Modern Vespa

If you change the primary drive sprocket on a Honda CB 500 X from a 15 tooth to a 16 tooth the speedo reads correctly.

They couldn't make it accurate at the factory

One can use a phone with cellular service turned off that only uses GPS satellites. There are quite a selection of apps, navigation and map, to chose from. Mire for Android than iOS.

These include Gaia, Locus Pro, OsmPro+, Scenic and more point-to-point options. Advrider has a number of threads on this. Map detail is far superior.

Me personally, literally thousands of motorcycle and 4 wheel miles using them.

One downside is screen sensitivity with gloves on, or lack there of. A stylus works and can be tethered. Still not as good as motorcycle GPS units.

My Speedo is optimistic.







Umm, meant my speedo. I just ride with the flow of traffic anyway, whatever the speed.

yes I know (I write android apps). as I said the gps in phones is more inaccurate then people realise. to be clear, when I say gps I mean gps not gps fused with cell tower and wifi to create a location. eg gmaps defaults to a fused source when it can but is able to fall back to pure.

aka Skyhook. I remember when it was added to the iPhone.

The main problem with pure GPS is the acquisition time. It's gotten much better over the years with some dedicated silicon-level hardware, but still not instant. And instant is what phone users generally expect, so...

Huh? Technology way over this old head. Seems that pretty much all 2 wheel speedos are optimistic. As has been stated above just go with traffic flow. If exact speed really mattered (has not so far) I'd look at the Garmin.

OFG

This may well be true, but my experience in comparing an Android phone and tablet with an in-dash Garmin GPS over thousands of miles is that it is not noticeable. Speed difference would be fractions of 1 mph as the same number is displayed. That said, I have not compared during acceleration and curves.

There could be some small number of feet error on location, but not a noticeable concern compared to the displayed map.

Altitude, the Android device is inaccurate.

Once both devices have been on for a while, it's quite possible that both phone and GPS receiver are using actual GPS satellites. But this is definitely not true for the phone when you first open the map, since it likely hasn't finished satellite acquisition yet.

(It also depends on whether or not the phone is using the doppler-shift technique or some primitive hack for speed readings, and that isn't easy to determine casually).

These Android devices are only using GPS, no cell service. Definitely talking about after satellite acquisition with a map app open. No idea how speed readings are being determined.

I was just pointing out that the GPS in a phone or a commercial handheld is not anywhere as accurate as people imagine them to be. There is always error in any measuring device, no matter what it is. Be it a roadside radar warning sign, your cell phone, a Garmin, whatever. And the speedometer on a vehicle certainly isn't accurate to 100%. It really doesn't matter if it is somewhat close. I'm sure there are cops out there that would ticket you for doing 1 mph or 1 kph over the limit, but most have better things to do. It's hard to make those tickets stick anyway. When I was younger, I had a state trooper tell me that if you aren't doing something crazy like 20mph over the limit, he's not going to bother you. Now, if you were doing 10mph over and you did something else, say improper lane change or pass on a double yellow or something, then he's going to pull you over. I think most are like that.

The speedo on my Primavera is 4% off. The one on my car is about 5% off. It's within specs, and not a big deal.

I'm getting the distinct impression that people don't actually want to know about the inner workings of GPS, judging by most of the responses.

As you wish. I'll be off to find a better way to waste my time.

Actually I've always found it very fascinating, just not the point I was making at the time. Cheers!

It was your specific post I was responding to, because it was completely off-base about how GPS speed readings actually worked. I tried to give you some better information, but...

You know what? Nevermind. I have no more fucks to give.

Ah, typical forum behavior. I was being general, not overly specific, and someone took it as a complete, specific, exhaustive statement. I was wondering how long it would take until that happened in this forum. It hadn't, until now.

I'm sorry I misspoke. I am sorry I didn't cite sources. I'm sorry I didn't write a 600 page missive. I am sorry you took the wrong message from what I was saying. Mea culpa!

I didn't take the wrong message. You put forth a completely bullshit version of how GPS speed measurements work. I corrected you. You objected that nothing is accurate, probably because you disliked being publicly corrected.

You're welcome.

If it makes you feel better, being pedantic. Good day.

You know what has a short shelf life at Modern Vespa? Newbies with an attitude.

You know what has an even shorter shelf life at Modern Vespa? Newbies with an attitude that don't know what they're talking about.

Good day indeed.

Well evidently pedantic Bay Area a-holes last a long time on the shelf. Hope you are proud of yourself for sucking the fun out of an otherwise pleasant forum.

There's one like you in every forum, making them a complete hellhole of assholery. Why can't people like you just leave well enough alone. Is it so damned important to you to be 100% correct that you have to alienate people?

For your information, I do know how GPS works. It wasn't in my interest, nor that of anyone else here, apparently to have a lecture on how they work. I don't have the energy to type that much. I have physical issue that limit the amount of time I can stay at a keyboard. I was merely just making a point that there are errors all over the place. Who cares if I didn't get every detail 100% correct and complete? The point is that there are errors all over the place and if your speedometer is within a few percent, then it is good enough. But I can see you are the sort of person that would niggle over 0.1% error on an analog speedometer.

Don't bother responding, I'm done with arguing with someone that can't see the big picture. But I know your type, you have to have the last word, so go ahead knock yourself out. Damn, there's one in every forum, every single last one of them!

What's funny here is that he doesn't even realize. I wasn't sure at first, but now I'm sure.

Troll.

It seems my post has been reported as a personal attack.

Oh shit, I might get banned.

Whenever people get a wild hair about picking a fight with Jess, I get this mental picture of them yelling "Witness Me!" at their browser and then rattlecanning their mouth silver...

I genuinely LOL'd.

If anyone wonders about the reference:

oh man... it's been a hot minute since we had a full scale melt down.

love it.

can't hardly wait for the re-register to come back and tell us all how much he doesn't have time for this and doesn't care.

If you want to be entertained, check the Abuse Log in modtools. I count 71 attempts.

Seventy. One.

impressive. it was only 35 when I checked about a half hour ago.

evidently spending all that precious keyboard time on the important activities.

About 2-3 miles per hour off here for me. Pretty normal.

Don't worry. I know the guy that makes that decision.

I'll talk to him.

Every Vespa, and most scooters and small displacement bikes tend to be about 5-10% optimistic. 10% optimistic on my Piaggio and KYMCO products for sure. For bigger liter bikes, flagship bikes, that sort of thing, you might see them much less 'off'. Interesting, my G650GS that I shipped to Italy is pretty much bang on. It surprised me because it's none of the things I would expect to have an accurate speedo, but I don't know if that's by design, by modification, or by dumb luck.

I just bought a second G650GS, so I can have one on each side of the ocean. When I get it on the road I'll see if it's also accurate or not. Simple but great video. Looks like you're getting anywhere from 3%-9% off most of the time. Food for thought. Should you ever get into an accident, in many parts of the world paramedics in an ambulance can get to your phone, if it's on you, and call your ICE number (in case emergency). If they're in a rush to get you in an ambulance and to a hospital, there's no guarantee your backpack is making it with you. You may want to, at the very least, have your phone in your pocket.

Your life, your ride. Personally if shit hits the fan, I want to be able to reach out. I'm going to count teeth on my G650GS sprockets when I get back to Italy... Holy, I missed out on the fun lol Second one this week, look at you go!

That guy didn't know I was the admin and owned the forum.

You, though -- you actually know better. Which makes yours just a futile stunt.

Nah. No stunt. Just being a good forum member and reporting foul play when I see it. Would of done the same if it was someone trying to sell knock off Vespa t-shirts or what have you.

Thoroughly unconvincing.

or maybe, disemvoweled?!?

Adri, c'mon man. Ticking the dragon's tail only worked so many times for Louis Slotin.

Nice Canadian reference!

At the current level of annoyance, I'm unlikely to ban Adri.

In fact, I might bestow a title upon him!

Where can I find this log.

You can't. It's part of the back-end of Modern Vespa for the moderators.

The Abuse Log is a running log of everything that is automatically blocked -- things like spambots, high-bandwidth scraping, SQL injection attacks, failed logins, and attempted re-registrations by banned users.

Here's a sample, with IP addresses obfuscated:

All I can say is...Thanks Jess, and keep up the great work with this forum.

I'm sure I speak for many. We really appreciate your dedication.

Glad everyone's having fun

Re: whatever the 1950s reference was earlier, wayyyy before my time. Not even sure my parents were born yet.