i seem to have a gift for this
iv,e gone down the path of big hill loads of braking to bed them in but to no avail.
think i read somewhere about the use of water doing this.
can anyone shed any light.
Bike Forum
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Natural gift for glazing pads
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Posted 1 year ago #
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tbh i swear new pads never have that awesome bite for very long....
cleaned discs and pads with disc brake cleaner.....
and also sanded.....
and its lost its bite.
im pretty sure my brakes always feel better after pulsing the brakes rather than dragging them.
what pads are you using?
Posted 1 year ago # -
used a few kinds sintered/organic and now got kevlar on both bikes
just about to bed a new set in so just wanted some spot on advice first before i glaze another set.lolPosted 1 year ago # -
Don't bed them in too much.
I found a local hill and went crazy with the bedding in, 3-4 times sprinting 100m down a 15% gradient road coming to a hard stop but not dead stop then splashing with water at the bottom, and they never felt on top form. This time I did two short runs of 50m down 10% gradient with no water and they've got crazy good bite. Superstar kevlar btw.Shouldn't matter much but, for curiosity - your weight, bike, brakes and terrain you ride?
I'm only about 12 stone with kit on hope m4's so they never get too much of a work out.
Posted 1 year ago # -
just go ride them in the mud
Posted 1 year ago # -
db100 about 11 st,spicy516,trance X1,hayes stroker trail and ride as crazy as i can get away with
Posted 1 year ago # -
Do not use water on them -
Bedding in is 3 things, conforming the pad to the disc,curing the pad under heat and pressure and smearing a thin layer of pad material on the disc
You need to get them hot hundreds of degrees hot then use them hard when hot.
So I drag them while pedalling to get the heat then stop hard - repeat afew times until you can feel the characteristics change
Posted 1 year ago # -
My seals had gone in my callipers - I though I was glazing pads or whatever, turns out my callipers were spraying the discs with a fine mist of brake oil.
Change callipers.
Posted 1 year ago # -
So I drag them while pedalling to get the heat then stop hard - repeat a few times until you can feel the characteristics change
or just learn to use your brakes properly.Posted 1 year ago # -
Do not use water on them...
Absolutely no reason why not. How do you think cooling would help the bedding in process?
Posted 1 year ago # -
I think TJ's theory is supported by reading I've done on this topic where any (and there is little) research has been done - Predominantly in automotive circles, but I can't see any fundamental differences between the processes in auto brakes and mtb brakes (other than disc material, which is really a kind of substrate for deposition of pad material in a 'correctly working' brake.
The idea is to cure the pads initially under pressure and heat to allow them to deposit a micons thick layer of pad material on the disc and allow the pads to mate fully with the disc surface. This facilitates adhesive friction between the two layers of pad material
After that, during continued use the pads need to get adequately hot to renew/topup the layer of pad material on the disc. Otherwise the layer of material on the disc gets removed and you're relying on abraisive friction - generally a weaker friction force and much more erosive on materials (both disc and pads).
This is why bedded in pads can feel great to start with and get worse with use if they never get hot enough again.
Sound familiar? Rear disc brakes in the dead of winter any one? Pads disappearing in one ride because they're not getting hot enough to get past the abraisive wear/friction stage?
The inference is that disc brakes need to be run hot hot enough to continue the pad material transfer process, but not so hot that they boil and fade.
This would suggest that many of us are running discs too large that don't get hot enough, often enough after our initial efforts at bedding pads in.
Glazed pads (if they are actually glazed) are a function of this, but are effectivly being polished shiny due to the inadequate force and heat being put into them.
They're either not getting hot enough for long enough, or are contaminated.
Posted 1 year ago # -
Scienceofficer-now thats the kind on answer i was looking for
Posted 1 year ago # -
Brakes feel awesome now! Did 30 miles around afan!!! Although I'm pretty sure I didn't do much dragging at all. Just trying not to fall off the trail and prove that a well sorted hardtail is win for me!
Posted 1 year ago # -
I put mine in the oven.
Posted 1 year ago # -
Oven is what 250deg and full of oil from all your cooking.
Disk brakes ~800degC and no oil.
Putting them in the oven is probably worse than counter productive, they'll have been hotter than that during the sintering process when they were made.
Odly it's my front brake that feels 'off' first, not figured that out yet. I'm trying the TJ school of thought and running tiny rotors (160/140 f/r) to keep them hot and 'bedded in' over the winter. The downside is despite being carefull with braking I can boil fluid riding arround Swinley/Tunnel Hill/PorridgePots (which arent exactly alpine!) if I'm following someone (who's folowing someone, who's folowing someone) and having to check my speed more often.
Posted 1 year ago # -
What do you wash your bike with? I made the mistake of using automotice wash'n wax once, once only...the residue on the discs rapidly glazed the pads.
Posted 1 year ago # -
TINAS
interesting experiment
am surprised yuo can overcook little discs but good datum
think 800C is a bit much but if they don't hit a few hundred degrees C then they ain't getting hot enough to work properly
teh tandem when the pads last for ever really puts a lot of energy into the brakes ad the whole set up gets very hot.
Posted 1 year ago # -
The "sweet spot" range for the ceramic brakes used in F1, and in high end performance cars, is near 1000 ºC - less than that and they simply lack effectiveness, so while the materials are likely different the technology is not a hundred miles away. The pad contact area is very small, but proportionally is going to be closer to a car than you think, I think so several hundred degrees doesn't sound far off.
How long before the best brakes have a thermocouple in them with a reading for optimum temperature on the handlebars?
Posted 1 year ago # -
I have had a mix of smoke and steam from hot muddy brakes on the tandem and blue discs from the heat.
Posted 1 year ago # -
My bedding in takes about 5 minutes, ride up a moderate hill and then ride back down and brake to a stop three times whilst still pedalling. Repeat once with three more stops and by then, they have normally got nice and hot, and there is a definite improvement in power and feel.
I've never noticed my brakes 'go off' but they are single pot 180/160's on the full susser and 160/140 on the hardtail so probably generate enough heat during use.
Posted 1 year ago # -
ceramic brakes aren't used in F1? They are constructed from compacted layers of carbon. The guy I used to deal With from Carbon Industries a French F1 brake supplier made himself some carbon disc and pads for his specialized, his riding was mainly in the alps but he claimed they worked well, from the pics he showed me they looked the bollox! This is not in the slightest bit helpful to you just thought it was an interesting if not rather expensive idea!
Posted 1 year ago # -
Hahah.
so i guess we won,t see Hope carbon brakes in the near future then.
probably cost about a million dollars Posted 1 year ago # -
Best way to bed pads in is just done on a flat road. Bring the bike up to speed quickly, then perform an emergency stop. Repeat 4-5 times. This should help bed them in nicely. Scienceofficer has pretty much filled in all the gaps.
Posted 1 year ago # -
ceramic brakes aren't used in F1? They are constructed from compacted layers of carbon.
It varies - they have used all sorts of different designs, and given that they also have a minium weight limit, sometimes it's not disadvantageous to go with a more robust setup - carbon ones are great, but as most people ay have seen on brake-abuse tracks, they can fail quite spectacularly.
The last time I was at Red Bull's factory I saw all manner of different combinations, but they all had the same basic issue: you need to get them hot and keep them that way, but not overcook them.
Posted 1 year ago # -
arghh,not this toast yer brakes thing again!
Read or find out what bedding in process for the brakes you have,THEN follow it.Not all brakes need heated up and braked hard to bed them in. Some require a gentle process.
why are folk referring to automotive procedures? Do formula take heed of AP`s bedding in process for a british touring car pad and disc combo?! NO!
Posted 1 year ago # -
And has been said - don't use rotors that are too big to properly generate heat (ie save the 203s for the trip to the Alps)
Posted 1 year ago #
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