Speedo Question

[Captain Scallawag]

How far off is the stock speedometer on a gen 1.... stock sprockets , 195 rear tire.... sometimes my speed seems to good to be true. .. and is a speedo healer really worth it.... to be somewhat accurate lets say the run speed is 150 mph

 

[kml]

7 % fast

Got a speedohealer, had it for years now, no problems.

Well worth the few bucks.

cheers
ken

 

[nosbig]

I have a gen 2 and it was off 8%.

 

[WuzzaCBXRider]

How far off is the stock speedometer on a gen 1.... stock sprockets , 195 rear tire.... sometimes my speed seems to good to be true. .. and is a speedo healer really worth it.... to be somewhat accurate lets say the run speed is 150 mph

Do you mean a 190? Mine is doing about 143 @ an indicated 150. I watch the tach as much as the speedo. @ 95 indicated, my favorite cruising speed, its only spinning 5,000 rpms, just loping along. I'll bet my actual speed is around 88 or so. Still enough to attract the revenuers so I also have a V1.

 

[13013]

Worth every penny

 

[Dennis]

The error isn't linear. The faster you go, the greater % error.

 

[Bad Teddy]

The error isn't linear. The faster you go, the greater % error.

Mmm... what makes you say that?

I'm asking because mathematically, an 8% variance is larger at higher speeds because it's a percentage of a larger number (IE, 8% of 100 MPH would be 8 MPH, 8% of 10 MPH is only 8/10ths of 1 mph) . Which would mean it's still linear (or rather, fixed).

Or are you saying the percentage itself varies?

 

[c10]

Mine was off ( 2014 Gen II ) in that 7 to 8 mph range at any hwy speed of GPS 65 to 90 mph . This is the 2nd bike that worked out like this ( other R6S 2009 ) I went from a 18 tooth to a 19 tooth front sprocket then the bike MPH was with in 1 mph of GPS at any free way speed . As the OEM tire out back wore down it got to be 2 to 3 mph off from GPS . When I went 190/55/17 over OEM 190/50 it was perfect matching GPS at all speeds even 150 mph . That was great for me .
Now the other item to discuss . Odometer ! It always matched the GPS millage with in 1 mile or less for 100 plus miles . Now it is OFF by 5 miles for every 100 miles so for the last 3500 miles since this change I reduced the Odometer reading by 175 miles . Personally This set up works for me for mpg / reduced vibration @ speed , and im a small guy . Speedo healer is the other way if you not going with Taller gearing .

 

[Dennis]

Mmm... what makes you say that?

I'm asking because mathematically, an 8% variance is larger at higher speeds because it's a percentage of a larger number (IE, 8% of 100 MPH would be 8 MPH, 8% of 10 MPH is only 8/10ths of 1 mph) . Which would mean it's still linear (or rather, fixed).

Or are you saying the percentage itself varies?

The percentage increases as speed increases. It started around that 7-8% at highway speeds but got up to 12% at around 140 mph. I checked a couple speeds on the highway. I checked higher speeds with my video camera. One method was using the trap speeds at the 1/4 mile. Another was when I got a plot of rpm vs wheel speed from the dyno and noted that there was no significant slippage and compared the actual speed vs what my video showed.

 

[Bad Teddy]

The percentage increases as speed increases. It started around that 7-8% at highway speeds but got up to 12% at around 140 mph. I checked a couple speeds on the highway. I checked higher speeds with my video camera. One method was using the trap speeds at the 1/4 mile. Another was when I got a plot of rpm vs wheel speed from the dyno and noted that there was no significant slippage and compared the actual speed vs what my video showed.

Interesting. Now I'm even more curious about this. Definitely good to know, thanks man.

 

[Dennis]

Interesting. Now I'm even more curious about this. Definitely good to know, thanks man.

Don't take my word for it. Check it out on your own .... legally of course.

 

[Captain Scallawag]

Thank you for all of your responses ... I did say 195 tire ... sorry I get ahead of myself. ... 190/55.... I see a healer in my future. ... and of course all this speed checking I'm doing is on a private roadway

 

[WuzzaCBXRider]

I know of a....sort of uh,.....semi-----private/public......infrequently travelled.....70 mile long two lane nearby......