Speedo under reading.

[rus998]

Long story short. Last Wednesday I took the bike for an MOT, on the way home I passed a camera van (speedo showed that I was doing 30) going from a 40 in to a 30. Yesterday I got a letter saying that I had been clocked doing 35. Took the bike out today with the Tom Tom fitted and 30 on the GPS shows 35 on the speedo. Looks like the GPS will be living on the bike from now on and I am booked in to do a Speed Awareness Course. What pissed me off more than anything is that this is my first speeding ticket in 42 years.

[Rusty Nuts]

Odd. If anything, my bikes have always over-estimated my speed.
Are you on standard wheels, tyres and gearing?


The speed awareness course can be quite interesting.

[cooltshirt]

It is often thought that speedos have to be accurate to +/- 5 or 10% . This is not correct they have to be between accurate and +10%. Although this is never tested at MOT or anything. If you have standard tyres then you have a fault somewhere. ABS sensor?
At least you got the option of a course rather than points.

[Brockett]

I am confused
You say ( avoiding the quote police)  The TomTom showed 30 and the speedo showed 35
So the speedo is showing a speed "higher" than the TomTom
If that is correct then  by following your speedo indicated speed you would be Under the speed limit.

Q. Were you entering a 30 limit?
Q. Was the camera forwards facing?
Q. if both answers were yes then were you at or below the limit when you reached the "30 sign"?

Confession time    It happened to me. As I approached a 30 limit I backed off rather than brake. Thus I entered the 30 at about 37 and was down to 29 when I passed the "nasty white van". I was given a ticket for 37 mph and took the option of a naughty driver's course. 
The course taught me some valuable lessons and I believed then, and still do now, that it was well worth the fee and these course should be available without first getting a ticket.   I also met there some of the most stupid people who are allowed to drive. Their level of ignorance about the road, and rules of the road were such that I find it difficult to believe anyone could be so daft. 
Since then I have been the slow old bloke who will not exceed a 20, 30,40 or 50 limit no matter how much hooting and flashing I get from behind.

[Rusty Nuts]

I've just re-read the first post, your speedo seems to be over-estimating just like all my others.
It seems likely you were still coming down from 40 and actually doing 35 when just in the 30 zone.

[crump]

Yep all my bikes speedos have shown a speed higher than the actual speed....it should make it easier to avoid speeding in a limit zone

[Barbel Mick]

If it was a camera van they can pick up your speed from close to a mile away on a straight bit of road, probably long before you spot him your number is logged and the letter is on the way!
Plus, just in case you're not aware they have cameras front & rear so if you are exceeding the speed limit, on a motorcycle, approaching from the rear of the van you will be logged & then your number plate picked up when you go past the front of the van. (Don't ask me how I know!  )

[purplebikeunicorn]

Speed awareness courses are easy - go with the flow, don't be obstructive, and show willing.

I did the same, coasted from where I normally do, before a new limit (in a different vehicle), and this vehicle did not have the same engine braking as I would have normally had. Got clocked at 35. Annoyed was an understatement, but I did the crime. People on my course ranged from 18-70, from all walks of life.

As others have said, the camera vans can get you from up to a km away, then they'll record your reg (on a bike) once you've gone past them. Once you've seen them, it's already too late if you're in the lower speed limit.

[rus998]

My bad, 30 on the speedo and 35 on the GPS, sorry for the confusion. Standard wheels and gearing. This was the first time that the bike had been used since last October due to work etc. A new battery was fitted and the bike started first time and everything worked as it should. Had the letter today to book the SAC. Thanks for the help and advice.