When to replace Stoptech rotors

[ShadowBolt]

Mine will be either two or three years old at TWS. They look the same as they did after three events.

JJ

[dtanker65]

That is impressive life. Brakes are the biggest issue I am having on my SI car. I am braking more than I need to (I 'm working on that), but I have had a lot of glazing issues. I have improved the cooling which has helped some. The first set of rotors were Brembo plain rotors which are expensive but lasted pretty well even though they fracked early. The cheap auto parts rotors glaze and frack on the first set of pads. I have been having the rotors turned to put on with new pads, but pads and rotors are still glazing. Any recommendations? I can only use Brembo brakes pre rules and the car is 3500#. I read a good article from a nascar team recommending hand grinding the rotors and sanding the pads between races, but I don't see anybody else doing that.

[marshall_mosty]

I've gone 5 seasons on a set of stoptech rings..

I purchased the kit used in 2007 and ran those rings until NOLA last year (May, 2014). I had a few lighter seasons, so would consider a full 5 seasons (25'ish events).

One of the rings got a "thru and thru" crack. The other was fine, but I wanted them the same "age".

They last like the original RA1's... ha.

[ShadowBolt]

i've gone 5 seasons on a set of stoptech rings..

wow!

[Casey_SS]

I got 3 seasons out of my Stoptech rings. I'm replacing them now because they have some cracks which go over the top edge of the rotor. One of the cracks made it all the way into the vanes in the middle of the rotor...that one goes in the trash. The thin spider-webby surface cracks are normal though and mine have been there a long time (2+ seasons). I watch for the cracks to get to the edge of the rotor face - when they start to wrap over the edge, it's time for new rings.

[ShadowBolt]

I got 3 seasons out of my Stoptech rings. I'm replacing them now because they have some cracks which go over the top edge of the rotor. One of the cracks made it all the way into the vanes in the middle of the rotor...that one goes in the trash. The thin spider-webby surface cracks are normal though and mine have been there a long time (2+ seasons). I watch for the cracks to get to the edge of the rotor face - when they start to wrap over the edge, it's time for new rings.
Thanks for the info. I will look closer.

Jerry

[dtanker65]

Thanks for the info guy's sounds like better metal is worth it. Do you have a limit to run the pads to keep from hurting the rotors?

Dennis

[ShadowBolt]

Thanks for the info guy's sounds like better metal is worth it. Do you have a limit to run the pads to keep from hurting the rotors?

Dennis

I run them down to about 1/8" thick.

JJ

[Casey_SS]

I run them down to about 1/8" thick.

Same here. On the Stoptech pad shape, there's a vertical split down the center of the pad. When it wears to the point the split is no longer visible, there's exactly 1/8" of material left and I try to stay at or above that point. Hurting the rotor is a mild concern but the bigger one for me is the increased heat transfer through the pads to the calipers and fluid. Nothing dramatic really happens, I've just noticed the pedal feel and braking performance get more inconsistent when the pads are too thin. It's still drive-able but it's not confidence inspiring.

The other issue is they wear MUCH faster at the end of their life than the beginning...it can be tough to gauge. I went out for a race once (ECR...of course) with what I thought was enough pad for 2 races and came back in on the backing plates, shooting sparks from what I was told. Car didn't stop so good and it smelled kinda funny but some fresh pads and a quick bleed later and everything was fine. Stoptech makes a pretty tough set of brakes.

[dtanker65]

Thanks Casey. I have a friend with a Bondurant S95 car and he said the Stoptech's dropped seconds off of his lap times. Are you going to TWS?

Dennis

[Casey_SS]

Yes, I'll be at TWS. :)

[ShadowBolt]

B
Thanks Casey. I have a friend with a Bondurant S95 car and he said the Stoptech's dropped seconds off of his lap times. Are you going to TWS?

Dennis

If that is true he had bad brakes in the first place. Stoptech' feel great but they will not take seconds off you lap times.

JJ

[dtanker65]

B

If that is true he had bad brakes in the first place. Stoptech' feel great but they will not take seconds off you lap times.

JJI think it was a big brake upgrade from stock. I have Stoptech rotors on order. I did notice the Stoptech rotors are left/right specific as opposed to the stock replacements. Hopefully the vane design will generate low pressure at the inlets. I have debated trying to make a soft seal between the cooling duct backing plate and the rotor to increase the air pressure at the inlets, but I am not sure what the airflow pattern through rotor looks like or how much excess air flow bypassing the rotor inlets to the caliper/pads is good.

[GlennCMC70]

I feel I was faster on OEM brakes.

[marshall_mosty]

I feel I was faster on OEM brakes.

Then don't use the brakes as much and you won't slow down...

[dtanker65]

Then don't use the brakes as much and you won't slow down...

The Miataheads I have been hanging around with are considering removing the brakes to save weight.

[JMR81]

How about the type of pads being used. Jack's preference is either the Cobalt or PFC. Does not like the Hawk pads we have tried. Our rotors have either been the the stock one that were on the car when we bought it or generic NAPA ones put on prior to Road Atlanta. We haven't experienced the glazing problem Dennis has described.

[GlennCMC70]

Then don't use the brakes as much and you won't slow down...

I question your engineer degree.........
I still have an increase in rotational mass.

[marshall_mosty]

I question your engineer degree.........
I still have an increase in rotational mass.

Going from 12" to 13", yes, but the total increase of inertia on the rotor/wheel/tire combination is minimal.

In fact, the increased inertia will allow you to carry more speed without your aero drag slowing you down...