Bicycle drafting experiment
 

About 4 times a week, my wife and I take the same route into the next town
over and do 3 or 4 laps around a quite residential area.

There is a small hill where we get a quick 330 yard coast. Many times, we will stop at the top of the hill & take a water break before starting the coast down. I mostly let my wife get about 20-30 yards ahead before I take off.
Once I start rolling, I get up to about 15 MPH and coast down to 10 or 11 at the end of the run.
I always pass my wife. Due to my weight (205), I'm always down at the turn around point long before she gets there.
She pedals on her way down. I never do.. At the start, I've waited for her to get 50 yards ahead, I usually pass her before the the half way mark.

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On our third lap this afternoon, I asked my wife to let me go first and for her to draft on me. I asked her to stay tucked in real close behind me.
I even told her to pedal a little if she needed to close up the space a bit.

Well, when we got about 40 yards down the hill, she asked me if I was hitting the brakes! "No", I wasn't. Then I see her pull off to the side a bit. (in the mirror)..
When we got down to the end, she explained. She was going so fast, that she would have hit me. She had to pull out to the side so our wheels wouldn't hit and she had to brake so she wouldn't pass me!!

I was amazed that she actually had to brake. If I had got on the pedals a little (up to 16 or 17 MPH), I think she would have kept right up with me, Without pedaling at all..

I think this was her fastest time down that hill..
Maybe tomorrow, I'll try going 16 and see if she stays in my draft while coasting..

I knew that drafting was common in bike racing, but I never knew just how effective it was.. These results were way more than I expected.

Cheers,
Rich

In a team time trial I will usually pull the downhills because I'm the heaviest of the group. On a downhill where I would easily outpace the other guys if I was in the back I can usually carry them up to 40 mph if they stay right on my wheel in a good tuck, :)

Bicycles can be incredibly draggy. Back in my mountain biking days I would draft on fast single track.

This is why all the HPV records are held by fully-faired recumbent bikes.

I drafted a tractor on my mountain bike, went 24mph which was 7 mph faster than usual on that stretch of road. Guy thought I was nuts but he was smiling the whole time :cool:

Here's a little info on it.

Maybe because he'd just dropped the manure spreader?

I thoght this might be interesting http://www.canosoarus.com/08LSRbicycle/LSR%20Bike01.htm

The rider causes 65% to 80% of the drag. !!!

Wow! I would be thinking about getting more streamlined helmet if I wasn't riding my bike mostly for the aerobic workout I get..

Reading about hypermiling has already got me coasted way more on my bike..
Now I'm burning less calories per mile! Meaning I have to cut back on my ice cream! :( Dang!

Yesterday we went out for lunch (14 mile round trip) and now that I know
how good drafting works, I was tucking in every time my wife took point.
I wasn't upset that I had to keep using my brakes on hills,
Now that I understand more of why she always seemed to be braking..
It wasn't her braking! It was me speeding up too much.. :o

We ride up-right bikes, so we are getting a good workout. http://i46.photobucket.com/albums/f1...nger/fanny.jpg
As you can see, I need it!!

Thanks Guys!
Rich

One of my favorite scenes from Breaking Away is when Dave drafts the Cinzano truck -

http://youtube.com/watch?v=7Qzn6opcusE

Unfortunately, the video quality on this clip is pretty poor, but the scene is a lot of fun.

I have to say that riding in a paceline is a blast, but it does take a bit of practice.

Tim

I love that movie. 60 mph in the small ring is pretty impressive.:p

Yeah, I had to laugh at that little continuity / logic goof too. I think pushing 50+ mph on a bike would be hard enough in the big ring!

Tim

Great video!! Too bad about the driver getting pulled over..

Humm, maybe I need to attach a 2x3 foot piece of wind load on the back of my wife's bike..?.
You know, so she gets a better workout, while creating a massive turbulence pipe! :rolleyes:

Drafting on bikes is huge! My buddy and I in highschool used to draft cubevans or other big vehicles on a windy road near our place on our mountain bikes. We'd "ambush" them at a slow corner and then sprint to get in the wake... We could hold it to about 55km/h if they didn't accelerate too fast. Higher speeds than that, we would tire and get dropped on any slight uphill. Good fun when you are young and invincible!
We would also be dumbasses to lone roadies on the bikepath, drafting together we would pass them and then could beat most of them over a mile or 2... Not many reacted to really race but some would. Usually together we could stay ahead but I don't think we ran into any real serious riders, a sustained 30 mph sprint would've left us way back... No one got mad, it was just some impropto street racing!

bicycle drafting
 

Way fun! Hoerner gave motorcycles and sky divers a Cd 0.90,not quite as bad as a sheet of plywood but not very slick.Bicyclists may not fair much better.Good reason for recumbants and enclosed bikes.

I love drafting on bikes. It's so cool when you just get sucked into the leaders rear tire. Great way to conserve energy. :)

Wow, here it is one year later
 

and this old thread got hit.. :)

I'm still drafting with my bike. It's still fun!

I've learned that just a small head-wind can really tire you out,
Unless, you get a good woman to lead the way.. :thumbup:

Some people think that aerodynamics aren't important at low speeds.
Let them go bike riding when it's windy out.

If something can be done to cut drag, it will help. Even at 10 MPH..

draft a tandem
 

I have friends with tandems which are wicked fast on a good down hill. I like to draft the tandem, when I start to overtake them pull out ever so slightly and give a push to the back seat of the tandem, or the the small of the stoker's back. They then go faster and I can pull back into the slipstream. Our top speed to date: 63.5 mph:thumbup:

"Our top speed to date: 63.5 mph"

Good Golly Miss Molly!!! That's Mass Turnpike speed!!

You will NEVER see me going anywhere near 1/2 that fast!!

Have you filled out your organ donation card?? ;)

I've agreed to donate organs, but crashing a bike at that speed might bang them up a bit.

Way back in the day Ron Howard set a land speed record of OVER 130 mph on a
B I C Y C L E! He did it at Bonneville while drafting off of a land speed record semi if I remember correctly

Hey, Indiana, that's John Howard, who made his name among the hoosiers. He went 152 behind a race car with a special tail, after a crash at near that speed. He was the first to use compound gearing for the record. On those runs, the pedals are used to mainly regulate the speed - considerable power comes from the difference in pressure created. I still love the early description of John's road race tactics. He'd usually be in the back half of the pack at half time, and then steadily move up to first at the finish. "Everybody knew about his plans, the problem was doing something about it."

I stand corrected....Little Opie Taylor never did such a thing.

Well, if you can cut drag massively (like you can with stance on a bike), then you get really good gains. It's still proportional. ;)

Wow! I really really really hope you have full disc brakes on both of the bikes! I think those tandem drums would not last very long trying to haul down that much weight at that much speed on an incline... :eek:

John Howard @ 152
 

ESPN has done "Great American Adventures",which include the World of Speed at Bonneville.In 1990.I believe,"Fast Freddy" Markham and John teamed up in a tandem streamliner "Gold Rush" to set a LSR.In the show,they have a clip of John behind the Vesco family streamliner,with the windbrake built on to the back settingn the 152-mph LSR that Bob has mentioned.If you can track this video down,it's worth a look.