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I believe there is a construction and use rule regarding the holding power of a handbrake, stated in terms such as that it must hold the vehicle on a 1:20 slope or a slope of so many degrees. Can anyone point me to the rule please?
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This may help...
Schedule 3
Table 1
Braking Requirements
Paragraphs 16 & 18
www.legislation.gov.uk/uksi/1986/1078/made
But you will need to check the meanings of the measures.
Last edited by: No FM2R on Thu 3 Jul 14 at 19:22
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Might this be it? Haven't actually examined the title of the document...
www.motinfo.gov.uk/htdocs/m4s03001001.htm
That says 16% efficiency required. I understand that to mean producing a retarding force of 16% of the vehicle weight.
That sounds as if it would hold the vehicle on a 16% grade assuming distance travelled is measured horizontally rather than on the hypotenuse (road surface). Near enough anyway, unless my reasoning is completely off.
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That sounds like good reasoning.
But I don't understand why efficiency is related to car weight - that sounds a bit arbitrary to me. Why is a force equal to that exerted by the weight of the car the measure of 100% efficiency?
Imagine you are parked on the top of a multi-storey car park. You attach a rope to the car, lead it over the parapet by a pulley, and hang another identical car on the end. The limiting factor would be the friction of the tyres, which would have nothing to do with the efficiency of the brakes. Even if the brakes were immoveably seized solid, the dangling car could still pull the upper car to the edge if the tyres were worn or the floor slippery.
Alternatively, if the car had massively studded tyres on a ridged concrete surface, you might be able to hang two cars on the rope. 200% efficient brakes?
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I wonder if efficiency is really the right word or if it is used conventionally in this context - it's certainly universal.
The reason I say that is that the documents linked above refer to the requirement for vehicles to have "efficient" brakes, when they can only mean effective, can't they? What do they care about efficiency in the sense of work done:energy used.
So I'm speculating it's just a convention to measure that way, and that they could be better than 100% - mechanically it's pretty obvious they can and that the limiting factor is the tyre-road frictional force.
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On reflection, I think the "rule" is probably a memory of the days when car reviews were more detailed than now and sentences such as "The handbrake held on a one in six hill" were common.
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>> You attach a
>> rope to the car, lead it over the parapet by a pulley, and hang another
>> identical car on the end of the rope.
>>
Lol, takes me back to the days when I was doing my Applied Maths A-level - shouldn't the cars be joined by a "light inextensible string"? ;-)
Last edited by: Mike H on Fri 4 Jul 14 at 08:02
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>> Lol, takes me back to the days when I was doing my Applied Maths A-level
>> - shouldn't the cars be joined by a "light inextensible string"? ;-)
Surely that's a physics A-level question - is a string extensible by the action of light?
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>> Lol, takes me back to the days when I was doing my Applied Maths A-level
>> - shouldn't the cars be joined by a "light inextensible string"? ;-)
>>
Yes, and a frictionless pulley of course. (You may ignore the variation of the gravitational constant with height)
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Thanks No FM2R but I can't find the exact sections you refer to. I did find this:
www.ukmot.com/MOT%20test/handbrake.asp
But I'm not sure what the number of clicks has got to do with it. In any case, the extract says "The handbrake should stop the car from rolling on a hill" without saying anything about the gradient. I calculate that my driveway has a 10 degree slope and my new Hyundai i10 is not held by the handbrake. Surely this can't be right? I tried the click test and found I had only three (the handbook says there should be six to eight).
The dealer has now got me six clicks but says the system is otherwise normal.
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I always leave my manual cars in gear anyway. Couldn't bear not to.
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Me too but it shouldn't be essential. Furthermore some owners have suggested that a shunt from another vehicle could cause transmission damage if the gear is engaged.
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>> I always leave my manual cars in gear anyway. Couldn't bear not to.
With the steered wheels turned towards, but not quite touching, the kerb at some very precise number of degrees from straight ahead?
Forgive me for recalling that you have a slight OCD condition about which you have been very open over the years. I seem to remember something about putting your shoes and socks on in the same order every day, anything else resulting in an ill-starred day in which nothing goes as planned.
You can say I made that up if you like. Perhaps I did. Anyway no one will check.
:o}
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>> I seem to remember something about putting your shoes
>> and socks on in the same order every day, anything else resulting in an ill-starred
>> day in which nothing goes as planned.
>>
Don't we all have routines ?
I do when I'm riding the bike. After putting my helmet on and before putting my gloves on, I always rub my nose both sides. The right glove then goes on followed by the left. Anything else just feels 'wrong'.
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>> >> I seem to remember something about putting your shoes
>> >> and socks on in the same order every day,
Socks first is more conventional. :)
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>> I always leave my manual cars in gear anyway. Couldn't bear not to.
>>
It depends who is likely to be driving it after you. My wife quite often doesn't bother checking whether a car is in gear before starting, so we often lurch forwards.
But of course the excellent handbrake always stalls the engine before it has a chance to start.
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I always leave my car in Park or I could not remove the keys and lock the doors.
Pip pip :-)
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>> I always leave my car in Park or I could not remove the keys and
>> lock the doors.
>>
>> Pip pip :-)
>>
SAAB ?
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MiL has one (Jazz CVT), just been reminded by Mrs gmac what a PITA it is. Couldn't remember myself, after driving a SAAB auto I always stick an auto in Park before trying to switch off.
Last edited by: gmac on Sat 5 Jul 14 at 18:33
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Don't think you can remove the keys in our Viano until its in park IIRC
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>> >> I always leave my car in Park or I could not remove the keys
>> and
>> >> lock the doors.
>> >>
>> >> Pip pip :-)
>> >>
>> SAAB ?
>>
+1 LEC
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The handbrake on the vintage car being a bit poor and if left in gear - which is my normal routine with ordinary cars, leans on the dogs so hard you can't get it into neutral. So I carry a chock for it.
Unwise to use the curb as a brake when the car doesn't have a reverse gear...
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>> The handbrake on the vintage car being a bit poor and if left in gear
>> - which is my normal routine with ordinary cars, leans on the dogs so hard
>> you can't get it into neutral. So I carry a chock for it.
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>> Unwise to use the curb as a brake when the car doesn't have a reverse
>> gear...
>>
If you do have a bit of an iffy handbrake, this is quite a good idea.:-
tinyurl.com/nbswjcl
Well, I wish I had thought of it!
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I'm beginning to think the MOT test for handbrakes is less than stringent.
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I'm beginning to think the MOT test for handbrakes is less than stringent.
Probably. Vintage car is now MOT exempt, but the only way you could test it was to use a Tapley as the main brake is the rear one and you can't test a single wheel on a lot of brake rollers.
Morgan only fitted front wheel brakes from the 1926 model year I think, and early front brakes are known as coco tins! The drum is pressed steel, nothing like thick enough so expands under a brake force. Mine now has better drums.
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I've found the solution which is to press down hard on the brake pedal when parking on a slope. This gives an extra handbrake notch which does the trick.
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>> I've found the solution which is to press down hard on the brake pedal when
>> parking on a slope. This gives an extra handbrake notch which does the trick.
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...and leave it in gear, with the front wheels turned into the kerb.
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>> >> with the front wheels turned into the kerb.
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If facing downhill. Outwards if facing up hill.
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I've found the solution which is to press down hard on the brake pedal when parking on a slope. This gives an extra handbrake notch which does the trick.
Works on some cars - doesn't on others. Some handbrakes are utterly separate from the footbrake circuit. Was the case with some Subarus as they have disks all around and the handbrake only bits work on a drum inside the disc.
Last edited by: Slidingpillar on Sun 6 Jul 14 at 19:51
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>> from the 1926 model year I think, and early front brakes are known as coco tins! The drum is pressed steel, nothing like thick enough so expands under a brake force.
Early fwb chain-drive Frazer-Nashes - another 1920s cyclecar of course - had front brakes like that. They worked well with an initial prod, but deteriorated rapidly as they heated up.
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The chain drive Frazer Nash I think was made up to WW2 and is a piece of extreme motoring fun. No rear differential so off power understeers like crazy, but can be provoked into oversteer at the drop of a hat.
Not driven one, but I have been a passenger in one.
The history of motoring does explain why initially most cars had no front wheel brakes, and the first front wheel brakes were a little ineffective. Basically there was a strong opinion that front wheel brakes were extremely dangerous and locking up the fronts was tantamount to being measured for a coffin...
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What, as in they disliked understeer? Hmmm...
;-)
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I could understand it if you had cars that would lock the rears but not the fronts, as would naturally happen with equal brake force. Safer to have no front brakes in those circumstances.
That is seriously dangerous and rather terrifying when you are approaching a parked car, forced to brake for oncoming, and you have to come off the brakes when it starts to spin from a straight line. That one from the Land Rover diaries.
The bloke who bought it from me took it home to Brighton in the rain. He looked a bit sceptical when I advised him not to exceed 40, always to brake at the earliest opportunity and as gently as possible. Haven't heard from him since. No news is probably good news.
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My tractor has rear brakes only. It is frighteningly easy to lock them. The only safe rule is when going down any kind of slope, be in the right gear for total engine control.
As a farmer friend said - if it won't hold with engine breaking alone, jump off.
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>> The chain drive Frazer Nash I think was made up to WW2 and is a piece of extreme motoring fun. No rear differential so off power understeers like crazy, but can be provoked into oversteer at the drop of a hat.
>> Not driven one, but I have been a passenger in one.
Likewise.
I was surprised the chain-drive was still being made in 1959, although I should have known because I was at school with an Aldington sprog in the fifties. Of course he (and I) were much more interested in the BMW 328-based Bristol-engined sports-racing 'Nashes, and I particularly liked the very good-looking Le Mans Replica model.
Of course all Frazer-Nashes were made in very small numbers, and they were far from cheap. To order a chain-drive model in the fifties would have been an eccentric thing to do, showing a deep love for Vintage motoring. But I must say I fancy all of them, especially the late 6-cylinder models... saw one Julian Ghosh campaigning one of those at Shelsley Walsh, wow!
Last edited by: Armel Coussine on Mon 7 Jul 14 at 13:24
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I was surprised the chain-drive was still being made in 1959
I did say up to WW2, ie 1939. The cars made in the early 30s seem to be most numerous. Apparently sorting out and adjusting the tensions in the various chains is quite a task.
The post war cars have a normal type of gearbox and the Le Mans replica is now exceedingly valuable. So much so that some of the replicas have increased in value too. Of these, perhaps the Werner Oswald Kits and the Crossthwaite and Gardner have certainly increased in value and use the word 'replica' in a way that no normal kit car manufacturer could ever do. Both of these have the correct engine.
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>> I was surprised the chain-drive was still being made in 1959
>> I did say up to WW2, ie 1939
Tsk, careless of me, I googled too hastily. Actually though the same observation applies even in the thirties... the chain-drive was still raw Vintage in a decade when sporting PVT cars were becoming far more sophisticated (e.g. 328 BMW, various Alfas, Lagonda V12 and many others).
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>>Furthermore some owners have suggested that a shunt from another vehicle could cause transmission damage if the gear is engaged.
Likely to be the least of your worries. Just another cost of being pranged for your insurance company to deal with.
Whereas if you leave the car otherwise than in gear, and it runs away, and squashes a child, you run a good risk of a custodial sentence. I've mentioned before, my mother's house was crashed into by a runaway Golf that had travelled a couple of hundred yards. Wrote off my car parked in her garage. Car had been parked about half an hour before incident.
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My dad, who started driving in 1924 as a by the by, always used to leave his cars in gear in the garage but with the handbrake off. He felt it was the right thing to do in preserving the life of handbrake cables. He used to leave a window open too when it was locked in the garage. Kept the inside fresher he felt.
I can still see him now in my mind's eye, lifting each corner of the car before leaving it at night to "ease the springs".
Never sat or passed a test of course, and what's more never had an accident. So far I obviously can't claim the former but up until now I've managed to match his latter record. Still plenty of time for that one to go wrong though I suppose...
;-)
Last edited by: Runfer D'Hills on Mon 7 Jul 14 at 12:59
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>>I can still see him now in my mind's eye, lifting each corner of the car before leaving it at night to "ease the springs".
The father of a friend of mine died about 10 years ago in his late 80s. He had a 5 year old E240 saloon with about 3,200 miles on it.
It had never been out in the wet. If it was booked in for a service, and it rained when the day came, he would rearrange it.
The plastic was till on the seats, and he regularly ran a dehumidifier in the garage. The doors and boot lid were left slightly ajar so as not to squash the rubber seals (battery disconnected I think). Parking brake off, of course.
He had made himself a big wooden spanner type lever to turn the engine with now and again, so he didn't have to start it to keep it free.
An amazing exercise in car preservation, and it looked like new. It was worth about £11,000-12,000 in the book IIRC and my friend wanted £15,000 for it. I offered him £13k I think as I liked it, but there was really no point paying too much for a concours car if the first thing I was going to do was drive it around in the wet and muck, which of course I would have.
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The handbrake on my Triumph Spitfire only worked on one side for a while. It was of course meant to work both sides but something was wrong with it.
The front brakes only worked on one side too eventually which required a bit of forward planning when braking on Edinburgh's wet cobbles.
Deerskin seat covers it had. With the hair still on.
Itchy things. Think they had fleas.
Last edited by: Runfer D'Hills on Mon 7 Jul 14 at 13:38
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>> Deerskin seat covers it had.
>> Itchy things. Think they had fleas.
Ticks. You probably have advanced Lyme disease Humph.
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My dad, who started driving in 1924 as a by the by, always used to leave his cars in gear in the garage but with the handbrake off. He felt it was the right thing to do in preserving the life of handbrake cables. He used to leave a window open too when it was locked in the garage. Kept the inside fresher he felt.
My garage floor is nice and flat. So both the four-wheeled Morgan I had and now the three wheeled one is parked in neutral and handbrake off. I'm not worried about it moving, as it won't in normal circumstances. It could move in an earthquake, but I suspect I'd have far more to worry about at that point.
Last edited by: Slidingpillar on Mon 7 Jul 14 at 13:52
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Car handbrake/slope rule - No FM2R
