Speedo adjusting?

[sunhuntin]

ive been wondering about the accuracy of my speedo for a while, so tested it against a "your speed is" sign. i went past with my needle exactly on 50. the sign told me speed was 45! is it possible to have the speedo adjusted so its accurate? i tried upping my speed by 5, but it was impossible to keep it steady and watch the road at the same time.

cheers!!

[grusomhat]

If it's not cable driven then you can install a speedhealer. They aren't cheap, but can come with wiring harnesses for most bikes for a plug and play type deal. They will fix the speed but mess up the odo. It's a case of compromise as manufactures build in an error in speed but the odometer reading is fairly accurate so fixing the speed, makes the odo out.

You can also pick up speed correctors from JayCar but you need to know how to wire them up.

[sunhuntin]

its cable driven i think. no computers on my bike, lol. shes not flash enough for that, hehehe. :wari: thanks though!

[Virago]

Bike speedos are notoriously inaccurate, generally over-reading like yours. 10% is par for the course I'm afraid, Mutley's 250 Virago is the same.

[Clivoris]

Bike speedos are notoriously inaccurate, generally over-reading like yours. 10% is par for the course I'm afraid, Mutley's 250 Virago is the same.

Get an Aprilia. Officially timed at 254kmh. Speedo read 256kmh.

[PrincessBandit]

Same with both my bandit and Balu's burgman. We have fun seeing how our speeds compare with the GPS unit we sometimes use while we're out. Anything from 5 - 8 kph discrepancy depending - somewhere about 7 - 8 % according to Mr Mathmetician Balu!

[Warr]

3 options come to mind.
1. Put-up with it :)
2. Buy a push bike electronic speedo. They can all be programmed to different wheel sizes & can give you other useful info like ride average speed etc. Can be tricky mounting the wheel magnet tho.
3. Get a GPS

[grusomhat]

My KR is 20% out which I consider to be pretty bad. Just put up with it and mark on your speedo what normal speeds should be, like 50, 70, 100. Otherwise bike speedos are great but don't read above 99kmh usually.

[p.dath]

Note that bikes of European origin often have a deliberate 7% error built in. This is because in Europe manufacturers aren't allowed to make a speedo that tells you you are going faster than you actually are. So to fix this problem, they make them deliberately say you are going 7% faster than you really are.

Very noticable in BMW cars as well ... If you have a GPS then it is really obvious.

[p.dath]

Oh, and the error only affects the speedo, not the odometer. The odometer is still correct.

[sil3nt]

All vehicles are like this. Car magazines usually publish real speed at indicated 100kph and its usually around 95kph.

Just get a bicycle computer and use that. You can get wireless ones.

[MotoKuzzi]

its cable driven i think. no computers on my bike, lol. shes not flash enough for that, hehehe. :wari: thanks though!

I don't know if it's possible on a motorcycle but I once had a hot rod speedo corrected by the addition of a ratio box made by some outfit in Hamilton. Basically a little box with a couple of gears connected into the cable which alters the speed of the cable at the speedo end.

[Mully]

A lot of those "your speed is..." signs are out as well. I wouldn't take a reading off those as gospel.

Use a GPS and mark 50, 70 and 100km on your speedo.

[p.dath]

All vehicles are like this. Car magazines usually publish real speed at indicated 100kph and its usually around 95kph.

Just get a bicycle computer and use that. You can get wireless ones.

I haven't had that experience with vehicles not from Europe.

For example, my Holden Commodore says exactly the same speed as my GPS reports.
I'm sure Ford XR6 and XR8's will be the same.

[AllanB]

What a lot of hard work you lot are suggesting. I have a much simpler plan.

Ride like a mad bastard and eventually the police will tell you exactly how fast you were travelling at :yes:

[sunhuntin]

ok, so it seems im stuck with it. bummer. lol. gps could be an option. might look into it.

allan... i had a cop accuse me speeding last time i was down south. was a 70k zone, and i had my speedo sitting exactly on the 70. going by the new info, i was actually going 5k slower than the speed.

[pritch]

eventually the police will tell you exactly how fast you were travelling at :yes:

This is a current worry of mine. (There's always something. :rolleyes:)

The Ducati speedo reads slow by at least 10kph but possibly more, I don't know exactly... I'm hoping it won't be the Highway Patrol that informs me.

[bogan]

if its possible (i havent figured out how to do this without breaking shit) take off the speedo glass etc, and just replace the numbered backing with an accurate one. Record the major speeds with gps, and mark on glass/original backing to aid in calibrating the new one.

[Goblin]

I reckon those "Your speed is..." thingies are there to lull you into a false sense of security, then just around the next corner there'll be a :Police: ready to dish out speeding tickets. :spanking:

My bike and car always read faster than the speed on those things. I like to speed up so it tells me to "SLOW DOWN!"

[Cheshire Cat]

I reckon those "Your speed is..." thingies are there to lull you into a false sense of security, then just around the next corner there'll be a :Police: ready to dish out speeding tickets. :spanking:

My bike and car always read faster than the speed on those things. I like to speed up so it tells me to "SLOW DOWN!"

Me too! :rofl: :devil2:

[keithbuckby]

checked with gps, showing 60, actually going 50, just remember what to ride at and you will be fine. if you are passing too many cars maybe a bit quick tho! lol

[CookMySock]

i had a cop accuse me speeding last time i was down south. was a 70k zone, and i had my speedo sitting exactly on the 70.I hope you told him to jam it up his bum.


take off the speedo glass etc, and just replace the numbered backing with an accurate one.You don't need to do that. Just lever the indicator needle off with two screwdrivers and slide it back on in the correct location, and give the needle-boss a whap with the screwdriver handle to seat it. The hard part is figuring out how it comes apart.


Steve

[Warr]

.....
Just get a bicycle computer and use that. You can get wireless ones.
No dont get a wireless one...
The ones I have seen & tried :( require as good as line of sight between sender & receiver and distance is a problem on a m/bike.
To conserve battery life the transmitters are Very low power and Any obstruction will render them useless. Go for a cable one tho tis a good chance you'll need to lengthen it.
The most difficult thing is mounting the fixed magnet on the rim somewhere. But there are ways and means :)



.......
Otherwise bike speedos are great but don't read above 99kmh usually.
No last one I bought CATEYE Velo 8, nothing flash, goes to 299kph and my previous Echo was the same I think.

[slofox]

Another option that I have used is to wait until you come across some gentlemen in blue playing with their tools....err I mean, laser guns.
When I saw them, I stopped and asked one of them if he would be so kind as to check my speed with his little toy, which he very happily did. With my speedo flicking between 49 and 50k, his gun read 47....so maybe 5% over.
Personally I think it over-reads more than that...(that way I can go faster without thinking I am too far over the limit...hurhurhur). At around the 100 - 120 k mark, I deduct some 8k from what the dial reads...so far so good...

[slofox]

I like to speed up so it tells me to "SLOW DOWN!"

There's a permanent electronic warning sign just south of Pirongia on SH39, on the way to Otorohanga. It's set up just before an interesting set of S bends...so far I have never gone through it without it saying "SLOW DOWN". But I have never managed to get it to say "YOU FOOL!!!!!" yet...

[bogan]

You don't need to do that. Just lever the indicator needle off with two screwdrivers and slide it back on in the correct location, and give the needle-boss a whap with the screwdriver handle to seat it. The hard part is figuring out how it comes apart.


Thatll just be a speed offset though, and at 10kmhr itll still show 0 etc. So youd still be out at either 100, or 50, wouldnt you? An if you replace the backing you can also bling it up somewhat :bleh:

[vifferman]

Note that bikes of European origin often have a deliberate 7% error built in. This is because in Europe manufacturers aren't allowed to make a speedo that tells you you are going faster than you actually are. So to fix this problem, they make them deliberately say you are going 7% faster than you really are.
This makes no sense - I think you meant, "This is because in Europe manufacturers aren't allowed to make a speedo that tells you you are going slower than you actually are."
In any case, you are incorrect. My wife's Peugeot's speedo has only around 2% optimism.
I suspect it's a general vehicle manufacturers thing, to avoid any comeback from people getting tickets, then saying, "It's not my fault - I had the speedo checked and it's wrong, therefore it's the car/bike/truck manufacturer who should be liable!".
It also allows for some variation in tyre sizes/profiles, so that even if they decrease the speedo reading, it's still not going to be reading low.

Note that even though speedos are invariably optimistic, the odometer is usually pretty accurate.

On the VFR, ihave the gearing lowered by 6%, and the speedo was already around 6% optimisitic. I fitted a kitset speedo correctr (from Jaycar Electronics) and adjusted it based on a guesstimate to give a 12% reduction (making the odometer 6% pessimistic). Subsequent testing against a GPS found it was under-reading, so I dropped it to 10% correction, which was spot on. Unfortunately, shortly thereafter, it carked it. :(

[vifferman]

There's a permanent electronic warning sign just south of Pirongia on SH39, on the way to Otorohanga. It's set up just before an interesting set of S bends...so far I have never gone through it without it saying "SLOW DOWN". But I have never managed to get it to say "YOU FOOL!!!!!" yet...
The first ones I saw used to give your speed, no matter how fast you were going. My favourite trick on spotting them was to chop down a gear or two, to see how fast I could go in the short time between when I spotted the sign, and passing it.
Then the next type I saw displayed your speed up to the local speed limit, then over that flashed up money, like "$60....$90...$120...etc."
Kewl! I've just earned $200! :niceone:

Now they're REALLY lame, just flashing "Slow Down!!" Where's the sport in that?!?

The most sensible use of these devices was in the Hunter Valley at some road works, where their deployment was a good safety measure. They flashed up something like, "Road Workers Ahead!! Speed limit: 35km/h.... Your speed: 45km/h. .... SLOW DOWN ... SLOW DOWN"

[Bass]

The roadside speed indicating signs told me that my speedo was about 10% optimistic in the 50 kph region. No surprises there.
However, the cop with the laser explained that it was only 3% optimistic at about 120 kph.
Bugger!

[CookMySock]

Thatll just be a speed offset though, and at 10kmhr itll still show 0 etc. So youd still be out at either 100, or 50, wouldnt you? An if you replace the backing you can also bling it up somewhat :bleh:Normally it sits on the stopper needle at 0 km/hr. It doesn't matter if there is an error at 10km/hr, what you need is it most accurate where it counts, and that is at either 50k or 100k.

Steve

[sunhuntin]

I hope you told him to jam it up his bum.



i wanted to, but i was a bit beyond speechless. lol. i dont do well in such situations. i think he was in a foul mood before i got there though. he couldnt get me on having been drinking [one rule i imposed and always follow], so accused me of speeding when he had no cameras or lasers to back up his claims.
how many of us remember what speed we are meant to be doing once we are past the sign? he asked what speed the sign said, but i couldnt remember as i had adjusted my speed to what was asked and then forgotten what id read as the info was no longer needed.

[dogsnbikes]

ive been wondering about the accuracy of my speedo for a while, so tested it against a "your speed is" sign. i went past with my needle exactly on 50. the sign told me speed was 45! is it possible to have the speedo adjusted so its accurate? i tried upping my speed by 5, but it was impossible to keep it steady and watch the road at the same time.

cheers!!

call in sometime or PM me and we can compare your speedo with the bold'ors speedo as that has just been calibrated by robinson's instruments in STH Auckland.....
but 5kph at 50kph I wouldn't worry about spending a couple of hundy on as most of the time you will be going with the flow of the traffic in a 50k zone

lets see how much Variation there is at 100kph,then you can decide what you want too do with your speedo

[ready4whatever]

how accurate are those speed sensors? my ute does the same thing, although i have replaced the gearbox, never know what these mechanics do

[Cajun]

Note that bikes of European origin often have a deliberate 7% error built in. This is because in Europe manufacturers aren't allowed to make a speedo that tells you you are going faster than you actually are. So to fix this problem, they make them deliberately say you are going 7% faster than you really are.

Very noticable in BMW cars as well ... If you have a GPS then it is really obvious.

Hmmm i think you a bit incorrect

I have a speedohealer on my gsx-r, which i have measured with a gps, at 100km/h its with in 0.5kms,


I have then in turn compared my bike with our Italian RSV-R, and what you know at 50km/h same speed, and at 100km/h both read the same also. Which shows its is not out. The rsvr goes off rear wheel revolotions, so changing sprockets, tire sizes etc does not throw it out, since its taken off the bolts that hold the rear brake disc to the rim, unlike japanese bikes which take it from the front sprocket



I did this due to fact i have changed the sprockets which throws out speedo, and suzukis on average are 8% out (before i correct it)

[Goblin]

There's a permanent electronic warning sign just south of Pirongia on SH39, on the way to Otorohanga. It's set up just before an interesting set of S bends...so far I have never gone through it without it saying "SLOW DOWN". But I have never managed to get it to say "YOU FOOL!!!!!" yet... Maybe cos you're not breaking the "two second rule".

[slofox]

Maybe cos you're not breaking the "two second rule".

Ahhh..mmmm could be!!! Din't think of that!

[Disco Dan]

ive been wondering about the accuracy of my speedo for a while, so tested it against a "your speed is" sign. i went past with my needle exactly on 50. the sign told me speed was 45! is it possible to have the speedo adjusted so its accurate? i tried upping my speed by 5, but it was impossible to keep it steady and watch the road at the same time.

cheers!!

Your speedo should have a number printed on the face (more likely the older it is). Usually 3 digits long and gives the drive gear - revolutions per mile/kilometer. If this is wrong which could be the case with different front tire size, wheel size etc then it would be possible to change the gear drive from the front wheel to read more accurately. This number will most likely be printed behind the speedo face on more modern speedos.

[Swoop]

I like to speed up so it tells me to "SLOW DOWN!"
The devices we have up here tell me I ride like a nana. It always says "NOW SLOW".:weep:

[CookMySock]

i wanted to, but i was a bit beyond speechless. lol. i dont do well in such situations.What you need is practice, my dear. Try wandering around all day approaching family and perfect strangers alike - "Hey you! Jam it up your bum!"

In a week, you will be an expert, hehe.. Everyone will be wondering what the HELL has got into you. :niceone:

Steve

[Max Preload]

I haven't had that experience with vehicles not from Europe.

For example, my Holden Commodore says exactly the same speed as my GPS reports.
I'm sure Ford XR6 and XR8's will be the same.

My 'coon is spot on at 100km/h according to my GPS.

[sunhuntin]

What you need is practice, my dear. Try wandering around all day approaching family and perfect strangers alike - "Hey you! Jam it up your bum!"

In a week, you will be an expert, hehe.. Everyone will be wondering what the HELL has got into you. :niceone:

Steve

hell, i do that already. i nearly belted a guy at work cos they used my hose without asking and returned it with tape wrapped around it claiming it had a hole. didnt have a bloody hole last time i used it, the cock suckers. they wont be getting into my cupboard anymore cos my keys are coming home with me from now on.
would have told the cop to shove it, but i was shocked at being accused of speeding in the first place. plus i didnt want a ticket just cos i was giving back what he was dishing out.

dogs... cheers for that! will pm you for your addy when i know ive got some time spare. dont get very much of it anymore, lol.

disco... only numbers on my speedo are the speed ones [50, 100 etc] shes a 98, so im picking the number you mean is hidden. never thought about front wheel size making a difference, even though ive read about it on here. cheers for that.

[Disco Dan]

This will also help:

[TimeOut]

if its possible (i havent figured out how to do this without breaking shit) take off the speedo glass etc, and just replace the numbered backing with an accurate one. Record the major speeds with gps, and mark on glass/original backing to aid in calibrating the new one.

I got a corrected face plate from the States (in metric), looks exactly the same as the old one but the numbers are in the right place (have checked it with the GPS)

[Disco Dan]

I got a corrected face plate from the States (in metric), looks exactly the same as the old one but the numbers are in the right place (have checked it with the GPS)

Good thinking, however that method is flawed.

A gear spinning either at the wheel or sprocket spins the speedo gauge - now if that gear is wrong for the size of the wheels etc etc and is giving an incorrect reading then the inaccuracy would be progressive. Ie at 20k would say 21k at 50k would say 53k at 100k would say 112k etc etc

This would mean your gauge would have numbers not equally spaced in order to give accurate reading throughout the range.

Quite often an inaccurate gauge reading can be rectified simply by changing tire profile or in the case of a stock standard setup - a light oiling of cable and speedo assembly. More drastic measures (as I already stated) require a tooth count of the sender gear and replacement with correct tooth count of gear to give rev per k correctly to speedo.

[CookMySock]

Bah, just ride along at exactly 100km/hr on the GPS, and carefully pull the needle off the speedo and put it back on at the correct position. Easy!

Steve