Front sprocket 15T vs 16T

[ZR468]

I asked this question before the dismise of the old forum, of course now I cannot retrieve the valued answers. So I need to ask it again. I recall someone said the 16T is less rev or hurry at highway speed. My questions today are how much of the performance is affected at city speed? Is it noticable? Do I need to ride one gear lower to get the same acceleration?
My bike is a 1992 ZR750. Thank you in advance to all your sage advices.
Kenny

[hugojose]

No, unless you are racing (...and you shouldn't be on these old ladies), the slightly slower acceleration will not be noticed. This is a trade off; less revs = Lower acceleration, higher top speed..... Higher reves = Higher acceleration, less top speed.

The RPM will drop about 300. The chain will appreciate the bigger sprocket. I run a 17T. The successor to the Zephyr, and last KZ750 in North America, the ZR-7 came with 16/39 combination, vs the 15/38 of the Zeph, which would drop the revs about 400

[Shedman]

No, unless you are racing (...and you shouldn't be on these old ladies)

As I'm a lot older than my bike that doesn't apply to me!

[David Richard]

i have a d1 I have put it on 17 teeth front I had some spaces made up ,its great the engine is far more relaxed and you an still do 30 mph in top ,it could have had 6 gears for a better spread of power,give it ago ,david

[Freddy]

I asked this question before the dismise of the old forum, of course now I cannot retrieve the valued answers. So I need to ask it again. I recall someone said the 16T is less rev or hurry at highway speed. My questions today are how much of the performance is affected at city speed? Is it noticable? Do I need to ride one gear lower to get the same acceleration?
My bike is a 1992 ZR750. Thank you in advance to all your sage advices.
Kenny

You probably won't notice any difference at city speeds, but on the open highway you most certainly will notice it. You've made the final drive a higher gear ratio so acceleration has to suffer, unless you change down to one lower gear than previously.

Where the loss of acceleration will be most noticeable is overtaking vehicles on the open road. Even with stock gearing changing down to 4th still puts the engine below where it 'wakes up' around 6000 rpm. If you run higher final gearing in the same 4th gear you will be even further away from the power band unless you change down to 3rd gear. I hate spending more time on the wrong side of the road that absolutely necessary.

I ran a 16 for some time, and changed back to a 15 because it did affect open road acceleration to much. I find the 750 silky smooth at 4500-5000 rpm at posted limits on the highway with stock gearing so don't really see a reason to alter this characteristic.

[ZR468]

Fredy, what is the posted highway speed at your part of the world? Around here, it is 100km, but the flow speed is 120km. On certain major highway, the posted speed is 120km, flow speed is around 140km, the ZR750 has to go to 150KPH to keep up.

[Freddy]

Fredy, what is the posted highway speed at your part of the world? Around here, it is 100km, but the flow speed is 120km. On certain major highway, the posted speed is 120km, flow speed is around 140km, the ZR750 has to go to 150KPH to keep up.

My experience was that the bike went no faster, even possibly had a slower top speed, with a 16 T sprocket. That's because the engine didn't have enough grunt to actually pull the higher gearing when you got up over 200 kph.

There wouldn't be a day ride I go on where the speeds traveled at times don't exceed 140 kph.

If I had to regularly maintain speeds of 150 kph on a freeway for sustained periods with heavy traffic, a naked 750 Zephyr would probably be about on the bottom of the list of bikes I'd consider suitable. Actually I'd consider such riding boring no matter what bike I was on and would prefer to drive a car under those circumstances.

[ZR468]

Freddy, you are right about boring travelling at 150KPH. It is basically a straight highway. Unfortunately, most of our nice riding roads take a bit of the freeway to get there. That is urban living. I think the decision I made last time I visited this topic was to buy a 16T sprocket and try it. That is the only way to find out for myself whether I like it or not. Thanks everyone.
Kenny

[Freddy]

Freddy, you are right about boring travelling at 150KPH. It is basically a straight highway. Unfortunately, most of our nice riding roads take a bit of the freeway to get there. That is urban living. I think the decision I made last time I visited this topic was to buy a 16T sprocket and try it. That is the only way to find out for myself whether I like it or not. Thanks everyone.
Kenny

Yep, that's the only way to decide. Cost is minimal and no change is necessary to the chain length. A decent torque wrench capable of 72 ft/lbs and ideally an impact gun to make undoing the sprocket nut a breeze are about the only special tools necessary.

[ZR468]

No, unless you are racing (...and you shouldn't be on these old ladies), the slightly slower acceleration will not be noticed. This is a trade off; less revs = Lower acceleration, higher top speed..... Higher reves = Higher acceleration, less top speed.

The RPM will drop about 300. The chain will appreciate the bigger sprocket. I run a 17T. The successor to the Zephyr, and last KZ750 in North America, the ZR-7 came with 16/39 combination, vs the 15/38 of the Zeph, which would drop the revs about 400

Just figured the math of the gear ratios of the front and rear sprockets. It gave me a point of reference to the different RPM drops. From the parts catalog, I see the ZR750 - C2 comes with 15/39 combination and the ZR-7S (2002) comes with 16/38 combo.
Hogojose, do you want to double check your combinations?