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Speedo Error and Sprocket Change Questions

2261 Views 8 Replies 4 Participants Last post by  Rolex
Curious if my thinking is correct or have I had too much coffee this morning...
With the speedo being about +10% off; speedo shows faster than actual speed, if the sprockets are changed that increase the drive ratio from the OEM 2.41 (17/41 sprockets), does this decrease the speedo error?.....but also creates an odometer error to show less than actual mileage?

17/41 sprockets = 2.411 ratio
17/42 sprockets = 2.47 ratio (what my Vee came with); an increase of only 2.47%

Doing some reading showed to take the OEM ratio and divide by new ratio....which would yield 2.411 / 2.47 = 0.976, meaning that the speedo error would be decreased.
But seems to me that it should be....new ratio divided by OEM ratio.....2.47/2.411 = 1.024....speedo error would be increased.

Maybe more coffee will make this clear.......
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What's not clear to me after two cups of weapons grade French Roast, is what year and model you have. Reading the tea leaves 馃槈 I gather this is a DL 650. Sincnce 2011, I believe, all V-Stroms came with ABS standard and the speedometer was linked to the front wheel ABS sensor digitally, so changing sprockets will only change engine rpm at a given speed. Older bikes (2004-'09) were mechanically driven and sprocket change will have an effect.

But if you're happy with the performance of the bike, a speedometer correction device would greatly improve the accuracy and costs about the same or less than a set of sprockets. Adventure Tech sells one that will fit any V-Strom, and Owner @richlandrick is an advertiser and member here, and can answer any questions on any of his products.
Excellent service before and after the sale.
I have a '08 DL1000.
A speedo healer will indeed correct the speedo, which then makes the odometer incorrect...less miles shown than actual.
I think the better option would be to get the replacement speedo face that corrects the speedo error and leaves the odometer alone.
You said "Vee", so I'll assume you mean a DL1000 of some unknown vintage. On a Vee with the pickup on the front sprocket, lowering the gearing increases the error. Pretty much everyone lowers the ridiculously tall stock gearing, so we'll go with that scenario.

For example, I went from the 17/41 stock gearing to 17/43 on my 2002; a minor change, but I was very happy with the result. However, that increased the error from 7-8-ish percent to about 11%. I installed a SpeedoDRD and set it to 10% correction so I'd end up with speed reading only slightly higher than actual, same as what I'm accustomed to in my car.

The sucky part is that odometers are more or less accurate in stock form. So electronically adjusting the speedo like this means that the odo is now 10% low. This may or may not matter much to you, or it may be something to keep track of.

AFAIK, all years of the DL650 use a speedo pickup on the front wheel, so gearing changes don't affect the amount of error. They still come from the factory with a ridiculous amount of error built in, but changing the gearing doesn't make it better or worse.
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Has this additional odometer error actually been verified? As mentioned, the speedo is way off, but the odo is reasonably accurate. I'm thinking it is, as I assume there is only one signal sent to the instrument cluster and the firmware there distributes it separately to speedo & odo, but maybe it's a pulsed thing: first pulse = speedo, second pulse = odo. If so, a DRD could be designed to alter only the speedo pulse. Does the 12 O'clock Labs DRD affect both or does it only correct the speedometer?
Asking for a friend; I use GPS for both readings.
The 1st Gen VStrom use four pulses per rotation of the output shaft via a Hall effect. A speedo healer usually reduces the number of pulses to the speedo in order to correct the indicated speed. I guess these devices could also add pulses as well...IDK...never had one.

Anyways, so bwringer....you had speedo error increase due to increasing the final ratio, which to me says that the correct method is to take the new drive ratio and divide by the OEM drive ratio...yielding a number greater than one; speedo error increased. This makes sense to me and is opposite of what I read on another site..which is what prompted my questions.
As I noted in my first post, my '08 DL1000 has a 17 / 42 ....the change was even less than on your '02. I have yet to compare my phone's GPS with the V-Strom's speedo. I have just been assuming it to be about 10% slow....have not been stopped by police....yet anyways. My Honda VFR750's speedo is about the same, so I am used to always adding that 10%.
I will likely be replacing the chain/sprockets in June which gives me the Spring to have far more seat time on the VStrom than I do now to determine if I want to change the rear to 43-45 teeth and of course deal with the speedo error.
Also have to clarify the statement I made above about replacing the speedo face with a corrected one....that only works with OEM 17/41 setup.

Thanks for the replies.
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Yes, I've verified using my 2002 DL1000 and mile markers over a long distance (20+ miles) that with the speedo DRD correcting the speedo, the odometer reading is off by the same amount. Not much else to do on long flat straight interstates... A DRD or "healer" slows down the pulses coming from the pickup at the front sprocket by an amount you set.

I believe the root of the problem is that regulations allow for speedo readings to read high by any amount, but never low. Odo readings apparently have a lower error tolerance. Not sure, but no one has ever really figured out why almost every motorcycle on the planet has a speedo that reads 5-10% high, while cars are almost all within 1 or 2% high. Maybe it's some sort of performance perception arms race thing.

The "real" solution would be to either:

1) Juggle/reprogram the math used in the internal electronics and programming to keep the odo accurate while correcting the speedo. This probably isn't possible in the DL1000, at least the earlier ones. It is possible on some bikes that do the math in the ECU; on the Yamaha FJ-09/Tracer, for example, this is a pretty standard part of a common ECU flash to improve ridability. If you like, they'll re-flash the speedo math and leave the ODO math alone.

2) A custom speedo face would also be another way to keep an accurate odo while correcting the speedo. These used to be available for the DL1000, but the guy making them stopped long ago, and they weren't available in custom offsets; they came in one "standard" offset to match the most common situation. This was a great solution, but apparently having them made was kind of a pain in the ass, and the size of the market was not very large.
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I agree with you....seems every motorcycle's speedo is off by +7-10%. It would be wonderful if I could get into the speedo/odometer firmware and be able to change it depending upon the sprockets....not even remotely possible.
Like everyone, just have to live with what is available.
I have a DRD on my v2, it gets the pulse from the front ABS, I have never actually tested the odometer but on a number of occasions the distance to home shown on my Zumo matched my odometer exactly all the way home so over a hundred kilometres or so they are very very close.
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