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Discussion Starter · #1 ·
Hi guys,

Since we just released our two piece rotors, I wanted to give you a close up look and a little bit of info about two piece rotors in general.

Two Piece Rotors


There are many companies out there that offer two piece rotors as upgrades for your car. So what makes a two piece rotor an upgrade?

WEIGHT
By changing the center section of the rotor from a heavy cast iron piece to a lighter material like aluminum you can remove a lot of un-sprung and rotational weight from your car. In some cases over 10 lbs per corner can be lost. Loosing rotational weight will give you a car that can accelerate and decelerate much quicker than it did before. Un-sprung weight lets the shock and spring package do more of what it was designed for, holding up the chassis.

COOLING
Most two piece rotors are going to have an upgraded iron section for better cooling efficiency than the OEM rotors. Not only that a lot of companies are adding in vanes and fins to the hats of the rotors to further help pump air to cool the rotor. The number of vanes in the rotor also matter as to how much air it can move. You can do fewer vanes and remove weight, but that typically sacrifices cooling. The aluminum hat is also going to dissipate heat quicker than the iron, which transfers less heat into the wheel bearing assembly.

KNOCK BACK, FLOATING OR FIXED
Most street customers will not notice this, but you road racers will. There is always some flex to the brake assembly, and tolerance in the parts assembled. As the loads increase you have deflection at the bearing, and this causes the entire rotor to move as well. This movement causes the pads to be pushed, and the pistons to be pushed into the bores. When you apply the brakes you must first take up the slack and push the pads back out, then the brakes start to work. This is not a comfortable feeling for a race car driver to have to pump the brake pedal going into a corner.

Base Corvette's and most production cars have a floating caliper so the caliper just slides on it's pins and moves with the rotor. The Z06, ZR1, and most aftermarket companies use a fixed caliper which is much stiffer, and more likely to see this under hard use. There are ways to stop this from happening. One is to use a good quality wheel bearing like an SKF but that is only part of the solution. The next step in the solution is going to be to float or not, your rotors.

Not all two piece rotors are going to be of a floating design and everyone uses a different method to do so. At the same point not everyone needs a floating rotor, but it does give you a more stable pedal.

What a floating hat and rotor does is allows all of the hardware to remain tight, but give a small gap between the hat and the iron so the hat can move with the bearing and the rotor spin true, even if they are not running 100% parallel with each other. This acts like a shock between the two giving you a more consistent brake pedal at the track.

There are numerous ways to do this from small bobbins, to drive flanges, to twin plates. Every company has its own trademarked floating and attachment system to do so. StopTech and Brembo use a small drive pin, or bobbin that bolts through the hat and rotor. Alcon uses a bolt on stand that the rotor slips into, sandwiching the hat but not bolting through it. PFC uses a similar design to Alcon only uses a full plate on the back side (see above figure). Most are going to have some noise to them, which typically sounds like loose coins at low speeds depending on the design. Some like Brembo and our own LG Motorsports two piece have 'anti-rattle' clips which dampen so you have a floating rotor, but no noises. Some like StopTech can be built either way fixed or floating depending on customer setup.

How we did it....

LG Motorsports two piece Rotors



Our two piece rotor is a direct replacement for the front on a Z06 or GrandSport using OEM calipers. This 32 vane rotor gives you the best of both worlds. Lighter than stock, but keeps enough 'meat' and vanes to make sure it will hold up on track.

Hardware Close up





We wanted to give you a full floating rotor without the noise of a floater so we used a drive pin design that allows for the rotor to expand and contract due to heat without running the risk of a cracked rotor or hat. We also gave it room to float as well to correct for any upright flex or slight wheel bearing tolerance. To keep it quiet on the street they also have anti-rattle clips installed.

With the rotor hat off of the rotor you can see how the hat has room to move as well around the drive pins.







The drive pins themselves are held to the rotor using high temp stainless hardware. This allows the hat to be trapped to the rotor, and move so you know you have a constant pedal at all times.

Now you can upgrade your factory brakes, remove weight, and be ready for the track with a lot less money out of pocket than doing a complete upgrade. For you street guys and occasional track day cars this will be a very nice upgrade.





If you have questions about upgrading your rotors, or your entire system let me know. I would be more than happy to assist on any specific kit you have in mind.

Our two piece front rotors are in stock now and ready to ship. We are finishing up a design for a matching rear set to go as well, which should be out later this year. These will have the same rotor and vane design with the alum. hat as you see here, and will retain the factory parking brake.
 

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huh, I had no idea there was such a thing as a floating rotor. How much float are we talking? Just a few thousandths?
 

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Discussion Starter · #3 ·
huh, I had no idea there was such a thing as a floating rotor. How much float are we talking? Just a few thousandths?
Yes sir, almost evey race will have them if nothing more than weight and just to get the two different materials not to damage each other from the intense heat.


Min. we are talking 0.010" float in them, most I have used on any of the race cars was 0.025".

It is a little odd for those that have never been around them because they feel like all of the bolts are loose. To some degree they are.
 

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Min. we are talking 0.010" float in them, most I have used on any of the race cars was 0.025".
holy smokes! :surprised

never would have thought it'd be that much. So you're saying the I shaped piece in this pic can be up to 0.025" taller than the thickness of the hat?

 

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Discussion Starter · #5 ·
holy smokes! :surprised

never would have thought it'd be that much. So you're saying the I shaped piece in this pic can be up to 0.025" taller than the thickness of the hat?

In some cases yes...not in this particular setup as the street cars are not going to need that much room.
 
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