V85 Speedometer inaccuracy

[rocker59]

Do you think the odometer is out by the same ratio as the speedo?
 

Normally, the odometers are correct.  It's the speedometers which are programmed to be optimistic.

[Huzo]

Normally, the odometers are correct.  It's the speedometers which are programmed to be optimistic.

That might be my downfall though.
If I alter the input to reduce the reading, then the odo reading might also reduce..
Time will tell..

[Xlratr]

That might be my downfall though.
If I alter the input to reduce the reading, then the odo reading might also reduce..
Time will tell..

It will. See my earlier post.

[Huzo]

It will. See my earlier post.

Damn that.
I’ve got my fingers into it that far now I don’t want to let it go.
I think I want the speedo accurate more than the odo. It would not be worth the effort to have two bob each way and aim for 3% because I’d end up with nothing that was right and two things that were wrong.
If I have to choose and it seems like I must, then I still prefer the accurate speedo option. I’ll run an odometer test though when I get back home, I’m keen to find out the guts on that.
I’d be keen to hear from anyone else though.
Seems to me that you pick a destination of say 100 k on the GPS and run that distance, then comparing it to the displayed value on the on board trip meter.
What was that about a free lunch ?

[rocker59]

Damn that.
I’ve got my fingers into it that far now I don’t want to let it go.
I think I want the speedo accurate more than the odo. It would not be worth the effort to have two bob each way and aim for 3% because I’d end up with nothing that was right and two things that were wrong.
If I have to choose and it seems like I must, then I still prefer the accurate speedo option. I’ll run an odometer test though when I get back home, I’m keen to find out the guts on that.
I’d be keen to hear from anyone else though.
Seems to me that you pick a destination of say 100 k on the GPS and run that distance, then comparing it to the displayed value on the on board trip meter.
What was that about a free lunch ?

Here in The States, we have "mile markers" on the highways.  No need to go far to check an odometer or speedometer.

[Moparnut72]

I agree that the ECU or BCM is counting the number of pulses for certain amount of time. I would also assume that it is a pretty short amount of time. I am somewhat new to the Guzzi community so if I make an incorrect statement please excuse me. I am assuming your bike has anti-lock brakes, if not ignore what I am saying. But if it does it is going to have to be a short period of time for the anti lock feature to work correctly, i.e. safely. So in the situation I would think you wouldant to keep identical tone rings on both wheels for the ABS to work correctly. Just my thoughts but I may be all wet. Also I didn't go back and re-read everything.

I will also add that an inaccurate speedo drives me nuts also. My Audace is only just over 1 mph at all speeds as I said earlier which is fine by me. I can live with that.  The Harley I had before my MG was off by a bit over 3.5 mph. I was always having to mentally calculate the amount to adjust my speed so as not to attract the attention of the popo. I usually run at the upper end of the perceived tolerance before a stop by the law could occur.

I am also interested in your results just for my general education, I have neither the equipment nor the ability to do something like this.
kk

[rocker59]

  I would think you wouldant to keep identical tone rings on both wheels for the ABS to work correctly. Just my thoughts but I may be all wet. Also I didn't go back and re-read everything.
 

ABS measures changes between the two tone rings.  Each time you start your bike and roll away, the ABS recalibrates.  It doesn't care how many slots are in each tone ring.  ABS is only measuring dramatic changes between the two.  Same for Traction Control.

[Huzo]

I agree that the ECU or BCM is counting the number of pulses for certain amount of time. I would also assume that it is a pretty short amount of time. I am somewhat new to the Guzzi community so if I make an incorrect statement please excuse me. I am assuming your bike has anti-lock brakes, if not ignore what I am saying. But if it does it is going to have to be a short period of time for the anti lock feature to work correctly, i.e. safely. So in the situation I would think you wouldant to keep identical tone rings on both wheels for the ABS to work correctly. Just my thoughts but I may be all wet. Also I didn't go back and re-read everything.

I will also add that an inaccurate speedo drives me nuts also. My Audace is only just over 1 mph at all speeds as I said earlier which is fine by me. I can live with that.  The Harley I had before my MG was off by a bit over 3.5 mph. I was always having to mentally calculate the amount to adjust my speed so as not to attract the attention of the popo. I usually run at the upper end of the perceived tolerance before a stop by the law could occur.

I am also interested in your results just for my general education, I have neither the equipment nor the ability to do something like this.
kk

No need to be apologetic about coming up to speed mate.
I’m finding my way in some respects too. My early calculations show 656 pulses per sec at 94 kph. I will be producing two replica tone rings to eliminate the possibility of a bug in that area.
Keep giving your insights please..
Every bit of input goes into the soup for easy digestion..

[Huzo]

ABS measures changes between the two tone rings.  Each time you start your bike and roll away, the ABS recalibrates.  It doesn't care how many slots are in each tone ring.  ABS is only measuring dramatic changes between the two.  Same for Traction Control.

Ahh..!
So does the speedo need info from two rings to do it’s job, or can I rely on one dedicated ring and let the recalibration satisfy the ABS and TC requirements ?

[Huzo]

Here in The States, we have "mile markers" on the highways.  No need to go far to check an odometer or speedometer.

Yeah, same thing here in places.

[LowRyter]

I think most of the newer bikes have pretty accurate speedometers compared to old ones.  They are generally calibrated about 5% registering faster than actual speed.  In fact, that is actually printed in the owner's manual for my Ducati.  It also has a recalibration feature when changing tires like the V85.

[pete mcgee]

Personally Peter I probably just use the gps or do the mental calibration and ride at an indicated 105 in a 100 zone.
Having said that, your questions and those of others above reveal one clear thing, no one knows for sure what will happen betwen speedo and odometer readings if you change the tone wheels.
That in itself is a reason to do it.
Knowing SFA about the V85 and not even having seen one apart from photos, is there a way to splice into the speedo signal wires to fit an electronic adjuster like this
https://www.jaycar.com.au/speedo-corrector-module/p/AA0376
Looking forward to seeing your solution and the results.
Cheers

[Huzo]

Personally Peter I probably just use the gps or do the mental calibration and ride at an indicated 105 in a 100 zone.
Having said that, your questions and those of others above reveal one clear thing, no one knows for sure what will happen betwen speedo and odometer readings if you change the tone wheels.
That in itself is a reason to do it.
Knowing SFA about the V85 and not even having seen one apart from photos, is there a way to splice into the speedo signal wires to fit an electronic adjuster like this
https://www.jaycar.com.au/speedo-corrector-module/p/AA0376
Looking forward to seeing your solution and the results.
Cheers

Yes mate there probably is, but I want to fix the problem and not mask it.
I take your point in the spirit it was offered.
If you wanted a red Guzzi but you owned a beige one, would you have it painted or wear a pair of glasses that made it look red ?
Furthermore..
I’ve had a quote to have new ones laser cut to my specs. I need to provide detailed dimensions of the slots, diameters, radii, patterns and such.
I can get two done with change from $500 and for a while I was tempted, then thought bugger it, I want to build them myself...
That was my point with the wheels..
I could have bought Griso ones, but I chose to use Bellagio hubs and.........(you know the rest)

[wyno]

No (s)tone unturned eh Pete?

[Huzo]

No (s)tone unturned eh Pete?

That’s witty Mick.
Don’t forget that oil change..

[Huzo]

Today I will conduct a test of the odometer.
Some of you will have done so no doubt. I’m hoping that it will have the same inaccuracy as the speedo, or at least in the same direction. If it’s out the other way my plan/s will be shelved.
But for now..
The slots in the tone wheel are tapered and the bars parallel, my new one will have parallel slots since they will be done with an end mill. So the bars will be tapered.
Also I’ll see what the ratio of slots/bar width is, this ratio will be preserved on the new one, they look 50/50 but I’ll measure to be certain. The reading will need to be at slot centre to account for the aforesaid taper.
I’ll refer to one slot/bar combination as an “element” from here on, think of it like a chain. One link/side plate combination is an “element”.
The point at mid slot will describe a circle of calculable circumference, call this “x”..
If “x” was say 288 mm, each element would be 6 mm (for 48 elements).
For the same  288 mm, each element would be 6.4 mm (for 45 elements).
Because a change in the width of a bar will also result in the same change in the slot with (for50/50)... you only need to increase your slot width by 1/2 of this 0.4 mm.. (0.2 for my example).
It’s not much.
That’s the thinking so far..

[LowRyter]

I think with the computer controlled displays when calibrated to tires (and gearing) you'll find the odos are dead straight and speedos are 5% off.

You can check it with GPS on your phone.

BTDT.

[Huzo]

I think with the computer controlled displays when calibrated to tires (and gearing) you'll find the odos are dead straight and speedos are 5% off.

You can check it with GPS on your phone.

BTDT.

Yep.

[Huzo]

Hmmm..
I went for a shorter ride of 30 k. The odometer was very accurate indeed, which is a bit of a bugger.
Tomorrow morning I’ll do the 100 k thing to calculate the percentage error. I reckon it’ll be in the region of 2 or 3%.
If that’s the case, I’ll put the speedo spot on and live with a 3% odo error.
Also I notice that spinning the rear wheel by hand activates the speedo, the front does not. Does this mean I can remake the rear tone wheel and recalibrate the front back into line ?

[Moparnut72]

The further we get into this the more new questions are raised.  Very interesting topic.
kk

[GonzoB]

Hi Huzo.

This won't help you fix the problem, but I thought you might be interested in my experience with my previous Honda CTX700 ride. The speedo/odo unit and the ECU worked separately on the same signal that came from a gearbox sensor. The pulses from the sensor were really fast, and it would have been a piece of cake to make the speedo the odo and the ECU all agree and be correct.

The errors were (according to my GPS)
Speedo +9%
Odometer +5.5%
ECU +4%

I added a speedo healer to get the speedo correct, but then all the rest were out proportionally, which stuffed my Fuelly reading. Still it was nice to know how fast I was going.

I understand the "legal" aspects of the speedo reading, but why didn't the ODO and ECU agree and why weren't they correct?

Good luck with your project.

Gonzo

[Huzo]

Thank you all and sundry..
Thanks mate for the commentary on your Honda, it’s all food for thought. I’m going to bounce out of bed now and go for my tour of discovery on the ‘85.
I took my Norge out the other day BTW.
After riding the V85 a lot, the Norge felt like it had legs 10’ long, velvet pistons and silk gearbox.
Rolling the power on, the Norge felt like being punched by a heavyweight boxer through a thick feather pillow, the V85 feels like being punched by a welterweight boxer a bit more often through a slightly thinner feather pillow.
I never thought I would enjoy being “ punched around the ring” so much...

[NWrider]

I woke my 8v Norge from it's long 8 month sleep after escaping the PNW for AZ and can echo Huzo's comparison.  The Norge is smoother, has excellent wind management, is more powerful (of course) and loves to run 65+ compared to my V85.  However, the Norge is lacking in leg room for me -- the only real negative.

[jacksonracingcomau]

Hi Huzo.

This won't help you fix the problem, but I thought you might be interested in my experience with my previous Honda CTX700 ride. The speedo/odo unit and the ECU worked separately on the same signal that came from a gearbox sensor. The pulses from the sensor were really fast, and it would have been a piece of cake to make the speedo the odo and the ECU all agree and be correct.

The errors were (according to my GPS)
Speedo +9%
Odometer +5.5%
ECU +4%

I added a speedo healer to get the speedo correct, but then all the rest were out proportionally, which stuffed my Fuelly reading. Still it was nice to know how fast I was going.

I understand the "legal" aspects of the speedo reading, but why didn't the ODO and ECU agree and why weren't they correct?

Good luck with your project.

Gonzo

That is, to me at least, mindboggingly incredible use of technology/ computers
3 different interpretations of actual distance travelled, apparently intentionally written.
If  i were to only have one correct, I’d choose ecu / fuel consumption/ range, I’d often wondered why that figure differs from actual, given the odo triggered by same signal.
Without clever dash, I’d still choose odo over speedo if they had to be different

I tend to use odometer/trip much more than speedo, accurate mpg and range important where I go. For speed, I use appropriate for conditions, eyes trained on road obstacles including hidden traffic officers, speed camera and, of course, farqueets, distractions like speedo staring can kill, just like looking at a phone or infotainment centre.

Waiting for geek fix sounding better by the post, fix all three at once

[Huzo]

Well the test went well, but the results were not what I’d hoped.
The ride was 123 k on the GPS and the odometer recorded 121 k. So an error of 1.6%, the wrong way.
I’m thinking I’ll try for a spot on speedo and accept an inaccurate odo, but it would have been nice if the odo had have been 1 or 2% the other way.

[jacksonracingcomau]

Well the test went well, but the results were not what I’d hoped.
The ride was 123 k on the GPS and the odometer recorded 121 k. So an error of 1.6%, the wrong way.
I’m thinking I’ll try for a spot on speedo and accept an inaccurate odo, but it would have been nice if the odo had have been 1 or 2% the other way.

Dash consumption accurate ?
Oh what a tangled web you weave, when first you try to deceive

[Huzo]

Dash consumption accurate ?
Oh what a tangled web you weave, when first you try to deceive

Dash consumption ?

[Huzo]

Well folks here’s today’s exciting episode...(brought to you by *******)
The story thus far....
Yesterday I did the odo test as mentioned and was crestfallen to discover that as warned, the odometer was damn near spot on bugger it. I ummed and arred whether to go on and have decided to do so since I have already invested time and money on the project, to not do so would constitute a criminal waste of resources.
I’ve already bought a $2.00 compass, blue pen and some paper.
Not to mention the time pouring over complex calculations that would leave Neil De Grasse Tyson scratching his head.
But as usual I digress..



The image you see before you is a dimensionless representation of the tone wheel on the ‘85. I think it will be sufficient to reproduce a new one on the trusty Myford.
The side box contains some measurements taken of the slot/bar sizes of the standard tone wheel, with a calculation of the ratio of slot to bar dimension.
This ratio will be preserved on the new one.
The slots and bars will be marginally wider to allow for the lesser number of elements, but knowing the 46/54 relationship, I will be able to calculate the circumference of the P.C.D. (pitched circle diameter), divide it by the new number (45), for the number of elements and come up with the slot size for the new wheel.
It needs to be added that to arrive with the 45 slots evenly spaced around the circle, I will make a disc about 500 mm diameter and step it out around the perimeter into 45 intervals. Any inaccuracy there, (not that there necessarily will be) will be divided by 10 or so on the product.
I fully expect that the sensor will not wet it’s pants even if the ratio is not preserved, but I may as well keep as many of the variables correct as is possible.
I expect that the sensor will think it has the standard tone wheel, but spinning at 6% less velocity.
Oh BTW..
Why is the drawing dimensionless..?
Because I don’t have a bloody 26 mm socket to get the rear axle nut off so as to get the wheel up on the bench..
Off to Total Tools....
WELL ALLLRIGHHTTYY THEN...!

[beetle]

[pedantic mode]

That would be "pair of compasses".

[/pedantic mode]

[Lannis]

[pedantic mode]

That would be "pair of compasses".

[/pedantic mode]

Don't turn "Pedantic mode" off yet!

What did you pour over the calculations?   Hope it didn't stain them too bad.

NOW

[/pedantic mode] off

Lannis