275/55R20 KO2 or LTZ

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Originally Posted by Graeme

The noise is quite intrusive and significantly worse when I'm in the driver's seat than the passenger seat. From both seats the noise seems to be emanating from the driver's foot-well area for both myself and my son when swapping seats. I think the open space below the brake booster through to the ground below is a major contributor but stuffing the void with old towels makes no difference.

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Graeme is this also the experience of others with the same tires? I thought the new bfg compound was meant to reduce noise. Which seems to be the case with the ko2s. My old man always said don't get mud terrains they are bloody noisy, but once he jumped in my p38 with them he was very surprised. Assuming this is the case with the compound and they are quieter I would have thought other all terrains would give the same problem. Particularly if it's just that location. In the car that's allowing the noise in.

Cheers Paul

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Originally Posted by rar110

Mate
A P38, your in deeper than I thought. 😀

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Yes one for all seasons. Well two seasons. I think with a Range Rover and for those who do their own repairs a second transport option is required. I'm still waiting on a call back from Mr McGoo for advice on what to do if both break down.

The noise seems only from the front right and as it doesn't change frequency with speed it must be a reverberation. There's also a lot of road noise on fast gravel. The noise from the front passenger seat position is only minimal. The battery on the left side might be preventing reverberation and though I cannot see what's below it, I would expect it to have the same opening to the ground as the right side.

Initially there was bad noise from the rear when the floor, raised on full-length sponge blocks because the spare doesn't sit on the bottom of the well, allowed the well's side and floor panels to reverberate. However since sound-deadening material was affixed to those panels the reverberation no longer occurs. Its possible that the noise is still coming from the rear so if the standard tyre on the front doesn't cure it then it will be put as the spare and the floor returned to normal for a test.

People have recently fitted large 18" KO2s to D4s yet I haven't seen any reports of intrusive noise. However reports from the US suggest that the KO2 is not as quiet as promoted by BFG.

Graeme can you get some dynamat into that area below the brake booster?

So far I've only applied a small piece to the vertical side panel right at the top but I'll have to see if I can get some further down.

I've just discovered that the driver's side plastic sill cover rattles significantly when tapped whereas the passenger side does not, so that will be fixed before trying anything else.

Edit: Padded material is already affixed to the firewall around the brake m/c so would have to remove it to fit dynamat behind.

Perhaps still clutching at straws, but I found the heat shield above the catalytic converter clanged solidly against a body rail if even quite gently bumped, which might be the cause of the reverberation. This is the worst heat shield clang that I've found so far and being very solid against the rail below the floor, it was a promising find.

Having decided that the plastic sill cover couldn't possibly cause that much noise I removed the heat shield from above the right ARB mount and rear wishbone bush to try to improve its "deadness" but on checking around the area discovered the catalytic converter heat shield's clang. The bush shield was also improved by giving it clearance above the ARB and its bush bracket rather than resting on them. Fingers are crossed - again.

It sounds like you could write an article about the L322 called - "all things that go clang"

Perhaps, but then none were the cause of the noise.

Other things to try...swap wheels/tyres around and stuff the open-ended box section below the floor with old rags.

Having swapped the RF & RR and the LF with the unused spare wheels and ensured that the floor of the spare wheel well cannot vibrate, I'm now considering the sill channels because they resonate when tapped with fingers. They are made of thin metal where not double-layered and are coated eternally with a thin layer of sprayed-on deadener, so presumably a concern even with road tyres. I thought about filling them with expanding foam but that would create a haven for rust, as would spray-on deadener on the insides so will look at what else might be possible, even as a temporary fix to prove or disprove the idea. Lengths of 6mm thick rubber attached with construction adhesive might be worth a try unless someone has a better idea.

The latest theory is a noisy FR wheel bearing so a new one will be fitted. It would be unusual with only 30K kms but if the vehicle had done 100K I wouldn't hesitate to blame the bearing. The noise is only from the FR corner and can even be heard at 50 kph on a gravel road with a rattly trailer in tow.