Gearing change WTF, someone care to explain?

[FinalImpact]

I agree with most of what you say BUT AS SOON as the sprockets are changed, the TRUE SPEED in relation to RPMS WILL CHANGE..

IE, if you could put a 50 tooth front sprocket on the engine, RPMs WILL BE LOWER FOR THE SAME SPEED, more chain is being pulled, thus spinning the rear tire faster...

You know as well as I do, change a sprocket #, the speedometer will also change. Put bigger tires on a car than stock, the speedometer READS LOW...

But that's not what he's pointing out. . . . if you held the bike in the air and tried a 15t, 16t and 17t front sprocket, what would the speedo report with the REAR TIRE IN THE AIR i.e. OR NO DRIVE CHAIN?
<< It should be the same for all gear sizes NO MATTER WHAT; Right! That's the point of this thread. It's not.
But there's a small errors in calculation and its making it look like a big factor. And when I say errors in calculation I mean ECM algorithms for RPM and Speed.

If Yama made 15t plastic one, I'd test the the other spectrum for MORE ERROR!!! :rockon:

 

[Cortez]

But that's not what he's pointing out. . . . if you held the bike in the air and tried a 15t, 16t and 17t front sprocket, what would the speedo report with the REAR TIRE IN THE AIR i.e. OR NO DRIVE CHAIN?
<< Should be the same for all gear sizes NO MATTER WHAT; Right! That's the point of this thread. It's not.
But its so small that errors in calculation are making it look like a big factor. And when I say errors in calculation I mean ECM algorithms for RPM and Speed.

If Yama made 15t plastic one, I'd test the the other spectrum for MORE ERROR!!! :rockon:

Thanks, that's the point, I can't believe how many people seem to miss the point and just blather in general about gearing changes.

One thing that the shop that did the sprocket swap pointed out is that
there might be something different because mine is an ABS model and ABS
relies on comparing front and rear speeds.. maybe there's some sort of
additional electronics involved that non of you non-abs guys have.

I guess that makes sense.. and that the speedohealer might be the
only option to fix this.

I'm having a harder time adjusting to the more then apparent loss of
acceleration then the speedo error, though..


It's was a lot less dramatic on my 650cc twin when I did this.
The FZ6 engine is so gutless down low.

 

[TownsendsFJR1300]

Point obviously missed, blathering is NOW discontinued.

 

[dpaul007]

That's something to research. Do the ABS bikes take the speed of the bike at the wheels and NOT the output shaft of the transmission? I'm sure someone who can find the right manual can find that answer for you. That would explain things perfectly


Sent from my iPhone using Tapatalk

 

[TownsendsFJR1300]

That's something to research. Do the ABS bikes take the speed of the bike at the wheels and NOT the output shaft of the transmission? I'm sure someone who can find the right manual can find that answer for you. That would explain things perfectly


Sent from my iPhone using Tapatalk

ABS has sensors at the front and rear wheels themselves. When the system senses a difference in speed (ONE WHEEL VS THE OTHER) while braking (a wheel locking up), it kicks in..

Anti spin (accelerating) (not available on the FZ6) uses the same technology, just in reverse, may chop the throttle, cut ignition, slightly apply brakes (several different methods) some (to keep the rear wheel the same speed as the front).

 

[FinalImpact]

Cortez, does your bike even have a sensor on the output shaft?

It very like just uses the wheels abs sensors. Most would poll the speed from the front as its not powered and is least likely to be slipping compared to the rear.

Great goose chase this thread has been. lol

 

[Cortez]

Cortez, does your bike even have a sensor on the output shaft?

It very like just uses the wheels abs sensors. Most would poll the speed from the front as its not powered and is least likely to be slipping compared to the rear.

Great goose chase this thread has been. lol

Yeah, the sensor is there..

 

[dpaul007]

I'd unplug it for giggles and go for a ride and see if the speedometer reads anything


Sent from my iPhone using Tapatalk

 

[Cortez]

I'd unplug it for giggles and go for a ride and see if the speedometer reads anything


Sent from my iPhone using Tapatalk

That's as good idea as it gets.

But somehow I figured I'd get a clear "it's that and that" answer a lot
sooner and I've lost interest by now.. it IS a bit more accurate then it
was, I'm gonna say it averaged 7%, now it's 5-6%, so I'm gonna deal
with it in my head and just keep on riding.

I don't see any other explanation then the ABS having something to do
with it.

 

[TownsendsFJR1300]

But that's not what he's pointing out. . . . if you held the bike in the air and tried a 15t, 16t and 17t front sprocket, what would the speedo report with the REAR TIRE IN THE AIR i.e. OR NO DRIVE CHAIN?
<< Should be the same for all gear sizes NO MATTER WHAT; Right! That's the point of this thread. It's not.
But its so small that errors in calculation are making it look like a big factor. And when I say errors in calculation I mean ECM algorithms for RPM and Speed.

If Yama made 15t plastic one, I'd test the the other spectrum for MORE ERROR!!! :rockon:

Ok, I know someone will disagree but thinking about it, here it is in a nut shell.

Yes, the engine RPM WILL ALWAYS be the SAME RELATIONSHIP (say 1:1) at the output shaft in say 6th gear.

That shaft has the speed sensor which the ECU reads.

The speedometer error occurs when changing sprockets.

Again, the engine RPM and output shaft RPM's DO NOT CHANGE, PERIOD. The sensor (unless altered by a Speedohealer or other electronic device) will read a certain #

Once you change ANY SPROCKET, up or down, the OUTPUT SHAFT (still turning the same ratio) is going to turn the rear wheel slower or faster (TRUE speed per a GPS) as the sprocket(s) changed thus altering the rear wheel speed.

The ECU is now going to give a higher or lower speed because its set at the factory (with stock gearing) to read approx 7% low (give or take).

That is why going up ONE TOOTH to a 17, up front speeds up the rear tire(thus increasing TRUE SPEED) and offsets the built in error with the ECU

Its got nothing to do with torque, ABS, brakes, etc...

 

[Cortez]

Ok, I know someone will disagree but thinking about it, here it is in a nut shell.

Yes, the engine RPM WILL ALWAYS be the SAME RELATIONSHIP (say 1:1) at the output shaft in say 6th gear.

That shaft has the speed sensor which the ECU reads.

The speedometer error occurs when changing sprockets.

Again, the engine RPM and output shaft RPM's DO NOT CHANGE, PERIOD. The sensor (unless altered by a Speedohealer or other electronic device) will read a certain #

Once you change ANY SPROCKET, up or down, the OUTPUT SHAFT (still turning the same ratio) is going to turn the rear wheel slower or faster (TRUE speed per a GPS) as the sprocket(s) changed thus altering the rear wheel speed.

The ECU is now going to give a higher or lower speed because its set at the factory (with stock gearing) to read approx 7% low (give or take).

That is why going up ONE TOOTH to a 17, up front speeds up the rear tire(thus increasing TRUE SPEED) and offsets the built in error with the ECU

Its got nothing to do with torque, ABS, brakes, etc...

Yeah, that's exactly what's should be going on, but apparently in my
case isn't.. and my dealer says that it might have something to do with
the ECU & ABS doing something differently on the ABS model.