I have stopped driving on roads with them, instead using different routes.
In many areas you don't get much of a choice.
There are two routes into our estate, one of which is littered with speed humps, and the other which is free of these abominations, but unfortunately seems to have last seen any form of surface repair/maintenance when Ramesses I was on the throne.
I think British roads in general are wrecking all our cars, speed humps or not.
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This subject is done to death, springs wear out like tyres, dampers, brakes....................
When a spark plug starts to misfire, was it the final journey that caused it or that its lifespan was exceeded?
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Hi
I find that some 'speed humps' may not conform to the Highway criteria. I recall reading in a local london free sheet that a lB was found guilty of constructing speed bumps that were too high and steep.
I find the ones with the sharp angled edges the most deadly if i misjudge one and not go over it centrally, ie the hump smack in the midle of my wheels.
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There are some makes/models that are always turning up with a broken spring. Some others you never do a spring replacement job on. So I think it is down to poor quality springs on certain cars.
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I'm not sure it's speed bumps per se that cause damage - it's the variability in size/design/construction that causes problems. You can adapt your driving style - which is their purpose
of course - but random variability can catch you out & damage vehicles.
Around my way along one stretch of about 500m , the speed bumps/cushions vary so much that unless you're aware of their peculiarities, you can quite easily get a crashing crack to your steering/suspension driving at the same speed as the previous/subsequent ones.
The council in these parts is particularly poor at doing anything vaguely called 'engineering' properly - to imagine them actually taking any sort of care over design, approach angles, hump profiles etc. is completely laughable.
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Considering how much testing expertise goes into a newly-designed car or tyre before it is marketed, it should be easy to construct rigs to test damage done by speed humps. I wonder why on earth this has not been done?
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.......... it should be easy to construct rigs to test damage done by speed humps. I wonder why on earth this has not been done?
Perhaps it has been done, and perhaps the manufacturers have shown that speed humps are not a primary cause of spring failure.
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There are some makes/models that are always turning up with a broken spring.
Corsas by any chance?! Rattle will know...;-)
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Spring failure was virtually unknown until recently. The design and manufacture of some mass market coil springs has obviously deteriorated in some way.
Spring failure isn't really the problem with speed bumps. The problem is the extra wear they impose, wholly gratuitous, even when the driver goes ridiculously slowly getting in everyone's way, on the bushes and ball joints of the front suspension and steering in particular. It applies especially when the design includes rubber bushes that flex with suspension movement (as in a Ford Escort's front bottom arms for example). One may think this is poor design - I do - but putting extra sharp bumps in the road is guaranteed to shorten the life of these components. No 'scientific proof' is needed.
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Spring failure isn't really the problem with speed bumps.
Tell that to HJ!
;-)
www.honestjohn.co.uk/faq/faq.htm?id=129
Edited by L'escargot on 10/01/2010 at 14:52
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This subject is done to death ...........
No, it hasn't been done to death. What has been done to death is supposition that speed humps damage road springs, without any proof. I've thrown down the gauntlet and I'm waiting for someone to pick it up and provide proof. I'm not going to hold my breath!
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impact of road humps on vehicles and their occupants. author J KENNEDY c oakley S Sumon
01/11/2004
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A mate of mine lives on a private road and he installed 15mph speed bumps - the local postman has proved without doubt you can drive over them at 40 mph without damage and you can hear him coming which is handy. ;-)
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the research suggests drivers slow down for fear of damage to vehicles ,more than they do for discomfort. company vehicles go over humps at great speed ,as a way of getting back at the boss
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You can't prove a negative.
I'm anything but a mimser, but I've yet to see a speed bump that would damage a car if approached at a modest speed.
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if this theory of road springs arent broken by road humps then the same should be said that potholes dont break springs either
maybe those people that dont think a speed bump that will suddenly and quickly load up what is already a spring under pressure have never had to have anti roll bar universal joints or bushes replaced either
next..............
ah yes the oil in the sump is ok to be taken out by a pump
at least the confederation of engine rebuilders keep their jobs just like the workers in quinton hazell making drop arms and all the spring manufacturers in eastern poland
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Unfortunately, the wrong question is being asked.
Every excursion from the static ride height can be potentially damaging to the spring. Once a crack has been initiated in the spring, time spent under the static loading is also damaging.
For a bit more, google the Palmgren-Miner damage summation method.
So, yes, speed hump cause damage, it's an infrequent high load event. Residual wheel imbalance will also cause damage, a low load event that happens millions of times. And all the other spectrum of loads in-between.
As I've written before, I'm of the view that it's a corrosion problem, where even tiny amounts of corrosion act as crack initiators - once a crack has initiated, the spring hasn't got much life left - as the springs are so heavily loaded, critical crack sizes are very small.
Speed humps aren't the root cause of the problem, if they were all makes of car would be having trouble, but, also, speed bumps do undoubtedly cause damage.
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I think your right about the corrosion. Sometimes we get a car where the spring has just broken and the owner come to us the same day because its rattling. When you look at the break there is bright metal, but then often a corroded arc around one outer edge of the break.
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>>but then often a corroded arc around one outer edge of the break.
Yes! If you're really quick on the scene, the size of the corroded thumbnail can give you an idea of the size that the fatigue crack was before the final fast fracture happened. In my experience, these thumbnail cracks are only about a millimetre or so across before sudden failure.
More often than not, you'll find this small corroded thumbnail on the inner of the spring, where the stress is highest - failure happens when the combination of the stress regime and the crack size become critical.
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QUOTE
>>>>>>>>-Suspension damage costs £1m per day, says warranty firm
Posted on 22 December 2009
Potholes contribute to 6% of suspension damage, according to Warranty Direct
Garages could see suspension repair work fall if Government proposals that could spell the end of speed humps in 20mph zones are introduced.
In plans unveiled last week, the Government called for more 20mph zones after research showed they reduced road casualties by more than 40%.
To aid the creation of more ‘go-slow’ zones, councils would be allowed to implement them without also having to back them up with traffic calming measures.
Warranty Direct welcomed the proposals and said they could help UK motorists save some of the “£1m a day” they spend on repairs to suspension and axle damage.
According to the firm, 6% of suspension damage can be traced back to the effect of traffic calming measures such as sleeping policemen as well as bad road surfaces and potholes.
Warranty Direct estimates that the average repair bill is £240, which equates to a potential £413m a year or £1.1m a day across Britain’s 28.2 million cars.
The company’s spokesman, Duncan McClure Fisher, said: “Speed humps are as much of a menace as potholes, and do much the same damage.
“It’s time for the Government to rely on the common sense and good driving manners of the majority of drivers, rather than punish everyone with big repair bills.”
>>>>>>>>>>>>
UNQUOTE
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Potholes contribute to 6% of suspension damage according to Warranty Direct
So they say, but do they provide proof? I doubt it.
I think that if a spring fails when going over a pothole, the spring was probably on its last legs having already got cracks initiated by corrosion. Sooner or later it would have failed anyway.
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........... the spring was probably on its last legs having already got cracks initiated by corrosion.
Stress corrosion cracking is well documented. For example tinyurl.com/y9ts3q6
I help to guard against it by washing the springs and the spring end face abutments every time I wash the car. I haven't had a single spring failure in 44 years of owning cars with coils springs.
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I live not that far form a built up road platform with Highways compliant riase and fall heights and rates. I fairly often , when walking past the platform pick up a turn from a spring and have seen several cars pulled over due to collapsed fron suspensio and a couple of cases of the busted spring bursting the tyre. Focus's from memory. Scientific and Fact and mixed. Some/many drivers hit these at 20/30 mph, what do you expect. Regards Peter
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When wife lends her car to daughter apparently when she takes the grandaughter out in it as she does she taught her to go weeeeeee as she piles over the speed cushions.
As the person that will have to replace the broken springs (its a fiesta so they can break on any corner) im not a happy bunny :-(
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If European manufacturers rolled the ends of the springs properly and had suitable anti-corrosion coatings we wouldn't have such a problem with broken springs - Japanese cars hardly ever suffer this fate coz their springs are of a much higher quality.
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