16T vs 15T sprockets

[cayuse]

OK, I'm eating my words a little here, but I now have to say there is a good argument for using the stock 15T front sprocket.

I converted my bike over the winter to the 16T sprocket and I've run it now for a couple of months and for the most part I just love it.
It stretches out the lower gears very nicely so 1st is good for more than just 10 feet and 2,3, and 4 have really nice torque at speeds
that feel really comfortable. So, for motoring around town and between towns on the secondary roads it’s perfect. The only problem is 5th gear.

The GZ doesn’t have a lot of power anyway but it really is crippled with the 16T sprocket at speeds over 100kph (60mph).
I found I could achieve speeds up to about 110kph (70mph) as long as the road was flat or downhill and the wind was not against me.
I couldn’t get mine to go faster than that without a tailwind. Throw in some hilly terrain and I’m downshifting very quickly to 4th
to keep up with (most) traffic. When that happens, fuel mileage goes out the window. This season I’m hitting the open road more
often so these experiences are somewhat disappointing. I was even starting to shop for a (gasp!) bigger bike.
But then I remembered everyone here saying the top speed would probably be reduced with the taller sprocket so I thought I would give the 15T another chance.

So, to do a fair comparison, I put the 15T sprocket back on and tried my work commute a couple of times on Hwy 1, the local “freeway”.
It’s hilly, everyone’s driving at 110-120kph and there is a little wind here and there so it’s a pretty good test. I don’t normally commute
on this route because, except for the speed, it’s pretty boring. Guess what? I’m keeping up with all the traffic, and no downshifting on
the hills! I’m even passing!! Of course the downside rears its ugly head: 1st gear is very short, I’m tempted to skip it and take off in 2nd
unless I’m parked on a hill, and all the other gears seem just a little short too.

So, what am I going to do? I’m going to stay with the 15T for a couple of weeks and make another run up into the mountains to give it a real good test.
If it works out the way I think it will I will probably switch back to the 16T sprocket and reserve the 15T unit for occasional ‘road trips’ into the mountains.
The 16T option is just too nice to give up for the local riding I do 95% of the time.
I can change the sprocket and tension the chain in a ½ hour so it’s not a big deal.

[JWR]

That is exactly what I did with my 250.

The GZ just will not pull any real hills, with the 15 or 16 tooth.

With the 16, you have a lot of throttle left, but it is not going anywhere ( no torque).

There are always trade off's.

[geezer]

ive been wanting to do a thead on the 140 rear wheel myself but you just nailed it on the head here. its pointless to try. i hear going a size tire bigger is like a 15 1/2 sproket and thats bad enough i cant imagine the loss of power using an actual 16t. all i know is when this tire finally wears out im going back to a 130! shoot im temped to try and find someone willing to trade

[cayuse]

It just comes down to what you want to do. If you want to blast up and down the freeway at 70mph then stay stock. If you want to putter around town and travel the backroads going no faster than ~55-60, then you'll probably find the 16T sprocket a great upgrade.

[jonathan180iq]

You could go with a 40 tooth rear sprocket and leave the 15 up front.

That would give you a final drive gearing of 2.66 which would fall right in between the experience of riding a 15T front sprocket and a 16T front sprocket. (15T = 2.73) (16T = 2.56)

[cayuse]

I wouldn't mind trying a 40T rear sprocket. Is there such an animal?

[jonathan180iq]

Where can I purchase a new sprocket?

"The Suzuki factory part number for a 16T sprocket is 27511-37200
The JT Sprockets part number is JTF 434.16

Sprocket Specialists make both front and rear sprockets for the GZ250.
The front sprockets are available from size 10-16. Part number: 528-(number of teeth)"

The rear sprockets are available from size 28-74. Part number: 461-(number of teeth)

[advant63]

have you done the carb mods? if not try it. it will pull you with the 16t. plus i'm sure engine will live longer for it.

[geezer]

the carb mods arent gonna change the power output much. its still gonna bog in 5th gear. and as far as i know bogging an engine is very bad for it

[MadCityRider]

I've had a grea experience bumping from the 15T to the 16T. In combination with new Air Intake, Exhaust, and the 130 Main Jet, this bike has become very fun to ride, and can now safely handle traffic over 55 MPH. I would highly recommend the change, as it's simple to do, and very effective. If anyone needs one of the 130 Main Jets, let me know I got extras...

:rawk:

- MCR