General Cycling Discussion - 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.

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.

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.

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!

If only one could harness this rock propelling ability and use it at will.

Sometimes I'll run over a pebble and then hear a loud DOINK! as it smacks into the side of a passing SUV. I just smile when that happens, like "Hey, good one!"

Every time that happens, it's like popping a good pimple...

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. :)

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.....

Last fall I spent a few days nursing a sore hand that was caused by an acorn shot up at high speed into my thumb. Road riding (through a wooded area) with 700c tires at ca. 7-8 bar inflation....

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. :)

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.

Every time that happens, it's like popping a good pimple...

or saddle sore

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.

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.

What feels really good is hitting a cop car. Especially a cop SUV. It's double the fun smugness: "Don't frigging drive so close, and you idiots need to fix the roads. Don't blame me."

If only one could harness this rock propelling ability and use it at will. then one has no fear at no dogs, saves weight and money!

This happens to me sometimes. Dont know if ive hit any cars yet. I run 700C x 28 at 100psi.

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.

It depends on the part of the car the rock strikes.

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)

This is quite the entertaining thread, thanks for sharing your genius.

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.

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.

7-ball...front pocket.

Game over.

If only one could harness this rock propelling ability and use it at will.

Pine cones.

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

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!

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.

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.

Thanks for giving me the best laugh I've had all day; that's quite an image... :beer: 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.