Rigid_EVO Somebody explain speedo being off

[roachhill]

I would have been happy if my speedo could stay within 5 mph or so. Took me awhile to figure out mine was claiming I was going a good 9 mph faster then I really was. No wonder everyone kept passing me. The problem is you have a genuine factory gauge, LOL.

[LuxBlue]

I know my speedo's accurate to 1 mph in 100 because I figured out the math by using my actual rear tire diameter and gearing ratios and knowing the number of teeth on the gear that the VSS reads. I then set my TC88A ignition to the correct corresponding Hz. When I ride with my buddy on his Softail, he's always claiming he's indicating 3-5 mph more than me. Our odometers are off too on a long ride by 3-5 miles out of 100.

[tmack-1]

Said this before. You might not be 5 mph off. You could be 2-3 high and they could 2-3 low.

I know on my '04 Chevy pickup, speedo saying 55 is really only around 52 or 53 mph. Found this out using a stop watch and the mile markers on the interstate (60 mph is 1 minute to go 1 mile, 5 minutes 5 miles), then reconfirmed on the GPS and again on those goofy police speed warning things.

On my 86, the original speedo was basically "spot on" compared to the GPS. Unfortunately the needle fell off. The new speedo reads about 1 -2 mph slower than the GPS.

NOTE: comparing your speedo to a GPS is a pain in the neck. Since GPS units use averages over so many seconds, you have to find a spot that is flat and level so you can go a few miles at the same speed. Not as easy as it sounds.

[ReddTigger]

Having worked for dealerships in automobiles, heavy trucks, school buses and motorcycles, 10% is considered normal operating parameters for any manufacturer.

[xllent01]

96+ have/utilize electronic speedos, 94's NOPE!

[LuxBlue]

In this era of VSS (vehicle speed sensors) and PWM (pulse width modulated) data busses, it's not hard to have an accurate speedo...you just have to program the ICM or ECM to the correct VSS Hz.

Mechanical speedos?..... Harder to calibrate.

[knut]

Really enjoy my 04' Sportster... but it has to have one of the most inaccurate speedometers I've ever encountered on a motorcycle... and that's sayin' something...

[denguy]

All things considered, I wish they had stuck to the cable drive.

[E65841]

Originally Posted by Motorhead52

Find a side of the road read out or time in a area with markers


mine is aout 1 to 2 MPH off low

Far too many riders have said they were doin 55 with me while my needle
is showing 50. I have gone through radar displays and I show 5mph slower
than what the radar displays. Not only that but the odometer ain't all that accurate either. FOR EXAMPLE: I have driven multiple vehicles from my driveway to a place down the road, and whatever vehicle it may be, shows from my driveway to that spot is exactly 8.0 miles. Not 8.1, or 7.9, but 8.0
consistantly. On the sporty though it is always 7.7 miles, that is 3/10 of a mile short for every eight driven. So basically for every 24.3 miles driven the
speedo is a mile short. but where I can't connect the dots is why do the rpm's on the tach match the displayed speed? ie: 60mph shows 3000 rpm,
If I,m actually going 65, which I am! Its a miracle I ain't been ticketed.

[xjjoe01]

My 93 sporty speedo is 5 mph slow as is my buddies 2007 dyna. I suppose it helps with the resale value....

-Joe