Joined Oct 2017
88 Posts | 8+
japan
Hey guys,
My bike unfortunately suffers from the super spongy brakes that some owners have complained about. It has the double pump, where you pull the lever in and it feels like no pressure. Then on the second pump it kicks in. No matter how many times you bleed the system, grease pistons, replace master cylinders under warranty etc nothing seemed to help. They go back to being spongy after awhile. One owner said the problems went away after he replaced the calipers and master.
Another forum member mentioned that there was a manufacturing defect and after much research some have found that the piston seals were to blame. One or more of the pistons were sticking due to a defect in the seals causing the pistons to come out unevenly and sucking air in. I tested this theory myself, taking the calipers off and squeezing the pistons out and 1 was sticking pretty bad. I took out the pistons greased them and the seals. The problem went away for awhile but spongy brakes eventually came back. And I don't like that initial super grabby bite the stock calipers have that drive the forks down into the ground. Time to replace.
I would like a more strong progressive feel at the lever. I'm wondering if I can achieve this with the RCS 19 and M4s. Or spending the extra $ on the M50s is the way to go. The M4s are 440Euros and come in Anodized Black which I'm partial too and the M50s are 530euros. Ive read on other forums that most preferred the feel of the M50s+rcs17 combo. I believe the M50s are a little lighter also? But couldn't find any info on how the M4's feel.
Any ideas?
My bike unfortunately suffers from the super spongy brakes that some owners have complained about. It has the double pump, where you pull the lever in and it feels like no pressure. Then on the second pump it kicks in. No matter how many times you bleed the system, grease pistons, replace master cylinders under warranty etc nothing seemed to help. They go back to being spongy after awhile. One owner said the problems went away after he replaced the calipers and master.
Another forum member mentioned that there was a manufacturing defect and after much research some have found that the piston seals were to blame. One or more of the pistons were sticking due to a defect in the seals causing the pistons to come out unevenly and sucking air in. I tested this theory myself, taking the calipers off and squeezing the pistons out and 1 was sticking pretty bad. I took out the pistons greased them and the seals. The problem went away for awhile but spongy brakes eventually came back. And I don't like that initial super grabby bite the stock calipers have that drive the forks down into the ground. Time to replace.
I would like a more strong progressive feel at the lever. I'm wondering if I can achieve this with the RCS 19 and M4s. Or spending the extra $ on the M50s is the way to go. The M4s are 440Euros and come in Anodized Black which I'm partial too and the M50s are 530euros. Ive read on other forums that most preferred the feel of the M50s+rcs17 combo. I believe the M50s are a little lighter also? But couldn't find any info on how the M4's feel.
Any ideas?
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