digital speedo

[STEVEBE]

Knowing how enthusiastic our local traffic Police are I wondered if anyone has thought that when the speedo indicated 30mph is it in fact 30.9. So the question is when does it trip, because if as it's so easy to do you think your speed is showing 32mph is in fact nearer to 33mph and a ticket. I appreciate that the speedo has variance and mine shows 27mph on the gps nav and the same on these street speed advisory devices. Just food for though?

[FROSTYBALLS]

Legally speedometer are required to over-read and must never under-read (show less than the true speed).

In the UK speedometer may show up to 110% of the true speed, and for actual speeds between 25 and 70mph, must not show 110% plus 6.25mph of the true speed.

As an examp!e, for true speed of 50mph, a speedometer can show 61.25mph (110% + 6.25) and still be legal.

GPS readings are an average over a number of points, so, although more accurate than speedometers, won't show the true speed.

[flash22]

A lot of forces have dropped the speed tolerance, it's 10% +2 mph inline with national guidelines, 30.9 is well with in the 10% spec 24, 35, 57 and 79 are the magic ticket numbers anything over 100 is an instant ban, The 72 mph limit on the M25 and M1 was a hoax created by Facebook boomers

be aware GPS speed has a delay, the council signs are +/- 10-30%

[STEVEBE]

interesting comments some of which I was aware of but the 'boys' here are still being ultra precise and dont comment on their criteria. So in effect its difficult to know what speed you are really doing and this might change as your tyres wear I guess.

[Roy124]

Steve, if you could measure to that accuracy you might find 30 indicated 29.5 to 30.5 rather than 30.9.

[Stevie J]

On both the Mk2 I had and the Mk3 I now have, both speedometers seem to read 3mph higher than what I am actually doing at 30MPH. The electric speed reading signs by the sides of the road that flash up your speed as you drive past them usually say I'm doing 27MPH when my speedo reads 30MPH. So if the highest speed I can go before getting done for speeding in a 30 limit would be 34 MPH, therefore my car's speedo can read a max of 37 MPH to be safe.

 

[STEVEBE]

still a gamble

 

You wonder after over a century of development and technological advancement manufacturers cant make it possible to tell what your speed you are doing.

[Cyker]

They can, but the margin is deliberate so if e.g. you change tyre and rim sizes or as the tyres wear down there is no risk of you 'accidentally' speeding, which would open them to some liability.

[STEVEBE]

I worked for GM in the US for some years and this subject came up more than once. There was a working solution in the pipeline which accounted for most variables but only held up if specific tyres were used. Perhaps T could offer a calibration service similar to service vehicles for those that want a reduced margin of error. 

[Roy124]

For many of us the GPS gives us an accurate speed though in reality this is an integrated speed but can be inaccurate on a curved or undulating road. 

A more accurate speed is that seen displayed on variable speed displays.  These measure the vehicle speech through radar and doppler. 

Now many modern cars, such as Toyota with ACC, have radar systems that could determine an accurate speed. 

[Starensis]

I always stick to 33mph in a 30, 44mph in a 40, 55mph in a 50 and 80mph on Motorway (digital speedo). As mentioned, allowance is 10% +2mph, however, the +2mph is not used in some areas of the UK by Police.

[Guest]

I don't understand the fuss or why it is necessary for a speedometer to be spot on?

As Mike (Frosty) has alluded to they have to err on the side of over reading by a certain amount, never under read.

Therefore just stick to the indicated speed and there should be no issues. Assuming there hasn't been any jiggery pokery with wheels and tyres.

It's a limit, not a target.

[ISL]

I find it quite easy to stick to the speed limit, just hit the cruise button at each speed limit and ignore the guy tailgating behind, you’ll probably lose him at the next national speed limit sign, only because most people find it easy to speed in 30’s and 40’s but fail to hit 60 when they have the chance 😂 

[Rhymes with Paris]

6 hours ago, olonas said:

I don't understand the fuss or why it is necessary for a speedometer to be spot on?

As Mike (Frosty) has alluded to they have to err on the side of over reading by a certain amount, never under read.

Therefore just stick to the indicated speed and there should be no issues. Assuming there hasn't been any jiggery pokery with wheels and tyres.

It's a limit, not a target.

I agree, but on my bike test the examiner,who was in a pretty bad mood, due to being clad in leather head to foot on a really hot day, and other anger issues disagreed.

Well he thought the 60 limit on a narrow road out of a village with jay walking pedestrians all over it was a target.

I didn't want to scoop up the elderly on the bike forks, and joined the other 3 who were failed by him that day.

In those days you could get a retest within a week, and myself and the other 3 on a block booking from the bike school all passed, with a more relaxed examiner,no problems.

Now I ain't one of those who blames all of life's difficulties on others, but I still to this day believe that two large bikes bearing down on pensioners on a country walk at speed is wrong.

But hey ho , I was only down trained to carry out CBTs after that, so did not have the superior skills of that Cardington trained instructor, subsequently bike test examiner.

 

 

 

 

[Cyker]

1 hour ago, ISL said:

I find it quite easy to stick to the speed limit, just hit the cruise button at each speed limit and ignore the guy tailgating behind, you’ll probably lose him at the next national speed limit sign, only because most people find it easy to speed in 30’s and 40’s but fail to hit 60 when they have the chance 😂 

Ugh I hate those people that do 40mph on a NSL road... and then carry on at 40mph through a 30 or even 20mph limit village road

I did love being able to catch right up and blast past them in my old D4D and especially in the Mk4 when we got back to a good clear bit of NSL tho'  

[ISL]

@cyker - I like to get my timing right, overtake on NSL just before a 30, so you have to immediately slam the anchors on 😂

 

[Roy124]

11 hours ago, Cyker said:

Ugh I hate those people that do 40mph on a NSL road... and then carry on at 40mph through a 30 or even 20mph limit village road

No, you mean slow down to 40 when they pass the white disc and black bar.  Everyone knows the line means NOT. 

 

[Guest]

15 hours ago, Rhymes with Paris said:

I agree, but on my bike test

Oh how things have changed, for the better in my opinion.

I passed my motorcycle test when Dinosaurs roamed the earth. All it comprised was the examiner standing at the roadside observing. A short route around a block of houses where he could quickly move and observe from a different place. One part was him walking alongside and me riding at the same speed without falling over! Emegency stop, arm in the air. A few Highway Code questions at the end.

I wouldn't even dream of trying a modern bike.

For my car test, 2nd time, 1st one, had a narrow miss with a double decker bus, instant fail, it was a freezing winter day. The examiner appeared and my Dad said, oh no, it's Mr King and renowned for being in a constant bad mood and miserable too.

I was driving wih the window open and asked him if he would prefer it shut. He replied gruffly "Please yourself." I did and left it open. I think he wished that he had worn an overcoat. He did pass me though in spite of chattering teeth and shivering.

[Cyker]

I've always fancied getting a bike licence but you have to be insane and/or possess gigantic brass balls to ride a bike in London. Also I could never get the hang of twisting the throttle while still keeping fingers on the brake lever without pulling it (And so do a lot of moped riders, judging by how many of them I see zooming off at full throttle with their brake lights on  )

 

[Roy124]

My BiLs are bikers.  One is ex police.  His gear is like an exo skeleton suit.  Apart from heaters/coolers and intercom/radio link it has a fibreglass frame undef very heavy nylon fabric.  If he came off it is almost like an escape pod. 

Compare and contrast jeans and trainers. 

[Rhymes with Paris]

2 hours ago, Cyker said:

I've always fancied getting a bike licence but you have to be insane and/or possess gigantic brass balls to ride a bike in London. Also I could never get the hang of twisting the throttle while still keeping fingers on the brake lever without pulling it (And so do a lot of moped riders, judging by how many of them I see zooming off at full throttle with their brake lights on  )

 

Moped riders 🙄, they like to simulate the clutch and gears on a proper bike by releasing the left hand brake lever (on a bike the clutch) which is the rear wheel brake while revving against it with an automatic clutch.

Then throttling off and on again to pretend that they are changing gears.

The brake lever on the right is for the front wheel brake, so no need to use it with the throttle, only while braking when moving.

The route I used to take the babies on had a very wide run off with soft landings on the first sharp corner,so when they inevitably ignored my instructions on the one way radio to do all the braking before the corner(always full of themselves lads who had ridden off road)at least it didn't hurt them, but shook some of them up enough to listen before the town centre part of the CBT.

I wouldn't recommend a new bike licence to the older person, but it's a lot of fun for for those still young and fit enough to enjoy it. 😉

 

[Rhymes with Paris]

2 hours ago, Roy124 said:

My BiLs are bikers.  One is ex police.  His gear is like an exo skeleton suit.  Apart from heaters/coolers and intercom/radio link it has a fibreglass frame undef very heavy nylon fabric.  If he came off it is almost like an escape pod. 

Compare and contrast jeans and trainers. 

Hello Roy, you can always recognise the ones who have never fallen off, and of course the ones who are clued up enough to wear proper gear in the first place.

As you say, trainers with those silly socks,t shirt,no gloves,all the boney bits ready to scrape along the road.

But they all have a cheap secondhand giant helmet that fits only because of the excessive padding,/lining, instead of a properly sized helmet.

As I used to tell 'em,if you've got a £10 head, get a £10 helmet.