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I need to replace the front rotors on my gti. I figure I may as well get slotted rotors. Any recommendations?
 

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I'd just get the stock rotors, the slotted ones aren't going to do anything for you besides cost more

sorry you are wrong on this one, the reason slotting is used on rotors is to help expel gases caused from the heat of breaking . basically what is happening is that the pads trap air while braking this air expands and pushes the pad away from the rotor the slotting gives these gasses a path to escape. This causes the brake pad to stay in better contact with the rotor in effect better braking. The only downside is a higher rate of pad wear caused by the slots
 

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sorry you are wrong on this one, the reason slotting is used on rotors is to help expel gases caused from the heat of breaking.
i thought newer brake pads didnt create that gas.....? :confused:

or at least not enough of it to separate the pad from the disc; unless under extreme braking conditions, e.g. racing.

normal daily driving shouldn't heat up the brakes enough to cause them to fail...
so imo, slotted/drilled aren't worth the cost of quicker pad wear, weaker discs and more expensive discs.
 

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The slotted rotors are 99% cosmetic. Hypothetically, in high heat / racing types of situations (with appropriate racing pads) you can get some pad glazing where the surface of the pad becomes slippery. The slot wipes away that glazed surface. If there were any gas trapped under the pad (pad material is porous, and doesn't sit flat on the rotor, so it's unlikely), the pushback from the tiny amount of gas would be nothing compared to the hydraulic pressure of the braking system.

The downside to the slots, as mentioned, is that you reduce the pad contact area on the rotor. Also, machining out the slots removes thermal mass, and you need the thermal mass to absorb heat in hard stops. Even those few grams count.

One plus side of the slots is that it should interrupt the higher frequency nodes, making it less likely to have high frequency squeal. The pads, backplates and calipers might still squeal, but not the rotor. But it might all be overshadowed by the grinding sound of the slots anyway.

I designed brakes for 9 years.
 

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They were a bt cheaper and more likely to be in stock at BBM... but you know, BFI ought to sell a mk1 part once a month or so, the boycott has been done for almost a year.
 
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