Shimano Aluminum disc brake rotors.

R

Retrorockit

1 kW
Joined
Feb 8, 2019
Messages
304
Location
South FL USA
OK they're Aluminum clad with Stainless steel faces, But Shimano is claiming 100*C temperature reduction with the basic version, and 140-150*C with ones featuring exposed cooling surfaces. They come in traditional sizes, and 6 bolt and Center Lock.
Thermal conductivity is 215W/mK for Aluminum, and 17W/mK for Stainless Steel so this may actually be true. Sending the heat away before it gets to the pads and calipers looks good to me.
Here is the Shimano page with the basic ICE Technolgy brake rotors. $50-$60 The graph looks like they reject heat at the same rate it's being applied.
bike.shimano.com

ICE TECHNOLOGIES | SHIMANO BIKE COMPONENT | SHIMANO BIKE-EU

To Build Closer Relationships between People, Nature, and Bicycles. We believe in the power of cycling to create a better world as we move forward. We inspire all people to enjoy our products in their everyday lives and where they take them.
bike.shimano.com bike.shimano.com
Here is the page with the high end exposed cooling fin versions. Called FREEZA. Close to $100 for big ones. Comparison chart between 4 types of rotors.
bike.shimano.com

ICE TECHNOLOGIES FREEZA | SHIMANO BIKE-EU

To Build Closer Relationships between People, Nature, and Bicycles. We believe in the power of cycling to create a better world as we move forward. We inspire all people to enjoy our products in their everyday lives and where they take them.
bike.shimano.com bike.shimano.com

I've ordered a pair of ICE rotors in 203mm and 180mm for my BBSHD to run with Avid BB7s and metallic pads with Jagwire Elite cables.
RT86 is the basic ICE rotor, RT76 is a standard SS rotor with an alloy spider. They look similar.
 
They ICE versions around $50 more or less depending on the size. I just got pair of them in today. About 28g. lightere than a similar sized 200mm Avid rotor. The Freeza ones with the exposed aluminum cooling areas are more $80-$100.
Aluminum has a thermal conductivity of 215W/mK, Stainless steel is 17W/mK. More than 10 times as much.
The instructions say don't use the 203mm with Hydraulic brakes. But I have BB7s with metallic pads. The only issue I had was I had to trim off the tab on the inner pad to clear the Aluminum spider. It would have been easier if I knew beforehand.
The linkss above didn't mention E bikes, but on the package it does, and metal or organic brake pads too.
The Shimano RT76 looks the same but isn't aluminum core. RT86 is the ICE version. These would be very good for hydraulic brakes. Getting the heat away form the caliper is a good idea.
 
I got these on the Ebike. It took a little fiddling around. On the rear the new SRAM 180mm bracket rotated the caliper forward a little compared to the 185mm Avid bracket. This required some trimming of the automotive hard line I'd installed to go from the original Vee brake down to the BB7 caliper. It actually produced a nice straight run of hard line on this bike. In the front for some reason the 203mm Shimano rotor was too large for the 203mm Avid BB7 bracket. I had to shim the caliper out 1/8" to match. They weren't completely flat but they are easy to correct. They would probably bend easily in transport or rough use if you aren't careful. I installed a set of SRAM metallic pads. I had used EBC before. The SRAM pads are quiet when bedded in. The EBC were too.
I unplugged the brake switches so I could use power to seat the pads. The only hill I have is a 3 level overpass. I went 30mph across the top and used just the rear brake to hold that speed down the other side. I felt no change in the pressure required to maintain speed. This indicates that the rotor is rejecting the heat as fast as it's being produced. The wide aluminum spider will touch things that a flat rotor wouldn't so check for rubbing here and there. I'm probably going to put these on my XC Softtail street bike too just for the weight savings and bling factor. My use is just for high speeds and flat terrain. For serious mountain road use I would step up the Freeza versions that drop tewmperature 140*C due to large exposed ares of the Aluminum core material. This added material may also stiffen up the rotor some.
This ranks right up there with Metallic pads for DIY brake upgrade. Be careful though. Some hydraulic brakes don't take well to metallic pads. These rotors may help with that problem but be sure to do some testing in a safe place if you try that. Time will tell how long they last with Metallic pads
 
nicobie said:
Strange that they would shed more heat. Any idea of what they cost?
Click to expand...
They don't really.

More. That's the point.

The most definitive factors for how much heat a brake rotor can dissipate are the swept surface area of the brake track, the total surface area of the brake track including cutouts, brake track material (not spider material), temperature gradient between rotor and air, and airspeed. So holes and slots in the brake track do help shed heat (increasing surface area and reducing mass, therefore increasing temperature gradient), but heatsink features on the carrier don't really. There's just not a very fast way for heat to migrate back through the rotor spokes to the hub. Stainless steel has low thermal conductivity for a metal, and the cross-sectional area of the spokes joining the brake track to the center of the rotor usually isn't much.
 
Aluminum only being a third as stiff as stainless steel, vulnerable to weakening from heat levels that are normal in disc brakes, plus the use of friction surfaces that have a much different coefficient of thermal expansion than the core they're attached to, suggests to me that laminated aluminum/stainless steel rotors will present reliability issues when compared to solid stainless rotors.

Ideally you don't want brake heat to soak into the center of the rotor and from there into the hub. Best if it convects and radiates out directly from the brake track into the ambient air, as long as the brake track and pads don't become so hot as to fail.
 
I just put them on my Bike and will see what actually happens. They've been around for a while and I've
heard no reports of the things you mention. They are Ebike rated parts.The high end Freeza versions dissipate heat directly to the air.
It's flat where I live. if I was running down the mountains I would step up to those. Shimano also offers these in Ulegra and Dura Ace versions. The highest level ones have black fins to radiate more heat, But these show that the spider isn't a part of that.
1687889294878.png1687889294878.png
 
Last edited:
The thermal conductivity of Aluminum is 215WmK, Stainless steel is 15Wmk. I think the alloy core will allow the heat to dissipate all the way Around the rotor better. If the rate of transfer is lower than the rate of thermal load, it will get hotter and hotter at the braking surface.
This appears to be what's happening in the first graph in the rotor section here. There are Aluminum Silicon hypereutectic alloys that have low thermal expansion. They're often used in gasoline engie pistons for dimensional stability.
bike.shimano.com

ICE TECHNOLOGIES | SHIMANO BIKE COMPONENT | SHIMANO BIKE-EU

To Build Closer Relationships between People, Nature, and Bicycles. We believe in the power of cycling to create a better world as we move forward. We inspire all people to enjoy our products in their everyday lives and where they take them.
bike.shimano.com bike.shimano.com
 
Retrorockit said:
If the rate of transfer is lower than the rate of thermal load, it will get hotter and hotter at the braking surface.
Click to expand...

And the hotter the braking surface, the faster heat can transfer to air. Until the braking surface is too hot to work correctly, hotter is better. Trying to shed heat through conduction is shedding it in the wrong direction. You want it away, not in the machine parts.

If Shimano is doing it one way and literally everybody else is doing it another way, the smart bet is Shimano is doing it wrong. If half the industry is going out of their way to do what Shimano is doing but without infringing on their patents, well that's a sign that Shimano is right.
 
I think this might be handy for dragging brakes on long descents, not for frequent starts and stops on a very heavy ebike... also, why not use copper/brass? More heat resistant, way better thermal conductivity, less thermal expansion... btw, stainless steel is indeed a bad material for brake disks and they are made this way for convinience.

If you want better braking performance, just laser cut yourself a set of custom ones, will be cheaper too I wager :)
 
Obvious;y you guys know more about bicycle brakes than Shimano. Why don't you put your money where your mouth is and make better stuff and offer it for sale? I have them on my bike and test them at 30mph dragging the rear brake going down hill. I can feel the consistency of them not getting hotter.
The Saint ICE brakes these go with are hydraulic. Sending the heat away from the caliper is a pretty good idea. Their finned brake pads do the same thing. Send it away from the brake fluid.
I agree that these would be better for long downhill runs, but I see no downside for stop and go except replacement cost which is up to the user.
E=MV squared says a 280# 35mph Ebike like mine needs to dump a bunch of heat in a hurry compared to a 20mph pedal bike, which is what most of us started out converting, or have those kind of brakes on our bikes. This is an upgrade than any bike owner can do easily.
Especially if you've converted a bike with 2 piston hydro brakes.
In another thread for a cargo bike I suggested TRP 220mm x 2.3mm solid rotors instead of these.
The reason not to use Copper or brass is because that's what the metallic brake pads are made of.
I wasn't aware this technology existed, I'm letting others know it's an option.
 
Cambria Bikes had these OEM packaged (no hardware) in 160mm for $37. I added them to my XComfort bike (2004 26" KHS Team Softtail with slicks).
cambriabike.com

Shimano RT86 6-bolt Disc Brake Rotor Only - OEM

Shimano RT86 6-bolt Disc Brake Rotor Only - OEM OEM packaging - no hardware - rotor only SM-RT86 Ice-Tec rotors give excellent performance made from a stainless steel / alloy 3-layer sandwich construction that manages heat while riding The clad steel/ alloy /steel rotor construction allows...
cambriabike.com cambriabike.com
 
If you think you need them, get them. I have a few Ice-Tech rotors, just because one of my calipers had metallic pads and would scrape up the normal rotors too much. I don't notice any difference in braking. If someone is doing long steep descents, yes they are worth trying. I have 2.4mm wide Tekro Orion rotors that do not have the center heat dissipators, and after one really steep fire road descent, the inner part of the front rotor turned black. The heat completely scorched it. Microcracks around the inner part. I thought the rotor was done for sure. 1000 miles later I'm still riding with it, it's fine. But if I did that over and over again on a hot humid summer day, maybe it would not be fine. I don't think most people here are extreme with their e-bikes but it would not hurt to get Ice-Tech level rotors. I don't think I need them again, but I'm sure others that are more maniacal offroad do need them.
 
The first Lotus Elise could also be ordered with aluminium brake rotors, and on the road they work very well.

As they began to ad more power and weight during the years they changed to steel brakes.

So if you never overheated your steel brakes, why not give aluminium a try
 
Last edited:
Chalo said:
And the hotter the braking surface, the faster heat can transfer to air. Until the braking surface is too hot to work correctly, hotter is better. Trying to shed heat through conduction is shedding it in the wrong direction. You want it away, not in the machine parts.

If Shimano is doing it one way and literally everybody else is doing it another way, the smart bet is Shimano is doing it wrong. If half the industry is going out of their way to do what Shimano is doing but without infringing on their patents, well that's a sign that Shimano is right.
Click to expand...
Hope tech also makes the same kind of floating rotor, with an aluminum spider.
 
richj8990 said:
If you think you need them, get them. I have a few Ice-Tech rotors, just because one of my calipers had metallic pads and would scrape up the normal rotors too much. I don't notice any difference in braking. If someone is doing long steep descents, yes they are worth trying. I have 2.4mm wide Tekro Orion rotors that do not have the center heat dissipators, and after one really steep fire road descent, the inner part of the front rotor turned black. The heat completely scorched it. Microcracks around the inner part. I thought the rotor was done for sure. 1000 miles later I'm still riding with it, it's fine. But if I did that over and over again on a hot humid summer day, maybe it would not be fine. I don't think most people here are extreme with their e-bikes but it would not hurt to get Ice-Tech level rotors. I don't think I need them again, but I'm sure others that are more maniacal offroad do need them.
Click to expand...
I just bought a "cheap" RT66 fixed rotor from shimano for 30 bucks. I hope your right. I had the ice tech rotor before and put hard hard use on it for many years. IT lasted for about two years. I am kind of over ebikes at this point and am trying to get an electric motorcycle or even just a motorcycle honestly. And even if I was going to spend a ton of money on a rotor I would buy 203mm ones and a new fork to slap them onto. But I don't have any cash right now. I am saving for surgery, and a bunch of other stuff.

I REALLY HOPE MY CALIPERS dont SEIZE up from heat. I had a pair of crappy shimano hydros seize up. I still don't have any idea how that happened. I've had good luck with my hope tech 3 v4 brake. It hasn't let me down. It's a MASSIVE 4 POT caliper. But I just hope this rotor doesn't f it up by letting it get too hot. i am pretty worried about it.

They crappiest part about disc brakes is they get bent so easy, from idiots. Like people putting their bikes into racks carelessly, the pricks. I also bent an expensive rotor from hitting a car, tacoed the whole front wheel. Rotor was bent too, I've been listening to that tick tick tick for two years. TOday is the day I change it. today is the day
 
MarkJohnston said:
They crappiest part about disc brakes is they get bent so easy, from idiots. Like people putting their bikes into racks carelessly, the pricks.
Click to expand...

That's a whole lot less about them and a whole lot more about you using equipment that isn't fit for your specific purpose. For city bikes that get parked in public a lot? Sturdy rims with lots of spokes, with rim brakes, drum brakes, or coaster brake (roller brake, band brake, etc.) Or you just be careful about how you lock up, and accept the consequences.

If you hang your fragile stuff out in harm's way, sooner or later it will get harmed.
 
Chalo said:
That's a whole lot less about them and a whole lot more about you using equipment that isn't fit for your specific purpose. For city bikes that get parked in public a lot? Sturdy rims with lots of spokes, with rim brakes, drum brakes, or coaster brake (roller brake, band brake, etc.) Or you just be careful about how you lock up, and accept the consequences.

If you hang your fragile stuff out in harm's way, sooner or later it will get harmed.
Click to expand...
It's not my fault that every city in America has an army of methheads and crack heads on the street. I shouldn't have to deal with people constantly trying to jack accessories and parts off my bike all the time.
 
You must log in or register to reply here.
Back
Top