Speedo calibration

[agentfox1942]

I've read a lot of mention on here about speedometers and odometers being off by as much as 10% on some bikes. I have an '05 1600 Classic. How much is my speedo off? Is it high or low? If I'm going 60 does that mean I'm really doing 66? Can it be recalibrated or do I need to by taller (higher profile) tires to compensate? So many questions.....lol
thanks for the help.

[Badrocks]

Mine was the other way around. If it indicated 66 I was going 60. That changed dramatically when I put the Metzelers on the bike. Now it's only off a couple MPH.

[vulcan_mojo_man]

I must have gotten a unusual 900. My speedo is fairly accurate but not as good as the one on my Harley.

[jack030]

Yeah, I think it's been mentioned that Kawasaki has calibrated them up to 11% fast. So the speedometer indicates a higher speed than actually traveled. Maybe it helps people from speeding and getting in accidents.

Personally I don't know what's safer than jumping on the highway and going 10mph under the speed limit and 20-25 under what everyone else is doing

[agentfox1942]

good point, Jack030. Someone coming up on your a$$ while you're thinking you're doing 70 is not good. Has anyone ever gotten theirs tested, like with a speed gun? Thanks guys.

[Badrocks]

I used my gps to find out how much it was off. It also showed how much of an impact the new tires had on the calibration. Personally I think the factory should ship the bike in a stock configuration with gauges giving accurate readings. If I decide to drive too fast that's my decision.

[cmptrmn.1]

Our government has given the OK on MC's to be up to 15% off. On my 900, it is 10% off. The odometer is spot on however. So, when you change the tire size or put a sprocket on or the speedo-healer, you may be fixing the speedometer, but now you just changed the odometer to be off.

[KawabungaOz]

A GPS crosscheck determines the error. Repeat if you change anything in the drive train, especially tire brands.

Gary

[RichLockyer]

Originally Posted by agentfox1942

I've read a lot of mention on here about speedometers and odometers being off by as much as 10% on some bikes. I have an '05 1600 Classic. How much is my speedo off? Is it high or low? If I'm going 60 does that mean I'm really doing 66? Can it be recalibrated or do I need to by taller (higher profile) tires to compensate? So many questions.....lol
thanks for the help.

Normally between 6-10% high.... manufacturers get into BIG trouble in Europe if the speedo reads lower than actual, so they err on the high side with keeps it from reading low even if (the commonly used) oversized tires are mounted.

To recalibrate, install a Speedo Healer (about $100), then take it up to 80 or 90mph and compare the speedo to a GPS. Plug those numbers into the programming software and it will give you the procedure for calibration.

Keep in mind, this will also slow down your odometer, and the factory error on the odometer is about half the speedo error, so if your speedo is currently 10% fast, when corrected the odometer will read 5% low.
Also, calculated fuel economy will drop by the same percentage as the correction factor (40mpg calculated now will become 36mpg calculated after a 10% correction with no ACTUAL change in fuel economy).

[agentfox1942]

thanks Rich. I'll look into the speedo healer. My experience with GPS's is that the civilian versions are also off, even though the built-in error compensation has been removed (almost) completely. But I guess it's as close as we're going to get. I may have to borrow one of the military grade trackers and see what it shows.

[RichLockyer]

Originally Posted by agentfox1942

thanks Rich. I'll look into the speedo healer. My experience with GPS's is that the civilian versions are also off, even though the built-in error compensation has been removed (almost) completely. But I guess it's as close as we're going to get. I may have to borrow one of the military grade trackers and see what it shows.

I think the civilian GPS units are good for speed... just off slightly on location.

I've used 3 different Garmin units and they all read the same.

[B3ancounter]

+1 on the Speed-o-healer. I installed one on my Mean Streak and then calibrated it to what I thought was the correct speed. Then one afternoon I saw a sheriff running radar and stopped and told him that I had just re-calibrated my speedo. I asked him if I went by at 35 (according to my speedo) if he could confirm my speed. He said sure. My speedo was right on.

I should have asked him if he would confirm it at 100 mph!

[BOURBON BOY]

+2 on the Speed-o-healer, down here the locals drive 75-80 MPH on the interstates, the speed limit is 70. Nothing worse than a Kenworth filling up both of your rearview mirrors! BB

[agentfox1942]

Originally Posted by RichLockyer

I think the civilian GPS units are good for speed... just off slightly on location.

I've used 3 different Garmin units and they all read the same.

Isn't the speed calibrated by location and time?

[Pooker]

I have a stock 2008 Nomad and I use the Speed Healer. I have mine set at -08.7 and it puts me within 1/2 of a kilometer per hour.

[RichLockyer]

Originally Posted by agentfox1942

Isn't the speed calibrated by location and time?

Location change and time.
If it's consistently off by 30ft, it's not going to impact speed readings... and really, even if it's not THAT consistent, 30-100ft isn't going to be that big of an impact after the software averages it out for the display.

What I found with my GPS-V, Streetpilot-3, Streetpilot 2610, and Nuvi 660 is that every now and then it will "glitch" and show a distance of like 200ft covered in 0-seconds. It'll show in the track log as a 600mph segment, and show on the unit's max speed. The Zumo does not do that... at least not that I've found in the track logs, and if it DOES do it in the tracklog, it's not storing it under the "max speed" entry.

But these are momentary (literally) glitches and don't impact actual speed displayed.

I've heard that steep elevation changes in deep canyons (IE, marginal sat coverage) are the least accurate for speed... and when measuring for a S.H. calibration, I do it on level, open ground, but I've honestly never seen and speed "drift" on the bike or in the cage, regardless of terrain. If I have coverage, speed seems consistent.


The main thing to keep in mind is that the GPS speed display, like it's compass display, is a lagging indication. This gets "sunday boaters" into trouble all the time and they can't seem to follow a course because they're constantly "chasing" the GPS heading.. that's because the speed and heading displayed are what you WERE doing a second or two ago... so trying to use the GPS as a compass results in a constant zig-zag.
Same for trying to nail a specific speed, except heading is worse.... you can easily be 10 degrees off course.

Bring the vehicle to the target "test" speed based on the speedo and hold it steady there. After 2-3 seconds steady, the GPS will have settled down and zeroed in on your actual speed. You can drop 5mph and immediately accelerate again and the GPS may or may not show a drop at all.

[Pooker]

Originally Posted by RichLockyer

Location change and time.
If it's consistently off by 30ft, it's not going to impact speed readings... and really, even if it's not THAT consistent, 30-100ft isn't going to be that big of an impact after the software averages it out for the display.

What I found with my GPS-V, Streetpilot-3, Streetpilot 2610, and Nuvi 660 is that every now and then it will "glitch" and show a distance of like 200ft covered in 0-seconds. It'll show in the track log as a 600mph segment, and show on the unit's max speed. The Zumo does not do that... at least not that I've found in the track logs, and if it DOES do it in the tracklog, it's not storing it under the "max speed" entry.

But these are momentary (literally) glitches and don't impact actual speed displayed.

I've heard that steep elevation changes in deep canyons (IE, marginal sat coverage) are the least accurate for speed... and when measuring for a S.H. calibration, I do it on level, open ground, but I've honestly never seen and speed "drift" on the bike or in the cage, regardless of terrain. If I have coverage, speed seems consistent.


The main thing to keep in mind is that the GPS speed display, like it's compass display, is a lagging indication. This gets "sunday boaters" into trouble all the time and they can't seem to follow a course because they're constantly "chasing" the GPS heading.. that's because the speed and heading displayed are what you WERE doing a second or two ago... so trying to use the GPS as a compass results in a constant zig-zag.
Same for trying to nail a specific speed, except heading is worse.... you can easily be 10 degrees off course.

Bring the vehicle to the target "test" speed based on the speedo and hold it steady there. After 2-3 seconds steady, the GPS will have settled down and zeroed in on your actual speed. You can drop 5mph and immediately accelerate again and the GPS may or may not show a drop at all.

I did have my bicycle computer on the Nomad. It's so simple, measure the circumference of the front wheel, install the magnet , zip tie the the receiver and it's very, very close.
I borrowed a Garmin Nuvi GPS to check my speed.
The the bike read 100 kms, the bicycle computer read 91 kms, the GPS read 91.6 kms.
So I set the speed healer and now the bike and the bicycle computer are within,.......about .8 of a kilometer.
I don't know anything else about the GPS units,...I would never own one simply because everyone I know that has one gets lost! Go figure!

A full tank of gas is the best GPS.