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@ EssThree, know what you mean about just buying good quality discs. Have a look at the discs on Movits site. They take what looks like a Porsche disc( same vane and hole design) and machine the integral bell off, drill 8 or 10 holes on a PCD
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I thought these used genuine Porsche discs...from a 993 Turbo, which are 2 pc rotor and bell type discs anyway.
That would explain the similarity in looks.
Rich's ECS stuff uses Porsche rotors in thier kits...
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The forces acting on this portion of the disc do not change whether there is an integral bell or an aluminium seperate one.
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You simply cannot go drilling multiple holes in a peice of metal that has been designed as a single piece disc, and expect it to be as strong.
I'm just not having it...
Over many years I've broken (cracked) many discs on the track, and there is NO WAY I would ever consider running a hacked about disc as a rotor.
I am personally very hard on brakes...and I wouldn't risk my life on a modified piece of braking equipment like that...but, each to their own.
I just don't see the need, when you can buy a safe, properly designed off the shelf product from Porsche, Brembo, AP, Alcon etc...
As for the forces...they are still there.
As you hit the brakes the rotational force is transferred into the hub via the strength of the disc.
If you drill 8 or 10 extra holes in the section of disc just inside the friction surface, and mount a bell on here...you have just added 8 - 10 weak spots...hit the brakes hard with sticky tyres and aggressive brake pads...and where do the forces go?
Through the disc and towards the hub...add high temperatures and bumps / vibration...and I wouldn't put my life on the strength of the set-up.
I would only trust a properly designed rotor for this type of application.
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Godspeed brakes have been doing this for twenty or so years. No failures or complaints.
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They have?
I'm amazed...
Their website suggests they have suitable rotors made for them...correctly disigned rotors, not machined 1pc discs.
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If its good enough for Movit, Godspeed and Hi-spec then its ok by me.
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As I said, I thought Movit used Porsche rotors designed for 2 pc applications.
I also thought this was the case with Hi-Spec..I thought they used a rotor designed for 2pc use....the facts on thier website suggest this.
What makes you think they are machined 1pc discs that they sell as rotors?
To me, it looks obvious that they are dedicated rotors.
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I understand your reservations about the strength of the disc post machining, but the strength is the same. The purpose of the integral bell is to mount and locate the rotor. Have a look at the movit discs. See what you think.
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The strength is not the same...the discs resistance to shear forces is reduced as you have drilled 8 to 10 extra holes in it, in order to mount the disc...not to mention what the heat of machining has done to the granular structure of a heat treated disc!
The purpose of the bell is indeed to locate the disc, but also to transmit force from the friction material, through the disc and into the hub / drivetrain...through 8-10 weak spots if you modify a standard 1pc disc.
The issue I have is not the use of 2pc discs...it's the modification required (and associated loss of strength) to get discs not designed at 2pc rotors to act as such.