Electric cars and speed bumps

[bungeejumper]

Is it just me, or do EVs and PHEVs plough through speed bumps as through they weren't there? The local school run mums seem to think that's the way to do it.

No, not our local primary, but a deep-rural private school that's accessed by a narrow country lane, and these days it's becoming quite a dangerous place to take a walk. It's bad enough that people ignore the 20 mph speed limits; worse that they don't make a sound as they're rolling up behind you; and triple annoying that they don't slow down for the speed bumps either.

Nor, by the look of it, do they need to. The other day, I watched a Mitsubishi 4x4, a Tesla S and a couple of Nissan Leafs all launching themselves at the humps at full tilt, and they didn't bounce at all - just drove straight through them. I suppose that's the weight of the batteries? (A Leaf plus driver is getting on for two tonnes, and an Outlander is two and a half.) But how do their suspensions cope with it? And their wheels?

That, of course, is of little concern to me. I just wish the idiots would blooming well stop doing it. Thanks for listening. End of rant.

BJ

[gnawsome]

they don't slow down for the speed bumps either.

Nor, by the look of it, do they need to. The other day, I watched a Mitsubishi 4x4, a Tesla S and a couple of Nissan Leafs all launching themselves at the humps at full tilt, and they didn't bounce at all - just drove straight through them. I suppose that's the weight of the batteries? (A Leaf plus driver is getting on for two tonnes, and an Outlander is two and a half.) But how do their suspensions cope with it? And their wheels?

That, of course, is of little concern to me. I just wish the idiots would blooming well stop doing it. Thanks for listening. End of rant.

BJ

[/i]

A bit embarrassed to say so but I've long held the view that speedhumps can be taken at normal roads speeds modified to the shape of any particular set of humps.The practice of slowing down while going over accentuates the effect.
The 'short' ones are best taken at a speed that relies on the shock-absorbers to have absorbed the shock before the the mass of the vehicle has reacted. The longer ones have to be 'trialed' to find a speed that allows the first effect to be cancelled by the second effect.
Not very sophisticated but think ~ bending the legs the right amount when trampolining.

[Watis]

they don't slow down for the speed bumps either.

Nor, by the look of it, do they need to. The other day, I watched a Mitsubishi 4x4, a Tesla S and a couple of Nissan Leafs all launching themselves at the humps at full tilt, and they didn't bounce at all - just drove straight through them. I suppose that's the weight of the batteries? (A Leaf plus driver is getting on for two tonnes, and an Outlander is two and a half.) But how do their suspensions cope with it? And their wheels?

That, of course, is of little concern to me. I just wish the idiots would blooming well stop doing it. Thanks for listening. End of rant.

BJ

[/i]

A bit embarrassed to say so but I've long held the view that speedhumps can be taken at normal roads speeds modified to the shape of any particular set of humps.The practice of slowing down while going over accentuates the effect.
The 'short' ones are best taken at a speed that relies on the shock-absorbers to have absorbed the shock before the the mass of the vehicle has reacted. The longer ones have to be 'trialed' to find a speed that allows the first effect to be cancelled by the second effect.
Not very sophisticated but think ~ bending the legs the right amount when trampolining.

My technique is to brake for the final few yards, then quickly take my foot off the brake pedal. The front of the car then unweights just as the front wheels hit the hump, meaning the springs, shockers and tyres are less stressed. Get it right, and you don't feel the front wheels strike the hump at all.

Watis

[gnawsome]

...My technique is to brake for the final few yards, then quickly take my foot off the brake pedal. The front of the car then unweights just as the front wheels hit the hump, meaning the springs, shockers and tyres are less stressed. Get it right, and you don't feel the front wheels strike the hump at all.

Watis

I can see what you mean but I think that would be a new 'style' I would have trouble getting right.
Also I have rationalised that the tyres and shockers are only dealing with what they are designed for (I know that should read "what they have been designed down to do") and as has been observed, traversing at normal roadspeed has very little effect on the vehicle mass and thus the occupants.

[richlist]

As unpopular as it is, I slow down significantly when driving over speed bumps. I know it's unpopular by the reaction of other drivers and particularly those following me. Tough, I slow down because its very uncomfortable to drive over them at speed.

I notice that many of the drivers who don't slow down for the speed bumps are the same drivers who don't adhere to the speed limits, often outside schools.

[gnawsome]

As unpopular as it is, I slow down significantly when driving over speed bumps. I know it's unpopular by the reaction of other drivers and particularly those following me. Tough, I slow down because its very uncomfortable to drive over them at speed.

I notice that many of the drivers who don't slow down for the speed bumps are the same drivers who don't adhere to the speed limits, often outside schools.

Do I misinterpret - or was that a little aggreessive?
Drivers following are obliged to adjust for the drivers leading.
If that means a driver speeds up between and slows down at speedhumps the following drivers have to adjust.
I find that allowing the distance to increase and reduce is all it takes for a smooth and comfortable journey

[AF62]

But how do their suspensions cope with it? And their wheels?

Those cars will be leased and handed back at two years old so they don't care.

As unpopular as it is, I slow down significantly when driving over speed bumps. I know it's unpopular by the reaction of other drivers and particularly those following me. Tough, I slow down because its very uncomfortable to drive over them at speed.

So do I, and yes it is unpopular - mind you I drove into central London back in September for the first time in many, many years and the centre is covered in 20 mph zones. Not knowing the level of enforcement I stuck to 20 mph (easy when you have a speed limiter on the car) - I could see the smoke coming out of the ears of those behind me.

As for speedbumps I have always considered them pointless as a safety measure. The vehicles you would least want to hit you as a pedestrian (SUVs, buses, trucks, vans, etc.) are those they make the least impact on because either their wheels straddle them or they can just blast over them anyway.