creaking going over speed bumps

At about 7,000 miles my Leaf has started a loud creaking/groaning sound going over small speed bumps. The more people in the car, the more severe and louder. Other than than that car has been perfect. I guess a trip to dealer is required.

Mine has no trouble going normal speeds on city streets; I just have to slow to 18 MPH or so, but in parking lots where the speed should be 10 -12 MPH I find that it has trouble when the rear axle clears the bump. It sounds like the car's rear end just fell of the curb. I have to slow to 5 - 6 MPH or if possible take it at a slight angle to avoid this so one wheel is halfway down when the other is at the peak of the bump. The front end has no trouble. It was like this from day one. I think it's just a design flaw - or "feature."

I don't get a creaking or groaning, but mine has started making a whistle or "whoop" sound from the front left when I hit speed bumps at speed. It didn't used to do that. I'll have them look at it when I bring it in for inspection.

In past cars of mine, this behavior usually pointed to dry or worn-out stabilizer bushings. I don't even know if the LEAF has these....

In the front, yes. The rear uses the twist beam axle as a form of anti-roll bar.

Nubo said:

In past cars of mine, this behavior usually pointed to dry or worn-out stabilizer bushings. I don't even know if the LEAF has these....

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1stnewtonleaf said:

At about 7,000 miles my Leaf has started a loud creaking/groaning sound going over small speed bumps. The more people in the car, the more severe and louder. Other than than that car has been perfect. I guess a trip to dealer is required.

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Nubo said:

In past cars of mine, this behavior usually pointed to dry or worn-out stabilizer bushings. I don't even know if the LEAF has these....

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TomT said:

In the front, yes.

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Yes, see these pics, specifically the 4th and 6th ones.

TomT said:

The rear uses the twist beam axle as a form of anti-roll bar.

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1stnewtonleaf: Does this happen when the front wheels go over the speed bump, or the back wheels? How about when only one side (front or rear) goes over a bump?

GeekEV said:

... mine has started making a whistle or "whoop" sound from the front left when I hit speed bumps at speed. ...

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I thought the point of speed bumps was NOT to hit them "at speed"

Patient: Doctor it hurts when I raise my arm like this. (raises arm)
Doctor: Then don't raise your arm like that!

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davewill said:

GeekEV said:

... mine has started making a whistle or "whoop" sound from the front left when I hit speed bumps at speed. ...

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I thought the point of speed bumps was NOT to hit them "at speed"

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This is a common misconception. Any well-designed** speed bump is designed to regulate your speed to the desired limit. They can usually be taken safely and with minimal bump at that speed. Taking them too slow or too fast is what jars you...


** an important distinction, some are just a lump of asphalt laid down without thought or planning

Definitely only the front wheels. Only when 3 or more people in car, not going excessively fast, maybe 5 mph. Happens at different size speed bumps. My other cars have never made a noise like this even going much faster.

GeekEV said:

This is a common misconception. Any well-designed** speed bump is designed to regulate your speed to the desired limit. They can usually be taken safely and with minimal bump at that speed. Taking them too slow or too fast is what jars you...

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I don't know about where you live, but here we have speed 'bumps' and speed 'humps'. Speed bumps should be taken at a very low speed...under 5mph...these are mostly in shopping areas and are yellow bars of concrete. Speed humps can be taken safely at 20-25mph as these are on side streets meant to keep traffic at the speed limit and are just humps of asphalt over asphalt.

1stnewtonleaf said:

Definitely only the front wheels. Only when 3 or more people in car, not going excessively fast, maybe 5 mph. Happens at different size speed bumps. My other cars have never made a noise like this even going much faster.

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Then I think Nubo's diagnosis of the stabilizer bar's bushings lacking lubrication might be correct. Maybe it's because of a manufacturing glitch, or maybe it's because of frequent use of a "touchless" car wash with high-pressure undercarriage sprayers...

If you come across a speed bump that's not all the way across the thoroughfare, try running just one front wheel over the speed bump. If bumping either wheel causes squeaks equally, it's even more likely that it's the stabilizer bar's bushings. If only one side squeaks, it might be the spring or the damper (the "strut") on that side.

Sometimes also, the brackets/clamps holding down the stabilizer bushings can be loose and simply need to have the bolts re-torqued.

LEAFfan said:

I don't know about where you live, but here we have speed 'bumps' and speed 'humps'. Speed bumps should be taken at a very low speed...under 5mph...these are mostly in shopping areas and are yellow bars of concrete. Speed humps can be taken safely at 20-25mph as these are on side streets meant to keep traffic at the speed limit and are just humps of asphalt over asphalt.

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Both areas typically have correspondingly posted speed limits (parking lots are typically 5 mph). You should be able to take the bumps/humps at the posted limit. If you can't, they weren't designed right.

Looking forward to a report back as the the actual cause.

How well did the dealer diagnose the issue? Did they think a "noise" issue warranted as much attention as say as dashboard light issue would?

Since the LEAF suspension is not "fully" adjustable,
I take the speed bumps (some around here are "vicious")
very slowly, and straight across (Left and Right tires together),
if possible.

My LEAF makes no squeeks or groans (that I can hear).

As i said, my two other cars don't do it on the same bumps and humps. And it only started about 1,000 miles ago.
Will bring it to dealer at 12,000 mile check.

I've got the same on my UK leaf, even at 5 mph going over a speed bump.

It seems worse the colder it is? I notice it more because the leaf is so quiet!

I had it checked by 'Kwikfit' - a retail outlet that does exhausts/suspension/brakes. They couldn't find anything obviously amiss.

It's due a service soon anyway, so will get it checked and report back.