Between my GPS and those drive-by police speed signs on the side of the road, my 696's speed seems off by 4-5 MPH. While those two sources may not be the most accurate way to find my true speed, it's consistent. Could changing the front sprocket to 14T have thrown off my speedo? I'm wondering if my odometer is off too.
TIA
this is universal among ducs. mine is off (fast) by about 7mph.
my understanding is that it's very difficult to make a motorcycle speedo 100% accurate. So, since that can't be done, mfg's make them read high. From what I've seen and all my friends I've spoken to, no one has an accurate speedo. Mine is about 8% high.
edit: Forgot to say that changing the sprocket on a duc won't change the speedo reading. Mine reads speed off the rear brake disc I believe.
Now I might be pulling this out of my ass but isn't it true that when you change the final drive ratio, the speed changes as well? It wouldn't surprise me that the speed would be off because of the 14T. 4-5 MPH difference isn't going to make or break the bike...unless you ride the speed limit all the time and need to be EXACT.
Quote from: 1313 on May 31, 2009, 12:58:53 PM
Now I might be pulling this out of my ass but isn't it true that when you change the final drive ratio, the speed changes as well? It wouldn't surprise me that the speed would be off because of the 14T. 4-5 MPH difference isn't going to make or break the bike...unless you ride the speed limit all the time and need to be EXACT.
Depends on where the speed is read. In this situation it's a magnet by the rear brake disc, so the only thing that will change the accuracy is the distance from the axle to the road (even tire pressure affects this to some extent).
You can at least brag that your bike accelerates faster than it actually does. ;D
According to page 19 of the .pdf version of the 696 Owner's Manual, "the dashboard receives actual speed value (expressed in km/h) from the control unit and displays the value increased by 8%."
They don't, however, say why on earth they designed it that way.
Quote from: mstevens on August 05, 2009, 08:48:39 PM
According to page 19 of the .pdf version of the 696 Owner's Manual, "the dashboard receives actual speed value (expressed in km/h) from the control unit and displays the value increased by 8%."
They don't, however, say why on earth they designed it that way.
It's to slow people down. Never heard of a [modern] car or bike without that "feature" ...which makes me think it must be some bureaucrat's doing. [roll]
i've seen a product out there that 'corrects' this 'error'
http://www.speedohealer.com/eng/faq.htm (http://www.speedohealer.com/eng/faq.htm)
Quote from: Holden on August 05, 2009, 10:48:33 PMNever heard of a [modern] car or bike without that "feature"
My BMW Z4 3.0's speedo is off by 2mph at all speeds between (indicated) 15mph and 85mph according to GPS. In this case, then, it's certainly not a percentage and more like a simple needle error.
No one has stated the only true reason why the speedos in both cars and motorcycles come from the factory reading fast:
To prevent YOU the consumer from getting a speeding ticket.
Lets say you go to your local Toyota dealer, and buy yourself a brand new Avalon, fully loaded. That's a $40k dollar car, I believe. So you're heading home in your shiny new car on the local highway, where the speed limit is 55 mph. You set your cruise control to exactly 55 mph. 3 miles down the road, a cop pulls you over, and gives you a ticket for doing 59 mph.
Are you going to be fine with this situation, or pissed off at Toyota for selling you a car that reads slow, from the factory?
The manufacturers add in a buffer zone because in the future, your tire tread will wear out, and you will replace them with other tires. Not all tires that are the same size are the same diameter, so this will affect the speedo reading by a small amount.
BC.
Quote from: 1313 on May 31, 2009, 12:58:53 PM
Now I might be pulling this out of my ass but isn't it true that when you change the final drive ratio, the speed changes as well? It wouldn't surprise me that the speed would be off because of the 14T. 4-5 MPH difference isn't going to make or break the bike...unless you ride the speed limit all the time and need to be EXACT.
Only true if the speedo reads off the transmission tailshaft like it does on your car. Also affected by tire diameter. Ie: changing from 14" wheels to those funnylooking 20" with 2" tires.