Speedo Error

[BMWGSER]

Doesn't matter last time I got stopped I was looking 800 metres up the road and not at the speedo.

[Taxythingy]

My Hyosung reads 116 at 100kph. Checked once with gps gaffer taped to the bars. The last one was about 112 at 100kph. Whereas my PoS Corolla can manage within 2%.

[release_the_bees]

Pretty much every bike I've ever owned has read 10% more than the actual speed. The exceptions being a GS500 that was bang on, and a KR150 that was so far off that I just ignored the speedo and followed the traffic. (following traffic on the motorway showed a speed of almost 140km/h on the speedo)

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[Ocean1]

My Ducati book tells me the speedo is set 8% high by the factory. So I ride everywhere at 110

You read the manual?

Hand in your Kiwi Bloke card immediately!

The SDR speedo is out by at least 15k at 100k, so my target is 120k. I've never seen anything standard out by that much, but bitched at by journos about it they simply pointed to those reg's I mentioned.

[HEsch]

GPS units tend to be inaccurate at speed on steep inclines. Something to do with physics and triangulation and whatnot (fuck knows).

The Surf is generally about 8% out. I know that if I hover around 108 I'm probably doing 100, and unlikely to get a ticket. I tend to sit at 104 on the GPS or 110-112 on the speedo depending on incline. Amount of tread on the tyres will influence actual speed and distance travelled. I've done a good 65k on those tyres so I'm sure I travel slower now than I did when I put them on.

I have noticed that riding bikes has killed my sense of speed in the large, lumbering SUV. I often have to check myself for travelling at (speedo reading) 120-130... No interest in paying tickets.

[slofox]

Well...

I have it all calibrated - on the vehicles I ride/drive now anyway.

I took my GPS and stopwatch in the wahine's cruise control car. We drove south on d'Auckland's southern motorway, cruise control on, along the dead straight bit towards Bombay where there is a 5km odometer check. We watched the GPS readout stabilise, then measured (stopwatch) time per kilometer. Adjusted the cruise to get 36 seconds per kilometer (100km/hr). Car speedo read 105km/hr. 5% optimistic. GPS read 100km/hr.

Yes, I know, GPS units are not that accurate. But on a long steady straight I reckon they get close enough. Especially if they read 100km/hr at 36 seconds per km.

Have used the GPS and the stopwatch in/on other vehicles. The bike was 9% optimistic - which I found difficult to deal with so fitted a speedo healer. It now agrees with the GPS - as long as the tyres are not worn.

So yes, speedos do overread.

[nzspokes]

You read the manual?

Hand in your Kiwi Bloke card immediately!

The SDR speedo is out by at least 15k at 100k, so my target is 120k. I've never seen anything standard out by that much, but bitched at by journos about it they simply pointed to those reg's I mentioned.

Dude in Australia sells new abs rings which correct the error.

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[Ocean1]

Dude in Australia sells new abs rings which correct the error.

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Which would be quite a valuable mod.

If you had some difficulty with arithmetic.

Or some deviant form of obsessive/compulsive disorder.

Or used the speedo to unequivocally define absolutely precisely when you enter that certain unavoidable zone of death velocity.

[Jeeper]

GPS units tend to be inaccurate at speed on steep inclines. Something to do with physics and triangulation and whatnot (fuck knows).

The Surf is generally about 8% out. I know that if I hover around 108 I'm probably doing 100, and unlikely to get a ticket. I tend to sit at 104 on the GPS or 110-112 on the speedo depending on incline. Amount of tread on the tyres will influence actual speed and distance travelled. I've done a good 65k on those tyres so I'm sure I travel slower now than I did when I put them on.

I have noticed that riding bikes has killed my sense of speed in the large, lumbering SUV. I often have to check myself for travelling at (speedo reading) 120-130... No interest in paying tickets.

My last Jeep was off by about 4%. It was an easy fix with a recalibration unit after bigger tyres. It became accurate to 0.25%, which meant when I over took people on motorway doing 100 most people thought I was speeding.

My current Jeep has a computer that can be reprogrammed easily in 10 seconds to match tyres and diff gearing changes. It accurate from the factory to 0.5% at the moment.

[Jeeper]

There are a couple of places on the Southern motorway with measured 5 km marked for speedo checking. They will be more accurate to measure against than GPS, which can be inaccurate due to inclination or curves in roads.

[nzspokes]

Which would be quite a valuable mod.

If you had some difficulty with arithmetic.

Or some deviant form of obsessive/compulsive disorder.

Or used the speedo to unequivocally define absolutely precisely when you enter that certain unavoidable zone of death velocity.

Or you have multiple bikes and can't be arsed trying to remember which bike does what at what speed.

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[Old Steve]

Those 'speedo' check signs, aren't they actually odometer checks? Is there any need to time how long it takes to do one kilometre at 100 km/hr, and how accurately can you keep a set speed for 1 km? I think the odometer and speedo are inextricably linked so if your odo says you've travelled 1.1 km between signs 1 km apart, then your speedo will be out by 10% as well won't it?

And I thought that there was a requirement for a speedo to not register below the actual speed, but the Land Transport Rule only states, "a motor vehicle that is capable of a speed exceeding 50 km/h and that was first registered in New Zealand on or after 1 December 1951, must be fitted with a speedometer in good working order that operates while the vehicle is moving forward" and there is NO mention of the speedo accuracy.

I would suppose the motor manufacturers make sure the speedo is over reading to avoid Joe Blog asking for compensation for speeding tickets if the speedo was under recorded.

[neels]

I think the odometer and speedo are inextricably linked so if your odo says you've travelled 1.1 km between signs 1 km apart, then your speedo will be out by 10% as well won't it?.

If it's electronic then it wouldn't be unreasonable to expect them to be the same.

If it's mechanical and driven by a cable, it's usually just a spinning magnet and drag cup that turns the needle so can be variable, the odo is gears from end to end so no excuses to not be correct other than tyre size.

The DRZ400 I had could be corrected on the instrument panel, can't remember if it was the odo or speedo that was adjustable, seemed strange that it didn't do both though.

[slofox]

There are a couple of places on the Southern motorway with measured 5 km marked for speedo checking. They will be more accurate to measure against than GPS, which can be inaccurate due to inclination or curves in roads.

See post 36...

[slofox]

I think the odometer and speedo are inextricably linked .

This is true for the gixxer. When I installed a speedo healer, I noticed that regular trips suddenly changed their length. I actually travel 8% further than the odometer says. (According to the numbers anyway, )