I'm thinking about going to a 15T front sprocket to make the bike a little more aggressive. Anybody else have different sized sprockets? What are your impressions?

Tried 15T. Tried 17T.
16 tooth sprocket is best, unless you only ride like a hooligan in town or only do long stints on the highway. Suzuki got it right.

Wouldn't say I ride like a hooligan by any means, but most of my riding is either my short ride to work or on twisty backroads so I wouldn't say I do long stints on the highway super often.

15 th sprocket will only make a difference in the first 1/2 second of a max acceleration from a dead stop.  (drag race)...it will make no performance difference once you are "rolling" ...it may have an effect on all out top speed, and oddly it could be either way..."depending"  (If wind drag gets so high, that you hit the "drag wall" before max HP rpm, then a lower gear could be a tad faster)...but who is driving their GS500 at top speed? And how often if they do?

Stock gearing is just right.


Cookie

Quote from: qcbaker on April 18, 2018, 05:18:33 AM
I'm thinking about going to a 15T front sprocket to make the bike a little more aggressive. Anybody else have different sized sprockets? What are your impressions?

Quote from: twocool on April 19, 2018, 11:33:38 AM


15 th sprocket will only make a difference in the first 1/2 second of a max acceleration from a dead stop.  (drag race)...it will make no performance difference once you are "rolling" ...it may have an effect on all out top speed, and oddly it could be either way..."depending"  (If wind drag gets so high, that you hit the "drag wall" before max HP rpm, then a lower gear could be a tad faster)...but who is driving their GS500 at top speed? And how often if they do?

Stock gearing is just right.


Cookie

Quote from: qcbaker on April 18, 2018, 05:18:33 AM
I'm thinking about going to a 15T front sprocket to make the bike a little more aggressive. Anybody else have different sized sprockets? What are your impressions?

That sounds tempting to me, actually. I've always wanted a better take-off. Just how much high-end does it cost though?

Someone will know for sure but the thing that always drew me away from doing this is not that it'd change the top speed, which I doubt it will, but that it will increase the revs per mph. Right now my GS is pretty annoyingly loud and somewhat touchy at 65mph and I am not sure I'd really like it to be worse, although in theory it would only increase it 400 or so rpm at 65mph. I'm just not sure it's worth the trade off.

Quote from: twocool on April 19, 2018, 11:33:38 AM
15 th sprocket will only make a difference in the first 1/2 second of a max acceleration from a dead stop.  (drag race)...it will make no performance difference once you are "rolling" ...it may have an effect on all out top speed, and oddly it could be either way..."depending"  (If wind drag gets so high, that you hit the "drag wall" before max HP rpm, then a lower gear could be a tad faster)...but who is driving their GS500 at top speed? And how often if they do?

Stock gearing is just right.

What do you mean it wont have any effect once the bike is rolling? The different gear ratio means that the engine RPMs will be higher at any given speed. Wouldn't that mean that at any speed where engine RPMs are lower than ~8.5K, I'll have more torque than I would with the stock sprocket?

it makes no difference in performance...the difference will be the shift points...


But if you graph the HP, torque, and speed......for each gear, then "blend them together"  the curves will be exactly the same, except for a minuscule difference at the very beginning (dead start in 1st gear,) and possibly at the end at top speed in 6th gear.   The rest of the curve  (where you actually drive) will follow the exact same curve.  The shift points will come sooner with the lower ratio but the power curve will not change.

Another way to look at it...you can run ANY gear ratio right up to redline (well probably not 6th) ....then you MUST shift.

Maximum acceleration is derived when you shift at or near redline, so the next higher gear has the engine at peak HP rpm.

hey, go ahead and experiment!  It's a free country...see what happens ...maybe you'll like it!

But I've had this argument many times...and NOBODY has ever produced actual data as to improving say 1/4 mile or 0-60 speeds.....they just say it "feels" better.  If it makes you feel better, why not?

If there is any slight advantage in acceleration, in will only be in the first 1/2 second, and will have infinitesimal effect on performance of any kind.


Now running a HIGHER gear, may have some actual merits for those who do long highway cruise or commute, and don't want to listen to the engine screaming at high rpm for the whole ride...possibly a slight MPG advantage...but no "performance" advantage either...and probably lower top speed  (yes a higher gear can cause lower top speed, because the engine can't rev up to the max HP range)

Lots of data available on the internet to research this stuff...with pictures and arrows and expalinations.

Cookie

Quote from: qcbaker on April 19, 2018, 01:13:37 PM

Quote from: twocool on April 19, 2018, 11:33:38 AM
15 th sprocket will only make a difference in the first 1/2 second of a max acceleration from a dead stop.  (drag race)...it will make no performance difference once you are "rolling" ...it may have an effect on all out top speed, and oddly it could be either way..."depending"  (If wind drag gets so high, that you hit the "drag wall" before max HP rpm, then a lower gear could be a tad faster)...but who is driving their GS500 at top speed? And how often if they do?

Stock gearing is just right.

What do you mean it wont have any effect once the bike is rolling? The different gear ratio means that the engine RPMs will be higher at any given speed. Wouldn't that mean that at any speed where engine RPMs are lower than ~8.5K, I'll have more torque than I would with the stock sprocket?

http://motorcycleperformanceanalyzer.com/suzuki/gt-550-1974/

Link gives performance graphs for various bikes....you can change out the gear teeth and see what happens!


They don't have a gs500 in the data base so the GT 550 is similar in power.

If you drop the front sprocket by one tooth, you can see that the two graphs are nearly identical above 40kn/hr.

You do see that slight advantage in first gear with the lower ratio but once up to 40 km/hr they are the same.

But if you go to the 1/4 mile times you see that the difference is almost imperceptible!

you can also see a slight loss of top speed.

But all this only matters if you are driving like a nut and extracting maximum performance out of your bike at every possible second.  This cannot be done in street riding...maybe on a track?


Cookie

Yup, its all about shift points and where you want 1st gear to start and 6th gear to end. Its going to depend on your specific riding needs.

With 15t 1st gear becomes almost unnecessary. The one thing I liked about it was that I could sit in 2nd gear while navigating neighborhood streets. I lived in Seattle at the time I had the 15t sprocket and Seattle's neighborhood intersections are almost all uncontrolled (4 way grid with no stop sign or yield signs). With stock gearing I would have to switch between 1st and 2nd between each intersection. With 15t 2nd gear was perfect. Imagine a 1.5 gear on stock gearing, that's what 2nd gear feels like with a 15 tooth sprocket.

With 17t sprocket you feel like you are working the clutch on every start from 0mph. 6th gear is already drag limited with stock gearing so the 17t just makes 6th gear that much more useless on steep hills, strong headwinds, and when carrying a passenger. On long flat highway it is really nice to cruise 400 rpm lower. If you live someplace flat maybe you will like the 17t sprocket. On a 2-up trip through San Francisco with the 17t I almost stalled the bike starting on some of their more insanely steep hills. Seriously, steepest hills you have ever driven on and they put a stop sign before the crest of the hill. I would have to rev the bike up towards the red line before releasing the clutch lever in order to prevent stalling.

Seriously though, just try it. 15t and 17t can get put on the bike with the stock chain length. The sprockets are like what, $20? And maybe an hour to put on? Just do it and decide for yourself.

Edit: Just had to make note of this exact moment in time where twocool and I both have the exact same number of posts! 1670. What are the odds of that? Which one of us will mess it up first?

1671

Quote from: Bluesmudge on April 19, 2018, 05:43:25 PM
Seriously though, just try it. 15t and 17t can get put on the bike with the stock chain length. The sprockets are like what, $20? And maybe an hour to put on? Just do it and decide for yourself.

I think after I move next week and have access to a garage, I may try out a 15T sprocket just to see how it feels. If I don't like it, I'll just put the old one back on.