Was discussing this in a different off-topic thread but thought I'd start it here for more opinions. I've read somewhere that Magna speedo's are set at factory to read approximately 2 - 4 km/h faster than what the car is actually doing, eg, at 60 true km/h the speedo reads 62, and at 100 true km/h it says 104km/h.. and I think this is true for a few reasons. I've driven side by side with a mate in his stock VT commodore, and this is our results:

Him: 60km/h Me: 64km/h
Him: 80km/h Me: 83km/h
Him: 107km/h Me: 111km/h

I've also compared to a few other cars, glancing at their dash as I'm driving etc, not as accurate, but even a soarer I think it was with a digital readout, and I was 5km/h ahead of him and we we're perfectly in line.

Also a few months ago when I set the cruise on 108-109km/h and started on a downhill slope I looked down at was sitting on 111-112kph then saw a speed camera, but didnt get flashed, and havent recieved anything in the mail.

Final test is those 5km speedo check signs, every time without fail I end up doing 5.1km in those tests, so its reading a little higher. Nothing much, but working the figures out, after 200,000km the car's only done 196,000. But i'm sure there are worse cases.

*Edit.. just realised this probably belongs in Members or General section.. :S

lol, yeah probably best to put it in the 3rd gen section, gotta keep up the consistent results!


As said in the other thread, I too think that my speedometer is reading faster then it is. This is based from a direct comparision when I changed cars from a 2nd gen to a 3rd gen, where I found a great deal more cars nearly tailgating me and overtaking me.

I've also done those 5km speedometer checks along the highway and by the 5th post my reading didn't correspond either.

Depends on the Rubber and Wheel size you have aswell

According to a Tyre size Calculator my Rims give me a -2.4k innaccuracy
So if I am doing 100ph on the Speedo, In actual fact I would be doing 97.6kph

I've sort of thought about this before aswell and I think that it's true. My car is TE and whenever I hop into another car and travel at my usual speed, I get tailgated and people fly past me and stuff. However, when I noticed it, I just thought that it was my girlfriends car's speedo was lower than actual or something. I think this could be a good thing, because we can travel 5km over the limit according to our speedos and still actually be doing legal speeds :D.

Well to add a bit more weight to my above post, I am running on stock size rims and rubber.

Heres one thing, i drive cars back from adelaide to the gawler hospital and i have to keep records of the kms i do. Following the same route a magna reads 45km and falcon/commodore 42km with camry at 43km, i can't work it out.

Have clocked my KJ's speedo with our K-band radar - its spot on.

Pin the needle right on top of the 100km/h mark and the radar is 100 too.

(stock wheels & stock tyres about 50% worn)

For some reason they do this to nearly all cars manufactured, even the como's and falc's are out. The police have them calibrated to make them accurate (if you dont beleive me have a look in the top right corner of there windscreen). The magnas are said to be out by yeah 2-4kmh, this was tested ages ago by magazines when the car was sat on its 215kmh limiter and the radar said 212kmh speedo read 215kmh. Appearently its the same gap through the full sweep of the speedo.

I think wheels magazine still put these details in the spec section of there articles (they have done for years) iirc

Him: 60km/h Me: 64km/h
Him: 80km/h Me: 83km/h
Him: 107km/h Me: 111km/h



I own a 3rd gen, and its on stock tyres, and my speedo plays the same tricks on me, i have be done for doing 114km etc, when i havent. So yeh it mite be a magna problem for a selected few of us.

I still haven't found the time to go and get my speedo actually checked. Do a search on this forum and you'll find a thread which i may have started a while back regarding my speedo issues :)

cheers
Madan

This is interesting.......I got caught at 77kmh a month back but that was because I wasnt looking at my speedo. And I do constantly drive at 60kmh sometimes feel fast and sometimes others are right behind me so its a bit not sure what I can say for this but I should check it out.

Those said about tyres etc I believe can be true.

And if our speedo is set faster in a way then its not good.

Police speed cameras should give and take a bigger limit actually but I heard they dont.

Cheers!

Police speed cameras should give and take a bigger limit actually but I heard they dont.
Coppers give you 3% variance (they already take it 'off' by the time you get your summons).

ADRs allow for +/- 10% variance on your speedo accuracy.

Coppers give you 3% variance (they already take it 'off' by the time you get your summons).

ADRs allow for +/- 10% variance on your speedo accuracy.

haha not here in victoria they did away with that last year no leway now i dont know how they get away with it the 10% leway is federal law i didnt think state law over-ruled federal but i could be wrong about that.

haha not here in victoria they did away with that last year no leeway now i dont know how they get away with it the 10% leway is federal law i didnt think state law over-ruled federal but i could be wrong about that.
Nah, VIC just takes 3km/h off your 'score' before they record it on your 'bill'.
(ie when you get your summons, that "78" they write was really "81" on their radar)
Copper told me that himself earlier this yr after clocking me at 'actual' 104.

Its 3% or 3km/h when below 100.


Used too be 10% or 10km/h back when I was younger. :P

(TN wagons can still go stupidly fast!)

Its 3kmh I think and even then is really a very small gap compared to other countries speed rules. Ultimately dont speed to get a fine. I laugh at ads of those down 5 saves lives, as they dun really do jack actually and even some at speeds at 50kmh do kill already so is not really a matter of 60-65kmh. I think is more of saving yourself from more fines.

Just came back and there was some police with a radar gun, a bit unfair that they targetting a bridge where is slopping a little. but I was at 60kmh so that means speedo is fine.

I'm thinking it's still 10% le-way in qld, I always cruise on the highway at 108.. but I spose, speedo inaccuracy kicks in :bowrofl:

I reckon having the needle reading faster is a good thing.. tho it adds more km on your clock. But nothing dramatic.

I really don't think my licence would last long in VIC if there's NO le-way. I feel sorry for ya's.. that's totally wrong I reckon.

have u got stock tyres coz that can change the speedo check this site out:

http://www.miata.net/garage/tirecalc.html

Interesting site, yeah that shows tyre size do count for speed, are there places that recabirate the speedo meter?

I believe most stock cars use are set from the factory to over read when new. After time the speedo will start to decrease its output. As said previously ADR requires only +-10% but take different rolling stock and everything can be out. My verada reads very close to real speed as I checked it with a GPS which are very accurate at high speed.

it's all well and good that our cars may deviate a bit from true speed, but what I want to know is, in relative to other cars, are our speedos more out then others, or is it that everybody on the road are all speeding?

Results so far are inconclusive :(

In my case, lets just say I am out by 5km/h doing 70. Guy behind me is doing a nice cruising speed of 73, just slightly above the speed limit but not enough to trigger a speed camera (assuming he's speedo is true speed). All up I would be going 8km/h slower in relative to this other car, enough to annoy the guy out of his nuts.

Interesting site, yeah that shows tyre size do count for speed, are there places that recabirate the speedo meter?

thats a good question does anyone know?

got mine checked with a gps... reads 96 at 100... but then the other day had cruise set at 110 and got done for 111!!!! was not happy!! also at the drags speedo reads 160 speed thru the trap is 154. my tyres are the same as standand diameter

Reviving this thread because I've booked Max in to have a speedo count and recalibration.

I'm on 205/65R15 94H tyres. They tell me they're 16" factory alloys. Insurance wanted to know the width of the wheel - apparently 6". :confused:

Does anyone have any expert advice - like what I should make sure they do?

On mine reads 96 when i am going a 100.When i was going 130 i was pulled by copers.And on they radar was 126.So it should be 4 diferents.

just cos it maybe be 4kms different at X amount of speed dosnt meant it willbe the same at a higher speed..

the only way that could happed is if ur needle has been knocked .. then it would read the same variants in speed all the time...

if u have bigger wheels then the faster u go the more the speedo will be out

i was on the princess Freeway (old geelong rd) going to Geelong the other day and my speedo was 100% accurate according to the speed tester. Driving a TJ vr-x series 1, done 91,000.

stock tyres and wheels.

maybe im just lucky???

Both my KH and KJ AWD are dead accurate. Both say 100 on the speed checks on Geelong road when doing 100 on the spedo.

Accurate one day, inaccurate the next. The accuracy of your speedo is not only determined by the calibration of your hardware, but also environmental and usage factors. Such as ambient temp/tyre pressure (co-related), payload in the car, tyre tread depth. This is why there is a 10% allowance in ADRs.

When we went to melbourne a couple of weeks ago we went through that speedo tester on the highway into melb I was sitting on 110kmh exactly the read out indicated I was doing 108kmh so -2kmh at 110kmh.:D

when wheels did theyre tests on the ralliart V xr6vct V xu6 it was

AT 100kph

ralliart - 99
xr6vt - 96
xu6 - 100

if thats anything to go by :D

Accurate one day, inaccurate the next. The accuracy of your speedo is not only determined by the calibration of your hardware, but also environmental and usage factors. Such as ambient temp/tyre pressure (co-related), payload in the car, tyre tread depth. This is why there is a 10% allowance in ADRs.So, basically, if we overcompensate for the inaccuracy, we're setting ourselves up for a ticket. What is the world coming to?

I thought I had mine pegged at 5k out (65 in a 70 zone according to hubby), but then we did a trip through Melbourne. I was following my brother in an 80 zone and my speedo said 90.:confused:

I seriously HATE slowing other people down.:(

What is the world coming to?




They're called the laws of physics mate, they've been around since time began.

Reviving this thread because I've booked Max in to have a speedo count and recalibration.

I'm on 205/65R15 94H tyres. They tell me they're 16" factory alloys. Insurance wanted to know the width of the wheel - apparently 6". :confused:

Does anyone have any expert advice - like what I should make sure they do?

Ahh, if you have 205/65R15 tyres, that means you have 15" alloys (if you have alloys, else its a steel wheel).

For a standard Magna 15" wheel, the width is 6".

no speedo will ever be 100% accurate, thats why they are allowed to be 5-10% out from the factory (yes, + or -) so technically 2 identical cars could have a 20% difference in speedo readout! :shock: and as many people have said, also depends on tyre sizes etc etc.

i've driven past those digital readouts on the freeways and mine seems pretty spot on :)

not bad for oversized rims and aftermarket dials!!

They're called the laws of physics mate, they've been around since time began.

easy tiger, get all technical and s**t, damn, my tf is 3 k down,i think, the over head ones only tell me speed limit is 110, not sure why

Him: 60km/h Me: 64km/h
Him: 80km/h Me: 83km/h
Him: 107km/h Me: 111km/h

Ive a 1998 TF with 17" x 235 x 45 tyres !

I was pinged by a multi nova at 77kms and I was doing just under 80ks
They sent me a $50 fine for that as well ! :rant:

On the speed limiter Im doing 219ks per hour but I under stand its set at 215Kms !
And of course I was not doing that speed on the "street" :cool:

When a "friend" of mine was pinged by a patrol car with mounted on board radar and clocked at 169ks he was doing 170ks by the clock ! :badgrin:

So the mitsubishi speedo's seem to have only a minimal variation !

Nic
WA

My speedo is so innacurate that it only starts working when you are doing above 20 :D

Gen I POWA!

Ahh, if you have 205/65R15 tyres, that means you have 15" alloys (if you have alloys, else its a steel wheel).

For a standard Magna 15" wheel, the width is 6".So if they're standard, they're not alloys? :confused:

Can you tell from my profile pic whether they are steel or alloys? The dealer told us they're alloys! We're paying extra insurance for alloys. How can I check?

Now I'm feeling like any persuasive man could tell me any old crap and I'll believe it.:doubt:

They are usually inaccurate. If you're concerened, make sure you're using the right tyres and put it on a dyno for a definitave answer.

My speedo is so innacurate that it only starts working when you are doing above 20 :D

Gen I POWA!

Speedo cable is probably frayed, or faulty instrument cluster.

Yeah sounds like speedo cable. Ya know when ya have to replace it when the needle bounces everywhere too. My old TR the cable was actually resting on something and wore right thru the cable.

So if they're standard, they're not alloys? :confused:

You have factory Alloys:D 15" 205 (tyre width)/65 (Tyre profile/sidewall)R15 (diamater of the wheels it's designed to fit)

You have factory Alloys:D 15" 205 (tyre width)/65 (Tyre profile/sidewall)R15 (diamater of the wheels it's designed to fit)Thanks Phonic.:D

hows this then....
in the morning 100km/h equals 2,450RPM
after the hour it takes me to get to work, it shows 2,250RPM
but i know that 2,250RPM is 100km/h so in the mornings im doing about 7km/h faster!
when every thing works, my speedo is spot on, even with 135/45 r17

so your speeding some times and not speeding at others.
Great hope everyone doesn't have this issue :doubt:

Quick update. The speedo guy here in Ballarat checked my car out and said it was 4k out at 60kph and got progressively worse with increased speed. He tells me it's fixed now. Does $90 for 2 hours' work sound reasonable?

I can't wait to take a spin through those highway speed checks between here and Melbourne. At least no-one was on my tail on the way home.:D

Speedo cable is probably frayed, or faulty instrument cluster.

The latter :P

Fuel guage very innacurate, speedo needle dont kick in till 20 and the tacho sits on 0

Recently added GPS in my car which has an accurate speedo. The car speedo is showing 1-2km/h more then I am going. Which I think the manufacturer puts in on purpose.

KE Verada was 100% accurate at 80 90, 100 and 110Kmh according to my garmin GPS a few years ago.

Haven't checked the GTVi but will in the next few days.

Cheers

Recently added GPS in my car which has an accurate speedo. The car speedo is showing 1-2km/h more then I am going. Which I think the manufacturer puts in on purpose.
That's right - manufacturers normally calibrate speedos to read slightly high.

I suppose one of the reasons the speedos read slightly high is to ensure you don't sue the manufacturer if you get a speeding ticket when the car speedo indicated you weren't speeding....

Cheers,
Martin.

zooms down to "do we get fined at 65kmh?" lol
:doubt: