SPROCKETS

1257 Views 18 Replies 10 Participants Last post by Manoah, Jan 16, 2005

Ice

Discussion Starter · Jan 10, 2005

Is there any advantage of having an aftermarket sprocket? Or a bigger sprocket than the stock? I bought my bike from someone and it have a much bigger sprocket on it and I was just wondering why you would buy a bigger sprocket. Thanks

1 - 19 of 19 Posts

z31maniac

· #2 · Jan 10, 2005

Increased acceleration. A popular mod for 6's is to go down one tooth on the front sprocket and up two in the rear. Giving you a 15/50 as opposed to the stock 16/48. Comes out to an 11% increase in torque to the wheel.

Which also means your speedo will read 11% fast, and your bike will show more miles than it actually has unless you get a speedohealer. Which means resale value drops.

Ice

Discussion Starter · #3 · Jan 10, 2005

THanks maniac. Do you know where I can find a speedohealer?

z31maniac

· #4 · Jan 10, 2005

Just about any place that sells sportbike accessories. PM CreePer on this board and he'll give you a good deal.

CreePer

· #5 · Jan 10, 2005

Every bike is different in the amount of factory error. Then adding a gear change maginfys the error. Send me a PM Ill hook you up with a deal on a healer.

:jump

Aldebaran

· #6 · Jan 11, 2005

is it true that our bike's speed is calculated with respect to our front sprocket? if so would changing to 16-50 make any significant difference in the torque, hp n speedo?

jasamb

· #7 · Jan 11, 2005

speed is derived from the transmission. any change in drive train geometry (including a taller or shorter (worn out) tire) will cause the speedo to be off. even from the factory, the speedo should be considered as more of a ... guideline...

jasamb

· #8 · Jan 11, 2005

z31maniac said:
Comes out to an 11% increase in torque to the wheel.

can you show me the calculations for this number?

z31maniac

· #9 · Jan 11, 2005

jasamb said:
z31maniac said:

Comes out to an 11% increase in torque to the wheel.

Click to expand...

can you show me the calculations for this number?

I found this from an old thread on sportrider.com:

Took this from another forum:

How To Figure Sprocket Change

Formula: The x is multiply
((new rear/new front)x(old front/old rear)-1)x100%

Example given:

((47/15)x(16/45)-1)x100%= 11.4%

R6:
((15/50)x(16/48)-1)x100% = 11.1%

When I e-mailed calsportbike.com and they told me that -1, +2 equals 11% more torque to the rear wheel.

I'm not a math whiz so I couldn't tell you if this 100% right, but once the guy from www.calsportbike.com told me the change =11%, i figured it was right.

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Aldebaran

· #10 · Jan 11, 2005

in that case am i stressing out my engine more? means that my mileage will show a higher value than it actually is??
would a 16-50 be recommended?

bbored130

· #11 · Jan 11, 2005

I put a RK 520 chain with the Vortex conversion sprockets on my bike... the miles did change as did the speed etc.... I bought a speedo heeler and put it on my bike and WOW that made the bike fairly accurate. The speed is generated off the top of the engine under the batter tray. I did the caculation that the website has and figured that it was off by 12%.... i set up the speedoheeler to fix this and then ran it using my friends GPS.. it is very accurate now. Wish I knew about this before!!!! Also, I have noticed a huge difference on how the bike rides after the change.. easier to get the front tire up and I don't care what people say about killing the top end... but after this change a few little others, I have done 160 MPH (corrected by speedo heeler). So if you do the sprocket conversion right and do some other mods, you will love the change... Oh and I paid $85 shipped for the speedoheeler... only company here in the states that is a distributor is calsportsbikes but they sell them to other companies here in the states who then retail them for some profit.

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yoda

· #12 · Jan 11, 2005

what is even funnier is that it is a REAL company!! LOL

Here is some funny reading:
http://www.thetoque.net/020917/sprockets.htm

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z31maniac

· #13 · Jan 11, 2005

Aldebaran said:
in that case am i stressing out my engine more? means that my mileage will show a higher value than it actually is??
would a 16-50 be recommended?

Not really stressing the engine, since the torque to wheel is amplified theoretically it should be less strain, just more RPM's. Any amount you change the gears by will affect the speedo and RPM's on the motor, % change will be based on gears chosen.

Use the formula above to determine what RPM's your willing to live with on the highway, if you commute, or spend alot of time on the highway. If you don't then I don't worry about going 15/50. If your in town just go to the next gear.

jasamb

· #14 · Jan 12, 2005

z31maniac said:
jasamb said:

z31maniac said:

Comes out to an 11% increase in torque to the wheel.

Click to expand...

can you show me the calculations for this number?

Click to expand...

I found this from an old thread on sportrider.com:

Took this from another forum:

How To Figure Sprocket Change

Formula: The x is multiply
((new rear/new front)x(old front/old rear)-1)x100%

Example given:

((47/15)x(16/45)-1)x100%= 11.4%

R6:
((15/50)x(16/48)-1)x100% = 11.1%

When I e-mailed calsportbike.com and they told me that -1, +2 equals 11% more torque to the rear wheel.

I'm not a math whiz so I couldn't tell you if this 100% right, but once the guy from www.calsportbike.com told me the change =11%, i figured it was right.

Keep in mind that the sprockets do not affect the torque of the bike.

The R6 doesnt really put out that much torque in the first place...it doesnt have to. It operates at such high rpms (where the bikes massive horsepower is) that torque is not a concern.

What changing the sprockets DOES do is cause the bikes engine to rev up faster (by slowing down the rear wheel at a given rpm) meaning that you get up into the higher rpms faster, you get up into the higher horsepower faster.

z31maniac

· #15 · Jan 12, 2005

jasamb said:
z31maniac said:

jasamb said:

z31maniac said:

Comes out to an 11% increase in torque to the wheel.

Click to expand...

can you show me the calculations for this number?

Click to expand...

I found this from an old thread on sportrider.com:

Took this from another forum:

How To Figure Sprocket Change

Formula: The x is multiply
((new rear/new front)x(old front/old rear)-1)x100%

Example given:

((47/15)x(16/45)-1)x100%= 11.4%

R6:
((15/50)x(16/48)-1)x100% = 11.1%

When I e-mailed calsportbike.com and they told me that -1, +2 equals 11% more torque to the rear wheel.

I'm not a math whiz so I couldn't tell you if this 100% right, but once the guy from www.calsportbike.com told me the change =11%, i figured it was right.

Click to expand...

Keep in mind that the sprockets do not affect the torque of the bike.

The R6 doesnt really put out that much torque in the first place...it doesnt have to. It operates at such high rpms (where the bikes massive horsepower is) that torque is not a concern.

What changing the sprockets DOES do is cause the bikes engine to rev up faster (by slowing down the rear wheel at a given rpm) meaning that you get up into the higher rpms faster, you get up into the higher horsepower faster.

Horsepower is a function of torque. Ever noticed that in ALL internal combustion engines the TQ and HP curves always cross ~5250 RPM's.

And the gears, or in this case sprockets determine how much the torque is multiplied to the rear wheel. In the case of the stock sprockets 16/48 or a 3:1 ratio the TQ is multiplied by three times from the output shaft to the rear wheel. So no, sprockets don't increase the output of the motor, they increase the output to the rear wheel. And in the case of -1, +2 it has the affect of increasing torque by 1.11 times, or 11%.

njk27

· #16 · Jan 16, 2005

^good explanation

z31maniac

· #17 · Jan 16, 2005

I also read in one of the British rags, that because of the way the R6 is geared stock it is the only 600 supersport to have 700lbs of thrust in first gear.

Damn I can't wait to get my conversion now.

RSixxr

· #18 · Jan 16, 2005

z31maniac said:
jasamb said:

z31maniac said:

jasamb said:

z31maniac said:

Comes out to an 11% increase in torque to the wheel.

Click to expand...

can you show me the calculations for this number?

Click to expand...

I found this from an old thread on sportrider.com:

Took this from another forum:

How To Figure Sprocket Change

Formula: The x is multiply
((new rear/new front)x(old front/old rear)-1)x100%

Example given:

((47/15)x(16/45)-1)x100%= 11.4%

R6:
((15/50)x(16/48)-1)x100% = 11.1%

When I e-mailed calsportbike.com and they told me that -1, +2 equals 11% more torque to the rear wheel.

I'm not a math whiz so I couldn't tell you if this 100% right, but once the guy from www.calsportbike.com told me the change =11%, i figured it was right.

Click to expand...

Keep in mind that the sprockets do not affect the torque of the bike.

The R6 doesnt really put out that much torque in the first place...it doesnt have to. It operates at such high rpms (where the bikes massive horsepower is) that torque is not a concern.

What changing the sprockets DOES do is cause the bikes engine to rev up faster (by slowing down the rear wheel at a given rpm) meaning that you get up into the higher rpms faster, you get up into the higher horsepower faster.

Click to expand...

Horsepower is a function of torque. Ever noticed that in ALL internal combustion engines the TQ and HP curves always cross ~5250 RPM's.

And the gears, or in this case sprockets determine how much the torque is multiplied to the rear wheel. In the case of the stock sprockets 16/48 or a 3:1 ratio the TQ is multiplied by three times from the output shaft to the rear wheel. So no, sprockets don't increase the output of the motor, they increase the output to the rear wheel. And in the case of -1, +2 it has the affect of increasing torque by 1.11 times, or 11%.

Enough with all the jibberish ........put that shit in motorcycle terms......CHANGING SPROCKET=MORE/LESS POWER......or something like that.....**** all of these conversions....it's too fuckin early for all that shit....

Manoah

· #19 · Jan 16, 2005

:stupic LOL!!!

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