Well, he solved the biggest issue by ensuring the trailer brakes were working. Without them, no upgrade will help. That being said, friend of mine upgraded w/one of the SSBC kits, and can haul (and stop) serious loads up & down hill easily...
My father has a 2009 GMC 2500HD with the Duramax/Allison drivetrain. He recently purchased a 30' fifth wheel with a loaded gross weight in the 17,000lb range (which the truck is rated for). He has 35k on the truck.
They recently did a 2800 mile trip to Alaska and the Yukon Territories. Prior to leaving he did a bunch of maintenance on the truck which included flushing the brake fluid and checking the rotors/pads. Unsurprisingly the pads were at 85% of new all around.
En route home, they encountered a stretch of road that had multiple 10-14% downgrades with nasty switchbacks. Even with using the truck's Tow/Haul mode and engine braking, he hit a point where the front brakes were smoking profusely at the bottom of one of the downgrades and pedal feel had seriously degraded with a pronounced wobble. After pulling over to let the brakes cool, he realized that the trailer brake controler wasn't properly set and the trailer brakes hadn't been activating as much as they should. Correcting that allowed them to complete the rest of the downgrade, and the 800+ miles home, without further drama.
After that experience he wants to ensure the brakes are fully up to severe use in the future. I've recommended he upgrade the pads to whatever severe duty option is considered to be best by other owners, and ensuring he is running a high temp brake fluid.
He's curious about cryo treated rotors. The claim is that they are less resistant to warping under extreme use. However, they are $550/pair so it's not a cheap experiment.
Does anyone have insight/experience with cryo treated rotors? If yes, are they worth the $ for severe use?
I don't think that cryo treated rotors would help much if a similar situation would occur in the future. I could see them possibly lasting a while longer, but he simply overheated his brakes. Aside from going with bigger rotors and/or calipers (bigger heat sinks), or brake venting (more efficient heat dissipation), I'm not sure what he could do.
I may be completely incorrect though.
I installed a set of Power Slot Cryo rotors on our 2009 Dodge Journey AWD R/T. The factory brake design is horrible and Dodge knows this. There has been a class action lawsuit against them for this reason and I received a settlement check from them. I would literately replace the rotors/pads every 10,000 to 15,000 miles due to excessive wear and heat (warping) issues. Part of the issue is the materials used to make the rotors. I suspect the factory and most aftermarket rotors, especially those made outside the US, use low carbon steel This makes them very soft and accelerates wear. In an effort to find high quality rotors I decided to try the cryo rotors. I can honestly say they made a huge difference in vehicle braking. Much harder/tougher wear surface. I've got about 1500 miles on them so far and they show almost no wear. Very impressed. All the brake problems I had before using Raybesto, Warner, etc brake rotors are GONE. No fade, shaking, etc. I highly recommend them for heavy duty use. They are worth the extra cost.
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There's no way they use low carbon steel. They use cast iron, just like most everyone else. Sorry, not be a dick, but I'm a metallurgist and this kind of thing irks me. They likely just chose the wrong alloy of cast iron along with pads that were too abrasive. Softer=quieter brakes usually.
And to answer the OP, I don't think that cryo treatment does much for cast iron. Its been shown to improve the wear resistance of high carbon tool steels, but it is due to a process that does not occur in cast iron. It might help relieve some residual stresses, but I haven't found any papers that gave concrete proof regarding the improved abrasive resistance of cast iron treated cryogenically.
Every set of cryo rotors I've had (on the GTI and on the SVT) have worn improperly. They were high quality rotors to begin with but for some reason they did not wear evenly and quickly became grooved and glazed. I think part of it was the Hawk pads that were kinda nasty, but as soon as I went to stock rotors and EBC pads on my SVT Focus, all was right with the world. I think you get a lot more out of high quality rotors and a good set of pads.
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geoff and msrothwell: Thanks for the input. My thinking was that any gain to be had in the stock braking system would be the typical ones--better pads and higher temp fluid rather than the cryo-treated rotors. I've used cryo-treating on internal engine parts previously, but had never heard of it being a big deal in improving rotor performance. msrothwell's explanation points to why that may be the case.
another thing could be the intensity of the "freeze" they used. theres light and heavy treatments... i believe light is only -100F compared to heavy which is in the -300F range.
The part also has to be "re-tempered" after being treated.
OP, you would be better off getting a good set of proven quality rotors and pads and finding someone to treat them for you... plenty of labs will allow you to ship the parts in.
I plan on treating all of my transmission internals, rods, etc. when i rebuild
check out www.nitrofreeze.com they provide pretty much any cryo service you can imagine.
Last edited by x_GTI_x; 09-13-2012 at 05:05 PM.