Speedometer MPH vs. Actual MPH

[interactive3]

I rode with my GPS to work this morning to try to figure out what the actual MPH are. It was very unscientific, but here's what I found:

Speedo 35mph = 33.0 mph gps
Speedo 40mph = 36.5 mph gps
Speedo 65mph = 59.5 mph gps
Speedo 77mph = 70.0 mph gps

My speeds varied a few mph so I averaged things out.
Does this sound right?

 

[Erci]

I've not tested mine, but I'm gonna go ahead and say that's about right.
Most bikes seem to be off by 7-10%

 

[mcteague]

A GPS is not all that accurate if you speed does not remain constant. I checked mine and, when I held a constant speed, I found the bike reported only 2mph under what the GPS showed for various speeds. I did not go over 70mph during this ride and most speedos get less accurate as the speed goes up.

Tim

 

[Goop]

We have several of the "speed check" units along the side of roads around here. While I realize these aren't the most accurate devices, they are pretty damn consistent with the readings I get when I ride. My speedo is about 8-10% off depending on speed. If I'm a 65 the units flash 59, which is 9% error. The faster you go the worse the error gets, as you see in your results.

 

[bcityroller]

Does this sound right?

It's consistent with what I've observed - pretty much anywhere over 50 mph I read about 10% high on the FZ compared to GPS. Below 50 it's still high but not by the full 10%

My cars (4 different ones) have always been within a mph or two with the same GPS.

 

[Erci]

It's off by a certain %. Does not matter what your speed is.. it's always off by same %. It just becomes more obvious, the faster you go.
So if your speedo is off by 5%, for example, at 20mph you're actually going 19, but at 80mph, you're actually going 76mph.

 

[bcityroller]

It's off by a certain %. Does not matter what your speed is.. it's always off by same %. It just becomes more obvious, the faster you go.
So if your speedo is off by 5%, for example, at 20mph you're actually going 19, but at 80mph, you're actually going 76mph.

I agree that's what you'd expect and with a mech system it would pretty much have to be a fixed percentage but based on what I've observed with the FZ it is not actually the same percentage across the whole range. YMMV.

 

[Boneman]

The only time I usually look at my speedo is if a cop is around. Other than that, how many times does one actually look at thier speedo when riding.....

On my daily commute to work I 'might' look at it once or twice. I go the speed of traffic, regardless of what number is displayed on my speedo.

 

[interactive3]

Tim & Bryan,
Your speedometers are showing a few miles per hour slower than either GPS or roadside radar. That's the opposite of what I'm observing. I decided to check my speed out because on the highway, keeping up with traffic my bike would register close to 80mph, whereas in my car it might be about 70 or a bit higher.

I did try to keep my speed as consistent as possible - for 77mph I was between 76 and 78 for several miles. I could adjust the GPS to take more sample points (and use more memory). I actually recorded the ride and looked at the speeds along the map route, looking at areas that I held my speed and noted the bike's MPH.

I'll have to do more testing on a longer ride.

 

[TownsendsFJR1300]

Most bikes, including the FZ have speedometers that read high. My FZ6 read high (approx 8% as I recall) as does my 04 FJR although the FJR isn't nearly as bad (maybe 2 mph at 70 MPH). I put a speedohealer on the FZ and got it adjusted within approx .3 MPH. My old Goldwing was also off approx 8% reading low.


My friends 1100 Ducuti Monster read high by about 10% at 70, it read 77MPH (we checked it with a lazer detector (police lazer unit)...

 

[Erci]

The only time I usually look at my speedo is if a cop is around. Other than that, how many times does one actually look at thier speedo when riding.....

On my daily commute to work I 'might' look at it once or twice. I go the speed of traffic, regardless of what number is displayed on my speedo.

99% of my riding is traffic-free. So going with speed of traffic is not applicable for me
I look at my speedo quite often to make sure I'm not WAY over limit.

 

[Aleziel]

ive got a 99% speedo accuracy according to my GPS, so i cannot really trust it.. when my speedo showed 205 Km/h, my GPS told me max speed 202

very unscientific, and just one test ride.

 

[Less]

My Speedo seems to be pretty consistently 9-10% higher than the GPS reading:

 

[Boneman]

I don't know why this is even being discussed yet AGAIN. Pretty much everyone knows that the FZ6 the speedo is out. Lord knows it's been discussed many, may times here. 5%, 7%, 8.2%, 10%, whatever; it's not 100% accurate. Show me one that is.

If 7% accuracy means THAT much to you, then solve the problem and go get a speedo healer and correct it. Problem sloved.

... I think speedo accuracy is taking a strong 2nd place to oil discussion threads.

 

[REO Scorpio]

I don't know why this is even being discussed yet AGAIN. Pretty much everyone knows that the FZ6 the speedo is out. Lord knows it's been discussed many, may times here. 5%, 7%, 8.2%, 10%, whatever; it's not 100% accurate. Show me one that is.

If 7% accuracy means THAT much to you, then solve the problem and go get a speedo healer and correct it. Problem sloved.

... I think speedo accuracy is taking a strong 2nd place to oil discussion threads.

Boneman speaks the truth.

Word is born.

Frankly, I'd rather drop the 110 and change on something else. I don't need a speedometer to know that I just went faster than the jag in the mustang who just revved his engine at that light back there

BTW, what oil does everyone prefer?:sinister:

Scorp

 

[VEGASRIDER]

I don't know why this is even being discussed yet AGAIN. Pretty much everyone knows that the FZ6 the speedo is out. Lord knows it's been discussed many, may times here. 5%, 7%, 8.2%, 10%, whatever; it's not 100% accurate. Show me one that is.

If 7% accuracy means THAT much to you, then solve the problem and go get a speedo healer and correct it. Problem sloved.

... I think speedo accuracy is taking a strong 2nd place to oil discussion threads.

+1 and don't forget to use search tab, it's mostly likely been beaten to death.

 

[Less]

I don't know why this is even being discussed yet AGAIN. Pretty much everyone knows that the FZ6 the speedo is out. Lord knows it's been discussed many, may times here. 5%, 7%, 8.2%, 10%, whatever; it's not 100% accurate. Show me one that is.

If 7% accuracy means THAT much to you, then solve the problem and go get a speedo healer and correct it. Problem sloved.

... I think speedo accuracy is taking a strong 2nd place to oil discussion threads.

Boneman speaks the truth.

Word is born.

Frankly, I'd rather drop the 110 and change on something else. I don't need a speedometer to know that I just went faster than the jag in the mustang who just revved his engine at that light back there

BTW, what oil does everyone prefer?:sinister:

Scorp

+1 and don't forget to use search tab, it's mostly likely been beaten to death.

Why do you have to jump on the guy for asking a question. So what, he didn't "search", big deal. If you don't want to answer him or be involved in this thread then just ignore it. Don't be an a hardass and think it's your job to scold someone. Just take a chill pill and move on. It's just a GD forum.

 

[VEGASRIDER]

Why do you have to jump on the guy for asking a question. So what, he didn't "search", big deal. If you don't want to answer him or be involved in this thread then just ignore it. Don't be an a hardass and think it's your job to scold someone. Just take a chill pill and move on. It's just a GD forum.

If you think I'm a hardass and scolding someone based on my post, you sure are a very sensitive guy. I definately appreciate his findings and having it posted, however there are plenty of similar threads that he could have just added onto.

Believe it or not, there are a lot of members who are not aware of the search function, as this feature is only available after you have become a member.

Simply just reminder.

 

[Nick J]

Now don't take this the wrong way or anything and let's all be friends on here.....but I thought boneman was kinda harsh, too. And by the way, my speedo reads about 10% faster than I'm actually going.

 

[interactive3]

+1 and don't forget to use search tab, it's mostly likely been beaten to death.

The search tab didn't return relevant results after several attempts with different terms... but I've gone back and now realize that after doing a search there's an option to use google to search, which yields plenty of accurate results. I didn't realize searching was a two step process. :spank: