Commuting - Drafting Buses, Trucks, etc during commute?

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brokenankle
10-05-06, 03:15 PM
I was hoping to get you guy's input on drafting vehicles. Occasionally on my commute, I put in a short stretch behind a bus or truck, assuming its going slow enough and there is little to zero traffic behind me. Do others do this? I can see the reasons why its a bad idea, such as: getting run over, inhaling diesel particulates, overriding your field of vision and hitting rotten roadkill with nails in it, etc, etc. But is sure is fun, and makes me feel fast (which I am not when solely under my own power). I am alone?


hockeyteeth
10-05-06, 03:21 PM
I usually grab onto cars instead. That way I am on the side of the vehicle and more prepared in case they stop short. If you are riding faster while drafting than you can on your own I'm assuming that is about 30+ mph? If so, I'd have to say that's a bad idea, haha.

I'm not one to criticize, though. I grab onto cars every once in a while.

moxfyre
10-05-06, 03:23 PM
I don't do it. I have molasses-slow reflexes and I don't want to breathe any more fumes than I have to :) I can see how it could be fun, but not for me...


Flimflam
10-05-06, 03:30 PM
I don't really have the chance to draft on my commute, if I did, I wouldn't bother really - I can keep up with the pace of traffic (apart from acceleration) for the most part around town during rush hour.

I'm a little iffy with the whole idea of drafting a big vehicle like a bus/truck anyway...

saraflux
10-05-06, 03:44 PM
I usually grab onto cars instead. That way I am on the side of the vehicle and more prepared in case they stop short. If you are riding faster while drafting than you can on your own I'm assuming that is about 30+ mph? If so, I'd have to say that's a bad idea, haha.

I'm not one to criticize, though. I grab onto cars every once in a while.


really? you actually grab onto cars?
wow. is that how you lost the teeth?

ivegotabike
10-05-06, 03:46 PM
id have to say that drafting is safer than gabbing the side of the car, skitching is REALY dangerous.
think of it this way: if you draft and skitch off of the same car, when your drafting you have both hands on the bars, and if the driver makes any suden moves your not comited to making the same move as the car, skitching you have one hand and it they dont see you and decide to change lanes it could push you over side ways and you might end up under their back wheel. also when drafting you have a warning of braking called "brake lights"


DONT GRAB CARS

Seggybop
10-05-06, 03:53 PM
I draft city buses whenever possible. They run on natural gas so the exhaust is primarily warm air. Nice when it's cold out. Conveniently, they have pretty crappy acceleration.

SDRider
10-05-06, 03:58 PM
I don't do this. Most of the roads I commute on are 40+ mph roads so getting up to and keeping up with a vehicle moving that fast isn't really an option. Besides, my commute is pretty hilly. I can stay with traffic on some of the slight downhill grades but I'm usually passing cars through there when traffic is backed up.

Sounds really dangerous to me.

same time
10-05-06, 04:00 PM
Problem is, you have very little warning for potholes and cracks in the pavement.

I don't do it, because I don't trust drivers who I don't know. And, because the cars around here don't go fast enough.

khuon
10-05-06, 04:03 PM
I will admit to having drafted busses and other vehicles (during my more stupid past) but I also consider it a dangerous practice and would not advise it. You do however get quite a few precious looks from people... especially those in other vehicles that you pass while going 40+ MPH.

And of course if you ever see that rare Cinzano truck go by, be sure to drop into the small ring and grab that slipstream for the 60MPH run. ;)

ranger5oh
10-05-06, 04:04 PM
I try to do this when possible... I love it.. its basically like riding in a vaccuum

noisebeam
10-05-06, 04:38 PM
There is a difference between drafting and getting a draft. ;)

Sure I get helped from larger acceralating vehicles, but the distance is always safe and increases from 6ft. to 50ft to infinity (dude) as the vehicle accelerates up to 45mph. One can get a headwind blocked and even some 'pull' from busses and trucks from quite far back, even 50ft.

I also get benefit when I move to the right to let faster vehicle pass, just them passing creates a pull, a signficant one from busses and trucks.

But I'll never ride 'drafting close' to a vehicle over 5mph.

All modern properly maintained motorized vehicles of any size or load can stop faster than a bike from the same starting speed

Al

Scorer75
10-05-06, 05:33 PM
I've done this but it's damn scary when you pull out as he crosses 30 mph. You have no idea what you are pulling into, kinda scary.

I prefer to hang alongside the back end of the bus, it's nice and warm there!!!

Seggybop
10-05-06, 05:35 PM
All modern properly maintained motorized vehicles of any size or load can stop faster than a bike from the same starting speed

Al
Where do you get that from? It's not like I've sat at the corner staring at buses waiting for one to make an emergency stop, but during normal operation their deceleration is quite bad.

rykoala
10-05-06, 05:40 PM
I drafted a backhoe doing 25mph for a couple of miles once. That was fun! He saw me, and didn't mind.

Alrocket
10-05-06, 07:02 PM
Where do you get that from? It's not like I've sat at the corner staring at buses waiting for one to make an emergency stop, but during normal operation their deceleration is quite bad.

What he said. There is no way in Hades that a double decker bus can slow down quicker than me sitting in his draft, totally concentrating on what speed he's doing, and with my hands on the V brake levels. That's the way to draft (and I think it's the only sane way to draft).

Junkdad
10-05-06, 07:23 PM
I'll ride 10' behind a city bus for short distances, they definitely pull you along...

Bikepacker67
10-05-06, 07:40 PM
Draft?
That would mean I'd have to give up the lane first... ;-)

bmclaughlin807
10-05-06, 07:53 PM
Sometimes I'll play leapfrog with a city bus on part of my commute. Draft off when it passes, (I'll be goin' 25 mph plus behind him!) then pass him when he stops, and draft when he catches up again.

I've got about a 2 mile stretch that's nice and straight and flat. I ride it everyday, so I know there aren't any potholes, so I don't consider it particularly dangerous. I just make sure to watch my tail for stupid cagers.

RomSpaceKnight
10-05-06, 08:15 PM
Traffic in my town moves fairly fast. I don't ride near fast enough to draft buses. While I am faster cross town than a bus and catch and over take them due to their stops. Drafting don't work. They pull ahead on me and then stop.

chephy
10-05-06, 08:38 PM
All modern properly maintained motorized vehicles of any size or load can stop faster than a bike from the same starting speed Yep. Not just faster. WAY faster. So no way I'd draft any of them.


Where do you get that from? It's not like I've sat at the corner staring at buses waiting for one to make an emergency stop, but during normal operation their deceleration is quite bad. During normal operation you can probably get away with drafting them. But how do you know it's always going to be normal operation? I've been in buses that stopped very suddenly because of jaywalkers or stupid drivers (or stupid bus driver who decided to accelerate for a yellow and changed his mind in the last second!)

MrCjolsen
10-05-06, 08:55 PM
Careful about drafting behind cop cars. I almost hit one once when he made a sudden U-turn to catch a speeder going the opposite direction.

noisebeam
10-05-06, 09:57 PM
OK, I know this is a web forum and I'm gonna be called on to dig up resources. In time I can. But for now... a few points
Busses have tires, COG and braking systems allowing amazingly fast stops. One rarely sees this, but they can stop fast enough that every standing passenger will be pilled up front if it must happen. Drivers are trained/expected to make gradual stops for passenger comfort, so one rarely sees the capabilties.
Bikes have a very high COG and with all braking force going to front tire stopping is limited by endo avoidance, not friction.
Cars, truck, busses do not have this issue. Ever see a bus do an endo?, nope the wheels will skid first, well probably not as modern ones have anti-lock. Good luck beating that.
I have seen the math, seen the sources, but for now I don't have the initiative to dig it all up, so you are welcome to not believe.

In the end its still a good rule to live by, so if your gonna err, I suggest erring for now on believing the guy with no data/proof. ;)

Al

hockeyteeth
10-06-06, 02:14 AM
wow. is that how you lost the teeth?
No, that's not how I lost my teeth, haha. I lost my teeth when a driver from the opposite side of the road cut me off to make a turn.

tuolumne
10-06-06, 06:32 AM
The first time I drafted a bus it was accidental. I was just moving out behind a bus to avoid getting doored and found myself in a wonderful vacuum. I do this occasionally on a few stretches of road where cars are typically parked in the right lane when I come through in the morning. I've found I can hover just to the right of the bus about 12 feet behind and get a nice pull with decent visibility. Regarding potholes, I think I have them all memorized at this point! Also, there are almost no potholes on the line between lanes, while 3/4 of the right line is chock full of them. The exhaust goes out the top and doesn't bother me. Frankly, this feels safer than trying to ride in what is left of the right lane between potential doorings and people passing without moving over. I drafted a combine in town a few weeks ago for several miles. He was up and down between 25 and 28 mph with a massive draft. I only pedaled occasionally, even from a safe distance back. Of course, it took about a week to cough the last of the chaff out of my lungs!

recursive
10-06-06, 07:22 AM
I do it whenever possible. I caught a beatiful draft off a pickup truck earlier this week. Before I pulled off, the driver signalled '3' then '4' to indicate our speed. It matched my computer. Fun stuff.

capejohn
10-06-06, 09:00 AM
I do it almost every day out of necessity. It's the same place, around the same time. It's as I'm approaching the left turn I need to take, I merge into the middle of the land and draft whoever is there for a hundred feet or so.

Every once in a great while, I get caught standing in the middle of the road with cars passing me on the right and cars approaching me on my left. Every time that has happened so far, the car or mostly pickup trucks, yeild and let me turn left.

My only concern is the 2nd car behind me that may not see me until the first one pulls right and passes me.

capejohn
10-06-06, 09:21 AM
I usually grab onto cars instead. That way I am on the side of the vehicle and more prepared in case they stop short. If you are riding faster while drafting than you can on your own I'm assuming that is about 30+ mph? If so, I'd have to say that's a bad idea, haha.

I'm not one to criticize, though. I grab onto cars every once in a while.

You can hook your foot onto the rear wheel well. That way you can keep both hands on your bars.

marqueemoon
10-06-06, 10:33 AM
Dumbest idea ever.