New Brake Discs Thickness issue

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May 6, 2014
hey all i forgot to take a photo but will get one up tomorrow. the new brake discs i received (vented ones) have a thicker plate on one side and thinner on the other. is this normal or a manufacturing issue? its the same on both of the discs in the box. iv seen this on some pagid discs for the aygo and its now happened with the fremax discs i bought for the ford fiesta. how can this happen from 2 different brands of discs for different cars? i thought with brake discs the plates should be even thickness on each side?
Originally Posted By: The Critic
This is normal- some applications will have one side that is thicker than the other.
Thats odd would it cause vibration or other issues?
Check your old rotors. If they wore evenly on both sides then unequal thickness replacements will have a shorter service live. If they wore more on the piston side then that would suggest the new ones are Just Right for the application.
It actually make sense as the piston side is more likely to wear out faster, especially if they use different material between inside (more bite) and outside (low dust).
iv attached some pics. overall disc thickness iv measured with the vernier caliper is 20mm at different points so it is in spec for overall thickness. however one plate is around 7.4mm thick and the other plate is around 6.5mm thick. the plate thats caliper piston side is the thicker one.
Considering that most cars uses 1-piston calipers, being thicker on the piston side makes sense, provided that the rotors are balanced properly at the factory
Originally Posted By: WyrTwister
Never seen that either . Are you saying one side of the rotor is thicker than the other ? Wyr God bless
yes one side is thicker
Wondering it was intended to be that way or if the center line of the casting is off ? That way on both sides of the car ? Best wishes , :-)
All you guys saying you never saw this either: Have not seen many different model discs, or Saw it but didn't pay attention and did not notice. Not a huge difference but always measureable. Very common and also very common that pads do not wear evenly inner vs outer.
Thats true for my cars the inn pad thats piston side always wears more than the outer pad.
Perfectly normal to see different thicknesses. I don't know why it is done like that, but it is not a defect. On Infiniti G37 OEM/stock front rotors have outer part probably 1.5x thicker than the inner. Immediately catches your eye.
Perhaps in manufacturing they have rotor blanks that they later machine to meet specific dimensions. Maybe it's more economical to cast 5 different thicknesses, or maybe just 1, and then machine that to obtain 15 different net thicknesses. Because they have to machine them anyway.
Fit and forget. I've never seen rotors with exactly the same width both sides, and I've fitted maybe thousands. Make sure you don't just bolt them on, but check all the moving parts ans sliding surfaces are in good shape. Claud.
Looks like the lathe put a larger chamfer on one side. I put a set of slotted Callahan rotors on early this year … definitely had a thick side … probably 20% thicker …
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