Speedo error

[sdcatman]

Has anyone corrected their speedometer, my wifes 09 seems to be about 4-5 mph fast, any easy fix other than speedohealer or similar item

[Some Guy]

welcome I've also noticed my speedo seems to be off...at least it's in the direction that will help prevent tickets! Though, I do tend to use the portable roadside radar units to tell me how fast I'm going...maybe they set those things low to mislead drivers of their speed and generate more speeding tickets... Wait...law enforcement would NEVER do something underhanded like that!

[NancysToy]

Most motorcycle speedometers read high. The main reason is that they calculate the speedo ratio based on the actual diameter of the rear tire. The rolling (effective) diameter is a bit smaller, since the weight of the loaded vehicle compresses the tire. As a result, the speedo thinks you go farther per revolution than you actually do. A lighter rider will run closer to the indicated speed, so will a rider with more air in the tires. Worn tires will be a little worse than new ones. As these things go, the Spyder is fairly close. Many of the old BMWs were notorious for being about 12-15% high! That's 6-8 mph too much at 50. 6-8% error is typical.

[Firefly]

Another good reason to get a GPS---- they are very accurate compared to the stock unit which is 1-4 MPH off depending on how fast you are going.

[BillGargan]

I just put in a full day of riding from NH to the ME coast and back -- about 300 miles or so.

I have checked my Spyder speedo against the GPS. The speedo is consistently 1 to 2 MPH higher than the GPS at any and all speeds -- occasionally I see it 3 high for short spurts. I find my car (2008 Subaru Tribeca) to be off about the same.

I like that it is slightly high.

Next I need to test the odometer to check it's accuracy against the GPS. I will be curious as to how the +/- error will impact the MPG.

[COOLMACHINE]

I questioned clicking on this thread. I didn't know if I really wanted to know or see something about a speedo error......
OK, anyway, my speedometer is right on the money.

[Lowflyingowl]

I just figure it keeps me from getting tickets. My VTX was 10% over at all speeds, but the Spyder seems to be only about 5% over. So that means if the speed limit is 65 and I'm going 75 ( per speedo) I''m actually closer to 72 and therefore relatively safe from a speeding ticket -- at least out here where 10 mph over the limit seems to be the trigger.

Actually, on some freeways 10 mph over the limit will get you run down..

[bone crusher]

I doubt that anyone's digitial read-out and needle speedometer read the same...they are usually off by a little.

As far as the GPS goes, there is such a delay that I don't even consider it an option for checking speed unless I'm staying at a constant speed for a period of time...

Bottom line: The speedometers (digital and needle) will be off by 1-4 mph...the GPS is usually slower than the digital speedometer and with quick bursts of speed it will lag by a couple of seconds...

[3wheeldemon]

Mine is consistently 3MPH faster that the GPS and land "warning" radars.

3WD

[Recluze]

I think that you will find that the odometer is off by the same amount that the speedometer is. At least in my case it is.

[Tom in NM]

Most motorcycle speedometers read high. The main reason is that they calculate the speedo ratio based on the actual diameter of the rear tire. The rolling (effective) diameter is a bit smaller, since the weight of the loaded vehicle compresses the tire. As a result, the speedo thinks you go farther per revolution than you actually do. A lighter rider will run closer to the indicated speed, so will a rider with more air in the tires. Worn tires will be a little worse than new ones. As these things go, the Spyder is fairly close. Many of the old BMWs were notorious for being about 12-15% high! That's 6-8 mph too much at 50. 6-8% error is typical.

. . . . I weigh in around 145#, travel light and no heavy add-ons, tires are very firm. I get readings from the radar signs that show I am going 2 or 3 mph lower than my speedometer says. Given all the factors that can be in error, I count my speedometer as being accurate.

Tom

[planter]

On a recent trip, I took advantage of our caravan, by driving along side the family car on the freeway.
At a speed of 70 mph, we were within 2 mph of each other.
Up until this crude test, I was thinking my Spyder was off by 5-7 mph.

[Firefly]

I doubt that anyone's digitial read-out and needle speedometer read the same...they are usually off by a little.

As far as the GPS goes, there is such a delay that I don't even consider it an option for checking speed unless I'm staying at a constant speed for a period of time...

Bottom line: The speedometers (digital and needle) will be off by 1-4 mph...the GPS is usually slower than the digital speedometer and with quick bursts of speed it will lag by a couple of seconds...

Strange--- my GPS is very fast on the speed updates - and also matches my VR2 computer which has it's own sensor on the rear wheel. Considered to be very accurate.

[bjt]

Strange--- my GPS is very fast on the speed updates .

+1 I consider my GPS speed readout as being "realtime". If my Spyder speedo increases by 1 MPH, the GPS follows at the same time.

EDIT: A slight retraction to my statement above. I paid close attention to the GPS vs the speedo on my way to work and the GPS seems to track what the Spyder speedo reads within 2 or 3 seconds. The GPS seems to take longer to get an accurate speed reading when I'm going real slow (under 5 MPH).