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Sproket setup

3K views 16 replies 9 participants last post by  dave zx12r 
#1 ·
Well looking at my bike everything needs a refreshment. What would be a good street setup for sprokets
 
#2 ·
Most people go 1 down in the front, and 1-2 up in the back. This improves launch, if that's important to you (informal street drags), but you lose ultimate top end speed and speedometer accuracy.

I went 1 up in the back, and I honestly can't tell much difference. I had to though, because that's all Supersprox had to match my new wheels.
 
#3 ·
If I remember correctly going down one in the front is about the same as going up 2 in the rear. So up or down 1 in the rear is not much of a change, you need 2 to get a real change.

I did down 1 in the front with stock rear, and I think the bike rides better than stock (the sweet spot feels like it is at a lower speed in each gear).

I have a SpeedoDRD Speed corrector, it is small, and when coupled with a wire extender, you can hide the module in the tail. I ziptied it to the rear frame inside the tail.

12oClockLabs LLC
 
#4 · (Edited)
BigSkip,

First I want to say I don't race, street or track so I've always found the stock gearing (18/46) to be perfect. My bike will pull cleanly from 2500 rpm in 6th if I so choose. My worst gas mileage has been about 25 mpg, best was about 44 mpg.

When deciding on sprockets keep in mind changing rear tire size has the same effect as changing either/both sprocket size. Increasing tire diameter, same as reducing rear sprocket size, or increasing front sprocket size. Decreasing rear tire diameter, same as increasing rear sprocket size or decreasing front sprocket size.

I use a 190/50 rear tire so there is approx. 1.5% change in gearing or the same as using a 47 tooth rear sprocket. It means at any given speed my engine is turning 1.5% more rpm than it would stock.

As an example: If you change the front to a 17 expecting a 5.9% change but are running a 190/50 rear you'll actually have a change of over 7%. Personally I like to have a goal in mind when I change gearing, better mileage, more relaxed cruising, move the engine's sweet spot to a different speed, faster acceleration, etc...... Then figure what percentage of change I want to make and what sprocket tire combination gets me closest to that percentage.

Also keep in mind that changing final drive gearing also changes the relationship of each gear to the one before and after it. So a 17 front sprocket brings the gears even closer to one another by 5.9%.
 
#8 ·
i went to a 16 t front ,with standard rear , and it was almost un-rideable , massive wheelies in the the 1st 3 gears !! so i went to a 17 t front standard rear ,and it rides perfect for me ,still wheelies on the throttle 1st and 2 nd ,and 3 rd if you really get carried away , but it is safer and easier bike to ride fast ..
like most things ,there are lots of varibles ie: state of tune ,how you ride ect ect .....
 
#9 ·
I dropped 1 tooth in front, went from 38.5mpg to 18mpg...and the acceleration gain wasn't worth the cost so I went back to the stock cog and tossed that 17 tooth in a box somewhere. Massive economy loss. I know tho...most guys here will hit ya with the "you din't buy the 12 for fuel economy..." blah blah....but for those who commute, yea, that cuts your mileage in half dropping 1 tooth in front. Prolly a combination of hitting the gas more often and just being in higher RPM's all the time. 2nd gear was pretty accurate with the speedo...2500 is 25mph, 3000 is 30mph ect, and with the 17 tooth, 3500 was 25mph indicated but 18 actual...yadda yadda...some shit like that. Imo, dropping 1 tooth ain't really worth it unless you want a gas station racer....haha. Kawasaki did good with their choices, for economy and such.

I still may try dropping a tooth in back tho once. I don't ride the old girl that often anymore. Had it out once to work this year....
 
#12 ·
Are you sure you actually dropped that much? My gas mileage stayed the same (slightly less to account for the higher RPM at the same cruising speed). I did adjust my speedo with a SpeedoDRD box. Before the -1 up front my speedo was dead on from the factory (once I put the 190 tire on), with the -1 and SpeedoDRD I got it back to dead on (it was off by around 18% before the box).

If you dropped the tooth without sinking up the speedo, it would make perfect sense that your mileage is actually 18% farther than your speedo indicates.
 
#11 ·
Try the 17 tooth front, stock rear, see how you like it. It's about the cheapest performance enhancement and you can go back easily enough if you don't like it. No changes to the rest of the bike required.
 
#13 ·
16/44 street which is equal to 17/47 ( both work well)
16/50/51/52/53 for strip depending on your,weight and RWHP :) Stockish engine the above works well.
Most the high HP turbo guys over here run stock 18/46
Its about finding what works for you best and your ultimate aims.
Some have commented that 16 rubs their swing arm but not on my A1.
I have just fitted a Robinson 1st gear which gives +2 on the rear in first.
So I will be going WOT off the lights at 16/55 wahaay! :)

Problem on strip gearing on street can be your tyre will be colder and you will spin out and not accelerate....
Just experiment and have fun :)
As others,have said, maybe try the 17 on the front first.. Good luck ..... :)
 
#14 ·
Yea...it factored bout 19mpg...however, you bring up a good point about the speedo being off. I did not factor that in now that ya mention it. I was in the gas a helluva lot more too tho. Seemed like I was fillin the thing up every 70 miles or so. Guys were growing tired of stopping at gas stations all the time on rides...haha.
 
#15 · (Edited)
I'd keep the gearing stock. It's what I'm back to now. While doing gear swaps is when my fork seals gave out at around 8-9k miles Coincidence, maybe. I think it was mentioned previously about swapping out 1st gear. I'd like to try a bike setup like this as I really like 2-6 as is.


Yea...it factored bout 19mpg...however, you bring up a good point about the speedo being off. I did not factor that in now that ya mention it. I was in the gas a helluva lot more too tho. Seemed like I was fillin the thing up every 70 miles or so. Guys were growing tired of stopping at gas stations all the time on rides...haha.
Completely stock my 12 would see 35mpg maybe more can't remember. Stock geared with a full exhaust its still in the 30s. So in other words your 19mpg is serious action. I'm lucky to be alive and not have wrecked. And you're killing it x2. Awesome :thumbup:
 
#17 ·
I'm riding my ZX/ZZR 1100 turbo stock gears
17/45. +1 on the rear as I have ZX12 rear hub and am using OEM 46 tooth zx12 sprocket.
Once rolling it pulls like a spaceship in any gear, however when cruising at motorway speeds etc the revs are nice and low around 4-5 k which makes it nice and of course means better mpg :)

Now my road bike, loving it like my first z x12 .

Just compromise to where you will get best all round use. Race gears are best on the race track.
:)
Minor changes are fun but at the expense of inaccurate speedo , mpg , etc. as everyone has pointed out.
Find what suits you best... Good luck .


I'd keep the gearing stock. It's what I'm back to now. While doing gear swaps is when my fork seals gave out at around 8-9k miles Coincidence, maybe. I think it was mentioned previously about swapping out 1st gear. I'd like to try a bike setup like this as I really like 2-6 as is.




Completely stock my 12 would see 35mpg maybe more can't remember. Stock geared with a full exhaust its still in the 30s. So in other words your 19mpg is serious action. I'm lucky to be alive and not have wrecked. And you're killing it x2. Awesome :thumbup:
 
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