<div class="FTQUOTE"><begin quote>Originally posted by: JustRandy

So, anyone tackling my sprocket math puzzle yet? Haven't heard to much from you guys about that. [img][/img]</end quote></div>

I'll take a closer look after classes. Do you have the diameters of the sprockets and the length from jack to axle?

Also one thing you might want to consider is the stress on the chain making that sharp turn on those baby sprockets.

 

Are you going to disregard the weight difference between the sets of sprockets?

 

i concur w Ugly88 and ATVMan. i think the added stress on the chain wouldn't be worth it. not only sharper bends but higher rotation speed too, right?

 

I am not sure the cost to go with custom sprockets is worth the little gain? But if you have been through every other part of the machi9ne for power then you know how it goes with power sports, it si the last 1/2-1 horse power that costs the most!

 

<div class="FTQUOTE"><begin quote>Originally posted by: MalHombre

Randy i think a +2 would be about ideal. +4 nice but it shifts the c.g. too much and makes wheelies a little harder. on the other hand. it's reeeeally easy to break the back end loose w just a little body english (and a handful of throttle[img][/img])</end quote></div>

I feel the same. Sometimes I have to stand up and sit down hard to get the tires to bite enough to pull the front wheels off the ground. Its hard to get the timing right though.... Have to let go of the clutch while slamming my weight into the seat and still managing to hang on with my left hand. [img]i/expressions/face-icon-small-shocked.gif[/img] But, that said, I'm not sure I'd want to trade being able to drift around turns in a tall gear for the ability to wheelie easy. It will wheelie, just not as easy as a stock quad. However a stock quad won't drift. [img]i/expressions/face-icon-small-happy.gif[/img] Love drifting!

 

<div class="FTQUOTE"><begin quote>Originally posted by: atvman29

<div class="FTQUOTE"><begin quote>Originally posted by: JustRandy



So, anyone tackling my sprocket math puzzle yet? Haven't heard to much from you guys about that. [IMG][/IMG]</end quote></div>



I'll take a closer look after classes. Do you have the diameters of the sprockets and the length from jack to axle?</end quote></div>

You can assume whatever length you want, so long as its consistent. I took a rough measurement of mine last fall when I was shopping for the perfect chain.

You can calculate the sprocket sizes with the dimensions of the chain. Cir = PI x Dia. http://www.gizmology.net/sprockets.htm


<div class="FTQUOTE"><begin quote>Also one thing you might want to consider is the stress on the chain making that sharp turn on those baby sprockets. </end quote></div>

Yeah, you'll have to make some kind of assumption about friction if you want to be very accurate. I don't know how to do that, so I just assumed friction was low.

 

<div class="FTQUOTE"><begin quote>Originally posted by: UGLY88

Are you going to disregard the weight difference between the sets of sprockets?</end quote></div>

I would if the question is merely will a smaller gearset make more power (or take less). Smaller, lighter sprockets would only be more efficient, and waste less energy,,,,, unless you believe the negative of chain friction around smaller sprockets outweighs the positive of light-weight sprockets. But then we're back to the complexities of quantifying friction.

I'm happy with whatever reasonable assumptions you want to make, so long as you state them. [img]i/expressions/beer.gif[/img]

 

<div class="FTQUOTE"><begin quote>Originally posted by: MalHombre

i concur w Ugly88 and ATVMan. i think the added stress on the chain wouldn't be worth it. not only sharper bends but higher rotation speed too, right?</end quote></div>

Rotational velocity of the chain should decrease with smaller sprockets since the rpms of the front sprocket doesn't change, nor does the gear ratio, so the rear-wheel speed also wouldn't change.... Yet the sprockets have gotten smaller.

I guess it all boils down to "How fast does/can a quad engine make a chain accelerate?" If it accelerates at the speed of a shotgun blast (to use an extreme example), the engine would most certainly feel the difference in a few grams of chain weight just like you'd feel the different in slugs and bird shot. And to make something seem heavier, stick it on the end of a longer lever.... Which is what a bigger front sprocket effectively does.

So, to answer your question would depend on knowing the acceleration of the chain. If the acceleration is high enough, it would certainly outweigh any frictional difference between the 2 sprockets. If the acceleration is low, maybe friction would matter most.

 

Ok, so according to my calculations, the weight saved in just the chain would be a tick under 2 ounces (.12144 lb). It would be a mere 2.5" of chain saved, so if its 3lb per 100 link, and the pitch on 520 chain is 5/8, 3/(5/8*100)=weight per inch then times that by 2.53 which is the difference in circumferences/2 (since you only use half the sprockets) for 13+39 and 11+33.

 

<div class="FTQUOTE"><begin quote>Originally posted by: UGLY88

I am not sure the cost to go with custom sprockets is worth the little gain? But if you have been through every other part of the machi9ne for power then you know how it goes with power sports, it si the last 1/2-1 horse power that costs the most! </end quote></div>

Yeah, ain't that the truth!

Bot not too bad this time.... My front 11T was 8 bucks I think from rockymountain. The 37T rear I found on ebay. I think it was $30 with shipping? Something like that. So, about the cost of a KN filter.

There's a bigger difference in power than you'd think. Something about that 11T that really puts the power to the ground. Its about like the difference you might notice with temperature or altitude differences. You know how somedays it seems your quad runs better than others??? Its kinda like that.

I've tried 14/41, 13/39, 13/41, 12/39, 12/41, and 11/37. 11/37 is a bit low, but its still a hair taller than the stock 12/41. I wish I could find a 36T for cheap.