How fast have you gone on your VFR?

And don't forget tire profile. A larger diameter tire, say a 190/ 55 changes it too, the speedo will be a few percent more accurate.

 

I can divide and convert to % but real world average folks dont speak that language. I say my speedo is 6% fast first thing someone is gonna ask is how many mph is that...for the record mine is now 2-3mph fast but not dead on. Or 4% lmao

 

:chaingun::chairshot::help::kaboom::hangme:

where is the banging my head on my desk smiley?

 

also it read 11mph fast at 40, 50, 60, 70, 80, 90, and 100. Never checked it slower or faster. If its 11mph fast at 40 thats something like 28% but 11mph fast at 80 is only around 14%

 

That's the first I have ever heard or seen of a fixed error. If that's true, I retract my previous statements, apparently my vfr does 170mph lol

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Damn! I have to get up to speed on all my bikes. The tach and speedo drives are all cables. No telling how that affects the arithmetic. Never quite figgered how a percentage of something could be more than 100% unless somebody is making up shit again. Maybe I can do some slick stuff and get away with some negative percentages, that will compensate for me not being a fast guy.

 

lmao.... I feel your pain.



https://www.youtube.com/watch?v=cJX1REQB12o

 

That particular one is now on reserve for dudes that have bought Harleys or followed up on some advice by SOW.

 

Maths is hard. Dang.

 

So apparently is reading three digit numbers on small screens.

 

It would be a lot easier to just rotate the speedo face by 90 degrees anticlockwise, that way you will guarantee your VFR is the fastest ever, and you'll look fast even standing still.

 

Agree. It takes nearly zero talent to go to top end.....unless it's on a twisty road, then you die. ; )

 

I saw someone doing 250 kmh for about 3 miles....indicated. Several years ago. BTW. We Canajuns are always faster than y'al Yanks cause we are metric.

 

So is speedometer error linear?

Like always 3 off, not worse as you go faster?

 

Definitely a percentage.

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Ya. The error become far greater the faster you go. As far as I am concerned, GPS is about the most accurate there is. Maybe laser is more accurate if the person is standing directly in from of the approaching vehicle when the reading is being taken but that is not a good place to stay.

With radar, there is an accepted and anticipated error or +- 2 kmh over a 100 kmh range. That would increase with a higher speed. I am not sure what error there is in laser if there is one. But with both there is a cosign error which goes to the benefit of the target. The actual ground speed is always higher than the reading because of this. That error increases as the target gets closer. It also increases if the reading is taken at a fairly wide angle. But it will never be higher than the actual ground speed.

 

Well, I suppose there's always mile markers and a stop watch. And algebra.

Put my tomtom rider in vfr classifieds by the way.

 

It was back in 83 or 84 when the vf750f was still pretty new, I got it to indicate 134. It felt like there was more than a little bit left in the throttle, and iirc the tach too. Absolutely stock, front wheel gear driven mechanical speedometer. No GPS back then. Funny how my bathroom scale indicated about the same nuumber at the time. Straight road, excellent pavement. I had my nose between the gauges, but had to quit because it felt like the wind was going to blow me off the bike.

Instrument and indicator errors can be linear and non linear, Judges admit what ever evidence they want to admit, and you should never underestimate the ability of others to dig up unflattering things about you. These things I know.

 

And I sent you a PM as was requested...

 

A bit inconvenient, but the accurate method (used for all drag strips, land speed records, etc) is elapsed time over a known distance. Not sure what is used at strips for trap length. For land speed it is both a measured mile and measured kilometer. I've done timing for LSR oddities a couple of times. The math is simple. Known are distance and time from entry to exit. Solve for speed. Flying mile in 30 seconds is 120 mph, etc....