Speed & Speedometers?

[spbwsean]

well I've added a vintage style bike speedo. to my latest build and wonder if anybody out there can comment on the reliability/ accuracy of these speedos?
According to my speedo i'm doing over 50mph on flatland at full throttle! Before I installed the speedo i figured my bike could go really fast but not that fast
I do 30mph uphill and on flatland full throttle my speedo redlines

I am running a PK80 on an aluminum frame and i weigh 160lbs...modded exhaust....light rimes etc

anybody going this fast? or is my speedo screwy?

I plan to see if a friend will pace my in his car to get an idea of my reall speed

 

[Junster]

Any chance you have access to a gps? Once your over 3 miles an hour they are very accurate on showing actual speed.

 

[Esteban]

Those vintage types can get fairly close to your correct speed. Use a GPS, & check while riding at top speed. Adjusting the little device on the fork up or down will change the speed + or - to become more accurate. If you get within 3-4 mph of the GPS, that is close.

 

[fetor56]

50mph on the flat....a rather optomistic speedo.

 

[spbwsean]

ok i figured it out.......i went by a park today where they had a radar gun for testing peoples baseball pitch speed.
my speedo's face says MPH but it's really reading in KPH
my top speed according to the radar was 35.3 MPH, which explains my redlining cuz in KPH thats about 56
thats all good cuz im in canada anyways and prefer KPH