| Author | Message | ||
     Old_mil |
Symptom: The front brake pulses. The more brake you apply, the higher speed you apply it at, the worse the pulsing. Solution: New rotor? If so, which American Sport Bike rotor should I go with? OEM replacement? Wave? | ||
| Blake |
Clean disk and pads. Check pads for even wear. Some pads can leave deposits on the disk that can produce the pulsing you describe. Such deposits often leave the disk with a mottled or blotchy finish. I run the EBC steel rotor and like it a lot.  | ||
| Buellistic |
Run a IRON ROTOR which will rust, BUT WILL COOL BETTER !!! | ||
| Chasespeed |
If you are gonna go the new rotor route...go with a wave... Chase | ||
| Djkaplan |
I just got an OEM from Al. It was cheap... inexpensive, I mean. | ||
| Al_lighton |
"Run a IRON ROTOR which will rust, BUT WILL COOL BETTER !!!" I can't think of why this could possibly be true. There may be some other reasons why running an iron rotor may be a good idea, though for the street, I wouldn't agree with most of them. But cooling isn't one of them. | ||
| Blake |
The EVC rotor I mentioned is not stainless steel, but it is not a pure iron piece either. It works great. Track tested and all. ![: ]](http://www.badweatherbikers.com/buell/clipart/proud.gif) Nothing wrong with the OEM rotor either. The steel EBC steel rotor does seem to provide improved bite. | ||
| Blake |
Al, Maybe the emissivity of iron is superior to that of stainless steel? | ||
| Knickers |
I too had a pulsing front rotor on my S3. I bought the EBC rotor from American Sport Bike and replaced pads with stock. After several track days the surface has become mottled or "hot-spotted" indicating some pretty high temps, but no pulsing. So far so good. Kurt | ||
| Blake |
I'm pretty darn sure that the mottled finish is due to deposits from the pads, not heating. | ||
| Natexlh1000 |
Cast iron can take heat without warping more than many other types of metal. I once ran my old cutlass 4.3 V8 out of coolant from Worcester to my parents' home. It overheated so badly that it discolored the sparkplugs and wouldn shut off. The aftermath: 8 new plugs, oilchange, BURNT rocker gaskets, MELTED PCV. It has 179,000 miles on it and it STILL didn't burn oil after that! But I digress..... I would stick with stainless. My first disk warped at 5000 miles and was replaced under warrantee. No brake problems since then. (62,000 miles) | ||
| Al_lighton |
"Maybe the emissivity of iron is superior to that of stainless steel?" Maybe...but I'd bet that if true, the difference is tiny. I think that the emissivity has more to do with color and finish at the temperatures that we're talking here, and I'd bet there isn't much difference there. Now, how the material deals with the heat that is there, and what the transient response to the energy input is, I'd believe that stuff. But cools better overall? I dunno, I'd have to see hard data on that before I'd buy it. Al | ||
| Djkaplan |
I looked up the emissivity of polished iron but couldn't find a steel alloy to compare it to. I always thought iron had a higher friction coefficient than steel alloys at high temps, that's why it was supposed to be better. | ||
| Bluzm2 |
Have Al set you up with a set of more aggressive pads first before you replace the rotor. They may remove the pad deposits and get rid of the pulsing. Less than half the cost of a new rotor and much easier to try then to R&R the rotor. Brad | ||
| Jack_fe |
You haven't mentioned which rotor you're running - if stock it's iron most likely. Ductile iron rotors have the best co-efficient of friction - they wont work with "metallic" pads" - they don't need them. I replaced the rotor on my '97 S3 because the rivets became very loose and it rattled when not in use. EBC rotor I used has less "sensitivity", requires slightly more pressure on the lever, but seems to have the same "stopping power" pulsing usually indicates a warped rotor The rotor bolts are "locktited" - heat the tops of them with a small torch before trying to remove - this will "release" the thread locker stuff - otherwise you'll round out the allen heads and have a royal PIA getting them out Ride Safe, Jack | ||
| Firemanjim |
Try taking out your pads and swapping them around so they are wearing in the opposite direction.Been known to cure some pulsing. | ||
| Sloppy |
There are so many different types of iron and stainless that it's hard to compare the two unless you know the grade (and finish) of both of them. In "general", though, iron outperforms stainless due to iron's improved heat transfer ability. Iron rotors are able to transfer heat faster than stainless steel, i.e., it takes heat away from the tpads faster AND it dissipates the rotor heat faster to the air. Both have similar densities, heat capacities and emmissivities (finish dependent). Jack has a good point as well - much depends on what pads you like to use. If you ride alot, then I'd recommend iron rotors. If you're a seasonal rider, I'd recommend stainless. To check for warped rotors, spin the tire and make a vertical reference mark on your forks with wire and a zip tie... find the high point in the "wave" and take a measurement with calipers. Better yet, go to your local hardware store and buy a dial indicator for $50, then you'll know for sure if you have to buy a $300 rotor... |
