What warps discs?

N

Naylz

Member
Hello again everyone 😎 I have noticed a slight vibration when braking, upon inspection I have found my front discs are slightly warped, as you turn the hub (wheel off) there’s a tight spot on each revolution and you can clearly see a good millimetre maybe more of gap change between the disc and pad face as it rotates.

so I am pretty confident this is giving my braking vibration. Anyone know What causes this to happen? Is it cheap discs? Calliper issues? Poor design? Now I wouldn’t say these cars are that heavy and having vented discs you wouldn’t think heat would cause it???

I am now looking to order new discs and pads, is there a recommended solution out there, ie drilled vented discs?? Or a particular brand to go for…or avoid. Should I be checking anything on the callipers? Or even the rear brakes? The discs fitted have plenty of thickness left on them and it has previously been serviced by BMW so I guess they are supposedly genuine ones fitted.

Any advice much appreciated as ever 😎
 
Disc warpiing on E89s for street use is pretty rare AFAIK..

I wonder if the set fitted were mounted correctly?

Most of the OE suppliers seem to provide good options..no need to buy BMW branded ones..autodoc has a good selection..

Unless its an OE class supplier I wouldn't go with drilled discs..all stock discs are vented..

Age/model/mileage may help us determine more..
 
I have have drilled and grooved discs, i think they are great.
They reduce wear and scoring. Mine have been on now around 45k miles, lots of life left.
And green stuff pads, very little if any dust.

Forgot, they look good.
 
I just had this on my Focus, after a third set of warped discs replaced Ford diagnosed damaged wheel hub. That's been replaced and it feels good as new. It seems the hub was slightly out and was causing the discs to warp.

I had a long chat with the mechanic about how the hubs can be damaged, and he said usually its wheels nuts being tightened incorrectly or impact from potholes. Very rare apparently.
 
Also check the shock absorber see if it wobbles when you pull on it, they seem a bit cheap on the Zed.
I changed my at 45k for Bilsteins.
 
Even the best branded discs can warp - a quick internet search will confirm.

I prefer discs with a high carbon content (for better thermal performance) and coated to prolong life. I was fortunate enough to purchase a set of brand new Brembo discs and pads (front and rear) for just £110 from a forum member that fit the bill.

Just make sure you don't apply any antiseize to the face of the hub as you could get run-out which can cause wobble.
 
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