Re: Disc's without power

cyclintom <cyclintom@yahoo.com> wrote:

On Fri May 2 14:08:13 2025 AMuzi  wrote:

On 5/2/2025 12:45 PM, cyclintom wrote:

 
Since this is nothing more than a guess on my part I would only be
willing to bet if you hsd an alternate answer other that "not that".

 
I had another answer, yesterday.
 
Symptoms from your 28 April original post:
 
"no power" is most probably air in the system.
 
"noisy" is more probably contaminated brake pads than
anything else.
 
Those are the two most common bicycle disc brake problems as
I noted. You cited both symptoms.
 
Had you said, "I cannot properly align and center the
caliper to the disc."  (which you did not write) I would
have suspected poor technique first and defective frame prep
as a very distant, highly unlikely, second possibility.

 
 
 
 
I'm afraid I don't follow you. The brakes were finally bled p;roperly
when I did not follow Shimanos instructions but those in a video
suggestining that you had to bleed them from top to bottom rather than
bottom to top as Shimano says. Once I did that they bled fine.

Lack of power suggests that it’s not been done correctly.

 
The brakes are noisy because braking is so bad that slowing down takes so much distance.

Not in my experience even if one has to brake hard disks aren’t
particularly noisy, they are noisy when contaminated or sometimes briefly
with a bit of muck on the rota.

 
You showed several rear dropout castings that all had the same unmachined
brake attachment surfaces and you say that all of the symptoms I said
from the frameset being sold for a quarter of the going price to the
surfaces not appearing to have been machined flat to Park Tool making
special tools to correct such problems are "highly unlikely".
 
I would agree that missing the machining process on a top end bike is
unlikely but inasmuch as the symptoms prrtty much point to a mistake like
that I would hardly call it highly unlikely
 

This is unlikely to be the cause! And even a misaligned calliper would have
plenty of power.

Roger Merriman