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Frankenbrakes and brake improvement discussion

Kanye West

220# bag of hacktastic
Aug 31, 2006
3,680
405
My bike is on its way to Whistler at the moment. Once I'm up there this weekend I'll be happy to get some info.
 

sethimus

scroll all you want!
Feb 5, 2006
3,511
1,186
not in Whistler anymore :/
I've added Magura and Hope hydraulic data to the spreadsheet.
If anyone could help and measure their lever dimensions for me it would be helpful, I will draw up what needs measuring a bit later.
dunno how good your german is, but have you read the linked article about combining shimano levers with magura brakes? there are some numbers in there:

http://www.mtb-news.de/forum/t/magura-mt7-mit-shimano-xtr-trail-hebeln.751103/page-4#post-13038607
http://www.mtb-news.de/forum/t/magura-mt7-mit-shimano-xtr-trail-hebeln.751103/page-4#post-13071787
http://www.mtb-news.de/forum/t/magura-mt7-mit-shimano-xtr-trail-hebeln.751103/page-5#post-13072282
http://www.mtb-news.de/forum/t/magura-mt7-mit-shimano-xtr-trail-hebeln.751103/page-5#post-13072357
 

troy

Monkey
Dec 3, 2008
901
545
Magura MC [mm]/Pistons [mm] (2008MY)
Joulie 13/2x28
Marta/Marta SL 10/2x22
Gustav 10.5/2x18
Louise 12/2x22

Even tho Marta brakes had much higher hydraulic leverage, they were just a tad WEAKER than the Louise brakes. Louise lever had higher mechanical leverage (lever pivot-cam distance is much shorter).

Magura MT 2/4/6/8 - 2x22 mm caliper pistons, no idea about the MC dimensions.
 
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Sandwich

Pig my fish!
Staff member
May 23, 2002
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so are we mostly satisfied that the answer to the shimano problem is leaky calipers allowing air into the system, which works its way into the MC and then alternates between reservoir and line? So you could in theory grab a different caliper to reduce leaks or another lever to reduce leak effects.
 
so are we mostly satisfied that the answer to the shimano problem is leaky calipers allowing air into the system, which works its way into the MC and then alternates between reservoir and line? So you could in theory grab a different caliper to reduce leaks or another lever to reduce leak effects.
No. See replies 22 and 23. Issue is air in master cylinder reservoir getting into brake lines under certain circumstances.
 

kickstand

Turbo Monkey
Sep 18, 2009
3,441
392
Fenton, MI
so are we mostly satisfied that the answer to the shimano problem is leaky calipers allowing air into the system, which works its way into the MC and then alternates between reservoir and line? So you could in theory grab a different caliper to reduce leaks or another lever to reduce leak effects.
So in theory what you are saying is replace the whole brake with one that works and we should be golden?

Or are we keeping the brake line itself?
 

Sandwich

Pig my fish!
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May 23, 2002
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if the caliper is the leaky bit and we seal it up, we should be good, right?

hayes V9 rotors are still available, 224mm, 268g.
 

Sandwich

Pig my fish!
Staff member
May 23, 2002
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by moto style, I mean "by pumping the levers and releasing pressure at the caliper". ie, without syringes. I've done this on my 810s and 785s and 775s with good luck on each, though the 775s always lacked power. I'm just wondering if perhaps operating the lever as part of the bleeding process chases bubbles out of the system, or if perhaps I'm just lucky or if I just suck.
 

slimshady

¡Mira, una ardilla!
by moto style, I mean "by pumping the levers and releasing pressure at the caliper". ie, without syringes. I've done this on my 810s and 785s and 775s with good luck on each, though the 775s always lacked power. I'm just wondering if perhaps operating the lever as part of the bleeding process chases bubbles out of the system, or if perhaps I'm just lucky or if I just suck.
I call that an emergency bleed. Usually compliment it by closing the caliper bleed port, hammering the spacer block between the pistons, and then unscrewing a bit the bleeding screw to allow the air bubbles (and a little amount of brake fluid) off.
 

buckoW

Turbo Monkey
Mar 1, 2007
3,118
3,292
Champery, Switzerland
The R1racing levers with the RO calipers along with Hope tech 3 - V4 brakes are the best solutions I've used. I want to be able to manual without fear and ride steep stuff without constant bleeding and those two are what I've found work well for my needs.
 

Sandwich

Pig my fish!
Staff member
May 23, 2002
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I call that an emergency bleed. Usually compliment it by closing the caliper bleed port, hammering the spacer block between the pistons, and then unscrewing a bit the bleeding screw to allow the air bubbles (and a little amount of brake fluid) off.
I've found tapping the caliper with a metal wrench can help knock bubbles out.
 

maxyedor

<b>TOOL PRO</b>
Oct 20, 2005
4,896
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In the bathroom, fighting a battle
This morning's random thought while I was pooping.

Most reliable brakes I've ever used are my 2005 vintage Magura Louise and my 2006 Louise FRs, both have an absolutely massive reservoir in the master compared to modern day brakes and in said reservoir is a pretty stout rubber baffle that is supposed to keep air out of the piston assembly when things get shaken up. I believe there's a lot more to it than just that, but how much have weight weenies hurt brake performance be minimizing the fluid volume and reservoir size? I'd gladly sacrifice 25-30grams in the name of reliability.
 

Udi

RM Chief Ornithologist: “I Brake for Birds”
Mar 14, 2005
4,897
1,162
The R1racing levers with the RO calipers along with Hope tech 3 - V4 brakes are the best solutions I've used. I want to be able to manual without fear and ride steep stuff without constant bleeding and those two are what I've found work well for my needs.
For anyone who hasn't ridden with Ben, his idea of a "fearless manual" is riding vertically on his back wheel for 3-4km down fireroads and long alpine paved roads (which tends to upset sram and shimano)… and "riding steep stuff" is a bunch of runs in and around Champery so I think there's some weighting to those recommendations.

Although at 201g vs 311g (RO-Racing vs. Tech3-V4) per end, the weight difference is huge. That's ~220g lighter for a pair, big enough difference to add 220mm rotors while staying lighter.

In fairness the Hope is still as light as the Saint M820 brake, and I do like that the Hope uses bigger pads than the RO. But I'm pretty tempted to try the Formulas personally, if they are a match for power… possibly with a 220mm front later.


Looks like they've improved the lever ergonomics and increased fluid volume with a bigger reservoir:


 

no skid marks

Monkey
Jan 15, 2006
2,511
29
ACT Australia
Great thread UDI.
Hayes did a 9" rotor not too long back. I have one and adaptor for it. Had it on some Monster Ts on my tandem.
I'm running the R1 Racing levers with The One front caliper on all my bikes(different rotor sizes but) and I dig them so far. In theory I prefer the closer lever pivot point, but I don't seem to like it more than when I jump on my closest lever point other Formulas. The pivot point seem to vary a touch between The Ones and T1s a minute amount, can't recall what was closer.
 
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Udi

RM Chief Ornithologist: “I Brake for Birds”
Mar 14, 2005
4,897
1,162
I found a company that makes heatsink-finned brake pads for every brand which might be useful. Keen to try them, or make a similar solution at home:
https://www.uberbikecomponents.com/category/447/Finned-Disc-Brake-Pads


I'd be applying a thin layer of thermal epoxy (must cure, so can't use paste) between the two parts on each pad change to make the most of that setup though, and put in the time to separate and sand clean for the next pad change. I like the re-usable heatsink but you'd lose transfer benefits without parts constantly connected.

What are the advantages of the R1 Race lever over the R0 lever? Weight?
I think buckoW might be better at answering that (he's used them for 3 seasons), but from my understanding:

- Larger fluid capacity than both T1 and RO
- Can set reach adjust closer than both, something many struggled with
- Lever pivot closer to bar than both, better lever motion relative to hand motion
- Lighter than both, 15g lighter than T1 and ~30g lighter than RO per lever

I ordered some today so will update when I've tried them, will be running with RO calipers.
 

HAB

Chelsea from Seattle
Apr 28, 2007
11,449
1,850
Seattle
A list of all the bad things that could come from running mineral oil in a dot designed system:

Go!
Biggest worry would be seals breaking down or swelling. There are some common(ish) seal materials that are compatible with both DOT fluid an mineral oil (e.g. EPDM), some only work with DOT (e.g. perfluoroelastomer).

That's per manufacturer data sheets. They pretty much just list "mineral oils" or similar. That doesn't account for how Shimano (or whoever) formulates their oil. Pretty good chance that they've got some additives in there that aren't accounted for by the standard data sheets.

I have no idea what gets used in brakes.

Edit: This mentions butyl for Sram Guides. That's listed as a class 2 ("fair") match with DOT 3, and a class 3 match ("doubtful") with mineral oil in the seal guide I have.
 
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kidwoo

Artisanal Tweet Curator
Aug 25, 2003
33,352
8,002
The old timey times
Biggest worry would be seals breaking down or swelling.
Definitely why I asked.

What's the worst case scenario though......"ooh my shit leaks and now I have air in my lines"


I've already been dealing with that since I went straight shimano anyway. :rofl:


I guess the pistons could lock up and bind. At least it would be something new and exciting.
 

HAB

Chelsea from Seattle
Apr 28, 2007
11,449
1,850
Seattle
Worst case is that they leak, but they could leak a lot worse than your Shimanos. And if they fuck up the seals, switching back to the right fluid won't save them, the seals are going to be toast. Bad fluid/material parings can really fuck shit up. I used a random syringe I got from a pharmacy to bleed some Formula brakes once, and the seal on the plunger had swelled to the point that it wouldn't stay on the plunger at all the next time I went to use the syringe. I have no idea what material that was.

Also, see my edit in the above post about materials.
 
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HAB

Chelsea from Seattle
Apr 28, 2007
11,449
1,850
Seattle
Good news though, beer is a go with most of the seal materials in the guide.

upload_2015-9-3_22-16-56.png


Someone needs to make a beer brake.
 

Gary

"S" is for "neo-luddite"
Aug 27, 2002
4,839
3,080
UK
Fearless DH manuals in my book are brakeless. (I can't manual using brakes tho)

Serious question. if you're getting all this trouble why not use mechanical discs?
 

Sandwich

Pig my fish!
Staff member
May 23, 2002
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@buckoW any time on the new Magura mt quad piston setups? Lots of positive feedback, mineral oil, and half the price of an ro setup.
 

buckoW

Turbo Monkey
Mar 1, 2007
3,118
3,292
Champery, Switzerland
I haven't tried those @Sandwich. I tried some super light Maguras recently but the levers were so flexy they made for such a spongy feel I took them off.
@Gary - The point was more about a consistent bite point at all times. Brakeless manuals are definitely ideal.
I doubt a mechanical setup could ever be close to the power of a hydraulic one. The trails are steep around here and with those two setups I have the least amount of issues.
 

Sandwich

Pig my fish!
Staff member
May 23, 2002
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Thanks buckoW. There are a lot of good reviews of the MT5/7 and you can apparently swap with a shimano lever if need be. Lots of people seem to say the power of saint combined with way more consistency and better lever feel, but the plastic lever and MC do scare me a little.
 

sethimus

scroll all you want!
Feb 5, 2006
3,511
1,186
not in Whistler anymore :/
I found a company that makes heatsink-finned brake pads for every brand which might be useful. Keen to try them, or make a similar solution at home:
https://www.uberbikecomponents.com/category/447/Finned-Disc-Brake-Pads


I'd be applying a thin layer of thermal epoxy (must cure, so can't use paste) between the two parts on each pad change to make the most of that setup though, and put in the time to separate and sand clean for the next pad change. I like the re-usable heatsink but you'd lose transfer benefits without parts constantly connected.


I think buckoW might be better at answering that (he's used them for 3 seasons), but from my understanding:

- Larger fluid capacity than both T1 and RO
- Can set reach adjust closer than both, something many struggled with
- Lever pivot closer to bar than both, better lever motion relative to hand motion
- Lighter than both, 15g lighter than T1 and ~30g lighter than RO per lever

I ordered some today so will update when I've tried them, will be running with RO calipers.
swissstop is also making them soon:

http://www.bikerumor.com/2015/07/29/swissstop-cools-off-with-new-exotherm-finned-disc-brake-pads-for-road-mountain-bikes/
 

Udi

RM Chief Ornithologist: “I Brake for Birds”
Mar 14, 2005
4,897
1,162
Nice, I didn't see those, good to know there's options. Let me know if you see the alloy versions of the Formula 220s anywhere too.

There are a lot of good reviews of the MT5/7 and you can apparently swap with a shimano lever if need be.
Heads up, the MT5/7 calipers are known for uneven pad wear. Enduro magazine showed calipers where one whole side worth of pads had worn with the other side fresh. Shame, could have been good brakes, and I like the magnetic pad retraction so that you can use the surface area where the clip would go as pad material. Maybe they will update them.

Also I think the Shimano M820 issues come from the lever rather than the caliper, so I'd sooner run the caliper with a different lever. If someone was adventurous they could try a seal conversion mixing with hope tech3, since the 820 and V4 calipers match in size but the 820 is much cheaper and includes heatsink pads.
 

HAB

Chelsea from Seattle
Apr 28, 2007
11,449
1,850
Seattle
Question for Shimano guys,

I have found the "air issue" to only happen with the rear brake. Front has been solid and dead consistent.
Is this true for the rest of you?
Yeah, though I've only had it happen to two brakes, so I don't know if I want to read anything into that.
 

Gary

"S" is for "neo-luddite"
Aug 27, 2002
4,839
3,080
UK
@buckoW Yeah, even though I can only manual brakeless I do get why consistent feel while dragging a brake is what you'd want most.

I don't really get why people think mechanical discs can't be powerful though. it's simply down to leverage to increase power at a mechanical caliper and when using a caliper design where both pistons move the pure power can be immense. The only thing pushbike hydros really solve is cable friction.
 

SDet

Monkey
Nov 19, 2014
150
42
Boulder Co
@buckoW Yeah, even though I can only manual brakeless I do get why consistent feel while dragging a brake is what you'd want most.

I don't really get why people think mechanical discs can't be powerful though. it's simply down to leverage to increase power at a mechanical caliper and when using a caliper design where both pistons move the pure power can be immense. The only thing pushbike hydros really solve is cable friction.
And the mechanical caliper friction. As your force increases, so does the friction. So you get a curve like this. With lever force on the bottom and brake force on the left.

 

troy

Monkey
Dec 3, 2008
901
545
If someone was adventurous they could try a seal conversion mixing with hope tech3, since the 820 and V4 calipers match in size but the 820 is much cheaper and includes heatsink pads.
Would be gr8, but what about the bladder? I've made custom seals for my T1s back in the day, but doing a very complicated bladder is a whole new story.

Heads up, the MT5/7 calipers are known for uneven pad wear.
MT5 or MT7, because MT5 pads are different than MT7's. They have common, much thicker back plate. MT7 pads are separate for each piston with thinner back plate (and thicker friction material), so MT5 shouldn't suffer that much in theory (?).



Also, if some1 is interested in bigger rotors, check out those guys, they are doing some really cool stuff :) https://www.facebook.com/Bremsscheibe
 
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troy

Monkey
Dec 3, 2008
901
545
Talked to a friend of mine and he is riding MT7 calipers with Shimano Saint levers. He says it is fantastic. Stronger than with stock lever, much better feel. He says that he feels like pads from one side of the caliper last longer, but he is riding stock pads since the begining of the season, and it is not such a big deal.

m1.jpg
m2.jpg
m3.jpg
m4.jpg
 
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