Stupid Sprocket Question

demp · September 7th, 2010, 08:04 AM

Okay... so a local shop has 13 front / 47 rear in stock. What drastic changes would I get in the bike if I were to install these?

want1sobad · September 7th, 2010, 08:09 AM

www.gearingcommander.com......is your friend.

to summarize, you'll get quicker acceleration offset with reduced top speed. also, rpms will go way up for a given speed vs. stock gearing (10.3k @ 75mph vs. 9.2k @ 75 mph w/ stock gearing). one other thing, the usability of each gear will be reduced (you'll be shifting through gears 1-4 very, very quickly).

backinthesaddleagain · September 7th, 2010, 08:09 AM

Matt - I can't remember the stock sizes but divide 47 by 13. Divide stock rear by stock front. The larger answer will rev quicker but use more rpm on the highway. I believe the stock front is a 14. Going smaller on the front can cause stress on the counter shaft, but one tooth less should be fine. Looking for stock sizes now.

demp · September 7th, 2010, 08:12 AM

Quote:

Originally Posted by want1sobad

www.gearingcommander.com......is your friend.

AWESOME SITE, Thanks!

demp · September 7th, 2010, 08:13 AM

Quote:

Originally Posted by backinthesaddleagain

Matt - I can't remember the stock sizes but divide 47 by 13. Divide stock rear by stock front. The larger answer will rev quicker but use more rpm on the highway. I believe the stock front is a 14. Going smaller on the front can cause stress on the counter shaft, but one tooth less should be fine. Looking for stock sizes now.

14/45 is stock I believe,

so yeah okay, you guys win - stupid idea xD I need my highway use, will order the proper sizes

backinthesaddleagain · September 7th, 2010, 08:18 AM

Matt, if it is 14/45 that would be a ratio of 3.3.214 vs 3.615 for the 13/47. So you are reducing the FS and increasing the RS. The chain would also need to be longer. I would probably stay away from that combo unless you are looking for quicker acceleration. Figure a lot of ninjetters are using 15/45 to reduce some revs and that is a ratio of 3.00.

demp · September 7th, 2010, 08:19 AM

Quote:

Originally Posted by backinthesaddleagain

Matt, if it is 14/45 that would be a ratio of 3.3.214 vs 3.615 for the 13/47. So you are reducing the FS and increasing the RS. The chain would also need to be longer. I would probably stay away from that combo unless you are looking for quicker acceleration. Figure a lot of ninjetters are using 15/45 to reduce some revs and that is a ratio of 3.00.

oooo thats right my chain would be too short, screw that

backinthesaddleagain · September 7th, 2010, 08:25 AM

Quote:

Originally Posted by demp

oooo thats right my chain would be too short, screw that

yeah i think so, dropping one in the front adding 2 in the rear, so net one, of course you can't add one link so maybe it would work or you would need 2 more links. I 'd probably pass on that combo.

Cuongism · September 7th, 2010, 09:59 AM

For a 250, definitely pass! Gears will be shorter and the 250 already requires a lot of shifting. 1st gear will somehow be even more useless.
What are you trying to get out of changing sprockets? Faster acceleration or more top speed? If you do a lot of highway, I recommend going up to 15T in the front or dropping a couple in the rear. That little change doesn't require a new chain and it'll drop your rpm on the highway.

demp · September 7th, 2010, 10:11 AM

Quote:

Originally Posted by Cuongism

For a 250, definitely pass! Gears will be shorter and the 250 already requires a lot of shifting. 1st gear will somehow be even more useless.
What are you trying to get out of changing sprockets? Faster acceleration or more top speed? If you do a lot of highway, I recommend going up to 15T in the front or dropping a couple in the rear. That little change doesn't require a new chain and it'll drop your rpm on the highway.

My current sprockets are beginning to look like they need help

just lookin for a replacement and this guy happened to have those in stock so I thought I'd check if it'd work

want1sobad · September 7th, 2010, 10:14 AM

15/45 is the way to go. if you find you want to drop rpms even further, you can experiment with 44,43,42,41, etc. keep in mind you'll be giving up acceleration and may get to the point where downshifting to pass will become a necessity.

Cuongism · September 7th, 2010, 10:20 AM

Sprockets from your 09? Sprockets should last longer than your chain, but most recommend changing both at the same time (I know people who swap sprockets every other chain). Chains should last 10k-15k without care and 25k-30k with care and maintenance.

demp · September 7th, 2010, 10:23 AM

Quote:

Originally Posted by Cuongism

Sprockets from your 09? Sprockets should last longer than your chain, but most recommend changing both at the same time (I know people who swap sprockets every other chain). Chains should last 10k-15k without care and 25k-30k with care and maintenance.

sprockets from 09. 32,500 km on the bike

BRUM BRUM!

Cuongism · September 7th, 2010, 10:25 AM

Wow, you get around

welcome2thedawn · September 7th, 2010, 01:32 PM

13/47 is more of a racing set up...

September 7th, 2010, 08:04 AM	#1
demp ninjette.org sage Name: Matthew Location: Toronto Join Date: May 2009 Motorcycle(s): 2015 V-Star 950 Tourer (Deep Blue) Posts: 570	Stupid Sprocket Question Okay... so a local shop has 13 front / 47 rear in stock. What drastic changes would I get in the bike if I were to install these?

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September 7th, 2010, 08:09 AM	#2
want1sobad Ninjette CPT Name: Vince Location: jacksonville, fl Join Date: May 2009 Motorcycle(s): Black 08 250r Posts: A lot.	www.gearingcommander.com......is your friend. to summarize, you'll get quicker acceleration offset with reduced top speed. also, rpms will go way up for a given speed vs. stock gearing (10.3k @ 75mph vs. 9.2k @ 75 mph w/ stock gearing). one other thing, the usability of each gear will be reduced (you'll be shifting through gears 1-4 very, very quickly).

September 7th, 2010, 08:09 AM	#3
backinthesaddleagain ninjette.org certified postwhore Name: Greg Location: Rhode Island Join Date: Apr 2009 Motorcycle(s): 2013 ZX6R 636 Posts: A lot.	Matt - I can't remember the stock sizes but divide 47 by 13. Divide stock rear by stock front. The larger answer will rev quicker but use more rpm on the highway. I believe the stock front is a 14. Going smaller on the front can cause stress on the counter shaft, but one tooth less should be fine. Looking for stock sizes now.

September 7th, 2010, 08:18 AM	#6
backinthesaddleagain ninjette.org certified postwhore Name: Greg Location: Rhode Island Join Date: Apr 2009 Motorcycle(s): 2013 ZX6R 636 Posts: A lot.	Matt, if it is 14/45 that would be a ratio of 3.3.214 vs 3.615 for the 13/47. So you are reducing the FS and increasing the RS. The chain would also need to be longer. I would probably stay away from that combo unless you are looking for quicker acceleration. Figure a lot of ninjetters are using 15/45 to reduce some revs and that is a ratio of 3.00.

September 7th, 2010, 09:59 AM	#9
Cuongism ninjette.org certified postwhore Name: Cuong Location: San Diego Join Date: Jul 2010 Motorcycle(s): 2008 Ninja 250r, 2007 Daytona 675 Posts: A lot.	For a 250, definitely pass! Gears will be shorter and the 250 already requires a lot of shifting. 1st gear will somehow be even more useless. What are you trying to get out of changing sprockets? Faster acceleration or more top speed? If you do a lot of highway, I recommend going up to 15T in the front or dropping a couple in the rear. That little change doesn't require a new chain and it'll drop your rpm on the highway.

September 7th, 2010, 10:14 AM	#11
want1sobad Ninjette CPT Name: Vince Location: jacksonville, fl Join Date: May 2009 Motorcycle(s): Black 08 250r Posts: A lot.	15/45 is the way to go. if you find you want to drop rpms even further, you can experiment with 44,43,42,41, etc. keep in mind you'll be giving up acceleration and may get to the point where downshifting to pass will become a necessity.

September 7th, 2010, 10:20 AM	#12
Cuongism ninjette.org certified postwhore Name: Cuong Location: San Diego Join Date: Jul 2010 Motorcycle(s): 2008 Ninja 250r, 2007 Daytona 675 Posts: A lot.	Sprockets from your 09? Sprockets should last longer than your chain, but most recommend changing both at the same time (I know people who swap sprockets every other chain). Chains should last 10k-15k without care and 25k-30k with care and maintenance.

September 7th, 2010, 10:25 AM	#14
Cuongism ninjette.org certified postwhore Name: Cuong Location: San Diego Join Date: Jul 2010 Motorcycle(s): 2008 Ninja 250r, 2007 Daytona 675 Posts: A lot.	Wow, you get around

September 7th, 2010, 01:32 PM	#15
welcome2thedawn ninjette.org guru Name: dawn Location: portland, or Join Date: Sep 2009 Motorcycle(s): 08 ninja 250r modded, 73 honda cl200, 74 kawasaki 400 triple Posts: 255	13/47 is more of a racing set up...