Wrong speed indication

[jsyzdek]

Well, as a teenager I've done things that I shouldn't talk about in public... Let's just say that 200km/h (125mph) was often near my AVERAGE speed. Now I don't drive my racing car any more (guess what, it's been converted into razor blades after a crash) and drive a little honda. I still stay in the 80-90mph range whenever I can, but hardly ever go higher than that.

With the GS I'm not really into speeding in straights. I love pushing it through corners and it's hard for the cops to really measure your speed precisely there (they don't even have a good spot to catch you).

Here in CA speeding policies depend on neighborhood. In some fancy areas cops are anal about it, my friend got a $120 ticket for going 27mph in a 25mph zone.

On I-5, where speed limit is 70mph, cops tell you to stay "in 70's". But another friend got a $350 ticket for doing 90. So the tolerance goes down very quickly as you cross the '80' line.

But why I'm not getting tickets? I just see them before they see me. About a month ago, going to LA, I was going around 90 (driving my little honda). All of a sudden I slam the brakes and my wife wakes up. Nobody on the road, so she asks - why did you do that? I said - you'll see. I keep driving and a mile later there are cops. I see them hiding on ramps at night by the freeway etc etc...

I just spend 75% of my attention for looking out for 

[jdoorn14]

Better yet is to coast down to a more legal speed with just a tap of the brakes for the benefit of those behind. Cops look for that front end dive as an admission of guilt.


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[jsyzdek]

If you go fast enough, coasting down to something close to legal will take too long and you'll end up with a ticket. I tend to take full advantage of my car being a stick-shift and use lots of engine braking in such situations (and help with the brakes if I have to). They also look for that flash of brake lights too

[jdoorn14]

If you're going that fast, unless you're keeping up with other traffic, you deserve what you get ticket-wise. By the same token, if you're the a-hole weaving through 4 lanes of traffic passing everyone, you're a hazard. Big difference between light traffic smooth sailing and pulling nascar maneuvers on a crowded expressway.


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[jsyzdek]

Nobody on the road

look for that magic set of 4 words in my 8:20am post   was hiding in the bushes on an empty road, hoping to enhance their stats...

[prmas]

You are correct "TWOCOOL". Moving the needle wil make the indication correct only within a limited range. I have used this method on my own speedo which was 10% optimistic. Using the GPS, my speedo is now (all in km/h) 4 slow at 40, 2 slow at 60, 1 slow at 70, correct at 80/90 and 1 fast at 100. Being a mechanical instrument the error is not linear like a digital unit due to internal friction, spring tension and magnetic field drag.
From my point of view this is close enough and a good compromise for the real world.

Macka

ps: for what is it worth, my standard bike (F) is flat out at 160km/h (100mph), true speed into a slight head wind. That's fast enough for me thank you!

[prmas]

Sorry Guys, I should clarify that "standard" means no jetting, exhaust or intake mods. It does however have 18/37 gearing and a 140/70/17 rear tyre. Top speed is reached in 5th gear at nearly 9000 rpm.  At 160km/h or 100mph in 6th it is only doing 7400 rpm so is below peak torque and power and can just hold the speed, not increase.

Macka

[twocool]

yes, "close" is "good enough"  As they say, "We are not making a Swiss watch here"

I do like the idea of making the speedo accurate at the most used and most important range.

One of my jobs in the airplane shop, is "calibrating" altimeters.......in a similar fashion we can only change the starting point.  The FAA allows fairly large errors...but the error must be small at the lower more common altitudes...and the error can be greater as you fly higher..

As you said, the error is not linear..and the error can even change directions...Like the altimeter may read low up to a certain altitude, then read high, but then read low again at even higher..

it's just the mechanical nature of the works.....

I guess nobody really liked the idea of making a new faceplate, with all the correct speeds in the correct places.....it would be a bit of work to track and write down the error at each speed, say every 5 mph...but you could create a very accurate speedo this way........

But really...who cares?  plus or minus 5 or 10 MPH...so what?

I really like using the GPS for speed anyway..and mine knows the speed limit, so it reads my speed vs the speed limit...turns red if I'm over the limit as a reminder..

BTW..I have future plans to build a "bobber" type bike...But I want it really stripped down and clean...so I will not have any gauges...just the smallest GPS I can find, attached as inconspicuously as possible..

Cookie

You are correct "TWOCOOL". Moving the needle wil make the indication correct only within a limited range. I have used this method on my own speedo which was 10% optimistic. Using the GPS, my speedo is now (all in km/h) 4 slow at 40, 2 slow at 60, 1 slow at 70, correct at 80/90 and 1 fast at 100. Being a mechanical instrument the error is not linear like a digital unit due to internal friction, spring tension and magnetic field drag.
From my point of view this is close enough and a good compromise for the real world.

Macka

ps: for what is it worth, my standard bike (F) is flat out at 160km/h (100mph), true speed into a slight head wind. That's fast enough for me thank you!

[Suzuki Stevo]

I got to the party late, but my '07F was off +8% while the odometer was spot on. I used 10% in my head to be on the safe side...66 Mph was 60, 38 Mph was 35 and so on.

[Suzuki Stevo]

But really...who cares?  plus or minus 5 or 10 MPH...so what?

In the rural places that I ride they are handing out tickets for 2 Mph over, it's called "Revenue Enhancement"...I care about keeping my cash in my pocket.

[twocool]

I was talking about the speedo accuracy plus or minus 5 or ten, not that you should drive + 10 over the limit...now we get into the idea of accuracy vs precision..our speedos, although "off" by 8 to 10%, are always off by the same amount at the same speed..so you can be pretty accurate if you want to.

A ticket for 2 over the limit seems pretty harsh...and with a good lawyer, probably you can beat this in court, because the accuracy of the method of determining your speed comes into question.

But the cops are tricky.....for instance, I was given a ticket for 9 over, but the actual radar reading was 16 over....so the cop has some leeway if challenged in court..

If the enforcement is going to be a ticket at +2...simply follow the speedo on the gs.....since it is 8% conservative..as long as it reads the limit or less...you're safe!
I think this was the whole idea of the conservative speedo in the first place!

Cookie

But really...who cares?  plus or minus 5 or 10 MPH...so what?

In the rural places that I ride they are handing out tickets for 2 Mph over, it's called "Revenue Enhancement"...I care about keeping my cash in my pocket.

[Suzuki Stevo]

Lolz...I just caught the "who cares" part and though..yeah I care about my funding!