Anyone notice stones flying up off front wheel

[BlackB12]

Today the snow melted and the temps were in the 40s so I got my 05 out and rode to my dr. appt. Just out of my driveway I rode through some less than pea-sized gravel that the township put on the roads the day before. Immediately I could hear the stones hitting the under side of the front fender, but then I saw a bunch of them come flinging up as high as the instrument panel. Keep in mind this is at about 10 mph. I couldn't beleive the stones had enough energy to fly up there. I guess what's happening is the stones are sticking to the tire long enough to fly back and hit the plastic below the radiator, then bounce off that up to instruments. Later I took the seat off and I found tiny stones pinched between the seat and the front of the tank. Not good. Luckily they were not there for long and I have a Magknight tank cover to protect the paint.

Anyone have a remedy for this? Do they make longer fender extenders?

Mike

 

[professor]

blackb12--Maybe I can shed a little light on the subject and offer you an easy solution. The stones weren't sticking to your tire, they were caught in the groves, just long enough to absorb enough energy in the form of speed before they were forced from the tires grip by centrifical force, at apx. 1/8 rotation, and ended up where you saw them. You've probably never thought about this, but at 10mph, a stone caught in the front tire threads will go from 0 mph to 20mph in just .21 seconds. Believe it or not, at 30mph, that same stone would have only .07 seconds to reach 60mph, thats 1/3 the time to gain 3 times the speed, and would most likely been thrown out at such a small angle you would never have seen it.

While I'm throwing figures around----Your tire rotates 856 times per mile. At 60 mph, the part that hits the pavement goes from 0 mph to 120 mph in just 35 THOUSANTHS of a second, and does that 856 times each minute. A nail in your tire, at that speed, will hit the pavement 14.3 times per second. (all figures are apx. and for the front tire only, someone check my math, I could be wrong----but I doubt it). MIKE

Oh yeah-- the solution to your problem-- MORE SPEED!!!!

 

[Bugnatr]

Just pull a wheelie throught the stones. :lol:

 

[nusman68]

Gotta love that...only here would you get a scientific explanation, followed by a simple solution!

The professor is right...the gravel is probably sticking in the tread grooves...so obviously you just need to run racing slicks in the front! Uh, better avoid rainy days though...

Seriously, though, short of having a one-off custom fabbed fender (or longer fender extension) done at great expense, I'm sure you could get a 'generic' rubber fender extension from *gasp* JC Whitney and with some careful carving & sanding get it to where it would look acceptable added on to your Fenda extenda...

 

[loingrader]

when it is cold and there is gravel on the road it seems to really stick to my tires and get thrown up onto the cowl. once the tires warm up the problem stops. in my opinion it is nothing to worry about. semi's throw up much more damaging rocks and such. it's the price you pay for putting on the miles. well worth it!

-b

 

[NoCage]

BlackB12... if you don't already have one, I'd recommend a radiator guard. Cox has 'em and so does BikeJohnny. They're easy to install.

 

[BlackB12]

Yeah I'll have to check out the rad guards. The stones were really smacking off it. I'm wondering if this is just a trademark of the stock BT020s. I've had many other tires on my last bike and they never flung up stones like these.

Mike

 

[yamahlr]

I've seen the same as well, with the small stones and when they come loose when you run over a curb or something. In the northeast and my county, they use alot of grit on the roads along w/ salt. They have to sweep it up in the spring, or riding can be trecherous.

 

[tripletango]

blackb12--Maybe I can shed a little light on the subject and offer you an easy solution.  The stones weren't sticking to your tire, they were caught in the groves, just long enough to absorb enough energy in the form of speed before they were forced from the tires grip by centrifical force, at apx. 1/8 rotation, and ended up where you saw them.  You've probably never thought about this,  but at 10mph, a stone caught in the front tire threads will go from 0 mph to 20mph in just .21 seconds.  Believe it or not, at 30mph, that same stone would have only .07 seconds to reach 60mph, thats 1/3 the time to gain 3 times the speed,  and would most likely been thrown out at such a small angle you would never have seen it.    While I'm throwing figures around----Your tire rotates 856 times per mile.  At 60 mph, the part that hits the pavement goes from 0 mph to 120 mph in just 35 THOUSANTHS of a second, and does that 856 times each minute.  A nail in your tire, at that speed, will hit the pavement 14.3 times per second.  (all figures are apx. and for the front tire only, someone check my math,  I could be wrong----but I doubt it).  MIKE 

  Oh yeah-- the solution to your problem-- MORE SPEED!!!!

Actually the tire contact patch is not moving relative to the road surface otherwise it would be sliding.

 

[S76]

Tires that live in fibreglass houses shouldn't throw stones. It's just wrong!

 

[Just Plain Dave]

Today the snow melted and the temps were in the 40s so I got my 05 out and rode to my dr. appt.  Just out of my driveway I rode through some less than pea-sized gravel that the township put on the roads the day before.  Immediately I could hear the stones hitting the under side of the front fender,  but then I saw a bunch of them come flinging up as high as the instrument panel.  Keep in mind this is at about 10 mph.  I couldn't beleive the stones had enough energy to fly up there.  I guess what's happening is the stones are sticking to the tire long enough to fly back and hit the plastic below the radiator, then bounce off that up to instruments.  Later I took the seat off and I found tiny stones pinched between the seat and the front of the tank.  Not good.  Luckily they were not there for long and I have a Magknight tank cover to protect the paint. 
Anyone have a remedy for this?  Do they make longer fender extenders?

Mike

I have seen some interesting numbers in these explanations. May be accurate, maybe not. Don't know for sure, and don't want to start another "If a jet was on a giant conveyor belt that was turning towards the plane as fast as the wheels on the jet was turning, would the jet take off" type of thing. however, I can offer a cure. Move to the Hill Country of Texas where they don't need salt or pea gravel to make the roads usable.

 

[professor]

just plain dave-- the accuracy of those figures are fairly easy to check. The circumference of the front tire, in inches, how many inches in a mile, etc. etc.. Its even kind of fun.

And yes, the contact patch is at 0 mph but by the time that spot rotates 90 degrees its traveling at the speed of the bike vertically AND horizontally, another 90 degrees and its going at twice the speed of the bike then of corse it slows down to 0 by the time it hits the road again. interesting, no? MIKE

 

[tripletango]

just plain dave-- the accuracy of those figures are fairly easy to check. The circumference of the front tire, in inches, how many inches in a mile, etc. etc.. Its even kind of fun. And yes, the contact patch is at 0 mph but by the time that spot rotates 90 degrees its traveling at the speed of the bike vertically AND horizontally, another 90 degrees and its going at twice the speed of the bike then of corse it slows down to 0 by the time it hits the road again. interesting, no? MIKE

Fo sho

 

[Just Plain Dave]

just plain dave-- the accuracy of those figures are fairly easy to check.  The circumference of the front tire, in inches, how many inches in a mile, etc. etc..  Its even kind of fun.   And yes, the contact patch is at 0 mph but by the time that spot rotates 90 degrees its traveling at the speed of the bike vertically AND horizontally, another 90 degrees and its going at twice the speed of the bike then of corse it slows down to 0 by the time it hits the road again. interesting,  no?  MIKE

I agree 100%. Went through the discussion 50+ years ago about the fact that the bottom of the tire sits on the ground going nowhere while the top is doing all the work. Always wondered why the part that is sitting there doing nothing is the part that's wearing out. (or maybe not)

 

[beeroux]

Stones?

HAHAHAHAHAHAHAHAHAHAHA!!!!!!!!!

I was once rolling quite briskly and hit a rabbit.

The wabbit found itself between the fender and wheel, and was shot out like a cannon towards the front and actually exceeded my speed for a second or so.

It was like having 50 cal. wabbit guns. B)

GZ

 

[Rogue]

It was like having 50 cal. wabbit guns. B)

:haha: :haha: :haha: :haha: :haha:

 

[kaitsdad]

Stones?
HAHAHAHAHAHAHAHAHAHAHA!!!!!!!!!

I was once rolling quite briskly and hit a rabbit.

The wabbit found itself between the fender and wheel, and was shot out like a cannon towards the front and actually exceeded my speed for a second or so.

It was like having 50 cal. wabbit guns. B)

GZ

Ya know, if you could just aim those wabbits at really slow cagers - .....

 

[Bounce]

Move to the Hill Country of Texas where they don't need salt or pea gravel to make the roads usable.

But they have an over abundance of tar snakes!

 

[tripletango]

Move to the Hill Country of Texas where they don't need salt or pea gravel to make the roads usable.

But they have an over abundance of tar snakes!

Deer don't fit there too well either! Plenty of rabbits there though