Triumphrat

Motoboard · 03-10-2007

My speedo on my Bonnie is fast by 7 mph. Has anyone taken theirs apart and tried to correct it. Im going to try it, but wanted some pointers if any of you have already done it.
Thanks in advance for any input.

LIJ · 03-10-2007

Doesn't all speedos show a higher speed than you actually drive? They do that in cars anyway.

road_dog · 03-10-2007

True... intentionally by the manufacturer. For a built-in margin of safety.

But fast 7 mph at what true speed? :???:

GrayMitchell · 03-10-2007

I clocked my speedo with my GPS...speedo is fast by 5 MPH.

-Gray

BornAgain · 03-10-2007

Mine was also 5 mph slower than my gps.

d2mini · 03-10-2007

Quote:

On 2007-03-10 09:32, GrayMitchell wrote:
I clocked my speedo with my GPS...speedo is fast by 5 MPH.

-Gray

Mine is dead nuts on. MAYBE off by 1 mph but hard to tell.

GrayMitchell · 03-10-2007

I guess its the luck of the draw with cable driven speedos.

FattRat · 03-10-2007

I was given reason to believe that mine is off by 10%, however I read here once that the closer one gets to 'the ton' the more accurate the speedo is (???).

Well, lending credence to the notion that my speedo is as accurate or inaccurate as a 2007 R1200S and an '03 FZ1, my riding partners commented how surprised they were that my "little Bonnie" was keeping up and right along side them at an indicated 110/115 mph.... exactly what MY speedo was reading.

I haven't done it yet, but the ONLY reason I want one of those little $90.00 GPS' is to check my speed. I actually put graduated marks on my old BonnieBlack where an actual 55 mph, 65 mph, and 70 mph was. If I'm not mistaken, my needle was straight up and at a right angle when I was at a real 70 mph.

I'm pretty anal 'bout these things, and have been looking to cruise along side a new Honda Civic with it's HUGE and conspicuous speedo that can be seen from outside the window. I'm willing to bet a Honda car's indicated speed would be pretty close to 'real' speed.

badrufus · 03-10-2007

I've read what road_dog said, that all vehicle speedos are manufactured with an intentional error of 5-10%. I've not told my husband--if he thinks he's doing 75, but really doing only 70, he'll be less likely to get a ticket. I think the only way you could tell how accurate the speedo is would be GPS or police radar, and I try to avoid the latter. I'm guessing that the reason for the intentional error is legal--if you had a speed-related accident and could later prove via testing that your speedo was biased to read LOWER than your true speed, you would have quite a case against the car manufacturer.

Spyder94 · 03-10-2007

To correct the problem, find out the actual speed error (gps), then do the math on how much taller the front tire needs to be. Next tire purchase, buy the taller tire. It is the revolutions per mile equation. Taller tire will slow the speedometer down (less revolutions). Or, buy and electronic speedo and calibrate it to the GPS. Everything is fixable.

Steve, gears and duel everything.

:yayyy: :chug: :yayyy: