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For kicks I tried running OEM dws tires and wheels.
In comparison to square pirellli Corsa’s front end plowed like my former 1971 Buick Electra.
Did get rotor temperature up 680 degrees F caliper 540 F after 5 minute drive to garage.
Never had the wheels get so hot your hands would burn touching them

Amazed no fluid boiling issues on 2 yr old fluid

When it rained the back tires maintained good traction judging by loosing only 5 mph in top speed (5 mph less at turn exit coming on to main straight) new back tires 05/2018 9000 miles ago
Front tires Installed new 04/2016 33,000 miles old were into abs way early
Then the Aquaplaning fun began

I now know the on track water collection spots
 

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Ok, I looked up the maintenance log PO had supplied and corrected tire age.
I am shocked front tires have 33,000 miles on them since the thread depth is better than Corsa tires with only 3,000 miles on them.
 

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I am still getting to know this m5 since I only had it a little over a year.

previous wet track the front end vibrated so bad that I thought the oem pads were glazed and skipping across rotor surface.

Hence change pads to dtc60, now it is doing it again could the abs be that harsh?

modern abs systems are much less obtrusive, however the deceleration was seamless unlike others I have experienced.

Also how do I know stability / traction control is working, all my other cars have light flashing whenever system is in action
 

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I very pleased with PO effort to maintain this car by the book.
Other than mistakenly thinking new front pads were required I have not turned a wrench on it, not even changed brake fluid.
In another week I will do a 6th track day on it no issues.
Still waiting on my 2006 m5 to relieve 2008 m5 sitting at track side so I can bring it home for some deferred fluid maintenance
 

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Regarding front end vibration, is there any vibration from low/lower speed braking at like 50-70%? What is the feedback on the steering wheel? What is the mileage and when (if ever) were the bushings replaced on the torque/strut arm?
 

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Somewhat related to front end vibrations, I went to mono balls in 2013 and never looked back.

 

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I've had stock pad transfer that resulted in a trashed set of rotors and the vibrations you describe. The second set with dtc60 suffered a similar faith when engaging abs but cold pads were able to clean the rotors by themselves.
 

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Yes monoballs are totally related. It could be bad bearing too, but both of those can be diagnosed easily by measuring run out. I’m planning on getting GAS mono balls for the track car, I haven’t chosen which one will be that yet, but I replace the arms as part of every rod bearing job. I’d venture to say most owners who have one of these with less than 100k miles are on the original strut arms or bushings. It’s easier and cheaper to replace the whole arm because the ball joints are not going to last more than 125k miles. Front suspension rebuilt is basically required by 125k, not that hard to do as DIY, especially if you have access to an alignment machine. another reason to not over pay for a used M5 because this is a going to cost at least 1k for all new links and labor. This is not including Springs and struts.
 

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Yes monoballs are totally related. It could be bad bearing too, but both of those can be diagnosed easily by measuring run out.
Today there are more choices for monoballs, with Turner and GAS. Of course, I picked up my balls before Dinan reduced their pricing. Speaking of wheel bearings, a soft brake pedal is also a sign of a bad bearing.
 

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Yes there are at least 5 distinct reasons why one would have front end vibration. however vibration only under braking is really only 1 of 2 things on a front multilink design. depending on how ticat responds it narrows it down very quickly. My SMG with 127k miles had this on the test drive and it was easy to figure out but I have experience with this professionally. The car also had powerflex bushings too. Seller later told me he had gone through a few sets of rotors and it never solved the issue, so I have 2 extra very lightly used rotors came with the car. Changing the front bearing is a major PITA, I would not change it if it isn’t bad.
 

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Thanks guys , I was not expecting such quick responses, m5board is always quick to help out when ones knowledge and experience is lacking.

The strange thing is that the previous track event in March it also rained BUT the square set up with Corsa tires were on the M5 along with the new DTC60 pads.
Braking in the wet now was silk smooth , could go deep into brake markers on main straight #3 I believe easy modulation short of abs.
At the time I thought true to my past experience with high performance braking decisions (since 1995 ) I had made the right call on pads.
 

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I believe my knowledge and experience is lacking with regards to m5 dsc function.

The dsc module/ computer was replaced with a rebuilt one by previous owner.

Another note when I went to get gas it started raining, I slowed for a turn the front wheels locked up.
Much less traction than I expected.

Also previous March event dsc light was flashing when accelerating out of turns in the wet
On the DWS tires no flashing occurred in the wet
 

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The ATE/conti DSC systems are known for their issues so no surprise it needed to be rebuilt. Sounds like you think you have some real DSC issue(s)? ABS pulsation and front end vibration are very distinct.

You said you’re having vibration. Describe how and when you are getting the vibration. Is it only in the pedal or also through the steering wheel? Is there steering wheel shake (Slight left and right)?

Tire and wheel imbalance are definitely a source of vibration but that will happen all the time and at higher speeds, if the vibration only happens while heavier braking, imbalance is not the culprit (that’s not to say your wheels are perfectly balanced though)

Wet traction is going to be a compromise if you have UHPs.
DWS has better wet traction than Corsas or the DW. Temperature makes a big difference on UHPs. DWS has a better compound for low temp, hence the S. I’d expect more hook up on DWS when it’s wet and cold.
 

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The vibration feel like pads slipping on rotors intermittently thus originally thought It was glazed pads.
Now thinking the 33,000 mile front tires have such low sliding friction vs. static friction it sets up oscillation in abs system.

Also high speed turns front end hops sideways 5 feet in the wet while rear stays planted

i think I just need new front tires

m5 is a balanced car thus having a mixture in age and mileage of tires upsets that balance

I almost forgot the wheels on the Corsa tires have no pressure sensors since they came off the 2006 m5
I wonder if that disables the dsc

thus easy modulation since no interference from abs
 

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I will figure it out next track day
Know better what to look for

I will mash the brake pedal on the Corsa’s to see what abs feels like, if I have any

one of the attributes of the Corsa’s is the break away traction is almost the same as traction at limit

the Conti’s you have traction on my front tires or you don’t and front washes out big time
 

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Regardless
I had great time, did continuous laps for 80 minutes in ever increasing down pour till a 4” deep puddle became unavoidable at end of au Rouge Spa like straight

rear calipers were 100 F warmer than front thus know traction control is working with DWS tires on the wheels with pressure sensors
 

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I will also check the date code of front tires if sitting at distributor for 2 yrs would make them 6 years old
 
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