is this possible?

[captain_chaos]

Ok I work for wokingham borough council in the traffic management team. Part of the job involves dealing with resident complaints about the highway, which is where this came in. A resident is saying that an engine mount on their car snapped while going (at 20mph) over a speed bump! They're claiming for all sorts of damages now and I've got to go and inspect the hump and do a report for the insurance department.
I've driven over this hump hundreds of times myself, as has many thousands of other people, and as far as I know my engine has stayed inside the bonnet.
What kind of force/speed must you travel at to do that kind of damage?

[woodwarm]

Warp speed


Are you inspecting the drivers hump or the road hump ?

[captain_chaos]

Got to see if the road hump conforms to The Highways (Road Humps) Regulations 1999

[andyverran]

20mph...hard to believe that, even if the hump is terrible (and they mostly are)...

[captain_chaos]

The hump was built in November so it's still in good condition

[andyverran]

The hump was built in November so it's still in good condition

lol, by terrible i wasn't refering to it's condition.

Despite my philosophical position, I can't see a genuine 20mph breaking an engine mount...

[captain_chaos]

I can't either, but still have to go through the process.

Also get complaints about people scuffing wheels on the 6'6" restriction points. They don't like the standard response "the restriction is signed appropriately, you should know how wide your car is"

[RebelV8]

Highly doubt that it would cause an engine mount to break. There are exceptions to every rule of course, is it a new car or an old car, are the engine mounts all welded or a combination of bolted and welded. How's the car been treat in the past, if the owner drives over every speed bump like Mario Andretti then through time it might be possible, engine mount bolts can shear off I suppose if the car is mistreated.
If the car has been modified and has stiffened suspension, this might contribute to it.
As an example, I once inadvertently drove over a level crossing where the road leading up to it was slightly ramped, I was going a lot faster than I should have been, the bang when I hit the ground was unbelievable lol, the only damage though was a whole in the oil sump and a ripple in the bonnet above the struts.
Engine mounts are designed to take a lot of abuse, vibration from the engine, uneven roads etc

[Tankerman]

I have at the moment, (sorry) a Nissan Patrol and I live in Potters Bar which has speed humps everywhere and I never hit them at less than 30mph and I haven't broken anything yet. This is one of the reasons I have a 4x4, having broken ordinary motors on humps in the past!!!

[tweak'e]

A resident is saying that an engine mount on their car snapped while going (at 20mph) over a speed bump!

lol the suspension would fail before an engine mount lets go.
a mate actually did that. to fast over some big bumps and pushed the shocks through the top of the towers. engine was fine.

more than likely whats happened is the mount has failed and has been sitting there for some time until they hit a big bump, which allowed the weight to come off momentarily and the mount shift. just dumb luck that it was a speed hump not a pot hole.

[Jameswallace]

Sounds like they went over it too fast and wont admit it!

If the engine was loose on its mounts and moved it could happen but id have thought only at excess speed

[andyverran]

I have at the moment, (sorry) a Nissan Patrol and I live in Potters Bar which has speed humps everywhere and I never hit them at less than 30mph and I haven't broken anything yet. This is one of the reasons I have a 4x4, having broken ordinary motors on humps in the past!!!

...and people wonder why 4x4’s are so popular in cities....

[andyverran]

As an example, I once inadvertently drove over a level crossing where the road leading up to it was slightly ramped, I was going a lot faster than I should have been, the bang when I hit the ground was unbelievable lol, the only damage though was a whole in the oil sump and a ripple in the bonnet above the struts.

I work with a chap with a similar story, except that when he came down there was no road under him, he'd done it over a hump back bridge and was a little 'off square'

[RebelV8]

I work with a chap with a similar story, except that when he came down there was no road under him, he'd done it over a hump back bridge and was a little 'off square'

There's a couple of hump back bridges around here like that, makes spirited driving entertaining, having to remember to turn the wheels as you come over the hump

[J i m s t e r]