Cabin drone when going over corrugations

[Alexl8891 Lurker Find all posts View Profile Close Alexl8891]

Posted this on WA Prado 150 group, but not too many responses,

Anyone here get a loud resonating drone when going over corrugations? Happens most times when going 80-90km/hr on corrugations.

The sound is really loud, maybe similar to the airbox drone but way more intense, almost to the point sometimes where I feel like I need to back off on the speed just to stop the drone.

Anyone experience the same kind of thing?
It's diesel, relatively new cooper at3 265/70

Thanks.

[JimmyC Advanced Member Find all posts View Profile Close JimmyC]

I know the noise you're talking of. I found it comes down to tyre pressures and speed. Not much you can do about it except alter those 2

[Alexl8891 Lurker Find all posts View Profile Close Alexl8891]

I know the noise you're talking of. I found it comes down to tyre pressures and speed. Not much you can do about it except alter those 2

Usually travel now at around 30psi on corrugations. But I do recall it was still the same if I went over them on highway pressures.

So the sound is normal you reckon? - you can't hear anyone talking when it resonates like that, and the ears almost can't cope with them.

[RanJ Avid PP Poster! Find all posts View Profile Close RanJ]

It's just the sound of your firewall cracking....

[ntp Addicted PP Member Find all posts View Profile Close ntp]

It's not the missus, is it?

[raydes Advanced Member Find all posts View Profile Close raydes]

30 psi is still to high,, You should hear the Pajero roof vibrate when on corrugations they ARE loud, sounds like Rolf Harris on his wobble board ,lol

[Alexl8891 Lurker Find all posts View Profile Close Alexl8891]

It's just the sound of your firewall cracking....

Are you taking the piss, if not please elaborate

[404pug Avid PP Poster! Find all posts View Profile Close 404pug]

As above- play with tyre pressures. Try 28 psi. Vary speed up or down 5kph as an experiment.

[Alexl8891 Lurker Find all posts View Profile Close Alexl8891]

So what your all saying is the drone us normal?

[RanJ Avid PP Poster! Find all posts View Profile Close RanJ]

What you're heading is sympathetic vibrations caused by a sustained speed. Perfectly naturally occurrence.

Same thing as the buffeting sound you hear sometimes with a window down.

My reference to the cracking firewall was a little bit of a piss take but also a reference to the 120 series thay had a habit of developing cracks in the firewall and inner guards after sustained high speed driving over corrugated roads with non-toyota bullbars.

[Alexl8891 Lurker Find all posts View Profile Close Alexl8891]

What you're heading is sympathetic vibrations caused by a sustained speed. Perfectly naturally occurrence.

Same thing as the buffeting sound you hear sometimes with a window down.

My reference to the cracking firewall was a little bit of a piss take but also a reference to the 120 series thay had a habit of developing cracks in the firewall and inner guards after sustained high speed driving over corrugated roads with non-toyota bullbars.

Thanks and yep it is like the buffeting sound, just don't recall it happening in other cars when going over corrugations.

[RanJ Avid PP Poster! Find all posts View Profile Close RanJ]

Probably weren't going fast enough lol.

[krypto Avid PP Poster! Find all posts View Profile Close krypto]

I checked today or a really corrugated road and there is a bit of a drone at certain speeds. IWhat tyres are you using and have you tried changing pressure as suggested?

[Alexl8891 Lurker Find all posts View Profile Close Alexl8891]

Thanks krypto. Will be doin a camping trip this weekend so will change it down to under 30psi if we encounter corrugations... bit of a pain in the ass though. Was on 30 psi with relatively new cooper at3 265/70... 2inch lift. Same sounds prior to lift kit as well.