15T vs 16T vs 17T

[bombjack]

Hi,

I bought a '95 GS last year that was completly stock.
After riding it for a couple of months I found the GStwin.com site and read about "the recommended mods". The 15T front sprocket mod was recommended by several people, so I ordered one, installed and went for a ride. Well, I was not that impressed. Sure, it was a little faster when accellerating from stand still, but on the other hand, second gear came much sooner. In fact, sometimes I would start in 2nd gear.
But it's even more annoying when I ride the freeway, I always try to upshift to 6th gear, only to realize I'm already in 6th  I needed a 7th gear so to speak.
I can't imagine how horrible a 14T sprocket must be.

I kept riding with this configuration for 6 months before I decided to buy a 17T sprocket. I just installed it two days ago and I'm really pleased with it. First gear is now usefull for slow riding (like traffic jams), instead of 2nd gear.
Freeway riding is so much more relaxed now. It will do 120kmh (75mph) @ 5000 rpm. Top speed has improved too. Mileage should improve too, but it's too early to say.
If I need to race, I just downshift and ride it at 6000-8000 rpm.

My recommendations would be:
15T : If you use your GS for racing and never ride the freeway
16T : For semi-racing and casual riding
17T : For semi-racing and touring

I might even consider a 18T if I find one.

[ojstinson]

I'm with you buddy, why make your engine spin faster and more times per mile than necessary. Just think of how many more times in 20 or 30 thousand miles the 15T engine has turned over as opposed to the 17T-----and for what?

[007brendan]

How is the odometer driven?  Is it off the front wheel?  Or does it need to be adjusted for changes to the final drive sprockets.

[black and silver twin]

How is the odometer driven?  Is it off the front wheel?  Or does it need to be adjusted for changes to the final drive sprockets.

Its driven off the front wheel, so no adjustments are necessary. although its high by ~10% stock.

I have the 15t sprocket and I love it, I do most of my riding on freeways/high-speed country roads. I was however thinking of reinstalling the 16t to see if my top speed would go up, but it might take forever to get there. On the other hand a 14t would bee awesome for wheelies. I only consider the 17t for freeway cruising. In the end I personally will sacrifice a few MPH for acceleration and I still get ~50mpg so the 15t will probably stay.

[Sbag0024]

 I did notice that my bike is way off on the odometer. . with a friend I was able to tell that at 55mph for him is 60+ on mine.. so is there any way to adjust that?  The 55 is not really an issue, but I do a lot of highway and I'm even more off at 65-70 mph,  just not sure how far off..(haven't tested that yet but cars blow by me and I'm going 75mph on my tac)

ps.. I have the stock size tiers on but a 47 or 49 (not sure what it is that the previous owner put on) though should not matter if the speed is reading from the front wheel.

[rger8]

I was thinking of a 17 tooth. Seems like the stock 16 is pretty good but it would be nice to have it cruise just a bit eaiser. Do you lose a noticable amount of bottom end? I guess I wouldn't mind a little, but I don't want to be bummed out

[the mole]

I changed to 17 tooth and its great.

[tt_four]

I have a 14t. its ok but definitely not ideal from 50mph and up. Ill probably go back to a 16t at some point. If my engine was smoother itd be ok. the engine isnt buzzy at those rpms but i get a lot of vibrations through the bars. with 14t Im at just over 5k rpm when I go 50mph. Im always trying to shift into 7th.

[DoD#i]

I did notice that my bike is way off on the odometer. . with a friend I was able to tell that at 55mph for him is 60+ on mine.. so is there any way to adjust that?  The 55 is not really an issue, but I do a lot of highway and I'm even more off at 65-70 mph,  just not sure how far off..(haven't tested that yet but cars blow by me and I'm going 75mph on my tac)

Adjust, not really, supplant, yes. Search the archives, there are several threads about various bicycle computers which can be adapted to give an accurate speedometer, or I guess you can slap on a GPS and get an accurate speed that way.

It's quite likely that neither your speedometer nor your friend's is actually accurate - few are even close.

On a typical mileposted interstate highway, all you need is a watch. Ride at a steady indicated speed, time the mileposts, get true speed at that indicated speed. 60 seconds is 60 mph, 48 seconds is 75 mph, generically, divide 3600 by seconds to get miles per hour, and divide 3600 by miles per hour to get seconds (so 75 seconds is 48 mph...) Don't try this in heavy traffic, you need all your wits about you in heavy traffic, and don't want to be sparing attention to look at a watch.

[Homer]

I need an air impact for the front on my V.   
And the housing's too small for an 18t.

[bombjack]

I was thinking of a 17 tooth. Seems like the stock 16 is pretty good but it would be nice to have it cruise just a bit eaiser. Do you lose a noticable amount of bottom end? I guess I wouldn't mind a little, but I don't want to be bummed out

I was worried about loosing low end power too, but keep in mind that it is only the first gear that starts out at lower rpms (compared to 15T or 16T). All other gears are relative, and you can rev it as high as you usually do, and you will have the exact same power.
I don't feel that I lost ANY low end power at all. With the 15T, first gear would start at 4000 rpm from standstill. With a 17T , first gear starts at 2500 rpm. I usually upshift at 6000 rpm, so the 15T makes first gear very short. The acceleration gain from 15T is easily lost to the extra time used for upshifting to an early 2nd gear.

Anyway, just wanted to say that the 17 T sprocket rocks! 

[bombjack]

I need an air impact for the front on my V.   
And the housing's too small for an 18t.

To bad the housing is too small for an 18T. I guess the second best thing to do is replace the rear sprocket.
What's the smallest rear sprocket for the GS500?
I want the lowest gearing I can get.

[bill14224]

After riding this bike for two minutes on the freeway I said to myself "this bike needs another gear" so I put a 17-tooth sprocket on it almost two years ago.  The change makes it 6% taller, about half a gear.  When going slower I just stay the the previous gear a little longer.  6th gear is truly an overdrive gear now although she will still accelerate in top gear.  She loves to cruise at 75, (80 on the speedo) unlike before.  I don't do wheelies so I don't miss anything.  A 17-tooth sprocket transforms the GS from a neighborhood bike to a road bike.

[marc]

Yep!
Just another 17teeth sprocket user.

I'm very pleased with it. The only bad effect is that I'm unable to go beyond 8000RPM with 6th gear. I first need to revv 5th gear to the top and then can shift to 6th.

But of course, speaking about 8000's and 9000's with a 17 teeth sprocket leads to speeds beyond 180Km/h (110MPH)

[drduimstra]

So where can I find the 17th sprocket?

[Toogoofy317]

Hmmm, guess I'm different. I'm quite pleased with the 15 tooth sprocket. It's nice to be a little bit faster at red lights and such. I didn't see a mpg decrease infact it seemed to go up a couple of miles. 94% of my riding is in town so I rarely see sixth gear. In the slow crawl of I-4 I can still stay in first realatively well and not immeditately have to shift up.

Guess YMMV!

Mary

[bill14224]

Hmmm, guess I'm different. I'm quite pleased with the 15 tooth sprocket. It's nice to be a little bit faster at red lights and such. I didn't see a mpg decrease infact it seemed to go up a couple of miles. 94% of my riding is in town so I rarely see sixth gear. In the slow crawl of I-4 I can still stay in first realatively well and not immeditately have to shift up.

Guess YMMV!

Mary

That's quite alright Mary, and I hope you are doing well.  It all depends on what you use the bike for.  I need to go light-to-light and also 75 on the freeway.  Our bike hates to hang at 75 without a 17-tooth sprocket.  That's why I preach the 17-tooth sprocket.  Since you're not a stunter I'd bet if you tried it you'd love it too.  You don't give up much on the bottom, especially once you're rolling.  First is very low.  First with a 17-tooth is sufficiently low, good enough for easy launches.  Your mileage will go up with taller gearing, the opposite just isn't possible unless you never leave your apartment complex or Suzuki geared the bike too tall to begin with, which they didn't.  Try it, you'll like it!  I swear to you if you're not into stunting you won't miss a thing.  You will just have a bike that's friendly like before but faster and more comfortable at highway speeds.

[black and silver twin]

why would you say the gs doesn't like 75mph without 17t? mine goes 75 much better with the 15t over the 16t. I do 75% freeway riding and think the 16t is too tall, but 15t is slightly too short. 15t with 140-70-17 rear tire is near perfect. obviously if your goal is long cruises and mpg then 17t is best. honestly though I wouldn't consider a 17t unless I was going cross country.
also why is it that alot of people say 1st gear is too short? heck with a 15t itll do 40 in 1st

[ohgood]

I did notice that my bike is way off on the odometer. . with a friend I was able to tell that at 55mph for him is 60+ on mine.. so is there any way to adjust that?  The 55 is not really an issue, but I do a lot of highway and I'm even more off at 65-70 mph,  just not sure how far off..(haven't tested that yet but cars blow by me and I'm going 75mph on my tac)

Adjust, not really, supplant, yes. Search the archives, there are several threads about various bicycle computers which can be adapted to give an accurate speedometer, or I guess you can slap on a GPS and get an accurate speed that way.

It's quite likely that neither your speedometer nor your friend's is actually accurate - few are even close.

On a typical mileposted interstate highway, all you need is a watch. Ride at a steady indicated speed, time the mileposts, get true speed at that indicated speed. 60 seconds is 60 mph, 48 seconds is 75 mph, generically, divide 3600 by seconds to get miles per hour, and divide 3600 by miles per hour to get seconds (so 75 seconds is 48 mph...) Don't try this in heavy traffic, you need all your wits about you in heavy traffic, and don't want to be sparing attention to look at a watch.

...or just use a gps. i've verified my (gone) gs's speedo with four different gps devices. memory serves- 10% high was the gs's speedo reading. remember, speedometers are set HIGH so you can't sue the manufacturer over speeding tickets.

changing your front tire size will change your speedometer's reading.

changing your rear will change your final ratio, but not speedometer, on the gs.

getting back to the 14 vs 17t discussion, it would be neat to see your milage results after a while.

i don't recall what the odometer's reading was on my gs. iirc the odometer was very close to actual. i'd assume thats true for all cars/trucks/whatever so that accurate milage figures can be documented. the speedo is more like a suggestion anyway.

[sledge]

Agreed.

Speedos are like every other component, they are made to a tolerance and the tighter the tolerance the more the cost. Manufacturers include the tolerance on the over-read side so it will never appear that you are traveling slower than you actually are.

If you want an accurate speedo you will have to pay more and have it regularly checked/calibrated to ensure it stays accurate......is it worth the cost? I just knock 10% off the indicated figure and I know I am in the ballpark.