Better braking with discs

[MultiRider]

I have Hope Trials discs on my Simtra and the rear doesn't grab as hard as I'd like. I've cleaned the rotor surface with rubbing alchohol, removed the pads and sanded them, and bled them. It's a 200mm rotor, so going bigger isn't an option.

They work pretty well, but to get a solid lock-up in the rear, I have to pull the lever REALLY hard. I can backhop without thinking about the brake, but if I launch the bike up onto a rock without focusing on a white-knuckle grip on the rear brake lever, the bike rolls backwards.

My guess is that scuffing up the rotor surface would be a bad idea, right?

Any other thoughts on how to get a solid lock-up on the rear?

[Rodmunch]

Did you get any oil on the pads? Maybe you can try baking them in the oven or cooking on a pan for a bit to burn it off.

[thetart20]

My guess is that scuffing up the rotor surface would be a bad idea, right?
Yes, discs work differently to rim brakes... I believe it is the 'Seisimir Effect' - where two very flat surfaces stick together.

My best advice would be a new rotor and new pads, once contaminated it's impossible to get a disc setup back to 100% in my experience. At the same time, look into having the mounts faced - it makes a huge difference.

I ran a ST-1 with 200mm Hope Trial at the rear for a long time, it was the best brake I ever had, loooaadds of lock and plenty of bite... persevere, it'll be worth it :)

[Cryo-Cube]

200mm hope trials and no power?
Something must be wrong with it.
What i found is that after cleaning the disk with alcohol or ethyl alcohol i have to wash away the alc too to get the disc working great. Just pooring and cleaning the disc with alcohol actually lowered the performance a bit and even caused braking noise to my otherwise silent setup.

[MultiRider]

I don't think I ever got anything on the pads, but it is possible. I've been trying to recall if they used to work better and now don't work as well (which would point to contamination), but the fact is my skills have improved and I'm now doing stuff I didn't do before. They are pretty powerful -- I can go to rear wheel and hop all day with plenty of confidence in my brakes. But when I hop up onto a rock, for instance, and don't quite get all the way on, instead of a solid lock-up, my rear wheel goes backwards a few inches. This is a move I'm learning and have not done previously. It puts a lot more pressure on the brake to stop the bike. I'm about 180 pounds plus the bike, so when I hop up on something and just catch the edge, that's a lot of pressure on the brakes.

As I think about it, it occurs to me that I used automotive rotor cleaner on it when I first got it, then read that automotive products should not be used on a Hope rotor. So I got the rubbing alchohol and cleaned it off. I don't think I actually used the brakes after applying the auto stuff and before using the rubbing alchohol.

Does baking brake pads really work? I'm willing to try it if it will actually help. My wife isn't too pleased with the idea.

Is rubbing alchohol the right thing to use to clean the rotor? Or?? Should I use water?

A friend recommended "bedding it in" by dragging the brake down a long hill. I'm skeptical -- would that really improve braking? I'm a little reluctant to do that since riding a single speed seatless bike back up a long hill would have a fun factor of zero, but if it would would add braking power, I'd do it.

I will check out the caliper alignment tonight. That could certainly be a factor.

[Cryo-Cube]

They are pretty powerful -- I can go to rear wheel and hop all day with plenty of confidence in my brakesThat is not pretty powerful, thats what even the shittiest brake should be able to do.
Try water and going down a hill (small hill, dont do it till the disc starts glowing or something) first. If that doens't help, try baking the pads. If that doens't help get new pads and a new disc.

Again my adivse is to always wash of the alcohol with water (just pour it over the disc and pads) when your done with cleaning.

[Fzo]

Never use brakeclean on bicycle brakes. That stuff never works, just ruins everything.

The best way to clean a rotor is acetone as it miscibles with waterbased and oilbased stuff and vaporates after using. And it is far more aggressive than alcohol.

Pads can be cleaned by giving them a little blowtorch action. Atleast it works well with sintered pads, but I dunno if you end up burning those organic pad of hope trial.

[Sondre]

You grinded it yet? :)









But seriously, I would go with the solution Tarty reccomended. No more hassle end of discussion.

[Macbeth]

I have always found Hope Mono brake calipers flexy and lacking in power..... To test for this, hold the caliper between your thumb and finger and squeeze the lever as hard as you can..... I am willing to bet that you will feel the caliper flexing apart in your hand..... Mine did it, so i got rid of it.....

Get yourself an Avid Code 185mm and never look back

[RomanC]

You might need to face the disc tab. If you lock the brake and see your rotor flex, then tab facing might be helpful.

[Juhan]

I have always found Hope Mono brake calipers flexy and lacking in power.....


Flexy - yes(but I like the feeling)
Lack of power - hell no.

[stocktrials]

A friend recommended "bedding it in" by dragging the brake down a long hill. I'm skeptical -- would that really improve braking? I'm a little reluctant to do that since riding a single speed seatless bike back up a long hill would have a fun factor of zero, but if it would would add braking power, I'd do it.

I've done this with Hope brakes and it does work.
Throw some water on the disc and caliper and ride around with the brake semi on, find a hill and gradually pull the lever in, then completely on. Stop. Repeat.

after 30 mins or so, give it some trials to test it out. If still not good repeat until good.

[Rudy]

Every time my Hopes crap out on me due to contamination I remove the rotor and wash it with genorous amounts of Dawn dish soap and remove the pads stick them in a vise by the tabs and heat them with a blow torch untill the brake compound is glowing red. The pads normally start on fire during this process, the flame will continue to burn when I remove the torch. That is just the contamination burning off. I have done this to my Hopes 10-15 times, same with the Avid. I have only once had problems where it screwed stuff up. As soon as the torch got close to the pads they more or less exploded. Must have been some water imbeded in the pad that vaporized. But to this day I still use the same method. I haven't found anything that works better. I also do this to every new disc brake i have to help speed up the brake in process. My last Avid was solid after just one ride with this method. (too cold to ride the hill this time of year)

[psyber_0ptix]

does the direction of the rotor have any effect on performance?

some say run the rears backwards

[eastside]

code with a 203.....

[bklmrkt91]

ummm beware baking pads can stink up the house. what ive done in the past is i used a blow torch on my pads if they got contaminated. i stopped after the pads were glowing red. works well for me

[[BMF] Chris]

being the master of fucked up rear hope brakes, leme tell you how ive figured out a full proof way-

if you get even a drop of oil on your rotor, or pad, youre screwed so here we go-

take off your rotor and pads. clean the rotor with acetone, and boil the brake pads. after you have done both of those, put your rotor and pads in your dishwasher with dish soap and run a cycle (as i was told to do buy the hope tech) while the dishwasher is running, spray out your caliper with water to keep any oil from hiding in there, also, be sure to tighten every nut and bolt on the caliper. after everything is clean, re assemble and dont drag the brake, just ride normal. it will take about 3 days for the rear brake to get to super lock. if for some reason you just cant wait, rub mud on your rotor, and ride around slowly (as recommened by the hope yech in the usa) the mud acts like an abreasive cleaner. anywho, enjoy your brake.

fyi, after about 4 months of rear brake trouble, i finally figured out the problem- there is a seal on your bore cap, and mine had a microsopic cut in it, constantly letting air into the system, making the brake feel like poo, and it kept dripping oil on my rotor. be sure to make sure your bore cap is tight. i bought a tool to tighten it, but you can always ghetto tighten by taking needle nose pilars and pulling them apart into the groves. anyway, hope this helped............ :bigthumb:

[goose]

just to chime in. You can get 9" rotors now from formula and hayes. Not that you should need it, but they are available. Just need to get an adaptor and make sure the larger disc will clear your chainstay/seatstays. Just in case you decide to throw money at it, and increase brake torque by ~13%

[Matt]

just to chime in. You can get 9" rotors now from formula and hayes. Not that you should need it, but they are available. Just need to get an adaptor and make sure the larger disc will clear your chainstay/seatstays. Just in case you decide to throw money at it, and increase brake torque by ~13%
:noes:

[MultiRider]

Excellent advice so far, thanks.

Several people have recommended heat -- sounds like a tried and true method. The dishwasher idea is interesting; seems less likely to ruin the pads. That's the first time I've heard that suggestion.

Any tips on facing the brake tabs? Just watch the brakes engage as I squeeze the lever and use a file to ensure the entire pad hits the rotor at the same time?

"there is a seal on your bore cap, and mine had a microsopic cut in it, constantly letting air into the system, making the brake feel like poo, and it kept dripping oil on my rotor. be sure to make sure your bore cap is tight."

What is the "bore cap"? Any chance you could post a pic with an arrow or circle or something so I can see what you're referring to?

9" rotor -- cool!

[KeepRollin]

http://www.hopetech.com/database/Mono_Trial_Caliper.pdf

[Juhan]

Excellent advice so far, thanks.
Any tips on facing the brake tabs? Just watch the brakes engage as I squeeze the lever and use a file to ensure the entire pad hits the rotor at the same time?


Go to a bike shop that has the correct tool for the job and if you have to, then pay them to do it. When I was building my dualdisc czar up at a lbs I had to take over 1mm off the tabs so the brake wouldn't rub, it was probably the most tedious process I've ever had to do on a bike, since the facing tool is meant for either qr forks or 135mm rear ends, not for a 116mm mod frame, so I used the fork tool with a 135mm QR ziptied to the frame. :hsugh:

[[BMF] Chris]

think about it, a dishwasher is made to clean the toughest grease on pots and pans. why not dot fluid? i preboil the pads just to get out what oil i can so it wont be flopping around in the dishwasher while its cleaning. and i just use acetone on the rotor and not pads because the acetone could damage the glue on the baking of the pads. dishwashers create steam, which is alot hotter than boiling water. from how i understand it, you heat the oil to thin it so it leaks out. i think the dishwater is a better choice not just because of steam, but water and oil wont mix. so if you have hot ass dish soap/steam soaking into your pad, all the oil is going to want out only to be washed away by the jet cycle, oh, and dot 5 or whatever is water soulable..... oooooooohhhhh yeaaaaaaaaa

[goose]

don't bake the pads... blowtorch them:
http://observedtrials.net/vb/showthread.php?t=20830&highlight=reviving+bb7

I 'think' i'm gonna disagree with tart, as I belive that my bb7 pads came back to original strength after two torchings. Its hard to disagree with the sheldon brown of trials tech....

If you've got access to a torch, do that... before you spend money on anything new.

[Carbon]

don't bake the pads... blowtorch them:
http://observedtrials.net/vb/showthread.php?t=20830&highlight=reviving+bb7

I 'think' i'm gonna disagree with tart, as I belive that my bb7 pads came back to original strength after two torchings. Its hard to disagree with the sheldon brown of trials tech....

If you've got access to a torch, do that... before you spend money on anything new.


Yes, the blowtorch is the answer.

If things still arent working. clean your rotor off with rubbing alcohol and a rag. Scrub it good. Get new pads. Go to a long hill. Go down it a few times. Make sure the pads and rotor get hot. Keep going till they start to bite good. go home, and clean it all up with water and a clean rag. You should see lots of brake residue come off. They should be good after this. Its always worked for me. if they start to fade on a ride, just splash some water on your rotors. The brake residue comes off and you have a clean braking surface again, and the brakes lock hard.

[Bryan]

9" rotor for sale - $50

[johnglazer]

Bryan says that if you take your bike on an airplane the TSA people will tune-up your brakes nicely with some special spray. :momaru:

[goose]

not to be a tool, Bryan, but 9" rotors are ~50 bucks new...
http://www.jensonusa.com/store/product/BR401C10-Hayes+V9+Rotoradapter+Kit.aspx

I still say you should torch the pads. From my experience it helps a lot (on avid pads, though). If the pads are contaminated, you'll see lots of spurts of fire popping from the pores of the pad. If that doesn't work, new pads are in order.

Also, you should try spraying water on the pad/disc next time you go out for a ride. If the power increases when the pads/disc are wet, then contamination is likely the problem. It seems that water interferes with the oil, and gives you great braking performance until it dries up. This certainly was evident when I was having trouble. Definitely do the water test!!! Some of the west coast disc riders were having trouble with their magura brakes leaking, so they rode with a water bottle handy and constantly sprayed their discs.

My experience has been with oils, like mineral oil in magura and shock oil for my bb7. I'm unsure if dot fluid has the same water repellance properties, but it can certainly be burned with heat. YES... i'm just remembering that i had to torch my hayes pads after a botched bleed, so the heat does definitely work with dot fluid.

Before you buy something new, or even order new pads and try this in the meantime, I suggest doing the water test and then a blowtorch test!! Contaminated pads are not garbage!!!

[beastoftheeast]

i dont know...my bb7 was not so great. then i rode in a creek then the brake felt way better and has felt the same since...and i dont think my brake was contaminated? i dont think i got anything from by hs33 on it. and it was brand new...maybe its just how long it took to break it in and it was a coincidence or something...

just go dip it in the nasty water at conflunce and then ride.

[mikeschiavone]

Water does indeed increase performance of the brake. If it's a relatively new brake then you still have a 'glaze' on the pads. Go ride down a hill with some water freshly dripped all over the disc system.

The most important element to disc brakes is alignment. Depending on the type of mounting system, it's beneficial to take it to a shop with a disc mount facing tool. Similar to a facing tool, this aligns both of the disc mounts with the dropout.

I remember when I first put on my bb7 I thought it sucked. Then it got wet on the roof rack, and I had to ride a hill to a riding spot. Then I realized it was worth it.

Good luck.

[bklmrkt91]

not to be a tool, Bryan, but 9" rotors are ~50 bucks new...
http://www.jensonusa.com/store/product/BR401C10-Hayes+V9+Rotoradapter+Kit.aspx

I still say you should torch the pads. From my experience it helps a lot (on avid pads, though). If the pads are contaminated, you'll see lots of spurts of fire popping from the pores of the pad. If that doesn't work, new pads are in order.

Also, you should try spraying water on the pad/disc next time you go out for a ride. If the power increases when the pads/disc are wet, then contamination is likely the problem. It seems that water interferes with the oil, and gives you great braking performance until it dries up. This certainly was evident when I was having trouble. Definitely do the water test!!! Some of the west coast disc riders were having trouble with their magura brakes leaking, so they rode with a water bottle handy and constantly sprayed their discs.

My experience has been with oils, like mineral oil in magura and shock oil for my bb7. I'm unsure if dot fluid has the same water repellance properties, but it can certainly be burned with heat. YES... i'm just remembering that i had to torch my hayes pads after a botched bleed, so the heat does definitely work with dot fluid.

Before you buy something new, or even order new pads and try this in the meantime, I suggest doing the water test and then a blowtorch test!! Contaminated pads are not garbage!!!
yeah! torch it! i torched mine until the pads were glowing red. im sure u dont need to do them for that long but it looked cool : ) anyways the torching method is the quickest and easiest to do. what i did was i just put the pads on the ground(concrete) with the backings on the ground and torched it till it was red. what happened to me was tri flow leaked out of the brake line onto the rotor XD worst thing ever. anyways the torching returned it to its original strength. good luck!

[Bryan]

not to be a tool, Bryan, but 9" rotors are ~50 bucks new...
http://www.jensonusa.com/store/product/BR401C10-Hayes+V9+Rotoradapter+Kit.aspx

It's a formula rotor. The hayes weren't available when I bought it. It cost a lot more than fifty bucks new. Would you sell a ti spindle bottom bracket for $20 because 128mm bottom brackets are available for $40 new?
The cost was shipped anyways.

IMHO it's just throwing more money and time at something that's a heavy, expensive, impractical pain in the ass

[goose]

It's a formula rotor. The hayes weren't available when I bought it. It cost a lot more than fifty bucks new. Would you sell a ti spindle bottom bracket for $20 because 128mm bottom brackets are available for $40 new?
The cost was shipped anyways.


i see your point, and having tried to sell so much stuff lately (to save up for naked), i've found that used stuff only moves if it's much cheaper than new stuff. I'm actually interested for 50 shipped. Been eying the formula... what adaptor did you use??? any??? I have a +40mmIS disc tab, so was gonna use a 7" or 185mm adaptor to space it out to the 9" size.


IMHO it's just throwing more money and time at something that's a heavy, expensive, impractical pain in the ass

true, it is just throwing money at it:)

[tomacropod]

goose, that would look insane. you can be my wingman anytime.

- Joel

[Bryan]

I had a +60 mount. I have a post mount 160 to 210 adapter that came with it if you want that? Otherwise just a +20 on a +40 mount will do the trick

[goose]

goose, that would look insane. you can be my wingman anytime.

- Joel

Bull$hit, you can be mine:)

Gotta love insanity.... I'm interested to see if it's possible to have TOO MUCH rear braking power.

Ya, for it to work, i'm gonna need a +20 adaptor.

back on topic, i hope multirider freakin gets back to us with some results after all these tips and suggestions we've made.

[MultiRider]

This thread is full of great ideas/recommendations. Maybe OTN should have a Tech Tips category and this could be a Sticky in there?

Due to work and other stuff, I've only had a little time here and there to spend on trials. So I rode instead of worked on the bike. Finally, last night, I decided to fix the brakes. I removed the rear pads and took a torch to them (thanks, Mark, for the torch). As others have described, each pad started on fire and burned on its own for a few seconds. Brake fluid? or other contaminent? I'm not sure. After torching the first, I set it aside in a pair of Vice Grips to cool off. Then torched the 2nd. Left it in the vice to cool. Hung the rotor by a wire from the rafters and torched it. Then sprayed high pressure water thoroughly throughout the caliper. Dried it off.

Ready to reassemble. Remounted the rotor. Went to get the pads. Bummer! The pad that was in the vice fell out. See pics. Apparently it fell out of the vice while still very hot and landed on the old carpet on the garage floor under my work bench. I tried to pry the pad out of the carpet, but the backing came off. Could not get the pad material out of the carpet. I'm very glad I had an extra pair of pads on the shelf.

So I put new pads in. Braking is bad. I guess I need to bed them in. But I ran out of time last night and had to give up. This is a classic case of why I typically choose to ride instead of work on it. It went from very rideable with one area of possible slight improvement to unrideable. ARGH!!!

When I reassembled with the new pads, I bled it just to be sure there's no air in the line. While doing that, I noticed that when the rear brake lever is squeezed very slowly, the rotor deforms just a bit about halfway through the squeeze -- the rotor at the front edge of the caliper deforms slightly to the right from about 1/2 to full squeeze. It appears there is a slight alignment problem which could cause the ever-so-slight mushy feeling in the brake. I've bled it several times and am always confident it is right, then I ride it and think "hmm, still just a little mushy". That must be the caliper alignment. I plan to take a file to the rear mount and see if I can get it to line up 100% correctly and see if that eliminates that little bit of mush. At this rate, though, it may be a while before I do that. I want it rideable again.

Water and riding around with the brake on to bed the new pads in is next on my agenda. Havin' some fun now!!

[MultiRider]

While working on my back brakes, it seems I must have spilled brake juice on the front because when I went riding, the front squealed and was virtually powerless. So, in spite of the issues of melting the back brake pads and just putting new pads in, I once again faced the issue of trying to save my pads.

I used a torch per many recommendations. Sanded them lightly after. They work great now! So . . . +1 for the torch method.

Apparently working on my back brake caused the bolt that holds the hydro line to the caliper to loosen. While doing some up-the-rock hopping, the lever went to the bars, juice squirted out, and my back brake failed. Which ripped the caliper off the frame. Bummer.

With Mark Hopsalot's help, I got the caliper out of the spokes and unwrapped from the rear hub, rotor mostly straightened out, torched the pads, re-filled the reservoir and bled it a couple times, and was riding again in about 40 minutes. Brakes work as well as ever. Unfortunately, Mark's front tire went flat and he was done. Not a great day on the rocks due to mechanicals. But I blazed some new ground for my skills by hopping off some fairly big rocks and learning to sidehop from rear wheel. That was pretty cool.

[johnglazer]

Wait, how did the caliper get 'ripped' off the frame? Did the bolts holding the caliper to the frame also come loose?

[MultiRider]

I'm not entirely clear on how it happened, but yes, the front bolt was out of the caliper and the caliper was twisted into the rotor rather severely; the rear bolt was quite bent. I am certain that I loctited and tightened both bolts when I was working on it previously. I distinctly remember squeezing the Locite tube to get the last couple drops out for each bolt because the tube was almost empty. And I'm certain I tightened the bolts. But when we took it back to the truck to see if we could get it up and running again, the bolts threaded into the caliper and tightened.

As I type this, I'm realizing that Mark put the bolts back in and tightened them. He gave me the extra washers which I had previously put on the bolt on the outside of the frame for safekeeping. It is likely that the bolts ripped half the threads out and Mark left the washers off so the bolts could reach the other half of the threads.

Anyway, it was quite surprising. I would have thought when the brake fluid squirted out and the lever went to the bars that it simply would have lost braking power (which it did). I'm not sure why the caliper ripped off the frame and then twisted the rotor to the point that the caliper went into the spokes. If I had a camera, I'd have taken a picture. It was pretty weird.

[johnglazer]

hmm. strange