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Registered-sold my '55
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Discussion Starter #1
Haven't posted for a while due to heavy work commitments, early mornings and late nights and stupid arbitration hearings while wearing 2 and sometimes 3 hats as staff retire and some get laid off...anyway enough of my misery...I just need some thoughts from the engineers and or enthusiasts among you.

So a few months ago I bought some after market wheels for the car...same size except the offset was just slight off which pushed the wheels out a few millimetres..anyway everything has been fine up to recently when vibration started as I hit 120 kms per hr through to 180..the faster I got the vibration got worse. Believing the problem to be balancing I took the car back to the shop who put the wheels on...owner knows his stuff, owns GTS and CLS63 and has had numerous other high performance cars....anyway that hasn't fixed the problem as the vibration is still there...now it may have been there since I swapped the wheels because I hadn't used the car much and rarely went above 120 kph due to traffic or just leisurely drives. When he sold me the wheels he said that they were about 5lbs lighter per wheel than the 10 spoke OEM wheels...and the steering certainly feels lighter.

So my question...is the vibration caused by a number of factors..wheel weight? effect on the suspension? slight difference in offset? The wheel alignment is near perfect and nothing has impacted the wheels. Suggestions anyone?...either that I simply go back to the OEM wheels and have them powder coated black.
Car is going to be put into hibernation next week or so depending on the weather... pic of cars and wheels attached
 

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Registered 2009 SLK200
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Haven't posted for a while due to heavy work commitments, early mornings and late nights and stupid arbitration hearings while wearing 2 and sometimes 3 hats as staff retire and some get laid off...anyway enough of my misery...I just need some thoughts from the engineers and or enthusiasts among you.

So a few months ago I bought some after market wheels for the car...same size except the offset was just slight off which pushed the wheels out a few millimetres..anyway everything has been fine up to recently when vibration started as I hit 120 kms per hr through to 180..the faster I got the vibration got worse. Believing the problem to be balancing I took the car back to the shop who put the wheels on...owner knows his stuff, owns GTS and CLS63 and has had numerous other high performance cars....anyway that hasn't fixed the problem as the vibration is still there...now it may have been there since I swapped the wheels because I hadn't used the car much and rarely went above 120 kph due to traffic or just leisurely drives. When he sold me the wheels he said that they were about 5lbs lighter per wheel than the 10 spoke OEM wheels...and the steering certainly feels lighter.

So my question...is the vibration caused by a number of factors..wheel weight? effect on the suspension? slight difference in offset? The wheel alignment is near perfect and nothing has impacted the wheels. Suggestions anyone?...either that I simply go back to the OEM wheels and have them powder coated black.
Car is going to be put into hibernation next week or so depending on the weather... pic of cars and wheels attached
If ive read correctly .......

Put your original wheels / tyres on if there is no vibration on the car then its the aftermarket wheels that are the problem .

Aftermarket alloys bring loads of issues to a car car needs to be re tracked / aligned
There lighter so that tells you not so much alloy in them . ( weaker and prone to cracking )
There off set so the car will behave a little diff than standard .

And there never machined exactly right compared to standard alloys .

Go back to standard and paint them or .......
 

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Registered-sold my '55
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Discussion Starter #4
If ive read correctly .......

Put your original wheels / tyres on if there is no vibration on the car then its the aftermarket wheels that are the problem .

Aftermarket alloys bring loads of issues to a car car needs to be re tracked / aligned
There lighter so that tells you not so much alloy in them . ( weaker and prone to cracking )
There off set so the car will behave a little diff than standard .

And there never machined exactly right compared to standard alloys .

Go back to standard and paint them or .......

The vibration only began when I put the wheels on ..(no problem with the OEM wheels)..and only when driving at speeds in excess of 120 does the vibration start, I think the weight of the wheels do play a part. According to the manufacturers web site they make 'aluminum alloy wheels'.The typical mix is 94% aluminum, 4% silica and about 2% miscellaneous other elements.


Not that I am a metallurgist ....

As a Canadian company FAST seem to have a good reputation within the marketplace, they have a 3 year warranty on their product...although the car seems perfectly aligned I might go and get it redone and see what that throws up...if not I guess its back with the OEM's either powder coat them or buy another set in black:|
 

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Registered 2009 SLK200
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The vibration only began when I put the wheels on ..(no problem with the OEM wheels)..and only when driving at speeds in excess of 120 does the vibration start, I think the weight of the wheels do play a part. According to the manufacturers web site they make 'aluminum alloy wheels'.The typical mix is 94% aluminum, 4% silica and about 2% miscellaneous other elements.


Not that I am a metallurgist ....

As a Canadian company FAST seem to have a good reputation within the marketplace, they have a 3 year warranty on their product...although the car seems perfectly aligned I might go and get it redone and see what that throws up...if not I guess its back with the OEM's either powder coat them or buy another set in black:|
It can purly down to wheel balancing ?
Or defective tyre ?

Causing vibration .
Original wheel bolts being used and are seating / bolting alloy down ?

Make sure your suspension / shocks / bushes / bearings ( front ) are all good no play / movement before wheel alignment .
 

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Did you reuse the tires from the stock wheels on the new wheels? How many miles have they got on them? The vibration could be caused by wear problems.

On my first SLK, I first installed a set of highly regarded Bridgestones that had been recommended. I was shocked at how quickly and unevenly they wore; they were vibrating all over the place and had wavy ripples across them in less than 3000 miles. I switched to Continental ExtremeDW with the second set of tires and they ran past their wear rating by a bit, then wore out to nothing very quickly with increased vibration and noise.

So look carefully at the tire condition ... with tires as low profile and wide as the ones we put on these cars, it's very important.

G
 

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Registered sold both-> SLK350, SLK '55
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it is the shops problem, and I would just make them stand up for the guarantee they give and change the wheels or refund.
Do not compromise.

Tapatalking
 
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Premium Member 2012 SLK55 AMG
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What brand are the wheels? If as the markings on the wheels suggest they are indeed manufactured using a flow forming process then I would doubt that they were inferior quality especially when compared to most aftermarket wheels. This is a relatively new process which results in a stronger structure using less volume of material and this is why they are lightweight.

Do they have oversized counterbores fitted with plastic spigot rings?
 

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Registered-sold my '55
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Discussion Starter #9
Thanks for all the responses to this quandary...I'll try and answer / summarize them in one response.

The wheel manufacturer is https://www.fastwheels.ca they have a good reputation and I know the shop that I bought the wheels from will help out; the owner is a great AMG enthusiast and besides his GTS and CLS 63 he has on order the GTR>:D but he is up to his eyeballs right now in his shop with the winter tire change over so his shop is manic. After he rebalanced them a few weeks ago he said if the problem continued to come back in the Spring. Now at the time of the rebalance he mentioned that it might be the alignment or tires as a couple of you suggested. I asked him to go ahead and change the tires but he didn't have any in stock at the time as his shop was full of the winter tires ...not summers. The trouble is that the weather has continued to be great even for this time of year so there is plenty of motoring left yet before going into hibernation.

At the time of buying the wheels I swapped the tires over from the OEM rims as the rears had just been put on a couple of weeks earlier and the fronts had a ton of tread on them; the wear on each tire appeared even across the tread - the fronts were on the car when I bought it roughly 20,000 kms ago and had just been put on a week before I bought the car. All four corners are Continental Contisport Contact 5P. I have had others look at the tires and they seem to agree that they don't need changing; however given the response to my dilemma by some of you this a serious consideration:| to fixing this problem despite the amount of tread on the tires. (I hate throwing good stuff away and $700 on two front tires may not fix the problem)

The off set and bore were different than OEM - OEM wheel nuts were not reused a new set of MB nuts in black were ordered as I had the new wheels powder coated black (they only come in Titanium and bronze)

The alignment is near perfect so I don't believe that to be the problem; take your hands off the wheel and it runs perfectly straight down the freeway without any deviation unless the camber of the road takes it depending on which lane I'm in.

Thanks for all you responses....I think I will try putting new tires on the front despite the amount of tread remaining as I intended to change them in the Spring anyway. For those interested :smile:I'll keep you updated.
 

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Premium Member 2012 SLK55 AMG
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The new wheel bolts you used, you said came from MB is that correct? If so it is possible they the wrong seat type for your new alloys?

Most aftermarket alloys require 60 degree tapered seat bolts/nuts. MB use a radius/ball seat.

Something else you should check if you're not sure, seeing as they are the other thing you've changed besides the wheels.

You should probably get the wheels checked for runout too, to make sure there's not something wrong with the wheels geometry due to a manufacturing defect.

Certainly a strange one, hope you get to the bottom of it and don't have to compromise on your wheel choice. :smile:
 

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I had a Camaro several years ago that had a vibration problem I chased for quite a while. The vibration was very bad starting at about 50 mph. It turned out to be the tires.
I found the tire problem by going to an indy shop that had a balancer with a road force measuring device attached.
The road force attachment put a drum against the tire while it is spinning to measure how much pressure the tire is putting on the road when it is spinning. Spikes in the measured pressure indicate hard spots in the tire. That can come from improperly layered ply or some other construction problem.
I now go to that same indy every time I put tires on a vehicle. I don't buy them there but I do have them mounted and balanced (and road force tested) there.
 

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Registered-sold my '55
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Discussion Starter #12
The new wheel bolts you used, you said came from MB is that correct? If so it is possible they the wrong seat type for your new alloys?

Most aftermarket alloys require 60 degree tapered seat bolts/nuts. MB use a radius/ball seat.

Something else you should check if you're not sure, seeing as they are the other thing you've changed besides the wheels.

You should probably get the wheels checked for runout too, to make sure there's not something wrong with the wheels geometry due to a manufacturing defect.

Certainly a strange one, hope you get to the bottom of it and don't have to compromise on your wheel choice. :smile:
Thanks for the info...I'll check on your query re the bolts but I know he had to order bolts to fit a MB and that was on my invoice. I'll get him to check the wheel geometry also if throwing on new tires doesn't solve the problem. I had a similar problem when I had my CLK a few years ago when I put aftermarket wheels on and in the end I took them off. I am generally wary of after market anything, because I always feel that the car is set up was designed for the original parts and if you change anything it has a knockdown effect to get everything perfect again....or may be I am paranoid:wink:
 
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