How to tell when I need new rotors

[lochness_monster]

I have 80k on my 135i.

[juld0zer]

Get a micrometer and measure, compare with the minimum thickness etched in the rotor hat

[cam36]

Not to highjack this thread, but I recently picked up my 1er with 30k on it. When I brake fairly hard I feel a vibration in the steering wheel– which leads me to believe my rotors are warped.

As I understand it, 135i rotors warping is pretty uncommon. Any thoughts as to what could be causing the vibration?

[MightyMouseTech]

Originally Posted by cam36

Not to highjack this thread, but I recently picked up my 1er with 30k on it. When I brake fairly hard I feel a vibration in the steering wheel– which leads me to believe my rotors are warped.

As I understand it, 135i rotors warping is pretty uncommon. Any thoughts as to what could be causing the vibration?

If they are actually warped, you have to measure them to know for sure, it is caused by improperly torqued wheel bolts.

[juld0zer]

Or a jackass who jacked the car up by the rotor edge to tighten suspension arms.. happened to me but over time it seems to have improved. It was a new rotor too. Aluminium hats dont take well to stupidity.

Could it be just the ABS doing its thing?
Pad deposits on the rotor surface?

[asbrr]

Originally Posted by juld0zer

Pad deposits on the rotor surface?

This is usually it, but as some have said the OEM rotors seem to resist this well, but it could depend on what kind of pads were on there.

[MightyMouseTech]

Originally Posted by juld0zer

Or a jackass who jacked the car up by the rotor edge to tighten suspension arms..

WT actual F?

[juld0zer]

Originally Posted by MightyMouseTech

WT actual F?

The guy was either lazy or tight on money to buy/make ramps so he jacked up the corner by the rotor edge and it popped off the hub. Dont think he put any wheel bolts in, so the poor little 6mm hex head screw was no match.

[Dackelone]

24.4 mm min rotor life... stamped into the rotor's hat...






On the brake rotor's hat it is stamped with the MIN brake rotor thickness. For the optional BMW Performance rotors it is 24.4 mm's.

Also IF you look at the edge of your rotor - you will probably see a lip at the edge, from the brake pads wearing down the rotor. Once this lip becomes deep... its time for replacement.

Check your rear pads... bc that e-diff/DSC can really wear out those rear pads fast.

OP - when you can feel a vibration when you brake hard(and/or bearing type noises), its time for new front brakes. I prefer the BMW OE pads bc they have great cold initial bite when first used on a cold morning. I also like BMW rotors bc they are so well made. Although you can find some really cheap rotors out there today. There IS a difference between BMW OE and OEM(aftermarket parts).

[mmmusty]

Originally Posted by Dackelone

24.4 mm min rotor life... stamped into the rotor's hat...
Attachment 1581454

Attachment 1581455

Attachment 1581456

On the brake rotor's hat it is stamped with the MIN brake rotor thickness. For the optional BMW Performance rotors it is 24.4 mm's.

Also IF you look at the edge of your rotor - you will probably see a lip at the edge, from the brake pads wearing down the rotor. Once this lip becomes deep... its time for replacement.

Check your rear pads... bc that e-diff/DSC can really wear out those rear pads fast.

OP - when you can feel a vibration when you brake hard(and/or bearing type noises), its time for new front brakes. I prefer the BMW OE pads bc they have great cold initial bite when first used on a cold morning. I also like BMW rotors bc they are so well made. Although you can find some really cheap rotors out there today. There IS a difference between BMW OE and OEM(aftermarket parts).

What's up Dackelone, what do you recommend for the 128i rotors, also OE?

[Dackelone]

Originally Posted by mmmusty

What's up Dackelone, what do you recommend for the 128i rotors, also OE?

When it comes to brakes... I always go with BMW parts, sold thru a dealership. The aftermarket brake calipers aren't that great.

You could go with ATE aftermarket rotors and pads... I have them on my e39 540i. But really you can feel the difference with BMW parts. The BMW rotors are heavier and last longer.

I'm not that happy with my BMW Performance rotors... they eat up the brake pads. So on my next brake rotor service... I will just go with normal BMW rotors for my 135i.


Dackel

[Detroit1er]

Originally Posted by Dackelone

When it comes to brakes... I always go with BMW parts, sold thru a dealership. The aftermarket brake calipers aren't that great.

Dackel

Sorry for the multiple resurrection of this thread...

Hey Dack - you're consistent about your preference for getting your parts through a dealer... Do you know a person at your local BMW dealer or do you feel there isn't a reliable online resource to make certain you're receiving true BMW spec parts?

[Dackelone]

Originally Posted by Detroit1er

Sorry for the multiple resurrection of this thread...

Hey Dack - you're consistent about your preference for getting your parts through a dealer... Do you know a person at your local BMW dealer or do you feel there isn't a reliable online resource to make certain you're receiving true BMW spec parts?

Yes, I know the guys at my BW dealer quite well. They normally give me a 20% discount off of the list price(no bump ie added markup from MSRP)... then I have a VAT form that I can get thru the US Army to take off the 19% German sales tax. So in the end the price is better than buying mail order from the states.

The best thing to do is build up a relationship with your parts guy. Order/buy small parts... and ask for a discount on big things. Often times they will cut you some slack. Tell them you will buy lots of parts fro them... IF you can get a decent discount.

I also try to use RealOEM.com to have all my part numbers ready to just hand over to the parts guy. That helps reduce their stress. I also will research what other online BMW dealers are selling parts for... and ask IF they can meet or beat that price.

For instance I needed a new rear allow wheel... I saw on line that a German dealer had it for 320 euros plus shipping... I asked my dealer for "their" price.... they wanted 368 euros(straight List price). I showed them the online ad from this "other" BMW dealer... in the end they dropped their price to 308 euros... PLUS I didn't have to pay for any shipping!! I call that a win win.

Also... when you order parts at your local BMW dealer... IF you need the parts ASAP... they get two deliveries each day from BMW AG(at least here in Germany)... or you get the parts the next day. BUT... IF you are not in a rush... order the parts to come in their next weekly shipment. That way the parts dept doesn't have to pay for "express" shipping. Maybe parts depts will appreciate this. Also... don't order parts for the next day and then wait a week to pick it up. This can piss off your parts guy.

So basically just ask nicely and see what kinds of deals you can get. I often will bring my parts guys some donuts or soda/beer as a thank you... this also helps building your relationship.

Dackel

[Gangplank]

In the US if you join the BMW Car Club, many dealers will give a discount. https://www.bmwcca.org. That said I also get OEM parts from online retailers like Turner/ECS.

[z32 fairlady]

Anyone had any experience with BavAuto's selection of parts? I am a fan of OEM parts and they seem to have decent pricing compared to the dealers.

https://www.bavauto.com/brakes/rotors.html