MBN Is loosing ground... Again. Look at this article./Chain debate

[standfast]

I know Yoshi, I was laughing a little bit myself but hell.  Who knows?  Bajatex on MBN tried some forced cooling on his and he seemed convinced that it made a difference. 

[Nutz4sand]

I would also add argue state mention etc. That the front sprocket gets a lot of heat into it from the motor itself in many cases.

Take any bike for a ride then put your hand on the engine case. Cold it aint.

Makes one wonder if this aint adding to the issue (I am betting it is)

Thus making the arguement of moving the sprockets out from the motor even more viable.

[fabr]

Again, I completely concede I may be wrong in my idea of what's going on here, as this is the first time i've thought about chain friction in this way, and have always thought bigger was better until I read the article.

What I meant was, every link that is touching the sprocket is being forced to rotate the entire time it is going around the sprocket.   As the chain is pulling the sprocket and the sprocket is resisting, there is a lot of force that wedges the link pin into each tooth, so for every second the link is touching the sprocket, it is making friction and it is pressing hard against the tooth, metal against metal will produce friction, so when the link is not touching the sprocket, it is not producing any friction, and even though it's got a tighter bend which does produce more friction than a more gradual bend from a bigger sprocket, it is in the air longer, and not bending at all for a longer period of time, so that longer/straighter airtime may very well be more than compensating for the friction from a tighter sprocket bend at high speeds.....

Remember that the pin that most recently fully engaged the sprocket is really the only one that is creating friction as it engages the sprocket. The other links/pins are just along for the ride until they come to the disengagement time when friction  is again induced. The larger sprocket gives more time for the chain to transfer heat into the sprocket . Bigger sprockets are better in this respect.

[fabr]

I think your missing the fact that while the chain is following around the sprocket. Its is only actually bending for a small part as it enters and leaves the sprocket and this is where the major part of the heat comes from. While its in the middle of the sprocket its shedding more heat than its generating due to air over it and the sprocket potentially drawing heat out of it. Being its one the bigger sprockets longer it has more time to shed than create heat. VS a smaller sprocket setup.

The small sprocket it bends farther and faster under more pressure as fewer links on the sprokcet at one time. So it makes more heat.

The larger sprocket bends them less. Over a wider path. Then it simply carries the bent link around to the exit.

I agree that metal on metal makes friction. But the chain vibrating under load as it comes on or off a sprocket makes more heat I bet than when the chain is on the large sprocket in the middle of the bend where its not doing anything but pulling (no bending movement)

Scince it enters and leaves a smaller sprocket more vilolently it will create more heat there too due to the smaller sprocket.
 

 

I should have read this first.Yes, I think you are correct in your thinking.

[fabr]

easy, i've been laughed at for suggesting that in the past, lol.....

LOL,and I will still laugh at it.BUT, I will concede that in a marginal overheat situation it MAY do the trick . For most of us with heat issues tho I am still very skeptical as to the benefit.

[Dunebound69]

Little of topic note, I notice we are all using the phrase "centripetal force". Centripetal force dose not exists. You will not find it mentioned in a physics book anywhere folks.  I know it is taut in elementary schools but it is wrong.(Let the hate mail start here.) By the book it is Centripetal Acceleration. That means its is the change in the direction of the velocity. I offer this info for sake of knowledge.

[fabr]

I think they were correctly or even incorrectly meaning  centrifugal force. To be honest I didn't know about centripetal till now tho. Thanks for the info.

[Dunebound69]

Back when I was in the class the professor was so forceful in his discussion that  centripetal force not existing as we where going through a chapter on centripetal acceleration it has stuck with for over a decade. Then living with a elementary school teacher I see so many things that are being reversed  in higher education. Many are in the fields of science. As the devil is always in the details.

[fabr]

I'm a curious sort .Can you help me see the difference in centripetal and centrifugal?

[Dunebound69]

I may be able to. But must admit I will need to check my old text book at home. I want to make sure I get it right.  It has been a while since I studied.

My big point was it is an acceleration not a force.

[fabr]

To be honest I thought it was just a misspelling. Shows how little I know!

[SPEC]

 :-\
So did I till I googled it just now

[Yoshi]

I'm a curious sort .Can you help me see the difference in centripetal and centrifugal?

example...

in twirling a mass on a string, the centripetal force transmitted by the string pulls in on the mass to keep it in its circular path, while the centrifugal force transmitted by the string pulls outward on its point of attachment at the center of the path.

[fabr]

eh? pics man,pics! LOL!!

[Yoshi]

eh? pics man,pics! LOL!!

Don't have any pics.  Think of riding on a merry go round.  If you sit in the middle and the thing is spinning, centrifugal force causes you to slide out, thrown away from the center, but if you grab onto the bar at the end before you fly off the thing, and start to craw your way back up, centripetal force is the act of your body continuing to spin around the same circle, but fighting the force trying to throw your body outward from the center. 

It is basically the difference between spinning around a point, and whether your going away from, or toward the center, one action will move away from the center(centrifugal), the other action is trying to go to the center(centripetal)....