|Brake pad break-in 101 |
|Description Brake pad break-in 101
Author Matthew Date Sat Sep 05, 2009 12:22 am Type Tech Article
Category Tech Tips
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Mar 19 2007, 08:33 PM
I recently attained this information from a respectable source who would like to remain anonymous, for obvious reasons, as brake-
related advice can translate to liability. Please spare the identity guesses, at least in writing.
Also, use some good sense (I didn't say common, as I feel that's a contradiction in terms) if you decide to utilize these suggestions on your own vehicle. It is bike-related, but not bike-specific.
I do not do anything to the brake rotors on anything unless they might be severely scored or grooved. There really is no need to do any surface treatment. The most important thing is to properly bed the new pads in on the rotors. Anytime new brake components are installed the mating parts do not mate very well, as you can imagine. So, the braking occurs on a very small amount of the available area of the pad/rotor surface. Hard braking at this point can easily overheat the brake contact patch (the relatively small, local areas of contact) and permanently damage or degrade the brake capability. You want to avoid severe braking with new parts until they are bedded in. The old wives tale of going out and doing some "panic" stops from 80 is NOT what is recommended to bed new brake parts. Find a deserted stretch of road and accelerate to 35 or 40 and then do a firm, rapid stop. Don't stop completely and sit with the pads stationary on the rotor, just brake hard to about a 95% stop, roll out and re-accelerate to 35-40. Stop again the same way. Do 10-12 hard stops from 35-40 like this. Then ride off and ride at speed to cool everything down. When cool, repeat the 10-12 hard stop routine. Cool down again. Consider the brakes "burnished" and do what you want with them. It is important to bed them like this to mate the parts together, optimize the contact patch between the pads and rotors, get the parts up to high temp to clean off any volatiles from the manufacturing or handling process and to transfer a bit of the pad material to the rotor surface for optimum friction characteristics. The stops should be hard but not panic and not hard enough to activate the ABS. Just a good, firm, hard stop to generate heat in the brakes. Braking from only 35-40 will minimize the amount of heat to prevent damage but you should be able to get them pretty warm and some smoke is usually evident after the 10th or 12th stop.
It is much better for the brakes to bed them in purposefully like this than to just ride and do it with various gentle stops as the temp will not be there and it will take much longer......and you risk damaging the brakes without even knowing it with a panic stop in an unforeseen emergency in the meantime. Even brand new parts fresh from the box need to get this bedding process before any further work is done. It just takes the unknown out of the brake break-in performance.
You don't want to come to a hard stop each time during the bed-in and sit with the pads held against the rotors as that will cause non- uniform pad material transfer to the rotors and potential heat damage, since the hot pad will insulate the hot rotor in that spot and uneven cooling will result. Just roll out the stop each time and accelerate back to speed for the next one.
35-40 mph stops are pretty conservative for a motorcycle. I use 50 mph stops to bed my motorcycle brakes since I pretty much know what sort of heat and smoke and smell I am expecting. Try 35-40 to get the hang of the schedule and then step up the speed a bit if the brakes don't seem to get very hot after 8 or 10 stops and/or just do 15 or 16 stops instead at 35-40 to build more temp. You want to build the temp in a controlled fashion without overheating anything with a single hard stop from higher speeds.
This sort of procedure is not the sort of thing you want to tell "everyone" to do for obvious reasons regarding liability and traffic laws. So, be careful and do it in a safe, controlled space. That is why you don't get this story very often and why vehicles come with a "recommended break-in schedule". It isn't for the engine nearly as much as for the brakes. If you take off slow with a sense of taking it easy to "break in" the engine then you will inherently take it easy on the brakes so it is sort of an underhanded way of mandating a customer brake burnish schedule.