How Accurate are Speedo Tests (Wodonga)

[normxb]

Driving from NSW to Shepparton today in the wife's ED , we went through the "Speedo Check" just south of Wodonga on the Hume . The Speedo was exactly on 100 k's going through the "gate" , BUT up on the overhead sign there was a big 91 .... : ... is our speedo out that much or or are those signs a bit Sus.

Has anyone been through them lately & how were your results . Were they Accurate ? ? ?

[EFFalcon]

mine have always been very consistant.
either they're all wrong, or all right :P
mine always reads 99 @ 100

[Steffo]

There was one on the City West Link in Sydney for a while, I drove past it at 70 and it told me 63.

Someone I know may or may not have passed it at 100km/h, indicated, and it said 75. And the car is brand new (so is mine). Wasn't the most accurate measuring thingie I've seen.

Another one once told us the van, loaded + 4 people in it, my dad's old one, was doing 90 in a 60 zone uphill when the speedo read 40. Hmmm....

[lethal_xr8]

i drive through this a bit and my speedo always reads 1k out everytime

[LTDHO]

Originally Posted by normxb

Driving from NSW to Shepparton today in the wife's ED , we went through the "Speedo Check" just south of Wodonga on the Hume . The Speedo was exactly on 100 k's going through the "gate" , BUT up on the overhead sign there was a big 91 .... : ... is our speedo out that much or or are those signs a bit Sus.

Has anyone been through them lately & how were your results . Were they Accurate ? ? ?

Drive faster then!

AFAIK they are accurate. There should be alot more of them.

[Fairlane]

I find them pretty good usually.

Car speedo's are usually out and out on the conservative side.

From the best i can gather through radar speedchecks at construction sites, time vs distance measurements and the police, mine reads 3/4kmh high.

[dogbreath_48]

I've had a bit of variation but i've been through once with GPS and it was spot on.

[4.9 EF Futura]

Originally Posted by normxb

Driving from NSW to Shepparton today in the wife's ED , we went through the "Speedo Check" just south of Wodonga on the Hume . The Speedo was exactly on 100 k's going through the "gate" , BUT up on the overhead sign there was a big 91 .... : ... is our speedo out that much or or are those signs a bit Sus.

Has anyone been through them lately & how were your results . Were they Accurate ? ? ?

That sounds about right mate.

Ive got a little GPS device for measuring speeds very accurately on flat roads. Both my cars are doing 51/51 when the speedo reads 60. Other cars ive tested have been similar.

Also consistent readings from my GPS to these novelty signs.

[bjr22n_]

is this the one a few Ks south of Wodonga on the Freeway?

i have been through that gate doing 110km/h on my speedo in my KJ2 Laser, and the sign read i was doing 107km/h

and this was only a month ago.

[normxb]

Originally Posted by bjr22n

is this the one a few Ks south of Wodonga on the Freeway?

i have been through that gate doing 110km/h on my speedo in my KJ2 Laser, and the sign read i was doing 107km/h

and this was only a month ago.

Yep , That's the one .

Thanks for all the replies , I think I'll get the Speedo checked by a Pro , the Mrs gets a "Little P####d" being passed all the time & doesn't want to get busted . She's been driving for 33 yrs and never had a ticket , but now she's a bit peeved that she's been holding up traffic all this time .

Once again , thanks everyone for your input.

Cars generally are made with speedos 1-3% faster than the actual road speed.

[jd dad]

My ED reads about the same, if I set the cruise to 108 it shows 100 on those readouts. Have been through the ones on the freeway between Geelong and Melbourne, the ones further up the Hume towards Wodonga and the distance markers up through NSW/QLand and always about the same. Have never been booked either so I think they must be pretty right.

[smciner1]

My XR6 is very accurate going by those Speedo Tests. My GT is out because of the Diff Ratio chance, but I now know how far out @ 100 km/h it is.

As someone else has said, there should be more of them, and less Speed Cameras.

[xbgs351]

Originally Posted by jd dad

My ED reads about the same, if I set the cruise to 108 it shows 100 on those readouts. Have been through the ones on the freeway between Geelong and Melbourne, the ones further up the Hume towards Wodonga and the distance markers up through NSW/QLand and always about the same. Have never been booked either so I think they must be pretty right.

The distance markers in NSW allow you to test the accuracy of your odometer or trip meter. They do not allow you to test the accuracy of the speedometer.

[Yellow_Festiva]

I changed the wheels and tyres on a very old car and i used a bike speedo (the type that pedal bikes use) clipped to the dash. Some models of speedo allow you to enter the diameter of the tyre in mm, so my speedo on the lcd display was 99.9% accurate i would imagine.

Cheers

[outback_ute]

My opinion is they are unreliable (better than a few years ago though) and can sometimes give too low a speed.
You are better off doing a time versus distance check to work out your actual speed - the Hume near Benalla is ideal for this, you can get 20-30km of mostly straight, flat road to hold a consistent speed, and there is a distance post every kilometre. Even timing with a normal watch to the second will give good accuracy (a 5sec error in a 12min measurement is 0.7% error for example)

[xbgs351]

Originally Posted by outback_ute

My opinion is they are unreliable (better than a few years ago though) and can sometimes give too low a speed.
You are better off doing a time versus distance check to work out your actual speed - the Hume near Benalla is ideal for this, you can get 20-30km of mostly straight, flat road to hold a consistent speed, and there is a distance post every kilometre. Even timing with a normal watch to the second will give good accuracy (a 5sec error in a 12min measurement is 0.7% error for example)

Fluctations in speed will add to the timing errors.

[outback_ute]

Originally Posted by xbgs351

Fluctations in speed will add to the timing errors.

That is true, which is why I mentioned that part of the Hume - I am sure you would be familiar with it given your location. I timed a 30min/50km section where the speedo needle did not move by more than a kay or so either way, and did that only a few times - over that time/distance it's still pretty insignificant. Obviously if the speed is not held steady (can judge this off the speedo) then the measurement is worthless.

[bdennis]

My ED is also out by about 10.
But. If I punch the average Km/h on the trip computer (while on cruise control) as I go through them, then the Trip computer is about 2 lower. If I use the NavMan Sat nav then the over head signs also are slow by about 3km/h..
I drive the sprint by the tacho not the speed as 2000rpm is more accurate than the speed. I must send the speed off to be recalibrated..!

[Dauphin]

I went through the one first just outside of Albury towards Melbourne a few months ago. Maybe it's the same one? It said I was doing 117 when at 120 indicated. This was a huge shock to me and I felt quite embarrassed and surprised.

Back in Easter I went through one near Daylesford at 110 indicated and it said 102.

From this reading in Easter I assumed that driving at 120 indicated on a 110 km/h road would present no problem.

Further evidence from dyno runs shows that at 60 indicated my car does 56 km/h. At 100 indicated it does 94 km/h.

On the way to Albury I passed a few speed cameras while doing 120 indicated and months later have not received any fines.

My wheel size hasn't changed the whole time, so I have no idea what to believe anymore.

[bdennis]

If all else fails. Believe the Speedo Or get a GPS...

[iCat]

Originally Posted by bdennis

If all else fails. Believe the Speedo

And then we face the abuse from others of driving 6-10k's under the speed limit.

The speedo on my xf reads exactly as per Dauphin's. At 100 on the speedo I am doing 94 in reality. I think. So on a road like Melb-Geelong, with tons of speed cam's, I sit on 100 as per the speedo and probably cause high blood pressure to everyone behind me.

[baboon]

Originally Posted by normxb

Driving from NSW to Shepparton today in the wife's ED , we went through the "Speedo Check" just south of Wodonga on the Hume .

I hope you didnt wear your jockeys that day! :nutsycuck

[schmidty]

I have never found them to be accurate when comparing with a gps reading.

I sit on the speed according to my gps, not the speedo or speed check. Speedo in the truck chaanged 3kph just by putting new tyres on it.

Know a guy with a new AUDI Allroad. Cost a pretty penny, and at 100kmh indicated it is only doing 90kmh. He too up his complaint with AUDI and they said they wont fix it because in means replacing his entire dash, at a cost of about 8k and that basically it still is within their 10% manufacturing tolerance! Just what you want to hear when you've spent over $100k on a car.

[ROOSTA]

I went through the one first just outside of Albury towards Melbourne a few months ago. Maybe it's the same one? It said I was doing 117 when at 120 indicated. This was a huge shock to me and I felt quite embarrassed and surprised.

Keep in mind the one just out of albury-wodonga only reads a maximum of 117km/h..

I have been through this particular speed "checker" and have had some mixed results.. i always set the cruise on 110km through them and can remember once getting 99km.. 116km.. 107km..

If you want an accurate speedo i suggest you either take your car and get it re-calibrated by a pro.. or buy a GPS type device..

Cheers,
Nik

[AU-Hog]

The other day I went north through the ones just north of Kalkallo on the Hume and it displayed 113KM/h compared with 112.8km/h on my GPS. Over the years I have seen some of them (the Ballarat road ones especially travelling west) read a long way out compared to the GPS, but recently they mostly have been fairly close(+/- 1Km/h). Can't comment on the Geelong Road ones though.

[new2ford]

For a while we had a contributor from Ford management on the Territory forum and he told us that speedos were deliberately made to underread by a few kph. Something to do with discouraging you from speeding I think! Would be interesting to know if the same applies to the car's black box that tells the police what you were doing before the accident!

[the_scotsman]

Tomtom on my PDA reports mine as spot on the money...

[woodsy109]

There is one at the top of the kuranda range and it is spot on with my bikes digital speedo at 80km/h. It's just one of those portable ones which I would assume might get calibrated more often than the permanant ones.

[aquahead2001]

I've recently checked the speed check device on the Geelong - Melbourne section of the Princess Fwy using 2 separate GPS devices and can advise that it was 100% accurate. GPS stated 100km/h and speed check indicated the same. The car's speedo however indicated 108km/h...

Earlier some indicated using the distance posts as a measure. It's pretty simple but works best with a flat road and cruise control. For a measured kilometre travelled at 100km/h it should take 36 seconds to traverse. To improve the accuracy, travel a longer distance. For 5kms @100km/h = 3 minutes. For 10kms @100km/h = 6 minutes.

On the same journey when I tested the GPS against the speedo and speed checker, the measured distance approach confirmed the speedo error.