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CTSmoto's custom rear rotors

4080 Views 25 Replies 9 Participants Last post by  drewpy
What do you think?

More info can be found on the MotoWizard page, but you can either buy a newly resurfaced rotor, or send in your rotor for machining.
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Gas Man said:
Well if BK, would log back on, he could tell us more about it!
Sorry guys, I've had a tough few weeks.

Here's what MotoWizard says about their process, a bit long but maybe it will answer some of your questions. I was hoping to get out there and get some miles on it this past weekend, but the blade had other plans. :(

MotoWizard said:
Warping can be an issue if they are not cut properly. Just like a piece of wood the metal has a grain. When the rotor reaches a temperature that overstressed the metal it will spring with the grain. This is warping. The biggest factor is heat.

You can warp a stock rotor if you don't change the pads at regular intervals. When braking the heat generated by the rotor is transfered to the pads until the pads are saturated with heat. The heat is wicked away by the pad mounting surface..... If you haven't noticed its copper.... and a lot of it. The copper plates on the back of the brake pads are designed to pull the heat away.

When the pads and the copper sub plates are completely saturated with heat they will radiate heat back into the rotor. This is where rotor design is a factor. First the thicker the rotor the more heat will take before it can potentially warp. This is why when we resurface we must have a minimum of 4mm of working surface when finished or you can run the risk of warping and why Galfer uses 5mm thick material to make those skinny little rotors. Second friction is the driving force of the heat. As surface area increases so does friction. By removing part of the rotor surface friction is greatly reduced. Some would say so is stopping response time. But so far this is unproven. Just look at some of the AMA guys using Galfer rotors when racing. It is possible to remove too much material and this will create hot spots that will over stress a rotor as it is cycled and can cause it to warp or even crack. This is why our designs are uniform in nature to help distribute the heat evenly through the rotor.

I have machined over 700 rotors to date and not one has warped. I do get rotors from customers that have stress fractures around all of the drilled holes. These rotor I won't touch. After machining these rotors can become very unstable. These stress fractures are caused from people not changing the brake bads until there is 1/8 of an inch of pad or less left on them. This brings me back to how the pads work. With very little pad thickness the heat generated by the rotor moves quickly through the pad and the copper plate and is radiated into the rotor surface much more quickly than with a thicker brake pad.

Long story short. Thin pads can damage even a stock rotor.

Our rotors are on average .8 to 1.2 lbs lighter than stock. This reduces rotational mass. They also run cooler and from our testing stop in a shorter distance without locking up the rear end. The only drawback so far is that they appear to use the rear pads about 15% faster than a stock rotor. The slots under pressure and heat act like a cutting surface that can shave the pads. This is actually a good thing because the pads will not glaze over. Glazed pads reflect a fraction of the heat that reduces stopping ability. Glazed pads can be sanded or if you cycle the brakes rapidly the glazing can be removed.

The front rotor we are making will at first be edge cut only. I will not be messing with designs in the stock rotors. 75 to 80% of you stopping power is with these front rotors. the custom designs will be cut into new front rotors but that will be later this summer.
Sounds to me llike they know what they are doing and have put a lot of thought into the warping dangers.
Hey Mike, good to see ya!

Welcome aboard!!!

I would encourage everyone to check out his site. Especially the "rides" section. His latest project is a beautiful CBR1000RR.

All the changes are well documented. Mike, you do beautiful work!
The comments I posted above are from Mike. :)
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