Kawasaki Concours Forum
The C-14, aka Kawasaki Concours-14, the new one :) => The Bike - C14/GTR 1400 => Topic started by: W14 on March 29, 2012, 09:25:29 AM
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Installed a GPS yesterday and was curious as to the accuracy of the C-14's speedometer. What I found was that speedometer was high by about 5%. At 40 mph the GPS read 38; at 80 mph the GPS read 77; don't know about speed higher than that.
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Yes that is correct, and pretty much the norm for any bike I have owned.
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For Harley's as well?
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Manufacturers are capable of creating accurate speedometers. It's more of a legal/regulatory issue. There is a lot of leeway for optimistic speedos, but none for pessimistic ones, so pretty much everybody plays it legally safe rather than accurate.
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For Harley's as well?
Yes. The Ultra Classic I had was off about that much too.
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190/55 rear tire will correct speedometer error quite nicely actually, just saying. 8)
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190/55 rear tire will correct speedometer error quite nicely actually, just saying. 8)
Really? :o
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I thought the speedo was connected to the front wheel, if so how does changing the rear do anything to the speed?
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I thought the speedo was connected to the front wheel, if so how does changing the rear do anything to the speed?
The only sensor on the front wheels is on ABS bikes. The C14 has the speed sensor around the primary drive IIRC. I would have around a 5% error with the 190/50, with the 190/55 (about 1/2 inch taller) it is more like 2-3%.
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The only sensor on the front wheels is on ABS bikes. The C14 has the speed sensor around the primary drive IIRC. I would have around a 5% error with the 190/50, with the 190/55 (about 1/2 inch taller) it is more like 2-3%.
My observations exactly!
Speed sensor is located on top of front gear case.
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I thought the speedo was connected to the front wheel, if so how does changing the rear do anything to the speed?
That is exactly the point. The speedometer reads the same as the front wheel continues at the same speed. But a taller rear tire reduces your RPM's at the same speed, or conversely raises your speed in relation to RPM and front tire rotation.
Mine read the same error rate and at top speed it is about 9 mph high. BTW, with the 55 tire mine is still off 1 mph at 70.
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I had a 190/55 on the rear of my 09 and it brought the speedo closer but not right on,
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That is exactly the point. The speedometer reads the same as the front wheel continues at the same speed. But a taller rear tire reduces your RPM's at the same speed, or conversely raises your speed in relation to RPM and front tire rotation.
Mine read the same error rate and at top speed it is about 9 mph high. BTW, with the 55 tire mine is still off 1 mph at 70.
I'm not sure if I follow what you are saying. A taller (or shorter) rear tire will affect the relationship of rpm's and actual speed, regardless of the speedo drive pickup.
But ....
1 - The C14's speedo is not driven off the front wheel.
2 - On a bike with the speedo driven off the front wheel, changing the rear wheel size (or gear ratio/sprocket sizes) will have no effect on the displayed speed.
3 - On a bike with a rear-drive speedo, changing the tire or sprocket sizes will affect the displayed speed.
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If you want to correct your soeedometer, get a Speed-O-Healer.
http://www.healtech-electronics.com/ (http://www.healtech-electronics.com/)
Fred H. did a write up on this : http://www.pbase.com/fredharmon/speedohealer (http://www.pbase.com/fredharmon/speedohealer)
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If you want to correct your soeedometer, get a Speed-O-Healer.
http://www.healtech-electronics.com/ (http://www.healtech-electronics.com/)
Fred H. did a write up on this : http://www.pbase.com/fredharmon/speedohealer (http://www.pbase.com/fredharmon/speedohealer)
I never understood the logic behind this. Why spend the money and go through the trouble of installing one of these things? You know that your speedo is off a bit but so what? I know, it's a farkle...
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I never understood the logic behind this. Why spend the money and go through the trouble of installing one of these things? You know that your speedo is off a bit but so what? I know, it's a farkle...
:rotflmao: that's enough reason for most of us (me included) but as Fred put it: a gauge is there to give me information. If it doesn't do that, it's useless.
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I never understood the logic behind this. Why spend the money and go through the trouble of installing one of these things? You know that your speedo is off a bit but so what? I know, it's a farkle...
Some people just like to have an accurate speedometer. I know I wish MINE were in all my vehicles. I am not sure I would expend that much money or effort to correct it, though.
What would be nice is if we could calculate the exact error with GPS, and then have the dealer simply adjust the computer to make it correct. No wiring, no installation, no box to fail, etc.
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I just go by what my speedo says. If in reality I'm not doing 70 but 67.2, or whatever, I'm fine. To each their own right? Besides, I'm usually speeding no matter what*.
*never in a school or construction zone though. ;D
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I honestly never give it much thought, I look at my GPS most the time anyways.
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On bikes with chain drive, if you swap out either of the sprockets, it changes the speedometer reading. That's where the Speed-O-Healer is needed the most. But then there's the guy that "must" have his sruff perfect! :o
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On bikes with chain drive, if you swap out either of the sprockets, it changes the speedometer reading. That's where the Speed-O-Healer is needed the most. But then there's the guy that "must" have his sruff perfect! :o
Not if speedo is driven by the speed of the front wheel. Changing sprockets will change engine RPM for the same speed. The amount of air in the rear tire can also effect the speedo input from the front tire. Example, the local Honda shop owner saw the rear tire on my 900. He suggested I add another 3 pounds of pressure to correct tread wear. I did and noticed at 4000 RPM the speedo had raised a couple of miles per hour.
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Not if speedo is driven by the speed of the front wheel. Changing sprockets will change engine RPM for the same speed. The amount of air in the rear tire can also effect the speedo input from the front tire. Example, the local Honda shop owner saw the rear tire on my 900. He suggested I add another 3 pounds of pressure to correct tread wear. I did and noticed at 4000 RPM the speedo had raised a couple of miles per hour.
Point taken. But on newer bikes that are FI, "most" pick up the signal for the speedometer off of the engine.
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Don't know about the newer ones ,but my(and everyone elses) BMW KLT was 10% high & I think all beemers were -yeah It often kept ya outta speeding tickets.....but I think the sales idea is/was to make you think you are faster than you are ::).
Mike
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I dont know where spedo is hooked or what it reads, but when i put on my 190/55 my gps would show speed 55 and speed would show 54. Way better than the 190/50..
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A friend of mine didn't look too closely at his speedo vs. GPS. He said during a recent run that he tucked in and rolled on during an open stretch... he said just glancing at his speedo it looked close to buring it? Checking the GPS he maybe was close :)
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A friend of mine didn't look too closely at his speedo vs. GPS. He said during a recent run that he tucked in and rolled on during an open stretch... he said just glancing at his speedo it looked close to buring it? Checking the GPS he maybe was close :)
175mph
A 'friend' eh? ;)
What's that on the right of your 'friend's' bike in the pic? An Espresso machine? I'm surprised that your friend's bike can attain that speed with all the 'stuff' on the bars. ;D
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hehehe :} left to right: iPhone case/charger, GPS, Escort via radio signal to helmet LED
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Some people just like to have an accurate speedometer. I know I wish MINE were in all my vehicles.
You DO realize your speedometer "accuracy" will change as the tire wears...particularly with round profile MC tires. An old tire will be what....1/2 to 3/4 inch less tall than a new one...and have a smaller circumference...so it will travel less distance with each rotation...and make more revolutions in any given distance...making a change in speedo accuracy of approximately 3% over the life of the tire.
So whatever degree of speedo accuracy you have with a new tire it will be less accurate with a worn tire. True to some extent with any vehicle.
I'm just sayin'....
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Don't worry about it. Drive 5 mph (indicated) over the posted speed limit, and you're OK still. Just forget about the difference, and don't get speeding tickets.
:)
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Don't worry about it. Drive 5 mph (indicated) over the posted speed limit, and you're OK still. Just forget about the difference, and don't get speeding tickets.
:)
Agree! I have a gps on mine most of the time and when I am indicating 80 on the speedo the gps shows 76. Perfect for the slab. I've never been pulled over for doing 1 over.