# Speed Limiter



## funnymunny (May 13, 2005)

Just read in a newspaper that as from today EU law says that all new vans over 3500kgs which are driven abroad must be fitted with speed limiters to cap thier speed at 56mph but those used only in the UK have until 1/1/2008 to fit them. All vans registered since Oct 1st 2001 will be required to fit them too. It doesnt say anything about existing vans driving abroad being given a time limit to fit.
Having driven vehicles with limiters before I am personaly against this as i consider them dangerous but the law is the law even when its an ass, speed limits i can accept quite happily. Does anybody have further information on this.


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## DABurleigh (May 9, 2005)

Rest easy. This only applies to Goods vehicles and Buses with more than 8 seats, both over 3500kg. A motorhome is neither.

http://www.vosa.gov.uk/vosa/publications/speed limiters - new regulations.pdf

Dave


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## Anonymous (Nov 10, 2000)

I was thinking I could hire my missus out as a speed limiter. Give me a break at the same time.


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## 91929 (May 1, 2005)

*sPEED lIMITERS*

What re speed limiters ?????????????

I use the GAS or accelerator pedal

SERIOUSLY I once was unfortunate enough to drive a firms van with a speed limiter on

You couldnt do more than 56mph or the engine cut out

Imagine your in the fast lane overtaking a truck & youstart to go down a grade & he speeds up just as you get level with his cab 7 YOUR engine cuts with anothr truck up your tail >>>>>>>>>>


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## funnymunny (May 13, 2005)

Dave,
Thanks for the info but still got my doubts, on the continent they have a way of grouping motorhomes all in with goods vehicles certainly when it comes to tolls etc and the newspaper article did say white van man will be affected if hes over 3500kg so I think i will keep an eye on it for now besides when that Spanish or French policman has his hand on his gun holster you dont argue. I certainly do hope you are right though.


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## 88724 (May 9, 2005)

Hi PamnPete

"Imagine your in the fast lane overtaking a truck & youstart to go down a grade & he speeds up just as you get level with his cab 7 YOUR engine cuts with anothr truck up your tail >>>>>>>>>>'

Not possible for five Reasons

1. Speed limiter equipped vehicles are not allowed in the Second overtaking (its Not the Fast lane)

2. The Truck you are overtaking is fitted with one as well, hence the 5 mile overtakes you see between lorries.

3. Up Hill and Down Dale its still stuck at 56 MPH same as you

4. The truck behind you is drivijng in the fast lane why there cant be that many trucks driving ilegally in the second overtaking lane in such a short space can there?

5. even if there was another ilegally driven truck behind you, he would be restricted to the same 56 MPH

PS The engine doesnt cut out, it just will not allow you to go any faster, you cant even feel any demarcation it justs seems to have reached "flat out"

While your thinking about the above spare a thought for lorry drivers, restricted to 56 MPH for mile after droning mile.

They are discussing this on a self build site.

For some reason they think

1. its going to be backwards enforced ie retro fitted to anything over 3.5 tonnes

2. Someone asked how do I work out the weight of my vehicle !! amazing how can you not know! he as a 35S12 so he as a 3.5 tonne 120 BHP engine

3. Next they have a discussion about Twin and single wheels ?? the consensus is (so far that if you have twin wheels its over 3.5 Tonne and Single wheels under 3.5 Tonne) In reality that as got nothing to do with it there are 3.5 tonners with both types of axle.

In the VOSA Leaflet it refers to *Diesel* Engined Goods Vehicles, so any large vehicle thats petrol or LPG powered is exempt?

The other part thats being forgotten here is Tachographs, Goods vehicles and or commercially driven vehicles must have tachographs fitted and used.

BTW this is another nail in the Big motorhomes are goods vehicles idea that the DVLA are trying to promote (at the moment the law disagrees with the DVLA on this point)

George

Edit altered 2 spelling mistakes


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## 93514 (May 1, 2005)

"Not possible for five Reasons"

I'm probably like a lot of others on this site who only visit to browse for specific bits of info and don't usually bother to get involved with pointless debate about the nitty gritty, but I'll make an exception in this case.

GeorgeTelford seems to post on numerous 'technical' subjects and I wont insult you by offering views or contradictions but please why dont you just let people air their views and leave it. 

My quote above highlights what is so annoying about your 'expertise'. It is perfectly possible for many reasons so unless you know exactly what you're on about dont post that sort of bovine waste. You don't know about lorries and the law about overtaking in the second lane nor do you know what certain lorry operators do to their speed limiters. It is possible to slip out of gear and travel at the legal limit of 60 for example.


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## 88724 (May 9, 2005)

Hi "Kev"

What a strange "first" post, are you asserting it is legal for these vehicles to use the second overtaking lane?

Without tons of monkey business and all the drivers messing about what I say above is true is it not. Would need every driver involved to be driving ilegally and like an idiot, possible but Highley unlikely.

Maybe my posts could be a little more diplomatic at times, but I post under my own name and try to stay factual.

George


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## 88838 (May 9, 2005)

surely 'kevs' point about coasting downhill at 60 and users 'fixing' the limiter reinforces the earlier statement that speed limiters are unsafe?
I've driven cars in the US with speed limiters set at 60, a 4.5 litre hire car - went like a bat out of hell - then hit a brick wall, governed by the revs so it was impossible to climb hills - frightening!

also results in synchronised driving when vehicles cannot achieve a safe overtaking speed, and causes tail backs and road rage.

8)


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## 88724 (May 9, 2005)

Hi Twooks 

I dont agree with speed limiters, I think there dangerous for the monotony, a Pro driver is sitting there with is foot to the floor, it must be tiring and boring.

I am not going to say it doesnt happen but there are big fines and it (a prosecution) could result in the business losing the operators licence (that means the business cannot operate any trucks)

I had a link to a police rep, who was dead against speed limiters.

George


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## hymmi (May 9, 2005)

Hi kevkarts,

I am not getting involved in this post as i don't drive,but i do think you are extremly rude,joining and coming straight in for George like this,however he chooses to express himself he at least trys to help people,most times new people into motorhoming,as we all do.

Unlike you as you say you just come onto the site to take good intentioned peoples advice and clear off and use it and do not want to get involved with us,why are we a bit too sad for you then.

I hope Dave and the mods don't mind me saying this,but i think this site doesn't need people like you


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## 91958 (May 1, 2005)

My first camper was a home conversion of an old commercial van and had a speed limiter on it. I didn't know till I'd had the thing for over a year when a mechanic friend sorted it out for me. i alwys thought it was slow because it was an old van!


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## AutoK (May 1, 2005)

Hi kevkarts.
George is is entitled to express his opinions on this forum just like you
he may not always be right, but nobody has to take any advice given by anybody.

Its all about getting involved in reasoned and sensible debate, check any facts for yourself, and make up your own mind.

If you have anything interesting or infomative about motorhoming, then please share it with the forum.

AutoK.


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## dodger148 (May 9, 2005)

OK enoughs, enough on the subject let it drop please. We dont want pages of arguments


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## Brambles (May 12, 2005)

Just thought I would add tuppence worth. Some HGVs are also fitted with retarders on the propshaft which cut in automatically when going above a set speed over the speed limit. You can often see lorries running down hill and the brake lights comes on - more often than not this is the retarder switching in to stop over run and speeding down hills out of gear.


Jon.


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## Anonymous (Nov 10, 2000)

*Speed limiters*

In the olden days, all you had to do to disable the speed limiter (and tachograph) was to turn off the ignition whilst driving. The all-mechanical diesel engines kept going until the fuel valve was closed. I don't suppose these new fangled electronic widgets allow this to happen any more. Can't make free telephone calls from phoneboxes anymore either; the A & B buttons have gone. Come to think of it, there wern't any speed limits in the good old days either. Sigh . . . .


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## Brambles (May 12, 2005)

Hi Peterthegrate,
In the even older olden days the mechanical tachographs would still record speed and the clock was permanently connected - so you could pull the fuse for the clock, suck a polo mint thin and loop it over the stylus to stop it rising. Later tachographs and the latest cannot be fiddled the same and record information if any fiddles are attempted. 
I have worked on Tachograph design and development for 23 years and have come across some very ingenious fiddles - none which work now a days but drivers still strive to find ways of fiddling the roadspeed limiters and tachographs.

edit - corrected typos.


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## 93795 (May 1, 2005)

Just a thought - if you switch off the engine ( to coast downhill ) surely you lose your servo assisted brakes? Sounds very risky and dangerous to me!
Phil.


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## Brambles (May 12, 2005)

Phil,

We are talking about the old days when if you turned off the Ignition a diesel engine would still run. You had to manually stop the engine with a pull stop. As the ignition was 'off ' crude speed limiters of the day would be disabled. 

The way HGV truck brakes work is by air holding the brakes off. If the driver was to stop his engine and coast he could still apply the brakes a few times but eventually the stored air pressure would be used up and the brakes would stay on. Hence when they coast down hill to over speed they keep the engine running.
Modern tachographs record speed very accurately and are next to impossible to fiddle, certainly by the normal person and also those in the know. Drivers can and are prosecuted if they are caught.
There have been some very clever devices used over the years to alter speed sensed from the gearbox but with the latest encryption technology and electronic programming of calibration data that is next to impossible to do now. Still does not stop fitting centres being corrupt and setting up to give a lower speed indication but a fitter would face severe penalties if caught and he would be in time.


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## 93795 (May 1, 2005)

Thanks for that Brambles, I remember now back in the 50s in Germany I used to drive the big Magirus Deutz and the engine didn't stop when the ignition was turned off, I'd forgotten all about that.
Phil.


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## 88724 (May 9, 2005)

Hi Brambles

My Optare as some Huge Gubbins in the middle of the propshaft also seems to be some electrics involved is this a speed limiter ?


















And can this be disabled easily (Legally because not required now)

George


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## 88941 (May 10, 2005)

Hi George

It looks like an electric brake to me...... sorry cant be of any more help

Keith n Debs.....


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## 88724 (May 9, 2005)

Hi

There was mention of a little switch on the dash which improved braking and was a mega expensive option (he was selling !!) it apparently saved in Brake shoe replacement. 

I just wondered as Brambles mentioned Propshaft speed limiting (or could it be tied in?)

George


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## Brambles (May 12, 2005)

Hi George.

Yep it is an induction brake. It basically works by switching on the large electro magnets. WHen the disc rotates eddie currents are set up in the disc and cause a drag. It also gets very hence the cooling fins.

They are often used to assist braking to save wear on the wheels brakes and for gentle slowing down. Another use is in conjunction with the overspeed limiter which mainly cuts back the engine power but if over run occurs to a higher speed then the induction brake cuts in and slows the vehicle down. They are very useful in preventing HGV and coaches coasting faster than the allowed maximum speed permitted. They used to be used on buses a lot before speed limiters. They are also useful for long down hill decents.

Disabling it is easy - just disconnect the wires to the unit or the control electics/electronics. However it should also be possible to adjust the speed it cuts in to a higher level than you will ever need. Afraid I cannot be any more specific than that, but as you say legally not required as you are converting the bus.

You might want to consider getting it working as you may find useful to save wear on your brakes. Afterall, it just needs a lot of power for the electro-magnets. 

ACTUALLY - I have taken a closer look at your pics - it looks like it could be an elecric brake with frition pads but i don't think it is. 

Jon.


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## 88724 (May 9, 2005)

Hi Jon

There is a light on the Dash which shows when its being used and a switch to disable. 

As a braking system fine willl keep, If it serves both purposes, I will want to disable the Speed limiting part.

If it isnt the speed limiter and assuming there is one somewhere (would there definately be one on a PSV Route bus?) I would want to disable just the Speed limiting function.

Looking round underneath there are Two Huge Fuel tanks :>))

George


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## bigfoot (May 16, 2005)

I purchased a couple of Optare Aleros for an acessible transport project, they were fitted with these devices as were the other Optares in the fleet.
The corect name for them is 'magetic retarder'. It is an electromagnetic brake on the drive shaft. very useful as well as reducing wear on wheel brakes they also reduce driver fatigue esp. on long downhill decents.
I think they were originally introduced by a firm called Telma.
George what model Optare is yours? Have you had any problems with the front windscreen/body bonding? and if so how did you overcome it


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## Brambles (May 12, 2005)

Hi George,
This is my 3rd attempt to reply to you without getting bogged down in to too much info so wil keep this one simple.
Look for an electronically contolled electo-mechanical actuator fitted to the diesel pump speed/power control input shaft (throttle). It will most likely have a heavy bowden cable connecting it to an actuator, or an actuator directly on the pump control shaft linkages. The electronic control could be mounted any where but most likely in the cab area for protection. The speed signal for the limiter can come form various sources but most likely the back of the speedo or tachograph if fitted.

The electromagnetic retarder can be controlled in various ways, either from speed sensing relay getting a speed signal in the same way as the limiter or from the overspeed output from a tachograph. So question is did the bus have a tachograph fitted and if so a pic of the wiring to it would help? Then I can tell you what signals and wires to follow. Also A pic of speedo wiring will help. I have no idea of the age model of your bus so this is all a stab in the dark. 
Jon


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## 88724 (May 9, 2005)

Hi Bigfoot

Its an Optare Starrider, The windscreen to Body Bond looks OK at the moment. Does the Electric brake work via normal footbrake as per normal when the electric brake is switched on?


Hi Jon

Yes it has got a tachograph/Speedo I will look for make and Model etc, I will also try and pull it forward and photograph the wiring later.

George


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## bigfoot (May 16, 2005)

George,
I think you may be ok on the windscreen issue it is more common on the Excel model.
Our retarders are operated via a stalk mounted on the steering colomn, which can be moved to put various levels of retardation on to the drive train. If you go on the website there is a lot of info and you can also request technical information also.


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## Malc (May 9, 2005)

Hi,
The majority of modern buses are governed by the engine management system via the fuel pump, the basis of most systems, most are set to about 50-52 mph and this usually rated for the tyres in use, most large companys use recuttable tyres and are rented on a mileage basis, this allows for recutting of tread and further use say onto the rear axle from the front. Retarders are now normally integrated into the gearbox and are activated by the normal brake pedal activity.
The manual stalks etc fitted to coaches are/were mostly a Telmar retarder acting on the prop shaft and saved a great deal of wear and brake fade.
Malc


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## Brambles (May 12, 2005)

George _ a note of intertest for you regarding the tachograph.

A tachograph fitted to a vehicle which is never used under the EC rules must still have an initial calibration and be sealed if it is acting as the sole speedometer on the vehicle. Provided the seals remain intact, and the vehicle is not subsequently used for an operation falling within the scope of the EC rules, it is not necessary to have the tachograph inspected every 2 years or re-calibrated every 6 years.


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## 88724 (May 9, 2005)

Hi all

Just had a look at the Telma website, what a Fantastic system !!

Braking without friction, Lasts a lifetime Virtually no wearing parts !!

http://www.telmausa.com/telma_htm/page3.htm

Main Telma Start Page

Looks like mine is for braking only, will have to delve deeper for Speed limiter if fitted.


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## 93135 (May 1, 2005)

The Telma retarder has been around for years, lots of them fitted to coaches. But they DO generate the same amount of heat as your brakes would otherwise generate if they were doing the same level of retardation.

In essence its an electrical generator with a variable load controlled by the driver. Nice though.
The even older method was to restrict the exhause gasses so that the engine operated as a compressor - Exhaust Brake. Telma is nicer though.

How much to have one fitted to my Sprinter??


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## bigfoot (May 16, 2005)

These can be very useful if you are doing a lot of Alpine driving or even Scotland, up and down those passes.


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## 93135 (May 1, 2005)

We do lots of Alpine driving, hence the genuine interest.

I could fit one to the rear propshaft??


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## bigfoot (May 16, 2005)

You should get useful info from the Telma website. I would strongly suggest you use the services of professional bus fitter. It is an auxillary braking system which can offer a retarding effort for prolonged periods and reduce the strain on your right foot.


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## 93135 (May 1, 2005)

Bus Fitter !
Well I,ve done some of this as well. and welding, and wiring, and plumbing. Previous camper was a Bedford Duple Vista Coach I converted.
14 MPG 5.6 litre (330 cubic inch in old money) and 90 BHP.
You should have seen us jacking the chassis rails apart to be able to change the engine mounts!
The brakes (Clayton Dewandre) were bl...y useless.


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## Brambles (May 12, 2005)

It works by coils generating a very strong magnetic fields. When the discs rotate through the magnetic fields (flux) a currents flow within the disc. These currents and the power is dissipated in the disc as heat caused by the resistivity of the steel used and the flowing currents oppose the force and rotation of the disc resulting in the braking action. They are actually very efficient at dissipating the power compared with brakes.

If you consider your front brakes do most of the braking - for argument sake I will use 70% and the induction brake can do 70% of the total braking required. Then there is the same power to be dissipated as in the two front conventional brake discs. As we have two discs on an induction brake and they have more efficient cooling fins than vented discs, are rotating much faster, then they will actually run a lot cooler and not reach the same temperature as normal brake discs. They are a winner really and the only fault being they are not efficient at low speed and cannot bring you to a halt. At high speed they are efficient, safe, do not suffer brake fade, and do not squeel or need maintenance.
The other factor to consider is they only operate on rear wheels not the front so maximum braking power is limited as the weight is thrown forward.


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## Brambles (May 12, 2005)

Webwobin, 
I know what you mean about the alpine passes ..... - and the smell of burning brake pads.
Jon.


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## 93135 (May 1, 2005)

With the old bus "If I don,t stop now I won,t be able to stop at all"

I remember in Canada a couple of years back on a coach tour the driver pulled up after a long winding decent, told us to go for a comfort break, opened up some side lockers and took out several buckets of water. He then douced each wheel in turn making instant steam.
Um!


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## bigfoot (May 16, 2005)

I used a bus fitted with a retarder through India and Nepal. The bus was a Volvo Plaxtons conversion. 
As regards using a bus fitter that was my way of ensuring that 'professional'expertise was used as it is involving brakes.
Sorry.


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## 93135 (May 1, 2005)

Bigfoot
I agree, sound advice. From my viewpoint its a difficult one, the Sprinter brakes are good and last a long time, so is it worth the expenditure? I,ve had it for 7 years now. Plus I am a (just retired) professional Engineer in the manufacturing industry making heavy (ish) vehicles.
Sometimes I would rather trust myself rather than someone else, but you cannot do it all.

The crunch question surely is "What would be your insurance companies viewpoint on this" My guess they would agree with you.

We are off to Shepton Mallet on thursday leaving mother-in-law behind to guard the fort. Will you be comming?
Lowline Scout on a sprinter with a blo..y great whip antenna on the roof - plus a couple of smaller ones will give it away. Personal "R" plate.


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