Excellent mileage with 17 tooth sprocket. More impressions.

[marc]

It's been more than 1000 miles (1600Km) since I installed my new
17-teeth sprocket. These are the impressions:

The good news:

- The mileage is awesome: in a tank of 10.5 litres (not including
reserve) I used to get 160Km. Now I get 240Km, that's 50% more.
(10.5 litres are 2.2 gallon, 160Km=100Mi and 240Km are 150Mi).

- RPMs decreased in 800, that means that where it was 120KPH@6000RPM
now I get 135KPH@6000RPM (was 75MPH@6000RPM now is 85MPH@6000RPM)

- Top speed was 170KMH (105MPH) and now I got 180KMH (112MPH)

- Oil consumption was slightly reduced, due to low RPMs used.

- Gears are longer, no need to shift gears continously when the road
has lots of turns, and accelerations are awesome! GS will pull hard
from 3000 up to 7000 (60KPH to 120KPH / 40MPH to 75MPH) in
4th gear.

The bad news:

- When commuting in very intense traffic, clutch becomes hotter, 1st gear
should have more demultiplication and the engine is required to work
smoothly in the range under 3000RPM (that's somehow difficult if using
racing exhausts).

- When downshifting, engine has few braking power, so I'll need to
use the brakes more often.

Hopefully, I do not need to commute in very intense traffic conditions,
I am not a hardcore racer and prefer long trips instead, so this
mod is perfect for me!

Last trip I made was 400Mi (650Km).

[jsamaniego]

It's been more than 1000 miles (1600Km) since I installed my new
17-teeth sprocket. These are the impressions:

The good news:

- The mileage is awesome: in a tank of 10.5 litres (not including
reserve) I used to get 160Km. Now I get 240Km, that's 50% more.
(10.5 litres are 2.2 gallon, 160Km=100Mi and 240Km are 150Mi).

- RPMs decreased in 800, that means that where it was 120KPH@6000RPM
now I get 135KPH@6000RPM (was 75MPH@6000RPM now is 85MPH@6000RPM)
........ deleted for brevity ...

Hopefully, I do not need to commute in very intense traffic conditions,
I am not a hardcore racer and prefer long trips instead, so this
mod is perfect for me!

Last trip I made was 400Mi (650Km).

Great!  I'll pick up a 17 sprocket myself today, and I'll also will post my impressions.
However I get some math trouble:
in 6th gear, 6000RPM = 120kph. with 16 tooth sprocket.  Hence:

maintaining the same speed and changing to a 17 sprocket:

RPM = 6000*16/17 = 5647!, or about 350 RPM lower, isn't it?:dunno:

in any case, common sense tells me that unless eager for power and wheelies, it should work, uh?  

[Chuck]

240km / 10.5L is 53.8 miles per US gallon.  That's what you should have been getting stock, and it's what I'm getting right now, stock.  Could you recheck with your original sprocket again, or something???

Sorry to be a skeptic, but I think your scientific method might have a wrench in it somewhere.

[leo]

I'm probably wrong, but by changing sprockets wouldn't the speedo be out of whack as well and thus your miles driven?  :dunno:

[Narcissus]

Hmmm I think I get like 300ish km on about 15L so getting a 17t might increase my mileage by a significant amount.  :mrgreen:

[Bluebellylint]

I'm probably wrong, but by changing sprockets wouldn't the speedo be out of whack as well and thus your miles driven?  :dunno:

you are wrong the speedo is driven by the front wheel rotating.

[RedShift]

Okay.  I'm in.  Have my wallet in my hand.  

One thing is keeping me from getting a 17-Tooth sprocket -- where to buy the right part -- one with a shoulder on it like the stock 16-Tooth sprocket.

Marc and Javier -- where did you get yours?

[jsamaniego]

Okay.  I'm in.  Have my wallet in my hand.  

One thing is keeping me from getting a 17-Tooth sprocket -- where to buy the right part -- one with a shoulder on it like the stock 16-Tooth sprocket.

Marc and Javier -- where did you get yours?

I bought mine from a local (Florence, Italy) bike parts store.  (Stavini to be concrete), and I paid 12 euros.  It is not a Suzuki part, and came from a large catalog of chains and sprockets, but forgot to ask the brand...

BTW, as expected I do net more than a few hundreds rpm's lower going 50 mph in 6th.  My first impression is that I like the slightly longer gears..
It is too early to conclude about gas mileage, but  I'll keep you posted. I've only made 40 miles with the new sprocket...

[RedShift]

Well, as much as I'd like to head on over to Florence and visit your parts store Javier, it is not going to happen this year.  

My early search of the Internet store fronts on this side of the Atlantic came up empty except for this AFAM 17-Tooth Sprocket from the Motorcycle Superstore.  All the other sprocket offerings are replacements or offer smaller number of teeth.  Interestingly, they are almost half the price of the AFAM's.

Anybody look into getting a smaller rear sprocket?  I looked around and no one seems to offer one with less than the 39-Teeth of a standard GS500 rear gear.

Roy...

[Toledo Jim]

Afam 17 tooth front sprocket at bikebandit, $26.99.

http://www.bikebandit.com/PartsBandit/product~pf_id~3185134~dept_id~1173303.asp

[jsamaniego]

Well, as much as I'd like to head on over to Florence and visit your parts store Javier, it is not going to happen this year.  

Roy...

Too bad, Redshift... there are a lot of nice rides around here... (ask Kerry)
My sprocket has a shoulder (I believe it is so from 2001 models onwards).

I've made some easy calculations:

   6th gear analysis going from 16 to 17-tooth sprocket            
                  
      ratio   =17/16 =   1,0625      
                  
for a given rpm, you get the speed gain (real, not read from speedometer):                  
       before  after     before  after    
   rpm    kph     kph     mph     mph
   3000    60     64       38       40
   4000    80     85       50       53
   5000    100     106     63      66
   6000    120     128     75     80
   8000    160     170     100     106
   9000    180     191     113     120
               
   for a given speed, you get lower rpms:            
                 RPM         
mph   (kph)   before            after      
37,5         (60)    -   3000           2824      
50          (80)     -   4000            3765      
62,5         (100)    -   5000           4706      
75        (120)     -   6000            5647      
100        (160)    -   8000            7529      
112,5       (180)   -   9000          8471

[marc]

I got mine from Sprocket Specialists. Did a online order at:
http://www.sprocketspecialists2.com/

They are very nice people to talk to, and they know about the
shoulder in some models, but their new web looks a little
confusing. Older web specified clearly GS500 88-93 and 94-03.

Chaparral is a distributor for Sprocket Specialists products.

About the mileage: looks like my bike has something that goes wrong
when it gets beyond 6000RPM. Just crossing that boundary will drop
its mileage badly.

The RPM readings are taken from the counter. It is not a 1000RPM
drop, but it doesn't look either like a 300RPM drop. Something like
800RPM is what I read in the counter.

And no, no wheelies with the sprocket.

My bike is stock, 64000Km old, with high oil consumption, and
Thunder competition exhaust.

[RedShift]

Javier, Marc, thanks for your replies.  This forum is better for the data & experiences you guys provide.

Nsp, thanks for pointing me to BikeBandit.  I've already got an account with them and will likely use them.

I still want to do the math on the change in gearing.  From what I read with the folks who put a 15-Tooth front on, there are subtle changes but nothing serious.

Will let you know via a post to this thread as to when I make a change.  

[jsamaniego]

Hi Marc,

I'd like to exchange some ideas with you.
Could you please contact me at javier.samaniego@iue.it?
TIA,