Micra Speedo Question.

[mattjo]

Are the micra speedo (or speedos in general) calibrated so that it gives you a higher speed reading. For example if the speedo says you're doing 30mph on the clock you are actually doing something like 27mph? I've heard this rumour for a while does anyone know if it's true?

 

[squarepants]

yearh its true, also goes worse when you have bigger wheels on. i.e if you have 17's on it says your doing 30mph when your doing somthing like 20-25mph..

if you have sat nav that tells you the real speed that your doing.

 

[mattjo]

That is interesting!

Reason i ask is my mate was doing 35mph in a 30 zone and went past a speed camera van which was hiding :glance: He's definate he's going to get done but if his speedo was saying 35MPH was he was actually doing 32MPh?? and i think your allowed upto 10% +2mph leeway on your speed? is this right?

 

[fatboyjim]

From ACPO Speed Enforcement Guidelines
Limit Fixed Penalty Summons
20 mph 25 mph 35 mph
30 mph 35 mph 50 mph
40 mph 46 mph 66 mph
50 mph 57 mph 76 mph
60 mph 68 mph 86 mph
70 mph 79 mph 96 mph

Coppers can pull you for doing lower than the above bearing in mind mitigating circumstances, but vans/GATSOs etc are usually set to the above, or higher

I could have sworn I was doing 40 in a 30 once past one of those vans with a camera in the back window... never heard anything.

They have 14 days not including the day of the offence to post you the fine... fingers crossed

Jim

 

[Tom Messy]

I've been past one of those village speed warning things several times when I could have sworn I was doing 35 and it's flashed up "thank you for not speeding". I have also put larger wheels on which wouldn't help the accuracy

Tom

 

[mattjo]

From ACPO Speed Enforcement Guidelines
Limit Fixed Penalty Summons
20 mph 25 mph 35 mph
30 mph 35 mph 50 mph
40 mph 46 mph 66 mph
50 mph 57 mph 76 mph
60 mph 68 mph 86 mph
70 mph 79 mph 96 mph

Cheers for that, having a dumb moment, what does the summons bit mean? And also it's says 30MPH and a fixed penalty of 35MPH does that mean you can't get done doing upto 35MPH?

 

[superls]

yearh its true, also goes worse when you have bigger wheels on. i.e if you have 17's on it says your doing 30mph when your doing somthing like 20-25mph..

if you have sat nav that tells you the real speed that your doing.

thats a little wrong mate if you put bigger wheels on, you then (most of the time) have a larger rolling radius, therefore your covering more ground per revolution, so if you do put 17's on the speedo will say 30 and you will be doin maybe 35-40, depending on size of wheel and tyre profile

 

[Robert]

^Yup.
With 15's my speedo read accurate with sat nav, now I'm on 14's the speedos a few mph below

 

[ollyc98]

Sat nav is not an accurate way of telling your speed. You would have to keep a perfectly constant speed for some distance to get an accurate reading

 

[superls]

yes and on a level road also

 

[esha]

I went past one of the sids recently (the ones with the angry face if your speeding!) and while it showed i was doin 30mph my speedo was roughly at about 33, ive been wondering if there was a way to recalibrate the speedo but its prob not worth it, if i get pulled ill use the speedo as an excuse to get out of it!

 

[ollyc98]

if i get pulled ill use the speedo as an excuse to get out of it!

Not knowing your speed is no excuse, in fact you will get in more trouble for that, to recalibrate your speedo just go 5 less on the tyre profile, for example instead of 50's go for 45's

 

[Alienfish360]

that's why they give you 10% I believe.

 

[fatboyjim]

Cheers for that, having a dumb moment, what does the summons bit mean? And also it's says 30MPH and a fixed penalty of 35MPH does that mean you can't get done doing upto 35MPH?

Summons means if you're caught doing said speed in that zone then you will be hauled in front of the courts and are likely to get a ban

35MPH means that the ACPO have said cameras should be calibrated to flag people for a ticket at no less than 35MPH, but this is just a guideline and the forces don't have to abide by it. I don't believe it is admissable as a defence in court (if you're speeding you're speeding). Also, a copper can pull you over and give you a ticket for doing any amount over the speed limit if he really wants to, I believe

The above is just stuff I've picked up from the web when I thought I was going to get a letter through the post A quick search has turned this up:
http://www.speedlimit.org.uk/faq.html

Not sure of accuracies of above, again it's just what I've read

 

[Robb]

yearh its true, also goes worse when you have bigger wheels on. i.e if you have 17's on it says your doing 30mph when your doing somthing like 20-25mph..

if you have sat nav that tells you the real speed that your doing.

Thats the wrong way round, if you increase the overall diameter of your wheels, they turn slower, giving the indication you are going slower, not faster.



Sorry just realised this has been adressed lol.