Safe Speed Forums

I have been issued with a new tractor. It is one with the new breed of all singing all dancing infinatly variable transmissions, it can perform all manner of amazing functions that I am yet to find out. The main one though is when the right buttons are pushed it acts like the smoothest automatic car you have ever driven and is great, but the brakes are just about redundant. When I want to slow down I just back off the pedal and it stops. No, it really does stop. Dead.

Now this is great and all, but tonight heading home through Southend I had to stop many times but didn't need the brakes. Am I oblidged (sp) to light the brake lights? If I take my foot right off the gas an apply the brakes, even just enough to light the lights, it is like performing an emergency stop, you get the fierce engine braking plus braking effect and it doesn't make for a smooth ride.

If someone runs into the back of me they will say my brake lights arn't working, but they won't if they are not being used.

Funnily enough, I found myself wondering the same thing myself just the other day.

It is possible that you, as the driver, have an obligation to signal your intent to "Slow down or stop" even if you do not actually use the "Brakes" to do so.

It is just that, by convention (and because of the way the technology worked) that it has become comon practice to assume that activation of the brake lights via the brake pedal fulfills this legal requirement.

|However, it is arguable that this may not be the case.

Perhaps the fact that your truck is capable of braking to a standstill, simply by taking your foot off the gas, means that the brake lights sshould be desinged to be lit when you do so (IYSWIM)

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"The road to a police state is paved with public safety legislation"

With modern technology it would be possible to activate the "brake lamps" from an accelerometer so that they illuminated whenever the vehicle was slowing down. Indeed. one could go further and arrange that the intensity or width of the lamps was related to the degree of deceleration

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When I see an adult on a bicycle, I do not despair for the future of the human race. H.G. Wells
When I see a youth in a motor car I do d.c.brown

Going off at a tangent:-
1. Please can I have a tractor like yours? is sounds like fun
2. I remember a scary incident once in my last car (an automatic). We were travelling in stop-start traffic on a slight downhill gradient on a motorway. I had already selected "3" on the (4-speed) transmission, and was using engine braking to keep a comfortable distance from the vehicles ahead. I could see a wave of brakelights approaching me, so decided to slow down a bit more by selecting "2" on the transmission... except that I accidentally pushed the selector further forward into "1". The transmission thought about this for a second or two, then slowed the car down as though I had hit a couple of hay bales (slightly gentler than a brick wall...). Cue much horn sounding, light flashing and gesticulation from the guy behind, who had had to emergency brake. OK, he was travelling too closely, but I should have given him a bit more warning by touching the brake pedal before touching the transmission selector.

I just looked in the Highway Code and couldn't see any mention of having to signal intention to slow down. You could use hand signals!

Also, I didn't realise that there were any vehicles in use with CVT, other than that rubber-band car of ages ago. I'd like to give one a go too.

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Andrew.

Audi's Multitronic automatic gearbox is CVT - I've had one of those as a courtesy car a couple of times. Takes some getting used to at first as when you accelerate the engine revs go up to 2,500-3,000 (2 litre TDI engine) and stay there as the speed increases, then drops back to around 2,000rpm as you feather off.

As automatics go it's quite a good system... they fit it in the longitudinal-engined FWD cars with up to 180bhp. Transverse engined cars (A3, TT) use the DSG system instead.

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Magistrates rule #1: "Never let justice get in the way of a conviction."

IVT/CVT/stepless/Vario, transmissions are becoming the norm down on the farm now they have got them sorted. They are real easy to computerise so we can programe them to do all manner of clever things. We can programe in preset speeds so when we reach the end of a row we can either speed up or slow down then return to the working speed with just pressing a button. Most of the work a tractor does is very sensitive to foward speed so the ability to speed up and slow down seamlessly is a massive advantage. Have a look on the inter web at Massey Fergusons Dyna VT transmissions and be prepared to wish you had one in a car. I can go from 0.03kmh-25kmh in low and 0.03kmh to 53.7kmh in high with out pressing the clutch pedal, with no steps, no jumps all completely seemless. Super.

I haven't looked yet, but am wondering if it does acually light the brake lights when it slows down. There are settings to make it drive like it has a torque converter, that way it would coast, but would then loose most of the engine braking. However these settings are buried deep in the heart of the beefy hand book, which I am wading through.

It's easier than you think. Go to a Honda dealer and ask to test a Jazz automatic (the model just being replaced). This has a CVT which works pretty well with paddle override for 7 "gears".

Ah, the DAF Daffodil ...

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Malcolm W.
The views expressed in this post are personal opinions and do not represent the views of Safespeed.

June (my other half) has a Civic IMA; that is CVT too. I did a road test report on it if anyone is interested (on a demonstrator, not the actual one!) - viewtopic.php?p=97627

I wouldn't have thought so but I guess it's possible! If I stick my car in 2nd at 70 and let the clutch out, it will slow down pretty smart-ish but it doesn't put the brake lights on!

I'm not back at work yet , but to give an idea as to what happen when I take my foot of the gas, I had to give a ride to 2 little lads (they are they boys of 2 friends). I'm doing 2kph around the yard and slowed up to a stand still. This machine is still new to me. I took my foot of the gas(diesel?) had had to grab one of the little ones as he shot across the floor of the cab . That's with no brakes. It will slow up almost this sharp without brakes when it's grossing over 20 tonnes. If I take my foot off the accelerator to press the brakes, it's emergency stop time.

It is basicly a fancy 2 speed hydro with all kinds of electric tricks (think iDrive, only better), when the weight is trying to push the machine, the pump becomes a motor.

Does any one remember an "improved brake light" that was offered in the after market many years ago? It consisted of two triangular red lights which illuminated when you lifted off the accelerator giving an earlier warning of braking. I think that there was a switch on the clutch so that the lights didn't come when you changed gear.

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When I see an adult on a bicycle, I do not despair for the future of the human race. H.G. Wells
When I see a youth in a motor car I do d.c.brown

I think the problem with devices like this is that they would take even more decision making away from the driver behind to pay attention to road conditions, what the vehicle in front is doing and what the driver him/herself is doing.

I do appreciate your irony but not your grammar.

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When I see an adult on a bicycle, I do not despair for the future of the human race. H.G. Wells
When I see a youth in a motor car I do d.c.brown

Having the brake lights connected to an accelerometer (decelerometer? ) sounds like a good idea to me... Maybe... But would it also want to be connected to the brake pedal? Probably.

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Andrew.

Of course it would have to be connected to the brake pedal. How else could you dazzle the driver of the car behind when waiting at traffic lights? Engage reverse gear I suppose.

And I shall be having cheese on toast for tea.

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When I see an adult on a bicycle, I do not despair for the future of the human race. H.G. Wells
When I see a youth in a motor car I do d.c.brown

When slowing I like to use my eyes before the brakes. Looking ahead I see something which will cause me to slow down or stop. By looking as far ahead as I can I reduce speed by lifting off the power, car slows down and if road becomes clear down a gear perhaps and go no brakes used. (Thats why brakes pads discs and tyres last longer and more mpg However that only works to best advantage if no traffic close behind. If there is power stays on a bit longer and a very gentle touch of brake just to make the brake lights come on and get their attention. Like to tell others what I am doing so that they can react accordingly.

I can do this, but it's likely to be boring...

By using a conventional analogue edge meter mounted anywhere conveniently in the correct plane somewhere near the brake circuit, you could generate an electronic pulse as you decelerate, (from the action of the needle moving forwards), passing through a comparator and set to a point of your choice for the brake light to come on via a solid state relay working in parallel with the brake circuit.

The needle will set itself automatically as you travel up or downhill, like a plumbline, so that only the acceleration or deceleration will be monitored. Think of what happens to you standing on a bus ride not holding onto anything. Uphill and down do not matter but when the bus brakes, time to hold on...

The comparator will detect an electronic version of you as the plumline on that bus for forwards only, deceleration, and have settings for sensitivity. It can easily be weighted or electronically dampened so that it automatically comes on when it detects either throttle off or actual braking because it works on momentum.

I know it works because it’s the same principle on which I based a motorcycle alarm some 25 years ago. Never did patient it. (Child born, divorce, mum died and lost my job all over several weeks). It may come on and go off a lot in the field but I’m guessing no-one’s going to be behind you to care.

I’ve long moved on since then but I know it works. Also, I'm guessing there's a much smaller, easier and cheaper way of doing it as I describe these days. I wouldn't be surprised if Volvo incorporate something like it on their latest model. Time for bed...

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The views expressed in this post are personal opinions and do not necessarily represent the views of Safe Speed.
You will be branded a threat to society by going over a speed limit where it is safe to do so, and suffer the consequences of your actions in a way criminals do not, more so than someone who is a real threat to our society.

I don't think that you are right there, Tone, Think of a very powerful bus going up a very steep hill, say 80 degrees. I suspect that if you stood up without holding on to the pole you would end up in a heap with the school-girls on the back seat (not a bad way to spend a journey ) Nor would your plumbline remain parallel to the poles.

You are correct that the needle acts like a plumbline/ Bur a plumbline is deflected by any force acting at right angles to the string. It cannot distinguish between a force caused by deceleration and a component of the force due to gravity, Nothing can.

I made a device similar to this some ten years ago to measure braking and acceleration whilst fettling sports cars. I used a potentiometer (volume control) with a metal rod with a weight on the end. When the car accelerated the weight swung back and rotated the pot which was easy to measure. But when used for hill climbs it had to be calibrated for the gradient so it wasn't much use.

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When I see an adult on a bicycle, I do not despair for the future of the human race. H.G. Wells
When I see a youth in a motor car I do d.c.brown

Ah, I wasn't sure if someone would pick up on that I was trying to draw an analgy for others who may not be electronically minded. I didn't want to go into too much detail because I'm terrible for going off topic: You're right that if it were people instead of a meter it doesn't hold true. I used the edge meter because it's small and will ignore any lateral movement of the vehicle and it's always 'standing up' of course . Although I didn't do it on my bike alarm, It could be amplified and made directional to ignore backwards movement, (Good old diode in there somewhere, not a big problem).

Well, that's true but, without trying it, wouldn't adam have to be going almost in freefall for that to start taking effect? Gentle movements of the needle produce small amounts of electricity which, like I say, the sensitivity and threshold of which can be set.

Just to complete the picture. The one I made, which I think I've still got on breadboard in my loft somewhere, worked great for my application. The idea was that a motorbike resting on the side stand can be on a hill, either up or down. The needle finds its own resting point and it doesn't move in the lateral plane so it won't matter how much the bike was tilting. This also cleverly makes it immune from false alarms from wind rocking the bike. (This was a big failure of the ones at the time which were housed under the number plate). However, if someone tried to steal the bike any movement forwards or backwards would trigger the alarm. It worked well, honestly dcbwhaley But for the grief I was going through at the time I fully intened to go all the way with it.

Without owning a tractor I can't honestly say it would definately work but I doesn't seem too far from what I made all those years ago. (Just counted and it's 26 years in a few months).

Oh, the final tweak was a big blob of solder on the end of the needle. There, I've given both my idea and last secret away now. Someone can make millions off this...

Now you’ve got me in trouble for the biggest topic drift

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The views expressed in this post are personal opinions and do not necessarily represent the views of Safe Speed.
You will be branded a threat to society by going over a speed limit where it is safe to do so, and suffer the consequences of your actions in a way criminals do not, more so than someone who is a real threat to our society.