09-24-2018, 05:57 AM
(09-24-2018, 05:06 AM)pekingduck_imp Wrote:(09-24-2018, 04:23 AM)caddy425_imp Wrote: The problem: Speedo reading 10-15% optomistic.
Theory - speedo reading off the rear wheel sensor - so any sprocket changes should (in my mind) make no difference to the speedometer reading
What I did: I went one tooth down on the front sprocket and one tooth up on the rear sprocket in order to get easier launches when riding two up. Which is most of the time lately. So that geared the bike down about 10%
As per the above assumptions is didn't expect to see any difference in the speedometer reading
Anyone know of an easy correction - or do i just live with it?
You are correct that the speedo speed reading takes its input from the rear wheel speed sensor, and gearing does not change that. Only rear tire diameter can affect that. I assume you are checking against GPS on your phone. I am curious if the inconsistancy is steady, or the % changes with speed.
Honda and the other Japanese manufacturers' speedometers read fast, usually somewhere between 5-10%, so that no blame can be assigned to them for speeding tickets. Any instrument has a margin of error, including GPS, so you may have a normal situation. I assume the speedo inconsistancy was there before any sprocket change.
You can get a Speedo Healer v4 ftom Healtech, or another aftermarket device like a Speedo Tuner.
You are correct that the speedo speed reading takes its input from the rear wheel speed sensor, and gearing does not change that. Only rear tire diameter can affect that. I assume you are checking against GPS on your phone. I am curious if the inconsistancy is steady, or the % changes with speed.
Honda and the other Japanese manufacturers' speedometers read fast, usually somewhere between 5-10%, so that no blame can be assigned to them for speeding tickets. Any instrument has a margin of error, including GPS, so you may have a normal situation. I assume the speedo inconsistancy was there before any sprocket change.
You can get a Speedo Healer v4 ftom Healtech, or another aftermarket device like a Speedo Tuner.
Before I changed the sprockets it seemed that speedo was about 5km/h optimistic across the board vs my Garmin GPS. And the limiter kicked in at an indicated 5km/h over the hard limit. Now it seems to be exponential leading to about 15km/h by the limiter. very odd sort of result when nothing else had changed. As to your point - won't be getting any speeding tickets. Thanks - just wondered if anyone else had seen this effect.