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From new my 2017 X1 has made excessive road noise, after a road test by BMW they advised that the noise is not excessive. 

 £250 later on new tyres advised by a leading magazine, still the road noise is unacceptable. 

On the odd UK smooth good quality road I might find myself upon it's fine and I love the car, then back on the rotten roads as normal it's deafening.

I'm looking at sound insulation any ideas anyone ??

  

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Hi Graham

Welcome to the Forum

OK give us a clue just where is this "Smooth Road" 😂 most of ours are like ploughed fields with white lines??

What wheel tyre combination are you running ? remember Runflat Tyres have a reputation for harsh ride characteristics. If I recall the X1 runs 18" with 225x50 tyres an alternative may be 17" with 225x55 tyres non runflat would give a better sidewall compliance

Dave

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Hi Dave 

Upon purchasing the vehicle new I insisted on 17" rims and that run-flats should not be fitted.

The car arrived with Bridgestone Turanza tyres fitted on 17" rims, great.

 On the first day and a few miles away from the dealership where the road test roads are very good I noticed the road noise on our normal roads.

I complained to the dealership, whereupon they road tested the car and found it to be in their words satisfactory.

I asked for the advice of the ''Diesel Car & Eco Car  mag'' who suggested a  change of tyres to Goodyear Efficient Grip's.

Before I changed the tyres I recorded sound pressure level readings over five specific roads at particular points.

Followed by reading with the new tyres (after 200 miles to remove the new edges) the average reduction was 3.72 dB. 

Unfortunately, in reality it takes a reduction of 5dB to make a reasonable noticeable difference for the human ear.

Hence my investigation into acoustic soundproofing, as I love everything else about the car.

Graham the engineer. 

 

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Morning Graham

As you will be well aware the suspension and bushes also contribute heavily to NVH transmission. So if your car is on 17" tyres already you and your suspension isn't Sport? you will have the softest settings. Sound proofing I am not aware of any kits for your (doesn't mean they are not out there) Measuring so clinically you will need a base line, do BMW actually release a base line? Also road surface type and ambient noise will effect outcomes.

As for tyres they can make a huge difference my X5 4.6is runs 275x40x20 Front and 315x35x20 rear so lots of contact opportunity for noise the last few sets were Michelin the current set are Yokohama. My X5 is 18 years old so I am used to it, but when my wife notices then the difference in road noise is marked with the Yoko's. I don't and never have actually measured NVH in my cars but these tyres have made a reduction I am not suggesting you change to them as your suspension set up is different just my observation. I rarely use the radio as I like the sound of my V8 which can be heard even at Motorway speed over tyre noise.

Good Luck with your hunt

Dave

 

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Going back a few years when I was in business we were upgrading the Baggage System at T4 Heathrow. Prior to contract one of the BAA engineering team announced that Noise for the system would have to have a noise level of 60DB measured 1m from the drive unit.

At midday (a quiet time for airports) ambient noise in the terminal was 89 DB outside the terminal with the M25 1mile away we measured 96 DB, we tried at 3am with everything shut down except the terminal air handling we measured 54 DB. I asked the BAA team were they measuring ambient noise + or did they seriously expect a piece of mechanical equipment to generate 6 DB? The real issue was until that point they had no Base Line, worse at that time Heathrow had 4 Terminals due to age and construction every building gave different readings even turning off fluorescent lights changed levels. Yet as we stood in the terminal at 3am to the human ear it was Cathedral like. 

My point is when in our car it isn't just noise but vibration that we hear/feel, our ears would hardly notice 3 or 4 DB (well mine won't to many years listening to Pink Floyd 😂)

I hope Graham can find a solution but I fear unless he get's used to it it won't be with his X1 

Dave

 

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