16T Sprocket for Suzuki GZ250

[Atanvaryar]

Hi there,
I'm a relatively new biker, moved to NZ this year and bought my first bike, which turned out to be a Suzuki GZ250 cruiser.
I've read a lot about the bike on the model forums and most people recommend replacing the front 15T sprocket with 16t to improve it's responsiveness on the road and it's top speed a little.
Now, I am not really after top speed, but being able to ride the speed limit on the motorway with the engine not screaming is good idea in my opinion so I decided to give it a go.
My only problem now is that all forums I've read are either for the American or the European riders, which leads me to this question:

Where would I acquire a 16T sprocket for my motorbike in NZ? I've found a few on trademe, but they mostly mention all kinds of sports bike models and not cruisers.
Is there any difference in front sprockets between cruisers, sports bikes, or even between makes?

Thanks for the answers.
Cheers.

[awayatc]

Only things that matter is that the sprocket you chose fits the shaft...
I.e same spline and diameter......
sport/ cruiser etc irrelevant.
but every make and model of bike has its own specific fit...

second thing to consider is wether there is physically enough room for a bigger sprocket.

you can also fit a smaller rear sprocket to achieve same result....

[awa355]

This is the link to the JT sprocket range for your GZ250. It lists for the 2010-11 models, but I think all the GZ 250's were the same ratios.

http://www.jtsprockets.com/catalogue/model/1609

It shows a 16t front sprocket avalible. This will raise the gearing slightly which will drop your revs at 100 kph just enough to make the engine feel a little less revvy. . You will still have much the same top gear pulling power and the occasional drop down a gear on a long climb wont hurt the engine at all.

I went up one tooth on the front sprocket on my Virago 250 for the same reason. I have now settled for the standard front sprocket and a lower toothed rear. The JT info doesn't list an alternative rear sprocket for your bike which would give you a greater choice of ratios, but a Suzuki dealer may have other options for you.

My JT front sprocket was about $20 with freight. I got it thru' the local Suzuki dealer with no problems. My rear 40t sprocket was $45 and the Suzy dealer changed my rear sprocket for no cost. If you go up one tooth on the front, you may have to add another joining link into the chain.

[Atanvaryar]

Thanks for the links.
Why did you go for a lower-toothed rear and not the increased front? What is the difference apart from more work in replacing the rear sprocket?

Cheers.

[awa355]

Thanks for the links.
Why did you go for a lower-toothed rear and not the increased front? What is the difference apart from more work in replacing the rear sprocket?

Cheers.

The original ratio on the Virago was 16/45. I went to 17/45 (better), then tried 17/40 (too high for pulling away from 60-70kph corners and holding cruising speeds on hills). Have settled on 16/40 now. It is spot on for the rolling country around the Waikato/Waipa districts. The 16 seems to get more torque response out of the engine.
Here is a link to my ride stories on this website. It might give you an idea of what you can do on a small cruiser. I explain a bit about the changing of ratios and why.

http://www.kiwibiker.co.nz/forums/showthread.php/173139-Waikato-rides

[FJRider]

Thanks for the links.
Why did you go for a lower-toothed rear and not the increased front? What is the difference apart from more work in replacing the rear sprocket?

Cheers.

Smalller increments in ratio change can be made if the change is made on the rear wheel sprocket.

As I recall .. the ratio is one tooth on the front ... is equal to (about) seven off the rear. For a 250 ... that is a major amount.

[awa355]

Here is a programme to calculate the original ratios and any changes. It works for any bike. Can be a bit complicated to use. One tooth up on the front is about equivalent to going down three teeth on the rear. I found that retaining the original 16t on my bike seems to allow the engine to put out more torque at lower revs eg 4000 than having a 17t front. With the 16/45 on my bike, I would be up to third gear within the width of a two lane intersection. It would pull away from 50kph in top gear without any struggle at all. Going to a 16/40 combo the bike outputs 80-100% of max torque between 80-105kph and still pulls from 65k in top gear.

http://www.gearingcommander.com/