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.
Frankenbrakes and brake improvement discussion
- Thread starter Udi
- Start date
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
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.
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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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.
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?
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.
hayes V9 rotors are still available, 224mm, 268g.
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.
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.
I've found tapping the caliper with a metal wrench can help knock bubbles out.
Yup, I do that too. And I also tap the hose with my fingers to help the bubbles travel up to the master cylinder.
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.
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.
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:
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.
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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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.
- 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.
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.
A list of all the bad things that could come from running mineral oil in a dot designed system:
Go!
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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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.
Also, see my edit in the above post about materials.
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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.
@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.
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.
swissstop is also making them soon: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.
http://www.bikerumor.com/2015/07/29/swissstop-cools-off-with-new-exotherm-finned-disc-brake-pads-for-road-mountain-bikes/
DOT brakes can be converted to mineral oil if you find the right sized seals: http://www.huckingkitty.com/forums/viewtopic.php?p=16343#p16343
@Udi - There are still some 9" discs on CRC
http://www.chainreactioncycles.com/ch/en/brake-spares?f=4294959384,4294958899
http://www.chainreactioncycles.com/ch/en/brake-spares?f=4294959384,4294958899
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.
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.
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?
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?
http://www.vitalmtb.com/photos/member/Pro-Bike-Check-Sam-Blenkinsops-2015-Norco-Aurum-Carbon-7,8897/New-brakes-coming-from-Formula-soon,91136/dhgnar,18548
whelp, it looks like buckoW isn't wrong...formula has a RORacing coming down the pipe, which looks like, to my eye, an RO caliper with the R1 lever.
whelp, it looks like buckoW isn't wrong...formula has a RORacing coming down the pipe, which looks like, to my eye, an RO caliper with the R1 lever.
Yeah, though I've only had it happen to two brakes, so I don't know if I want to read anything into that.
@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.
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.
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.
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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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.
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