Excessive R230 SL road noise from rear - what's yours like??

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martin_sv

New Member
Joined
Jul 2, 2012
Messages
29
Location
North Hampshire
Car
E350cdi Coupe 2012, R230 Sl350 2003 + CLK 320CDi ( will be putting it up for sale)
Could the new rear shocks have been fitted incorrectly?

( To any who have driven, worked on or just know about r230 rear suspension partic. SL 350 ie non ABC modell)

Hi to you all,
Sorry about my long (first) post.
I'm generaly very pleased with the refinement of my 2003 350Sl 2003. I've only done about a thousand miles so not too much experience particularly as most done with the roof down. In this state I can hear the rear tyres but at a level that seems perfectly acceptable ie mostly drowned out by wind noise. However with the roof up it's another story. With music on again it's drowned out but now I've got over the novelty of the high quality sounds emanting from the bose system I'm moving back to wanting (relative) silence. Those rear tyres Pirelli p zero rosso's really spoil the show. I always thought my previous drive an alfa 156's weak point was road noise, ( both front & rear) but this is definitely noisier. It's clearly the dominant sound at motorway speeds .
Front tyres seem very quiet in comparison. The tyres have appx 6mm equally worn across the treads so I'm just wondering whether the rear shocks have been replace incorrectly. Last owner had plenty of kit including full hydraulic lift and seemed pretty clued up. He had replaced the front control arm and ball joint -seems fine. The car was given a full geometry check after the shocks were fitted. The thing that sticks in my mind is the bill he gave me from Robinson Merc dealer of Peterborough for £114 to "fit spigs on shock absorbers" Not come across this before but have found them on the parts diagrams., seem to be some sort of top cap to the shocker itself. Is it possible for these or indeed the whole shocker to be replaced incorrectly eg rubber bushing/ washers in wrong order perhaps? Any help greatly appreciated as I dont want to be forced to listen to music or radio 4 whenever I'm on the motorway!! :mad:
 
What make tyres are fitted to the car?

Are they feathered?
 
I automatically assumed Pirelli's without reading the body of the thread which confirms P zero's.

I'd be tempted to see if you can find someone that has some suitable wheels you can swap to for a quick test drive. This will at least eliminate the tyre possibility.

My personal experience with Pirelli's is that they are particularly noisy.
 
What make tyres are fitted to the car?

Are they feathered?

Hi, they're Pirelli P Zero Rosso's ( all round ) rear size 285-35 -18. No feathering at all - look near new, measure 6mm tread left with equal wear across surface on both tyres. Seems strange as v quiet on the front even on course surfaces. I know the cabin isn't completely sealed from the boot and I was wondering if this was amplifying the noise a bit like I remember if I put the rear seats down im my wife's pug 306? Perhaps all SL's are like this? :confused:
 
I dont find my SL55 noisy - used to have P-Zero 18", now P-Zero Rosso 19" all round (285 wide)

Cabin is quite well sealed from the boot (given there is a fuel tank between you and it), but certainly when I didn't have my left rear boot carpet in, I could hear some noises and squeaks that weren't there before and it was more noisy. I wonder if you have lost some noise insulation somewhere

I think you probably need to find someone else with a SL350 (i.e so you have the non ABC suspension) and compare

Richard
 
I dont find my SL55 noisy - used to have P-Zero 18", now P-Zero Rosso 19" all round (285 wide)

Cabin is quite well sealed from the boot (given there is a fuel tank between you and it), but certainly when I didn't have my left rear boot carpet in, I could hear some noises and squeaks that weren't there before and it was more noisy. I wonder if you have lost some noise insulation somewhere

I think you probably need to find someone else with a SL350 (i.e so you have the non ABC suspension) and compare

Richard

It's good to know that SL's can be quiet (admittedly with a different suspension set up). I have a single boot floor carpeted cover over the spare + battery + PSE pump which seems to fit snugly. My concerns about the sealing of the cabin from boot was from the gaps around the roof folding mechanism. I might try stuffing some clean rag on each side to see if that's compounding the issue. ( my pic below is how I assume they all look, quite a large area on each side with direct communication through to the boot.

Regarding the sugestion to compare with other Sl350 owners that would prove v useful.No need to swop wheels if I could just passenger in your car to compare refinement over course surfaces. Anyone would be welcome to listen to mine!! So anyone around north Hants ( nr Basingstoke) who could assist??
 

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What is the date stamp on the tyres?

Interesting line to check---
15 09 on both fronts &
07 10 on both rears.
So the oldest (quiet) fronts appx 3 1/2 years from new and the noisy rears appx. 2 1/2 yrs from new. Not too old I would have thought but YMMV :)
I'm still thinking along the chance of an ommitted rubber bush/ spacer as a possible candidate. Do the so called "spigs" top caps have any rubber in them I wonder? What do the "spigs" do?
Isolation of road noise depends heavily on rubber I have been led to believe?
 

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