.

Dinstee

Usually the closer you are to the wheel of the rider in front of you the less wind resistance you will feel. But often the wind will be a factor in that if you have a crosswind then the drafting "tunnel" is going to be offset. (off to the side and rear of the rider in front of you)

I know drafting perhaps too well. Just ask my group ride mates. Early on in my riding my goal was to keep the group in sight. As I got stronger and more efficient my goal changed to stay in the draft. As I progress further my goal is to now pull whenever I can without holding people up.

CycleFreakLS

While drafting becomes more apparent at higher speeds, the effect can still be noticeable at lower speeds. Sometimes we're on a stretch where "normal" pace would be 20-21 mph. If the wind off the Pacific is hard enough, we can lose 25% or more (we're down sub 15 mph). Now, the speed is way off, but the effort we are using is the same as if we were doing 20. So, even at that speed, you can feel the draft effect immediately as soon as you get to do your turn up front ...

jreeder

There are two main forces working against forward motion of your bike. One of them is friction (between your wheels and the ground, between crank and BB, between chain and sprockets, etc), the other is wind resistance. Friction is more or less directly proportional to your velocity, while wind resistance is proportional to the square of your velocity. Meaning that if you double your speed, you double the friction working against you, but you quadruple wind resistance.

So at low speeds, say 12 mph, half your energy is going towards overcoming friction and half is going towards overcoming wind resistance. If you decrease wind resistance by 20% by drafting, you've only reduced the total forces against you by 10%. The benefits of drafting are there, but its harder to feel since wind isn't the prevailing force acting against you.

However, at 20 mph, more like 80% of your energy is going towards overcoming wind resistance. If you suddenly introduce a draft the difference will certainly be noticeable since wind is the majority of what you're up against at that speed.

go4broke44

if you move off to the side of the person in front of you, you will notice the benefits of the draft, especially on a cold day. its the difference between feeling the wind, and not, you can actually kinda hear it, but how much air is rushing past your face, if you concentrate on that.

Mirage-t

Last week I was doing my normal solo loop and pulling a high 19 mph ave when a group of 8 passed me in a pace line. The last rider hollared at me to hop on so I grabbed a gear and jumped on his tail. I told him I've never done pace line and he said just stay at the back and watch how it works. Most of them were in team jerseys and such and they worked smoothly together without a single word. It was a windy day and after 23 miles my average had gone up from 19.8 mph to 24.2 and I was hardly working. It was the first time I had drafted and there was a huge difference in wind resistance. I was working much harder at 19-20 mph solo than I was with the pace line at 25-27 mph.

JungleCat

That's awesome. I guess I just have to believe it works. Since I jumped onto these guys wheels without asking, I didn't stay too long. It was a blast riding in a line though.

Keith99

Jreeder got it all. I'd just add his numbers are assuming a well maintained street bike. A poorly maintained bike, a beach cruiser or a Mtn bike means more friction. Also the air drag depends on air speed not ground speed. So if you are going 15MPH and there is a 5 MPH headwind the air drag is 4 times as much as if there is a 5 MPH tailwind.

alison_in_oh

Long before I really got a feel for what it was like to be "in the draft", I was taking advantage of it -- we'd be travelling at 19+ uphill with me near the back going, "this isn't so hard!" and coasting, while the very strong riders at the front were pedaling hard, LOL! But then one day I was drifting back and struggling against the wind and my friend dropped back for me, looked at me and I knew I was supposed to "catch his wheel". Thinking this was hopeless, I accelerated and got closer to him, and voilá! It was suddenly easier to turn my pedals!

With a bit more experience I've learned to recognize the change in the sound of the wind and the feeling of decreased airflow across my forearms that indicate that I'm in the "sweet spot". The place to be varies according to the direction of the wind. I find I can only really feel a difference at >15 mph assuming the wind is low to moderate.

timmhaan

i notice i'm in a slip stream first by the reduced wind noise. a little less with one rider, but if you're in the middle of a pack you'll notice it's a lot quiter than being out there by yourself.

531Aussie

This is my little secret that I'm prepared to share with you guys because it's very unlikely I'll be racing any of you at the local drag strips.:

Wind direction and wind speed make a HUGE difference when it comes to drafting, and it still amazes me how many people just don't believe it.

The largest benefits from drafting occur when there's a very strong head wind -- probably even at speeds as low as 15mph -- and if speeds get up around 20 to 25mph, you're laughing as other guys do the work.


This is my big secret that no-one down here seems to understand :

With very strong tail winds -- and by "strong" I mean a wind that will have you comfortably sustaining 30mph on flat roads for extended periods -- the drafting is significantly reduced. Think about it: if I'm riding at the same speed as the wind (ok, not exactly the same speed), surely the slipstream is reduced. This is a good time for a solo attack against a small bunch because you're virtually going one-on-one with each member of the chasing group. This might sound dubious, but I've seen group rides break up time and time again when there's a very strong tail wind, and most of the guys don't get it; they just think "jeez, the ride was particularly hard tonight". Try it.

I'll repeat myself: time and time and time again I've seen half a dozen guys trying to chase one guy when there's a BIG tail wind, and SO often the one strong guy will get away (remember, I'm talking about speeds like 30 to 35mph). The guys in the chase group think they're working turns, but they're not really, because the 2nd, 3rd, 4th, 5th and 6th guys are almost working just as hard as the front guy. Once again: don't believe me? Try it, and you'll have some fun


Cross winds are a whole other nightmare that I don't wanna go into

EventServices

I could get a draft off a TREE if I had to... but only for a short period of time.

531Aussie

Well, if the wind is strong enough, then I agree

Smoothie104

Right on, I always attack with the tailwind when I can.