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Speed hump damage
macc man - 5/1/20 at 03:01 PM

Yesterday the rear leaf spring snapped on my Transit Connect van. I had just gone over several speed humps at low speed.
With the repair costs and van hire it will be about 300. Is it worth seeking redress with local council or a waste of time, any thoughts.

perksy - 5/1/20 at 03:40 PM

To be fair as long as the speed hump meets the relevant sizing I doubt you'd have much luck

Just playing devils advocate, but perhaps they'd argue that the spring was on the way out anyway and you'd driven over it too fast?

I think there's a standard somewhere on the internet about height they need to be etc

coyoteboy - 5/1/20 at 04:04 PM

100mm high, no vertical face greater than 6mm iirc.

If your spring snapped, it was already on the way out. Springs don't generally snap even when pushed to the limits, and the suspension should have bump stops to prevent over-travel. The only remaining failure modes are fatigue and existing physical damage.

If you drive over the bumps daily, you might argue fatigue.

I had a coil spring fail, a coil snapped off. The coil was a bit rusty but otherwise seemed OK. It failed on a flat straight road lol.

steve m - 5/1/20 at 04:54 PM

I think that I would be looking around for a nice deep pothole, and say that did it, while driving last night in the dark

A speed hump, I doubt you will eve3n get a reply


macc man - 5/1/20 at 08:28 PM

I tend to agree without proving the hump was too high there is little chance of any payment.
In the last 15 years almost all my cars have broken springs at some point. Are they less robust or are
the roads getting worse. Thanks for the replies.

steve m - 5/1/20 at 11:10 PM

Ive never broken a spring, nor done a wheel, am I lucky , mmm no, but I do drive defensive, and look at the road for what it can do to me

Its all wrong, as I should be looking in front of me, and behind, to see what other f ing idiots are doing,
and not looking at he road, for what we pay ridicules amounts to be safe, but as I work in the motor trade, we have a feeling, that one reason the halfwits don't fix the road, not financial, is that the roads themselves slow us down,

coyoteboy - 6/1/20 at 11:04 AM

To be fair, you can drive defensively but it won't help in some cases. I bent a shock and snapped a spring hitting a 2ft diameter pothole that was ~8 inches deep a few years ago. I couldn't brake hard due to a wagon up my backside, I couldn't swerve because of a bus on my right and I only got view of it at the last second because the safe space I left in front of my go swallowed up by another wagon who wanted back into the left lane.

Hit it at ~20mph. Council had the cheek to say I should have swerved round it too.

I've also ripped a tyre on "raised" ironwork which was deep in a pothole filled with water - looked like a normal surface water spot, blew out my tyre completely.

Both of which the council paid up on as they were well aware of them.

Grimsdale - 6/1/20 at 11:36 AM

My day job is doing metallurgical failure investigations, so i'd like to point out a few things.

The majority of spring failures are due to corrosion induced hydrogen embrittlement of high tensile steel springs. This mechanism occurs due to corrosion of steel in the absence of oxygen, for example under a corrosion deposit, road dirt, or flaking paint. Basically anywhere water can get to but oxygen has a harder time diffusing in.

Corrosion in oxygenated environments primarily involves reaction of oxygen dissolved in water to form an iron hydroxide (red rust). Without oxygen, water reacts with iron to form iron oxides, giving off hydrogen. This hydrogen can dissolve into the iron, and migrate into the structure. The dissolved hydrogen can recombine at grain boundaries, causing weakening (embrittlement) of the metal, which leads to cracking under load.

Steels of higher strength ratings are more susceptible, with steels under 1000MPa tensile strength being immune. In recent years, manufacturers have opted to make smaller springs out of higher strength materials in order to better package suspension assemblies, and giving better cabin space etc. These springs are then reliant upon the coating on them to prevent corrosion and therefore cracking and failure. If your springs are corroding they will eventually fail.

TLDR: springs break due to corrosion not fatigue. Repaint / grease your rusty springs.

Mr Whippy - 6/1/20 at 12:08 PM

just be glad it snapped there and not at speed could have cost a lot more than 300 imo you were very lucky

coyoteboy - 6/1/20 at 03:08 PM

Grimsdale - exactly - it's usually that rusty spring with the damaged paint/powdercoat eating itself under your wing. Though it's interesting to see you explaining hydrogen embrittlement not in a context of fatigue and crack propagation, which is new to me - I was not aware HE caused failures with static stresses too. Certainly every spring I've had fail has been a highly strung item, but the remaining coil piece has been left attached by a malleable section which is just plastically deformed. Every day is a school day.

[Edited on 6/1/20 by coyoteboy]

nick205 - 6/1/20 at 04:14 PM

It sounds bad luck to me.

I think you'd have to go quite a long way with quite a big wallet to take on a council or possibly the highways agency.

SWMBO had a front spring break on her VW Touran (57 plate) back in the summer. The spring was replaced and the garage left the broken one in the car boot for us. It had broken due to corrosion, difficult to see with road dirt on it, but that's what had caused it. Fortunate for her she was doing 5mph in her work car park when it went and works less than 2 miles from home.