Jambo - you blew my last theory on this out of the water. Hope brakes? Sintered?
Harry - ta muchly
Bike Forum
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HELP! *disc brakes are shite content*
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Posted 3 years ago #
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i use magura pads and do what magura tell me to regards bedding in.
they last for ages, regardless of conditions and i brake like a mincing tart all the time.Posted 3 years ago # -
Hi TJ.
Interesting, and I'm sure this may have some validity in clean conditions where most car brakes would work.
Do your articles suggest what happens to "adherant friction" when samples in question are sprayed with wet sand throughout their lifetime?Posted 3 years ago # -
Oh, and TJ. On the few occasions I go road biking with my family I do a lot of hard downhill braking (trailer bike in tow). Brakes thereafter do feel smoother - like indeed the friction material has worn to a gloss, they also often begin to squeal after these rides which they never normally do, indicating something has altered.
I'm sure pads like this would last me a long time if I could keep this up. (Is this your Adherent stuff?)
It doesn't last. First rainstorm on Surrey sand, and it's straight back to grinding pad demolition
Posted 3 years ago # -
Mountaincarrot - I believe but have no proof that its when the adherant friction no longer occurs because the boundary layer has worn faster than it is replenished that the excessive wear occurs.
One turn of the wheel will clean the disc of grit if the design of the disc and calliper is suitable.
There is some other factor here or some complex interplay of factors that is not fully known for sure. I ride my bikes in all sorts of conditions and get thousands of miles out of pads. The last set I changed on the tandem were above half thickness after well over a thousand miles. Now on the tandem the brakes get worked really hard - enough to smell hot and blue the discs. They had been in mud up to the axles many times - and sometimes gritty mud as well. Used hard in the quantocks on a filthy wet weekend where the folk I was riding with said they get rapid wear - no measureable wear. ( I measured them)
The description you give is of glazed pads - not the same thing. Glossy pads that squeal are glazed. Properly bedding in pads are a sort of matt / satin finish and don't squeal.
I don't pretend I know all the answers to this but I have read widely about it and have asked manufacturers and experienced mechanics about it.
some pads are formulated to give differing amounts of adherent and abrasive friction, this will also alter in different conditions and at different temperatures. Hopes seem to give long life for sure.
Posted 3 years ago # -
I'm with Jerry, i get 1000's of miles out of mine, i run Avid sintered in Juicys, and i love nothing more than a soaking wet ride right across the peak district. I live in sheffield for chrissakes how can i not be getting that good grit dust.
if you don't bed them in, they don't last. period.
Posted 3 years ago # -
OH MY GOD
Posted 3 years ago # -
Where as I get maybe 2 or 3 Peaks rides to a set of sintered Juicy pads in the winter, bedded in or not.
Posted 3 years ago # -
And between sq225917 and JonEdwards lies the conundrum. Same brakes, same conditions, both swear they have bedded them in, 100 fold difference in wear rates.
*scratches head*
Are you sure you are getting them bedded in properly Jon? Really really hot by braking hard a significant number of times? You need to get the pad to several hundred degrees C.
Posted 3 years ago # -
TJ is happy with his beliefs so I'll leave him to it.
In my experience riding conditions and make of pad play a much bigger part in pad life than any bedding-in mumbo jumbo (bedding in car pads is a completely different kettle of fish, the temperatures and pressures are in a different league). I'm getting very good results at the moment with M975 XTR's and Hope sawtooth floating rotors, I'm not sure if its the pad material (Shimano claim 50% longer lasting) of the larger holes in the Hope discs clearing the grit away from the braking surface faster.Posted 3 years ago # -
No need to be so patronising Dibbs. I follow the evidence and the advice from the manufacturers. but I'm sure you know better.
For what it is worth the temps are very similar as are the pressures.
Posted 3 years ago #
Topic Closed
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