road tire + good-sized rock = projectile?
#1
Thread Starter
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From: anywhere between DC and charlottesville VA
road tire + good-sized rock = projectile?
sometimes when my tires happen to roll over an average sized rock, the rock will fly off in who knows what direction and i'll hear it hit the pavement some distance away. wondered if there were any good (bad? depending on how humorous you find other people's misfortune) stories of this happening to people when a car, pedestrian, or something otherwise susceptible to breakage got in the way of these missile rocks. or if it only happens to me.
#2
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so --- You're talking about an atb-sized tire (26") ? I have the 700C size, in which I have run over tiny-size rocks: and those rocks with bounce, very hard, off those tires -- at 120 psi. I've heard some of them actually (quote Me on it) bounce onto cars. In which the driver/owner got puzzled/wondering what had hit it. Having no idea that it was from My bike.
#3
Double Naught Spy


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From: Pittsburgh, PA
Bikes: 2010 Scott CR1 Comp, 2013 Scott Scale 960 MTB
Quite a few times when riding rail-trails i've accidently sent stones into the same friends spokes. I just tell him his wheels are rock magnets. He usually answers with a verbal expletive, or hand-sign. If he uses the hand-sign, I remind him that it's not a proper way to signal a turn.
#4
Bike Dork

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From: Philadelphia, Pa
Bikes: Independent Fabrication steel delux(my baby), Raleigh Highlife (Single Speed Cyclocross), Surly CrossCheck (commuter.work bike when I was a courier), 1957 Schwinn Panther, Bilenky, Surly Karate Monkey Single Speed 29er, Specialized Stumpjumpper 29er,
I have hit many cars and peds as a courier. At the PSI I run my tires at and the speed I go, I can not even imagine what that must feel like!
#5
"I love lamp"

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From: Dirty Jersey
Bikes: 06 Fuji Track with upgrades, 06 Redline Flight Monocog, 01 Trek XO1, 2003 Cervelo P3, 2006 Bianchi San Jose monstercross
If only one could harness this rock propelling ability and use it at will.
#8
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From: Arizona, USA
Bikes: Mercier Corvus (commuter), Fila Taos (MTB), Trek 660(Got frame for free and put my LeMans Centurian components on it)
And I think to myself as the rock goes ping, if you really don't like rocks hitting your beautiful SUV, why don't you lobby the city to get the debris out of the shoulders and bike lanes.
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Sunrise saturday,
I was biking the backroads,
lost in the moment.
Sunrise saturday,
I was biking the backroads,
lost in the moment.
#9
Announcer

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From: Detroit's North Side.
Bikes: More than I need, really.
One day, a friend and I actually tried to make it happen. We spent several minutes hitting rocks and pebbles at different angles and different speeds. Couldn't do it. Not once.
Oh, but if I could.....
Oh, but if I could.....
#11
Gitchur SUV Away From Me
Joined: Aug 2004
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From: Carmichael, California
Originally Posted by Paul L.
And I think to myself as the rock goes ping, if you really don't like rocks hitting your beautiful SUV, why don't you lobby the city to get the debris out of the shoulders and bike lanes. 

#14
18 dog baby
Joined: Jul 2004
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From: Honolulu
Bikes: 2008 crosscheck complete, 1984 Pugeot fixed conversion
Originally Posted by Mageever
I've done this several times on my road bike. Each time it happens I seem to tag a car that is too close for comfort. Ohhhhh it feels good.
#15
senile member
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From: Taiwan
Bikes: 1 mtb converted for commuting (actually, collecting dust in the garage), a LHT with "durable components"
Originally Posted by sbeatonNJ
If only one could harness this rock propelling ability and use it at will.
#17
Senior Member

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From: Arizona, USA
Bikes: Mercier Corvus (commuter), Fila Taos (MTB), Trek 660(Got frame for free and put my LeMans Centurian components on it)
Originally Posted by JamesV
In my post I said it was a "doink" while you called it a "ping." You're right, Paul. It's closer to a PING than a DOINK.
Windshield = thwack
Steel Bumper = ping
plastic bumper = thud
Fiberglass/plastic body panel = doink
Steel body panel = ping
Convertable driver's side of head = ouch! $#@%^!&
Convertable drivers eye = SSSSCCCCREEEEEEECCCCHHHH HONK SCreeeech HONK BAMMMMM!
Motorcyclist = Silence (they are used to it. If you have ever driven behind a dump truck on the freeway on a motorcycle you know exactly what I mean)
__________________
Sunrise saturday,
I was biking the backroads,
lost in the moment.
Sunrise saturday,
I was biking the backroads,
lost in the moment.
#19
2-Cyl, 1/2 HP @ 90 RPM

Joined: Oct 2003
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From: NYC
Bikes: 04' Specialized Hardrock Sport, 03' Giant OCR2 (SOLD!), 04' Litespeed Firenze, 04' Giant OCR Touring, 07' Specialized Langster Comp
I end up launching a bunch every time I go to work. The best one was this one that went into someone's rear passenger window. I had one fly about 30 ft into someone's garage door.
Sometimes I can time it right and launch it if I hit it with about 1/3rd of the side of my tire.
Sometimes I can time it right and launch it if I hit it with about 1/3rd of the side of my tire.
#22
Originally Posted by sbeatonNJ
If only one could harness this rock propelling ability and use it at will.
As you roll by with the pine cone on your right side, time a quick left hand turn/snap of the bars with a little upward pull, right as the pine cone is towards the back of your front wheel. As the back half of your front wheel kicks outwards on the right side, and if you timed it correctly, your tire will bat the pine cone at a decent velocity somewhere off to your right.
A (still) friend and I practised this for a while a few years ago on a long ride in the Cuyamacas above San Diego. Very cone strewn trail. It was big fun bouncing cones off of each other at speed, until....you guessed it...one went into friend's front spokes and wedged into his front fork (sugarpine cones are about the size of a small pineapple) and he went for a little trip, not quite over the bars, but definately onto the ground. Broke two spokes, too.
Same technique can be used for small rocks. I tested it.
Ed
#23
Senior Member

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From: Middle of da Mitten
Bikes: Trek 7500, RANS V-Rex, Optima Baron, Velokraft NoCom, M-5 Carbon Highracer, Bacchetta Quattro, Catrike Speed
I've got ABS spoke covers that I use sometimes. So, I was riding along minding my own business when -BANG!- it sounded like my wheel had just exploded. I looked around to see where the shards were going, and my buddy sheepishly sez, "sorry 'bout that!" Whew, it was only a rock, making my wheel sound like a 26" drum. No damage to the spoke cover. Good thing, because I had all of about $2.00 tied up in that thing!
#24
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I seem to constantly be shooting rocks on the rural roads in my area.
A number of years ago one the cars tried to get even, I saw a 2 1/2" diameter rock heading for me at a relatively slow pace. Caught it at about waste level with a back handed catch and enjoyed the rest of my ride.
A number of years ago one the cars tried to get even, I saw a 2 1/2" diameter rock heading for me at a relatively slow pace. Caught it at about waste level with a back handed catch and enjoyed the rest of my ride.
#25
Descends Like Avalanche
Joined: Nov 2004
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From: Somewhere between Funkytown and Margaritaville, PA
Bikes: Lynskey R240, Sportive, and a Helix Sport disc model in the works; Eddy Merckx MX Leader; Specialized Rock Hopper Comp (1988!)
Originally Posted by Fatn40
It happended to me once but not on a bike...I was rolling pool balls across a busy street when one came right back at me like it was shot out of a cannon. That was enough to make me stop being such an idiot.
Makes you wonder about karma, doesn't it?On a slight tangent, since the original thread posting mentioned laughing at other's misfortune... I am reminded of a story that I heard in college. The man who instructed the bicycling phys ed course said that one of his students hit a bloated road kill on the side of the road. It had been simmering in the spring-time sun and popped like a hot water balloon. I can only imagine how bad of a day that poor student had. Ever since then, I have been worried whenever I see a road kill ahead in the middle of the road, and I hear a car coming up from behind. Karma can be a witch with a capital B sometimes.
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