It is a fair bet that virtually all drilled rotors will crack.  Eventually the cracks connect and the discs are done.  The process of drilling rotors introduces starting points for fracture.  Most manufacturers will attempt to alleviate this somewhat by chamfering the holes to relieve the stress.  This only works a little.

Porsche took it a step further and cast the discs with the holes in to have the metal formed around the hole rather than creating the stress risers.  It works better but still ends up with the same issue.

The original reason for drilling rotors was to allow gasses (hot air, lol) to escape from organic pads for better braking.  With modern compounds there is no outgassing so no need for the holes.  A slotted rotor is a much better design.  It allows shedding of water, pad waste, etc.. through the slot without causing stress in the rotor and dangerous cracking.

I hear you, Dave.  That's a perty rotor you have there!  

I don't think our bikes have enough braking power to crack a rotor.  And motorcycles have naturally ventilated brake rotors so heat disappation is good regardless of the type of rotor.

I'm not sure anybody can honestly say that their drilled rotors have better stopping power than smooth rotors on our bike.

The rumor I heard is that when pads get hot they outgas......and that gas can create a bit of pressure that pushes the pads away from the rotor.....the amount of braking is therefore reduced somewhat.

Drilling and slotting is supposed to provide a way for that gas to escape.  I suppose it could also provide a bit more cooling as air can move around in the holes.

verslagen1 wrote on 03/26/24 at 16:40:26:



Mine does not squeal.

Forgot to mention that my front brake is not stock, I’ve got the upgraded system.

A nice quality braided S/S brake hose helps firm up the lever. But if you want brakes get Shawn’s big brake kit , it’s a two finger grabber that will not disappoint. All brake rotors should be drilled for cooling , cooling helps minimize the effects out gassing.

Thats something I never see is a rating on the edge of the lining  , like on automotive brakes. Auto brakes have a coefficient rating on them “AA” to I think “HH” is the highest but not sure. First letter is cold coefficient rating and second letter is hot coefficient rating. So you can see what you’re buying. You might find “EF” rating too letters not always the same. A would be a low rating as far as temperature & coefficient rating , so. Helps you pick a suitable brake pad for type of vehicle,type of driving,load , etc. On a motorcycle it’s a crap shoot what your getting !

Ruttly wrote on 03/28/24 at 09:50:08:


Yep, and the set of $40 EBC pads (made in China) are probably made on the same manufacturing line as the no-name $15 pads.  I’m not bashing China here.  I’ve gotten many good parts made in China.  They actually know bikes pretty well with bikes being a primary mode of transportation over there.  Heck, even all KTM smaller displacement motors are made by CFMOTO in China, and CFMOTO makes the entire KTM bike for the Chinese market.