Speed humps test

SumoDog68 · 25-02-2011, 06:40 PM

This topic came up at work . Which car (if any) can be driven over a Decently sized speed hump without anything being felt by it's occupants.
Speed might be a factor but let's say at reasonable speed (30-50km/k) .
I ve driven a few cars but can't remember any being so plush. Most agree it would have to be some sort of 4wd or luxury sedan ...

mrbaxr6t · 25-02-2011, 06:45 PM

I can't think of a single car that can absorb a speedhump without occupants feeling it, the car is riding over a 50mm lump for a small speedhump, only way you won't feel it is if you are in a very soft riding car and you hit the bump really fast - your car on the other hand will hate you for doing this and you will soon need repairs to suspension

XBROO · 25-02-2011, 07:04 PM

I have an 80 series cruiser with 33 inch tyres and old man emu suspension, I can run up gutters at speed and speed humps the faster, the less I feel it. But you still feel somthing even if it's not that much. But put it this way if I hit a speed bump at about 80 to 100kays I don't spill my open cup of coffee.

SumoDog68 · 25-02-2011, 07:12 PM

[QUOTE=XBROO]I have an 80 series cruiser with 33 inch tyres and old man emu suspension, I can run up gutters at speed and speed humps the faster, the less I feel it. But you still feel somthing even if it's not that much. But put it this way if I hit a speed bump at about 80 to 100kays I don't spill my open cup of coffee. :-)[QUOTE=XBROO]

Wonder if it is the tyres or suspension setup that enable such capability .
With high sidewall baggy tyre with medium pressure one would think tyre would do most of work. Maybe that is why luxury sedans still use relatively high sidewall heights.

JC · 25-02-2011, 07:36 PM

They're misnamed - they are actually slow down humps (except in the above 80 series cruiser, I guess).

To answer the question - maybe a mining truck - those ones with 20 foot high tyres? Or a hovercraft?

Ford_The_Win · 25-02-2011, 07:38 PM

I always cringe when I see people go over speed humps faster than 20km/hr. You can hear the car grunt in discomfort.

SumoDog68 · 25-02-2011, 07:46 PM

Quote:

Originally Posted by Ford_The_Win

I always cringe when I see people go over speed humps faster than 20km/hr. You can hear the car grunt in discomfort.

I do have a laugh when ladies in prados and pajeros come to virtual stop to go over a speed hump

Zero_PSI · 25-02-2011, 08:13 PM

Dont feel much in the truck. Can still tell though

malazn mafia · 25-02-2011, 10:24 PM

90s camry with worn shockers would come close, it takes a lot to destroy their suspensions and they are quite bouncy.

Mickxr8 · 25-02-2011, 10:31 PM

I always thought they were called `extractor` humps

SpoolMan · 25-02-2011, 10:35 PM

Hate speed humps I have to go over 15 on the way to work and then same on the way home.....
they should replace them with these, go over slow little impact, go over quickly and you get full thump.
http://www.gizmag.com/bumpfree-dynam...th-ride/14156/

Road_Warrior · 25-02-2011, 11:43 PM

Quote:

Originally Posted by SumoDog68

I do have a laugh when ladies in prados and pajeros come to virtual stop to go over a speed hump

In my area they wouldn't notice them, they're too busy talking on their mobile phones and tailgating the car in front to see them properly.

Zero_PSI · 26-02-2011, 02:54 AM

Quote:

Originally Posted by Road_Warrior

In my area they wouldn't notice them, they're too busy talking on their mobile phones and tailgating the car in front to see them properly.

Ahahahahahahahahahaha. Seen a girl doing her make up and texting in a 100 zone once.

fmc351 · 26-02-2011, 03:41 AM

Citroen C6, or some of the older ones? Dont know about feeling nothing though. Top Gear did the horse race filming test.

NickyN · 26-02-2011, 12:51 PM

I've driven over 2 different kind of speed bumps. The ones that are high off the ground and literally bolted onto the road, everyone either slams their brakes when they notice how high it is, or for those who know it's there we already slow because seriously, anyone would feel those. The ones like at malls where it's not really a speed bump, I'd say more of the "slow down a bit" bump..... they are actually fairly wide and smooth, those I've umm.... just continued driving over, no probs.

Jim Goose · 26-02-2011, 01:53 PM

How about the other direction, drains which run across an intersection?
I constantly see cars bottom out at the intersection up the road where i live.
Its even got a STOP sign, yet you always see people drive through at 50kmh and wham!.. then Wham again as they hit the one on the other side of the intersection.

The amount of score marks in the road (and OIL) show how badly people treat their cars.
No care or concern they are doing damage to it....

pauljh74 · 26-02-2011, 03:55 PM

Anything that could soak up speed humps wouldn't handle or brake well and would wallow around like a waterbed

SumoDog68 · 26-02-2011, 09:03 PM

Quote:

Originally Posted by pauljh74

Anything that could soak up speed humps wouldn't handle or brake well and would wallow around like a waterbed

Not necessarily :-)

http://www.funco-motorsports.com/Hustler.htm

mik · 27-02-2011, 01:34 AM

not sure about the current model but some years (about 5) ago i had to do a quck trip from north western burbs melb across to the other side of richmond in a renault laguna hire car, i tested it out good

, i have to say best bump absorbing i`ve felt in a car.

BlueBear · 27-02-2011, 03:18 AM

Citroen 2CV followed by the DS would have to be the two best sedans for that test.
The latest Rolls Royce should be good also - uses the Citroen suspension.

The 2CV was one of only a few cars (Austin 1800 being another that comes to mind) that had their suspension connected front to back rather than side to side, yes they are independent suspensions, but no anti roll bars were used on the 2CV (1800 did) but when the front wheel hit a bump it lifted the back wheel ready for the bump as well, hence its uncanny ability to travel a ploughed field without breaking any eggs that were in a basket on the front seat, this was in fact the pre-requisite of the car.

**aussiblue** · 27-02-2011, 11:56 AM

Quote:

but when the front wheel hit a bump it lifted the back wheel ready for the bump as well

Not exactly; in fact the reverse happens it pushes the other wheel down so the height remains the same. What happened is when the front wheel is deflected up over a bump, the front pull rod compresses the front spring inside a suspension cylinder, against the front of the cylinder. This also compresses the front "volute" spring pulling the whole cylinder forwards. That action pushes the rear wheel down on the same side via the rear spring assembly and pull rod. When the rear wheel meets that bump a moment later, it does the same in reverse, keeping the car level front to rear.

Similarly with the hydralastic suspension in the mini and the later Austin hydragas systems. When a front wheel encounters a bump fluid is transferred to the corresponding rear displacer then lowers the rear wheel, hence lifting the rear, minimising pitch associated with the bump. The reverse occurs when it is a rear wheel that encounters a bump.

If you had said but when the front wheel hit a bump it lifted the back body (rather than wheel) ready for the bump as well you would have got it right.

sexyxe · 27-02-2011, 12:02 PM

A mates 86 Accord takes speed bumps like you're floating on a cloud.

But it handles and brakes like a house boat.

RAREV8 · 27-02-2011, 03:08 PM

There was a prototype barge Lexus fitted with a Bose developed suspension system that could do exactly that- I'll se if i can find the footage somewhere.....

here we go.....quite interesting but was damned expensive and very heavy too.
http://www.youtube.com/watch?v=eSi6J-QK1lw

BlueBear · 27-02-2011, 06:06 PM

Quote:

Originally Posted by aussiblue

Not exactly; in fact the reverse happens it pushes the other wheel down so the height remains the same. What happened is when the front wheel is deflected up over a bump, the front pull rod compresses the front spring inside a suspension cylinder, against the front of the cylinder. This also compresses the front "volute" spring pulling the whole cylinder forwards. That action pushes the rear wheel down on the same side via the rear spring assembly and pull rod. When the rear wheel meets that bump a moment later, it does the same in reverse, keeping the car level front to rear.

Similarly with the hydralastic suspension in the mini and the later Austin hydragas systems. When a front wheel encounters a bump fluid is transferred to the corresponding rear displacer then lowers the rear wheel, hence lifting the rear, minimising pitch associated with the bump. The reverse occurs when it is a rear wheel that encounters a bump.

If you had said but when the front wheel hit a bump it lifted the back body (rather than wheel) ready for the bump as well you would have got it right.

Correct, that's what I was meaning, just the wrong wording.
Cheers,

BlueBear · 27-02-2011, 06:11 PM

Quote:

Originally Posted by RAREV8

There was a prototype barge Lexus fitted with a Bose developed suspension system that could do exactly that- I'll se if i can find the footage somewhere.....

here we go.....quite interesting but was damned expensive and very heavy too.
http://www.youtube.com/watch?v=eSi6J-QK1lw

This was also pre-dated by a Citroen, check out a Citroen Xantia Activa, however they were tuned more for sports handling, also fitted with a low blow turbo.
Required quite a bit of maintenance though.

RAREV8 · 27-02-2011, 07:51 PM

Quote:

Originally Posted by BlueBear

This was also pre-dated by a Citroen, check out a Citroen Xantia Activa, however they were tuned more for sports handling, also fitted with a low blow turbo.
Required quite a bit of maintenance though.

Weve had more than our fair share of citroens- my first car was a 2CV as well as CX Safaris, BX's (hydropneumatic) but none of them were remotely as capable as that Lexus.....having said that, the Bose system hasn't gone into production for simply being cost prohibitive and weighty to say the least. The 2CV was basic but I still love that car- downright dangerous over 60mph and the CX was as floaty as any boat....car sick took on a whole new meaning!

Ben73 · 27-02-2011, 11:03 PM

I want a car that has great smooth suspension. That Bose system looks good to me. But can you get it onto any car easily or is it more of a "Look what we can do" type projext for Bose.

**aussiblue** · 27-02-2011, 11:16 PM

Caterpillar D9 with blade down copes nicely.

RAREV8 · 28-02-2011, 10:39 AM

Quote:

Originally Posted by Ben73

I want a car that has great smooth suspension. That Bose system looks good to me. But can you get it onto any car easily or is it more of a "Look what we can do" type projext for Bose.

It was initially developed many years ago in Framingham- Mercedes were approached to market it but the size and weight and cost of the complicated system was too high to be practically applied.
If you google it you might find pictures of the actual componentry used which shows how bulky it is!

new2ford · 28-02-2011, 11:41 AM

There's a type of speed bump that's not continuous across the road. It consists of thre groups of rubber pads bolted together in groups of four or five. The wheels of my Territory will straddle the four-pad if you get your aim right so you don't need to slow down. There are a couple of streets where I live where the council has used these and randomly alternates the four and five pad humps. So if you're a local you know which ones to slow down for. My favourite trick with tailgaters who don't know the streets is to go slow over the wide ones and then with the other low-slung car on your tail accelerate over the four-unit and listen to the sickening crunch as the drover behind hits the hump!