New Brake Rotors

[str8shot]

Originally Posted by dsh135

This is very interesting and a good find. Either BMW has these guys make their performance rotors or Dura has copied these down to the fine details. The only thing I noticed is that Dura makes no mention of being an OE supplier, which other companies typically do mention if they are (builds cred). When I replaced my worn rotors this summer I just went with Zimmerman non-drilled/slotted with the Coat-Z anti-corrosion coating. The price was decent and without having to stress over how/where they are made (German manufacture) they seemed like a good solution. I haven't tracked them yet but with my usual "spirited" street braking they've been every bit as good as stock and no unusual wear. Love the anti-corrosion coating on the hub.

This is a good find... I've been looking for rotors recently as well.

Don't want to go with a full steel rotor (ala Zimmerman) due to the increase in unsprung weight. Aluminum hat (even if not fully floating) is where it's at. I might try these out.

[hoki06]

Originally Posted by bNks334

I don't believe it is just deposits. I drive the car pretty hard when no one is around. This includes hard braking. I cant imagine deposits would persist/get worse over time either. I definitely don't want to think it could by anything else either because rotors would be the cheapest fix, lol.

You'd be surprised at what can cause deposits. You could have held your foot on the brake while the brakes were hot which will result in deposits on the rotors.

I'd still go give it a shot before throwing money at new rotors, it might fix your issue. If it doesn't work then all you've lost is a little time and gas.

[str8shot]

Originally Posted by str8shot

This is a good find... I've been looking for rotors recently as well.

Don't want to go with a full steel rotor (ala Zimmerman) due to the increase in unsprung weight. Aluminum hat (even if not fully floating) is where it's at. I might try these out.

Although after reading this:

http://abcnews.go.com/images/Blotter...0Complaint.pdf

I might still go with OEM.

[dcaron9999]

Had this vibration/warp effect happen to me on the track, but was using inappropriate brake pads (Cool Carbon) on BMW stock rotors, on my 135i. The vibration would occur towards the end of my session, but completely disappear when cooled down. I blamed my rotors at first, but quickly found out that proper track pads solved the issue, and more agressive brake pad compound wiped my rotor clean in the process.

Im still on stock rotors after buying my 135i second hand 2 years ago, about 20 days of tracking/year, and blowing through 4 sets of pads.

I found the "perfect" dual duty brake pad too in this whole learning exercise - Performance Friction PFC 08 brake pads (rebate going on right now at http://speedfreaksusa.com/). No noise on the street, great performance on the track (with proper DIY cooling ducts), good wear rate, no pad deposits and vibration at all.

Conclusion: Stock rotors with aluminium hats does the job, and can take the abuse. Just choose the appropriate pads for the task at hand.

[bNks334]

Originally Posted by MightyMouseTech

Just curious. Were the wheels off/on recently before you noticed the warp?

I put the stock wheels back on for the winter in September. Torqued to about 75 ft/lbs.

[MightyMouseTech]

Torque spec is 88 ft.lb. The most common reason for warped rotors is improperly torqued wheels.

[bNks334]

Originally Posted by dcaron9999

Had this vibration/warp effect happen to me on the track, but was using inappropriate brake pads (Cool Carbon) on BMW stock rotors, on my 135i. The vibration would occur towards the end of my session, but completely disappear when cooled down. I blamed my rotors at first, but quickly found out that proper track pads solved the issue, and more agressive brake pad compound wiped my rotor clean in the process.

Im still on stock rotors after buying my 135i second hand 2 years ago, about 20 days of tracking/year, and blowing through 4 sets of pads.

I found the "perfect" dual duty brake pad too in this whole learning exercise - Performance Friction PFC 08 brake pads (rebate going on right now at http://speedfreaksusa.com/). No noise on the street, great performance on the track (with proper DIY cooling ducts), good wear rate, no pad deposits and vibration at all.

Conclusion: Stock rotors with aluminium hats does the job, and can take the abuse. Just choose the appropriate pads for the task at hand.

I don't really get the vibration when cold. It becomes more transparent as the rotors heat up after driving hard. At times, even slight high speed braking causes quit a bit of vibration all the way through the steering wheel. I would definitely be upgrading to street performance pads if I bought new rotors.

Do you think at this point pads alone would help solve the issue? Should I bother having the stock rotors resurfaced?

I still cannot find any recommendations for lighter rotors for the 128i if they are needed.

[bNks334]

I have only heard of too much torque causing warpage, I have not heard of the opposite. That could've been a contributing factor I suppose.

I am guessing hot rotors + sitting at red lights is more of a problem than anything else. I'll look for signs of deposits.

[MightyMouseTech]

I find when rotors are warped, they do not show it when they are cold. As the rotor heats up, the warp becomes more pronounced.

Best bet is to replace the rotors and then torque the wheels to proper spec from here on in.

[BMWX1-35i]

Originally Posted by chris82

You won't see any benefit of slotted/drilled on a DD. But if you do it for looks then do slotted and not drilled; the holes just weaken the rotor

What he said ^^

[str8shot]

Originally Posted by MightyMouseTech

Torque spec is 88 ft.lb. The most common reason for warped rotors is improperly torqued wheels.

The most common reason for warped rotors is unevenly torqued wheels...

[MightyMouseTech]

Originally Posted by str8shot

The most common reason for warped rotors is unevenly torqued wheels...

Which would be improperly.

[BMWX1-35i]

Also, fast cool down (getting water splashed on them for example) after some hard braking or repeated braking that heats up the rotors.