HD speedometer accuracy
Ultimate HDF Member
Joined: Jan 2005
Posts: 7,950
Likes: 4
RE: HD speedometer accuracy
ORIGINAL: anniv03classic
Just rode past a portable radar display and my speedo read 37 and the police display read 36mph...........accurate enough for me
Just rode past a portable radar display and my speedo read 37 and the police display read 36mph...........accurate enough for me
Now that I've put on new tires, I gotta go find another portable radar and recheck as the diameter of the tires is a bit different.
Thread Starter
|
Road Warrior
Joined: Dec 2005
Posts: 1,828
Likes: 4
From: Central Jersey
RE: HD speedometer accuracy
I don't trust radar...at all...especially on a bike. Somehow I remember a simialr article (and I may actually still have that magazine laying around) where they tested bikes on police radar. If I remember correctly, bikes never seemed to give an accurate reading..compared with a car. Something about the size/angle of the bike...tell you the truth, I don't remember. But same with those roadside speed check things...they never give me a reading that's accurate in any vehicle I'm in/on...car or bike.
Really, I will only trust GPS. I don't really know much about it because I don't own one. But I've ridden with enough people...and ridden alongside a car with a nav system..and always, my bike's speedometer isn't accurate with the GPS/nav. It always seems to be reading about 5 mph faster than I'm actually going.
If I could do a more thorough test with a bunch of GPS/nav equipped vehicles, and then come out with an average, then I'd be happy. To be honest, it doesn't really bother me if my speedometer is reading 5mph higher than actual speed. If anything, it means I can safely go 5 miles per hour faster
But I won't be happy until I can do more tests....or get more replies from other harley owners. From the varied replies here, I can see that this isn't going to be easy to get a truly accurate answer.
Todd
Really, I will only trust GPS. I don't really know much about it because I don't own one. But I've ridden with enough people...and ridden alongside a car with a nav system..and always, my bike's speedometer isn't accurate with the GPS/nav. It always seems to be reading about 5 mph faster than I'm actually going.
If I could do a more thorough test with a bunch of GPS/nav equipped vehicles, and then come out with an average, then I'd be happy. To be honest, it doesn't really bother me if my speedometer is reading 5mph higher than actual speed. If anything, it means I can safely go 5 miles per hour faster
But I won't be happy until I can do more tests....or get more replies from other harley owners. From the varied replies here, I can see that this isn't going to be easy to get a truly accurate answer.Todd
Outstanding HDF Member
Joined: Apr 2006
Posts: 2,395
Likes: 25
From: St George, UT
RE: HD speedometer accuracy
My Ultra is spot on up to about 65, then it gets a tiny bit optimistic. According to the stopwatch/milepost method, it reads 78 mph at 75 mph calculated, a 4% error. Close enough for me.
Advanced
Joined: Aug 2006
Posts: 99
Likes: 0
From:
RE: HD speedometer accuracy
According to several of the mobile radar speed signs my RK is right on....Now my old Yamaha Warrior....Now it was way optimistic....60mph on the display was really about 54.... Really made you feel cool though when you looked down and the display was registering 115.....Once I had it to 150....but then I realized I had set the display to KPH by mistake....always meant to try to take a picture of that!
Seasoned HDF Member
Joined: Jan 2005
Posts: 68,021
Likes: 3,276
From:
RE: HD speedometer accuracy
This last weekend I took a long ride and happened to see one of those areas where you can test your mileage by the markers along side the road. I kept my bike at 60 and at the end of the 5 mile test area, my bike was only 2/10ths off from the start of the test. I don't know how accurate that test is, but I satisfied my curiosity anyway.
p.s. I also got stopped by a LEO and he said that he clocked me going 74 in a 55. He was right because I was speeding. Lucky for me, I talked my way out of the ticket. WHEW
p.s. I also got stopped by a LEO and he said that he clocked me going 74 in a 55. He was right because I was speeding. Lucky for me, I talked my way out of the ticket. WHEW
Road Warrior
Joined: Sep 2006
Posts: 1,480
Likes: 1
From: Ocean Springs, MS
RE: HD speedometer accuracy
ORIGINAL: AK97fxdwg
I'll bet that the setting on his GPS was for nautical miles. That is the default on most GPS units. One nautical mile is about 6,076' which is about 1.15 miles.
I'm a surveyor and we're ALWAYS running into this stuff. Now try checking different coordinate systems and see how confused we can all get.
I'll bet that the setting on his GPS was for nautical miles. That is the default on most GPS units. One nautical mile is about 6,076' which is about 1.15 miles.
I'm a surveyor and we're ALWAYS running into this stuff. Now try checking different coordinate systems and see how confused we can all get.
Road Warrior
Joined: Jun 2005
Posts: 1,324
Likes: 522
From: Dutchess County, NY
RE: HD speedometer accuracy
ORIGINAL: anniv03classic
Just rode past a portable radar display and my speedo read 37 and the police display read 36mph...........accurate enough for me
Just rode past a portable radar display and my speedo read 37 and the police display read 36mph...........accurate enough for me
My Sportster used to be off by about 5 mph.
Road Warrior
Joined: Nov 2005
Posts: 1,942
Likes: 2
From: LAKESIDE CA.
RE: HD speedometer accuracy
agree mine at 70 is =/- 1 mph by gps reading
[IMG]local://upfiles/5757/85C5E71C17E344F9AC878B7613267B10.jpg[/IMG]
ORIGINAL: Hogmonger
I've done a lot of rides w/ my GPS and it is always right on (or at least +/- 1 mph, hard to tell with an analog speedo). Even at higher speeds it is VERY close.
I've done a lot of rides w/ my GPS and it is always right on (or at least +/- 1 mph, hard to tell with an analog speedo). Even at higher speeds it is VERY close.
[IMG]local://upfiles/5757/85C5E71C17E344F9AC878B7613267B10.jpg[/IMG]
HD Forum Stories
The Best of Harley-Davidson for Lifelong Riders
7 Surprising Harley-Davidson Products that Are Not Motorcycles
Verdad Gallardo
8 Best Harley-Davidson Motorcycles Ever
Pouria Savadkouei
10 Worst Harley-Davidson Motorcycles Ever
Pouria Savadkouei
Killer Custom's Jail Break Is The Breakout That Refused to Blend In
Verdad Gallardo
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Verdad Gallardo
Harley-Davidson Reveals Super Cool Cafe Racer Concept
Verdad Gallardo
Engraved Rebellion: Inside Bundnerbike's Glam Rock II
Verdad Gallardo
10 Motorcycles You Should Never Buy
Joe Kucinski
10 Things Harley-Davidson Needs to Fix in 2026
Verdad Gallardo
Stellar HDF Member
Joined: Jun 2006
Posts: 2,457
Likes: 83
From:
RE: HD speedometer accuracy
when i went through my last police motorcycle operators course- there is a maneuver that requires you to enter a chute at 40mph and brake (hard) and at the end of the chute, make a hard right turn to avoid an obstacle (brake and escape).
our entry speed was checked with radar.
my particular motorcycle read about 2mph higher than indicated on radar.
however, it IS a police motorcycle which has been dropped MANY MANY times by varying riders....
my King is right on though
our entry speed was checked with radar.
my particular motorcycle read about 2mph higher than indicated on radar.
however, it IS a police motorcycle which has been dropped MANY MANY times by varying riders....
my King is right on though