- This topic has 116 replies, 48 voices, and was last updated 12 years ago by TandemJeremy.
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bedding in pads – is this bollox?
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BadlyWiredDogFull Member
For something like the puffer, I’d suggest getting a number of sets of spare pads (all same make as ones in the brake already if poss) and go through the bedding in process with each set before you need to use them in anger.
And so the whole thread goes full circle, wearing out its pads as it goes… TJ, come and ride your bedded-in resin pads in the Peak for a few hours on a sopping wet winter’s day and then see how your melted cheese looks 😉
ps: I think anyone who rides with pads made from cheese deserves everything they get. That’s just fantasy surely. Even the hardest cheese isn’t going to be as durable as even resin pads. Dangerous advice imho.
TandemJeremyFree MemberBWD – done it with no wear thank you but sintered pads- and other places where people get excessive wear. 9laps at the puffer less than one set of pads, others were going thru a set every 2 laps.
Its a whole multifactorial conundrum – two people can use the same pads in the same conditions and get vastly different wear rates.
twinklydaveFull Memberoooh, my name’s mentioned
yay me
I’ve been bedding in pads on the turbo trainer by pedaling with the rear brake dragging – occasionally splashing a bit of water on the disc to make sure it’s getting nice and hot.
It’s not as good as ‘proper’ bedding in, outside, down a big hill, but is preferable to getting blown away by the wind when I don’t need to!
“I find” bedded in pads last longer than ones taken straight from the packet. Your experience may be of no interest to me 😛
Fresh Goods Friday 696: The Middling Edition
Latest Singletrack VideosFresh Goods Friday 696: The Middlin...giantonagiantFull MemberDidn’t Mark Datz offer some good advice on bedding in pads a year or two ago?
😛bigyinnFree MemberBWD, im not sure why you’ve quoted me?
My point was that it needed doing in advance of the puffer and it needing doing on the bike. Heat on its own wont do it.BadlyWiredDogFull MemberBigyinn, I quoted you because in fact that’s pretty much what Mike Hall says. I think people are misunderstanding the heat treating thing, it’s not intended as a substitute for bedding in, but an additional thing.
TJ, I’m not even going to begin discussing anything with you. There’s a perfectly good brick wall out there if I want to beat my head against something, thanks.
bigyinnFree Memberlol @ BWD. Dont do that, you may dislodge some mortar.
Sadly TJ only knows Hopes, therefore everyone else must be using the wrong brakes or doing it wrong. The only way to silence him would be to
fit his tandem with an alternative make of disc brake and let him run it for a yearbeat him to death with a black rubber dildo (12″ pref).TandemJeremyFree MemberI have used other brakes. I have also been following the debate on pad wear for a long time. Some folk me included can ride in areas where the short pad life is common but still not get the short life.
GWFree Membernever understood anyone wearing out a set of disc pads in less than a year, never mind one lap of an XC course with any make of brake.
If I ever got anywhere close to that sort of wear I’d be switching back to V-brakes pronto.bigyinnFree MemberSo you can wear out your rims in a year instead? No thanks, I’d rather replace pads and or discs than rims anytime!
GEDAFree MemberAre brake pads not made by pressing the brake material at high pressures onto the backing plate while at high temperatures?
CaptJonFree MemberTandemJeremy – Member
I have used other brakes. I have also been following the debate on pad wear for a long time. Some folk me included can ride in areas where the short pad life is common but still not get the short life.Can you post your data so we can all analyse it?
TandemJeremyFree Membercaptjon – unfortunately its scattered around and mainly in my head so not of a great deal of use apart from for my interest
Lots of threads on here about it and lots of folks experiences on there Scienceofficer did some good analysis as well
GEDAFree MemberThe biggest factor in pad life is a. how much you brake and if you are not braking then if your pads are rubbing or not.
CaptJonFree MemberTandemJeremy – Member
captjon – unfortunately its scattered around and mainly in my head so not of a great deal of use apart from for my interestSo we’re stuck with your assertions based on your memory of posters self reporting..? How do you account for the myriad factors which affect pad wear and the variability between riders? And what about confounding variables?
TandemJeremyFree MemberCapt – plus the reading I have done and the discussions with the manufactures of brakes. Are yo really interested in what I have found =or are you looking to slag me off? Its unfortunate I have not collated the info well. The only thing I can be really sure of is that its a multi factorial conundrum when two riders using the same equipent doing the same rides in the same weather get dramatically different pad wear rates
If you are really interested I will spend some time typing out what I have foundGeda – the crucial thing I believe is the the formation of the boundary boundary layer and getting adherent friction – which requires heat in the pads. I brake a lot on the tandem and pads last thousands of miles – because they get very hot indeed even when ridden for multiple miles full of abrasive grit
CaptJonFree MemberTandemJeremy – Member
Capt – plus the reading I have done and the discussions with the manufactures of brakes. Are yo really interested in what I have found =or are you looking to slag me off?I’m interested in how you came to your conclusion because i hate it when people declare things but don’t back up their claims with evidence. It is even worse when they say they have data but can’t/won’t share it, or don’t explain their methodology. I think multifactorial is one word btw.
TandemJeremyFree MemberSorry – my spellchecker splits multifactorial 🙂 its a real shame I have not kept all the data so all I really have is whats in my memory and the various threads on here. I did not realise it would get so complex and interesting
I am about to have dinner – I will write up what I have found out and post it later on ad I’ll find as many sources as I can
TandemJeremyFree MemberOk – capt asked me to put down what I had found out . as above I have not kept most of the source material as I did not realise it would get so complex or interesting. I do not mean to be patronising but am trying to make this complete. I have looked at the wear that many different riders get and tryed to gain some understanding of how they ride
basics of how they work.
There are two types of friction generated between the pad and disc – abrasive and adherent friction. Abrasive is what we all know – like dragging your hand across sandpaper. Adherent is a little different as it only occurs when there is a microscopically thin layer of pad material on the disc and you get chemical bonds created and broken in a semi fluid boundary layer. as an analogy think about a layer of treacle between the sandpaper and your hand – still resistant to movement but its differnt and you don’t wear the skin off your hand.Abrasive friction occurs more at low temps, adherent at high temps. Abrasive friction creates more pad wear. Abrasive friction is more with sintered pads and less with organic – sintered pads are much harder hence even tho they have more abrasive friction they last longer.
disc brakes have a temperature range under which they work effectively and at the interface this will be hundreds of degrees C
Bedding in.
does 3 things – cures the pad under pressure and heat, puts thin layer of molten pad material on the disc and conforms the pad to the disc.
all this stuff is known and accepted in the automotive world. ?Some folk and brakes will need deliberate bedding in, some will bed in in normal usage. the key is you need to get them very hot
Now why do we get the rapid pad wear under some circumstances?
From what I have read and pondered it is when for whatever reason the deposit on the disc gets removed faster than it can be recreated and the brake system goes into abrasive not adherent friction which simply wears the pads away. But why does this happen?If the brake is being used in an abrasive environment the disc transfer layer will get worn off – however if the brake is hot it will get redeposited quickly enough ( its only a few molecules thick) to keep the brake in adherent friction. However if its cold and wet and the brake is not getting hot then it will not be redeposited at all or enough, the brake goes into abrasive friction and the pad wears out.
The braking surface will be completely clear of grit after one revolution of the wheel or less – its not the grit that wears the pad – its the lack of the disc transfer layer that wears the pad if the grit has removed the boundary layer.
some folk say the pad gets worn simply by the gritty disc running thru it with the brake not on – we have all heard the noise that makes. I believe the pad is too hard for this to create any significant wear
Dragging the brakes creates heat so should not cause excessive wear but a very light touch on the brake may allow grit to get between the pad and the disc and create wear by removing the transfer layer
Factors affecting the wear ratesIts obviously multifactorial and its when a number of conditions stack up against you that the rapid wear starts
this is where the conundrum starts ‘cos every time I think I have found a crucial factor someone comes along with experience that does not fit the theory.
Different pad materials and set ups have different working heat ranges – and it may be that some are better at running cooler than others
different disc drilling patterns may be better at clearing grit off the disc.
different manufactures pads will also be different composition and hardness.
Obviously diffent soil / gravel conditions are a factor but cannot be the only one for even in the areas such as afan and peaks where people get the rapid wear others do not.
Different riding styles clearly play a huge part as people with identical equipment in identical conditions some get the rapid wear some do not. However its not as simple as quick riders don’t get the wear or slow riders who brake a lot dont get the wear. I am fairly slow and tend to drag the brakes a lot – but don’t get rapid wear even in conditions where others do. Jambo is a quick rider and he does not get the rapid wear even tho he rides in areas where others get rapid wear
I believe a part of it is the number of times you apply the brake on each descent as each time you apply the brake ( when the brake is wet and gritty) for the first turn the transfer layer is getting worn away. I am dragging the brakes the whole way so generating a lot of heat and only one opportunity to remove the transfer layer. Jambo is only using the brakes twice the whole descent and each time he uses them hard – so little opportunity to wear the transfer layer and each time heat generated to replenish it. If you are on and off the brakes the whole descent but only using the brakes gently you are having a lot of opportunities to wear the transfer layer but are not generating enough heat to replenish it.
On the tandem the brakes get used hard the whole time and pad life is many thousands of miles
Smaller discs get hotter more easily so smaller discs should reduce the wear as they get hotter and the transfer layer is replenished more easily. certainly I run 160s only my solo and get long life.
I literally get many thousands of miles of life from my pads and all my discs are discoloured fro the heat. The front on my solo which probably gets the least heat in it wears quickest.
However some people still get short pad life in the alps where brakes get hot indeed. It may be possible that the rapid wear in the alps as well as reflecting a years use in a day is also down to the pads overheating and partly melting or going out of their heat range
conclusion
its complex and multifactorial. I believe the transfer layer is the key and this needs heat to generate it so it when the transfer layer gets worn away and not replenished quickly enough the rapid wear occurs. If the pad has never got hot it will wear as it will remain soft.
You need to keep the pad in its working temperature range and this varies from manufacturer to manufacturer. some generate heat more easily than others and some requite higher temps to create the transfer layer.
If you are getting the rapid wear try sintered pads obviously. try smaller discs if you have big ones, try dragging one brake rather than using two intermittently, try using the brakes in short hard bursts not gently.
IU shall try to keep note of teh info I collect on this in the future and I am very intersted in peoples experiences to see if they fit the pattern
there is also the issues of high temp glazing and low temp polishing of pads as well. It when this has happens abrading the pads with mud improves performance I beleve but that is a whole other issue.
Links to the other discussion on here
http://singletrackworld.com/forum/topic/natural-gift-for-glazing-pads
http://singletrackworld.com/forum/topic/why-do-my-brakes-keep-going-funny
CaptJonFree MemberThanks for taking the time to write that out TJ. But that doesn’t explain your assertion that hope brakes give better pad life.
coffeekingFree MemberBut that doesn’t explain your assertion that hope brakes give better pad life.
I presume that’s probably based on experience, testing and observation of others. I know a lot of people who claim to get better life from Hopes than other makes, which will depend on their pad materials and pad sizes. Whether it’s true or not, who knows, but lots of peoples experience seems to fit it, some people’s doesn’t <shrugs>. It’s not really important anyway, as it was a side comment to the point of the thread, which has been roundly answered and very well by TJ.
TandemJeremyFree MemberRight – thats simply from my experience and from what I remember of others experienes – and its a tendenccy not an absolute. No decent data as I have not saved it 🙁 TINAS has the same experience on this thread
I believe it may be to do with heat again. Hopes build up a lot of heat easily and / or have a lower working heat range which is why they have a reputation for overheating in the alps but why they dont get the rapid pad wear as often when its cold wet and gritty.
It may also be pad compound? they presumably got tested in UK conditions including winter use whereas in many other countries people don’t use bikes in the cold and wet. could be drilling patterns as well?
TandemJeremyFree MemberA lot of that long post is my theories not hard data but it developed over time looking at what is known and matching it with peoples experience – I want to be a real anorak and get some temp readings from a load of discs sometime
devsFree MemberI’ve ridden on a shitty day in the peak and lived! Further more, my pads lasted that day, another day, and then several months of riding in other gritty areas. My pads lasted 5 laps in the puffer last year. Their replacements lasted 6 and then several months of riding in other gritty areas. I use superstar haloumi pads, I find their feta ones are not as long lasting. Hmmmm haloumi and octopus, I can feel some carb loading coming on.
NorthwindFull MemberPretty sure Hope heat-treat their pads before sale btw (an old magazine feature showed loads of pads going into a kiln), which won’t make them last longer than a properly bedded in pad, but will probably make them last a bit better than an untreated, unbedded pad.
Less certain of this, but comparing X2s with OEM pads and with EBC pads, I suspect the OEM ones are a pretty hard compound, they seemed down on power compared to the EBCs and had less initial bite. But o’course there’s a lot of other things that could have caused that, so that’s mostly supposition.
TandemJeremyFree MemberDevs another one who does notwear out brakes!
Info would be nice ta
– what brakes?
Riding style? fast / slow? Brake dragger or hard use or light use?buzz-lightyearFree MemberI don’t bother bedding pads in. I typically get through two or three sets of superstar/clarks pads per year. Rich has had the same sets of Avid pads on his bike for 3 years!
I’ve experienced very rapid pad wear, e.g. a set every two hours, on rainy, splashy days at trail centres when the brakes are constantly being splashed with water and grit. The other time was an enduro near Andover which was sopping wet XC riding on flinty trails.
So the abrasive v.s. adhesive friction argument works for me.
devsFree MemberI always bed them in. The peak and puffer brakes were Hope 4 mono on 203 and 180 rotors but I also use hFX9, Louise and Formula K24s. I think I am a brake dragger but I’m also heavy at 17st so I think it’s the heat thing again.
coffeekingFree Member(an old magazine feature showed loads of pads going into a kiln)
That’ll be the sintered ones, it the standard way they’re made, hence my thinking sintered pads don’t require the heat element of bedding suggested in the article in the OP.
CaptJonFree MemberTandemJeremy – Member
Devs another one who does notwear out brakes!Info would be nice ta
– what brakes?
Riding style? fast / slow? Brake dragger or hard use or light use?Good, more systematic.
My pads last ages. The pads in my Magura Louises have lasted over a year even with regular riding. I bedded them in, weight 12st, not sure of my braking style, but i’m not one of the faster riders i know.
thisisnotaspoonFree MemberWhen I lived in sheffield I used hope C2’s, some hayes 9’s then shimano XTR’s. Being a uni student I’d not ridden in the peaks in summer untill this years summertime pootle! Couldn’t say which brake lasted longer as I didnt have them all at the same time.
But the key to getting any life at all from them was to drag the brake all the way from Crookes high street, to the arts tower, basicly every ride started with the brakes getting so hot the levers well and trully pumped up and the pad backing discoloured making a cool pattern showing the airflow arround the piston!
hilldodgerFree MemberHope 180/160 calipers, SS red pads, no deliberate “bedding in” just normal hard and late braking.
Type of riding, everything from daily tow path/bridleway commute to singletrack – local conditions are loamy soil with some sandy bits.
I try to brake as lttle and as late as possible and don’t drag.Roughly 500 miles a month, pads changed about once a year and even then there’s some left……
TandemJeremyFree MemberAny more want to share their tales of brake life / riding style etc?
GWFree MemberWhat you trying to prove TJ?
I personally think anyone who gets through brake pads at an alarming rate simply either brakes far too much or uses their brakes badly.currently I have 203, 185 and 160 discs as appropriate for the particular bike in question. brakes are currently Juicys (all sintered)and SLX(organic/resin?). I’ve only* used sintered pads for well over 10 years (prob closer to 15).
some of the brakes I’ve lots of experience using are BB7s, Juicys, Hayes, Hopes, Shimano.. there are many many more I’ve used but it doesn’t really matter what brake I have I don’t ever go through pads quickly!
Oh.. and I never bed pads in! preferring to just use brakes when they’re actually required instead*the new(ish) SLX I have on my hardtail I believe came with organic/resin (and funnily enough feel underwhelming) but even with those shitty pads after 9mths there are no real signs of wear
to the dick that suggested I’d need new rims every year with V-brakes Don’t make me laugh. 😆
TandemJeremyFree MemberNot try to prove anything in particular – trying to get to the reason why some folk get rapid pad wear ‘cos its an interesting conundrum as its not as simple as braking more – more wear
jimwFree MemberI have Hope mono mini’s on my Orange 5 – I weigh 90Kg with 183mm disks each end and original Hope organic pads. I had a half worn set when I started a four day trip to the Alps last summer which finished with the Passeporte de soleil. I had no issues with the brakes at all, no overheating, no fade I could discern and at the end I couldn’t see any appreciable extra wear. Others on the same trip with Hope M4’s seemed to have had some fade at times and have had more wear. Admittedly they were faster than me but I was probably on the brakes longer than them. Could this be that the mini’s were running hotter?
I have experienced brake fade with the M960 XTR brakes on my Litespeed locally on the Malverns so I don’t think it is technique?
Edit: I always have tried to bed the brakes in every time I change themeshershoreFree Memberrunning Avid X0 brakes on my bike, with sintered pads
on New Year’s day, went and rode for 6 hours on Pitch Hill, Surrey in foul conditions including deep mud and rain storm, lots of slithery braking action but not heat build up to speak of?
lost 3/4 of the material on very new, but bedded-in disc brake pads
(brakes bedded in by doing 30 emergency stops down a steep hill off Highgate, London) and 2 XC rides in NW london on relatively flat ground in dry conditions
Hope disc brake pads are somewhat different to other “manufacturers” in that Hope make the backing plates in-house, and then ship the backing plates to automotive manufacturer EBC who apply the material to the backing plates and then heat treat them
do other cycle brake pad manufacturers bother with this?
bigyinnFree MemberGW – Member
to the dick that suggested I’d need new rims every year with V-brakes Don’t make me laugh.This is the dick that suggested that, because I used to, smart arse! Ever considered a career in diplomacy GW?
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