Quantcast

Frankenbrakes and brake improvement discussion

chris_f

Monkey
Jun 20, 2007
390
409
Well fuck, if they work well, and more importantly can be bought without excessive wait times, I'm all for it. But you're going to need a very lizard-y name!
 

StiHacka

Compensating for something
Jan 4, 2013
21,560
12,504
In hell. Welcome!
It's easy to say "monobloc is stiffer", but it's just as likely that the entire system is different and therefore not accurately measurable.
I have only some anecdotal evidence but bolted MT6/MTS calipers are *significantly* stiffer than monobloc MT8 of the same generation. You can see the MT8 expand and deform under hydraulic pressure from a good lever (Saint), the MTS not so much.
 

ucsbwsr

Chimp
Jan 10, 2014
3
2
Question for those of you using MAGURA MT5 + SHIMANO SERVOWAVE Levers.

As background I have some Magura Louise FR brakes on my old 26" hardtail. 210mm rotor up front and 180mm rear, I enjoy the modulation and I found the power to be sufficient. Also, I am 6'8" 260 and stopping power is important to me.

My current bike is an XXL 2018 Santa Cruz Hightower LT, it came with Shimano M8000 brakes and I upgraded to 203mm rotors F/R. I have acclimated to the sensitive nature of the brakes but they get overwhelmed on steep descents and I am looking to get a set of Magura MT5.

My priorities are stopping power and value for money so the MT5 seem like the obvious choice over MT7s or Saints. The obvious fault of the MT5 are it's levers but that can be remedied be swapping in the MT5-specific HC levers. I scored a set of 203mm SL rotors for $35/pr and although I will be missing some surface area the reviews seem to be positive overall. In this thread the complaint I am hearing about the MT5 is they require more lever force realize the full braking potential although this wasn't ever noted in most of the braking reviews I have read.

So, my question is: Is there anyone who has ridden the MT5s with the upgraded 1 finger HC levers and also tried the MT5s with the Shimano levers? I am interested to hear your thoughts comparing the two.

Many thanks!
Evan
 

Flo33

Turbo Monkey
Mar 3, 2015
2,057
1,298
Styria
That one piece commentary is interesting. In theory, we will never know whether a monobloc caliper matters, at least in cycling, until somebody carefully designs and optimizes two calipers with the same piston size and lever. It's easy to say "monobloc is stiffer", but it's just as likely that the entire system is different and therefore not accurately measurable.

anybody got access to a cnc machine? imma start machining some brakes and charging you suckers a mortgage for them
Hey @mtg
 

Happymtb.fr

Turbo Monkey
Feb 9, 2016
1,907
1,252
SWE
@chris_f how did it went with your sticky pistons? And what treatment did you go for?

I kind of put a spell on me when opening this thread 3 times in row since I have now sticky pistons on my Shigura Trail... the lazy side is the one away from the banjo on both brakes and massages like I recommended you didn't help much. I even used brake oil to lubricate the pistons and seals since I don't have the right grease at hands for the moment. Not much luck with it either
 

chris_f

Monkey
Jun 20, 2007
390
409
I ended up sending them back to the importer/distributor here in Norway. They sent me some loaner brakes so I can still ride. I have no idea what they are doing to fix it, but I'll ask them about it when they're done.

I tried your advise, it didn't really help. Although I do appreciate the heads up.
 

Udi

RM Chief Ornithologist
Mar 14, 2005
4,915
1,200
@Sandwich / others
Caliper stiffness isn't a huge issue unless you're actually running out of lever throw, most brakes these days do have sufficiently stiff calipers (whether one-piece or bolted). I put that point last because the leverage and free stroke concerns are far more critical on current brakes, and these are areas with far more problems. It's certainly design dependent, in my experience RO and V4 calipers (both monoblock) are pretty stiff.

@StiHacka
I've noticed similar things myself, but it's important to note that total leverage has a huge impact on how stiff the lever feels (it impacts the total deflection you can generate as a summation of lever body flex / hose expansion / dissolved air compression effects / caliper flex). For an even remotely useful test you need identical hydraulic and mechanical leverage. This is why old Hayes HFX / Mag brakes felt so firm - it's easy to make a firm brake with not much peak force.

@Happymtb.fr
When these issues persist (on a brake without any material / design flaw at least) it's usually a sign that you should replace the caliper seals and pistons (the seals are used as springs, rubber deteriorates with time + heat cycles). With most brands (at least Formula / Hope) you can buy both cheap. Of course disassembly and reassembly after cleaning and greasing usually helps, but if going to that effort (rebleeding from empty) I think it's best to replace the parts, assuming cheap + available.

@ucsbwsr
The HC lever is shorter than the original lever so the brake will have reduced peak force compared to the stock brake. If you are a big guy struggling to stop, this is not an "upgrade". From what I recall the MT5 and MT7 should generate the same peak force, so I have a feeling the stopping concerns (for some) might be due to the pad differences between the two - they don't fit the same pads from memory. At least in my experience (mostly with the MT7) they stop very well, just the lever quality/ergonomics aren't great. Not a big deal if you have big hands.
 

StiHacka

Compensating for something
Jan 4, 2013
21,560
12,504
In hell. Welcome!
@StiHacka
I've noticed similar things myself, but it's important to note that total leverage has a huge impact on how stiff the lever feels (it impacts the total deflection you can generate as a summation of lever body flex / hose expansion / dissolved air compression effects / caliper flex). For an even remotely useful test you need identical hydraulic and mechanical leverage. This is why old Hayes HFX / Mag brakes felt so firm - it's easy to make a firm brake with not much peak force.
The MTS/MT6/MT8 share the same pistons AFAIK, and I had both calipers mated to the same Saint lever.
The MT8 was a truly terrible brake and its flexy piston was just an icing on the cake.
 

Udi

RM Chief Ornithologist
Mar 14, 2005
4,915
1,200
@StiHacka
Of course, my mistake - I read MT7 for some reason.
I believe it, noticed the same when Shimano first switched to monoblocks. I feel the Hope / Formula ones are pretty decent though, perhaps more bridge material / better bridge design.
 

Happymtb.fr

Turbo Monkey
Feb 9, 2016
1,907
1,252
SWE
Thanks @Udi !
Magura doesn't seem to have this kind if spare parts, probably just to be like Shimano :bonk:

Anyhow, the brakes are not even one year old and have been sitting on my trail bike the whole time: around 1700km so far. We don't have big hills around so that they have been exposed to what I consider a mild level of abuse. Do you think that the seals could already be damaged? Well, when comparing to Shimano, that might actually be the case... :brows:

I will try to clean and regrease what I've got. If it doesn't work I will try to warranty them and will have a good reason to get some Cura.
 

Sandwich

Pig my fish!
Staff member
May 23, 2002
21,031
5,921
borcester rhymes
@ucsbwsr
The HC lever is shorter than the original lever so the brake will have reduced peak force compared to the stock brake. If you are a big guy struggling to stop, this is not an "upgrade". From what I recall the MT5 and MT7 should generate the same peak force, so I have a feeling the stopping concerns (for some) might be due to the pad differences between the two - they don't fit the same pads from memory. At least in my experience (mostly with the MT7) they stop very well, just the lever quality/ergonomics aren't great. Not a big deal if you have big hands.
mt5s have a one-piece pad, mt7s have a two piece. THey also sell a "race" pad, which I have but haven't used, that ups power, apparently. I wanted a non-resin two piece jam, and the race compound was the cheapest and allegedly most powerful.

To @ucsbwsr
It's probably me that has mentioned MT5s in the past. They are good brakes, don't get me wrong. The big downside is the power comes on very gently (totally unlike shimano) and the lever ergonomics are rough at best. I think they'd be fine on a trail bike as brute power is not necessary as quickly, and you're not riding them for five minutes at a time. They are certainly more powerful than formula the ones, but it's hard to compare them to other brakes, like a saint or a zee, because the power comes on so strong for them.

@Happymtb.fr
are you having issues with stuck pistons with shimano levers and mt5 calipers?
 

roflbox

roflborx
Jan 23, 2017
3,163
834
Raleigh, NC
That one piece commentary is interesting. In theory, we will never know whether a monobloc caliper matters, at least in cycling, until somebody carefully designs and optimizes two calipers with the same piston size and lever. It's easy to say "monobloc is stiffer", but it's just as likely that the entire system is different and therefore not accurately measurable.

anybody got access to a cnc machine? imma start machining some brakes and charging you suckers a mortgage for them
new tormachs just came out :drool:
https://www.tormach.com/blog/introducing-tormach-m-series/
770M should be able to do what you are looking for
 

Happymtb.fr

Turbo Monkey
Feb 9, 2016
1,907
1,252
SWE
are you having issues with stuck pistons with shimano levers and mt5 calipers?
The pistons are definitively moving on both sides of the caliper on both the mt5 and mt4 calipers (I have the MT trail brake set) but one side is "lazy" which means that it doesn't push or progress at the same rate as the other side
 
Last edited:

Mo(n)arch

Turbo Monkey
Dec 27, 2010
4,441
1,422
Italy/south Tyrol
Not sure if that was already written but I thought it would be interesting for some people here:

Some germans are running „Triguras“ right now and seem to be very sucessful doing so. Pairing MT5/7 calipers with the DRT levers seems to be quite the hit. Customers even get support from Trickstuff directly. Trickstuff is actually very active on the froum and gives lots of information, tips and tricks. They even will build and bleed the brake for you if needed.
It seems that there is a compatibility list with 3rd party calipers in the works.

And the levers seem to be easier to get then complete brakes.
https://www.mtb-news.de/forum/t/trigura-how-to-direttissima-pumpe-und-mt5-sattel.820819/
 
Last edited:

Udi

RM Chief Ornithologist
Mar 14, 2005
4,915
1,200
That's interesting @Mo(n)arch, however I think the lever throw will be too long when using MT5/7 calipers and it could become problematic under heavy use. The DRT already exploits both low-rollback slaves and high hydraulic leverage to give a reasonable throw with high peak force - but the combination (and precision / consistency) is what makes the brake brilliant. You can see from the spreadsheet that an MT5/7 caliper throws out the hydraulic leverage by a HUGE amount, which means throw will grow proportionally. An MT6/MT8 caliper on the other hand would work very similarly to the stock DRT brake.

I think the important thing to remember is, there are physical limits to what you can do with brakes, particularly without an aggressive linkage (SW). The DRT exploits these physical limits in a very optimal way to solve a lot of issues. Now many of these issues will show up halfway into a lift season, so there's every chance some of the more "extreme" combinations will work for some people (read: punters), but if you want the DRT to perform as intended (at least to a reasonable extent), it's important to match or keep very close these parameters:

1. Total slave piston area
2. Piston rollback

The DRT already minimises rollback to the absolute max, you can't reduce rollback further without rotor rub, which means to maintain ideal throw you need to either match slave area on a caliper that has identical rollback OR sacrifice peak force on a caliper which has more rollback and opt for a slightly lower slave area. Now obviously we can't control these values, but for example, an XT brake caliper will work with a DRT lever but you'll get longer throw due to greater rollback even though the brake still develops the same peak force.

I considered all this myself (and was pretty interested in just buying the levers) but after owning them I firmly think perfection comes in the package. I don't know who from TS is encouraging this particular combo, but I'd take it with a grain of salt.

I'm not discouraging mixing, but I think the MT6/MT8 are the most ideal match, with any Shimano 22mm piston caliper taking 2nd place.
 

chris_f

Monkey
Jun 20, 2007
390
409
For what it's worth, the guy who runs Intend (who I believe had part in designing the DRT) runs Trickstuff Piccola levers with Gustav calipers. He claims it's "the best brake out there" but that can mean any number of things I guess.
 

Bike078

Monkey
Jan 11, 2018
561
405
Bike components.de says you have to wait up to 20 days to get the Trickstuff Direttissima. Is that true or do they have a longer waiting time?
 

HAB

Chelsea from Seattle
Apr 28, 2007
11,580
2,006
Seattle
Bike components.de says you have to wait up to 20 days to get the Trickstuff Direttissima. Is that true or do they have a longer waiting time?
That's the longest category that their automated system supports. Not accurate.
 

Mo(n)arch

Turbo Monkey
Dec 27, 2010
4,441
1,422
Italy/south Tyrol
Their homepage says six months at the moment.
But the levers seem to be available although in limited color combinations.
I have to dig through the Trigura thread again. TS gave some throw numbers which might be interesting and can be controled with Udi‘s chart.
 

Wuffles

Monkey
Feb 24, 2016
157
98
Trickstuff have updated their brake encyclopedia, funnily it covers many of the things I've posted recently.
http://www.trickstuff.de/en/know-how/index.php

I'll post some of the interesting parts, as they bust some common myths and re-state some facts which have been argued here recently:

View attachment 129151

View attachment 129152

View attachment 129155

View attachment 129153

View attachment 129154
Interesting reading for sure. I'm a little confused by their diverging statements on fluid- in the Direttissima section they say DOT vs Mineral oil is a wash out, but in the encyclopedia they tout the benefits of DOT for performance applications, surely the Direttissima's intended use would qualify?
 

Udi

RM Chief Ornithologist
Mar 14, 2005
4,915
1,200
Interesting reading for sure. I'm a little confused by their diverging statements on fluid- in the Direttissima section they say DOT vs Mineral oil is a wash out, but in the encyclopedia they tout the benefits of DOT for performance applications, surely the Direttissima's intended use would qualify?
They're correct on the EPDM vs. NBR situation but in real-world MTB use the differences are negligible. There's obviously an environmental push towards mineral oil, the DRT was actually originally a DOT brake.

The problems with virtually all currently available MTB brakes have absolutely nothing to do with the fluid choice (and thus seals) they use - and everything to do with the design choices made + mfg tolerances + materials used. Most designers aren't intimately familiar with ALL aspects needed to design a flawless brake, whereas TS have truly shown that they not only understand all problem areas, but the relative magnitudes of those problems in relation to the application at hand. This is exactly why those statements sound like a wash out, because in this application they actually are.

tout the benefits of DOT for performance
They don't actually say that when it comes to the fluids themselves, they suggest reasonably balanced advantage/disadvantage sets. None of them have much impact on MTB use (just on the potential health of shop mechanics with regular exposure, for single-consumer use I don't think DOT is a huge problem).

Interestingly, traditionally "high performance" DOT fluids are detrimental for MTB use, as evident from the "fluids" table in the brake spreadsheet. RBF660 for example has a high viscosity and would be a poor choice for an MTB DOT brake, compared to seemingly "lower performance" fluids.

tldr: There are excellent fluid choices available whether a brake uses DOT or M/O, and anything that sucks about current brakes has nothing to do with the fluid in them.
 

Udi

RM Chief Ornithologist
Mar 14, 2005
4,915
1,200
In more pressing issues - if someone could measure Saint / Zee (M820 / M640) slave pistons it would be appreciated. Additionally an M820 lever to take careful measurements from would be even better.

I've seen varying slave data from various sources now (18/16mm vs 17/15mm), and I think it'll be useful to have this firmly documented in the future since Shimano lead the pack (or certainly tie for the lead) when it comes to actually stopping. While a lot of this thread has been about reliability, I think it's important (especially with 29" increasing in popularity) to document "ideal" peak leverage, and have some quantifiable values to target.

I watched an official Shimano video lately where they say the XTR Trail lever has a larger MC piston / bore than the M820, and also read that the M615 deore lever has a less-aggressive servo wave profile, so there's a lot of potential unconfirmed variables.
 

Nick

My name is Nick
Sep 21, 2001
23,928
14,450
where the trails are
In more pressing issues - if someone could measure Saint / Zee (M820 / M640) slave pistons it would be appreciated. Additionally an M820 lever to take careful measurements from would be even better.
I've got a new front assembly in a box. What exactly do you want measurement of on the lever?
 

Udi

RM Chief Ornithologist
Mar 14, 2005
4,915
1,200
I've got a new front assembly in a box. What exactly do you want measurement of on the lever?
@troy can you possibly take the needed measurements from your deore levers for us, and photograph the caliper roughly in place (for each measurement) so Nick can take the exact same ones?

We could use it as a guide to check XT / XTR levers later too.
 

Udi

RM Chief Ornithologist
Mar 14, 2005
4,915
1,200
@StiHacka cheers, must spread rep.
I had a chat to troy and he'll be through within the next week hopefully with some pics of what to measure for you and Nick.

I've also been thinking about what you and kidwoo said about the Shimano calipers, and I've been wondering if some ceramic pistons (which have higher surface friction) might be messing with the rollback, since that could very directly cause throw variations, specifically a double-press to restore correct clearance + throw. Would be pretty cool to take a consistently known-bad Shimano brake and fit some of those ebay alloy pistons and change nothing else, to see if it fixed them or not.

Edit - actually I had an M775 that did it consistently and Sandwich had it with an M810 too, both from alloy-piston generation so maybe not. Still be interesting to try the pistons on a bad set.
 

slyfink

Turbo Monkey
Sep 16, 2008
9,289
5,029
Ottawa, Canada
@StiHacka
I've also been thinking about what you and kidwoo said about the Shimano calipers, and I've been wondering if some ceramic pistons (which have higher surface friction) might be messing with the rollback, since that could very directly cause throw variations, specifically a double-press to restore correct clearance + throw. Would be pretty cool to take a consistently known-bad Shimano brake and fit some of those ebay alloy pistons and change nothing else, to see if it fixed them or not.
@kidwoo did this before breaking his back. I was curious to know how that went, but it seems he's moved on to Formula now. I also wonder how much difference that would make since it seems a big part of the shimano problems is with the wear/contamination in the master cylinder assembly. (something to do with the parts not being anodized maybe?)

@StiHacka cheers, must spread rep.
covered
 

kidwoo

Artisanal Tweet Curator
@kidwoo did this before breaking his back. I was curious to know how that went, but it seems he's moved on to Formula now. I also wonder how much difference that would make since it seems a big part of the shimano problems is with the wear/contamination in the master cylinder assembly. (something to do with the parts not being anodized maybe?)


covered

Broke back, didn't ride for a while. Went to grab one of the bikes I have that still have shimanos and they damn near accelerate under braking. I never did stick the pistons in because those weren't leaking yet. Now they are. Weekend brake experimentation party at the woo house.
 

HAB

Chelsea from Seattle
Apr 28, 2007
11,580
2,006
Seattle
Do those piston kits come with new seals? Curious how it works out for you. I've got a pair of Shimanos that want to kill me that I'd love to resurrect.
 

kidwoo

Artisanal Tweet Curator
Yep, new rings.

Why shimano doesn't sell a rebuild kit, I have no idea. Super easy to do. I'll be interested to see how the heat gets handled. These are (I assume) ceramic cores surrounded by anodized aluminum. We shall see. I think they're actually lighter than the stock ones.
 

HAB

Chelsea from Seattle
Apr 28, 2007
11,580
2,006
Seattle
Yep, new rings.

Why shimano doesn't sell a rebuild kit, I have no idea. Super easy to do. I'll be interested to see how the heat gets handled. These are (I assume) ceramic cores surrounded by anodized aluminum. We shall see. I think they're actually lighter than the stock ones.
Yeah, replacing pistons and seals is super duper easy. I obviously haven't done it on Shimano because they're a bunch of dickbags and won't sell parts, but have on Formula and Hope shit. Even with monoblock calipers it's pretty straightforward.
 

Udi

RM Chief Ornithologist
Mar 14, 2005
4,915
1,200
I'll be interested to see how the heat gets handled. These are (I assume) ceramic cores surrounded by anodized aluminum.
Should be OK, I'm sure you remember the old M800 (and M810) pistons with a similar setup - metal piston and a polymer insert to provide thermal isolation.

Interested to hear how they go (especially if you ever fit them to one of the "throw varying" calipers), also curious if you notice any difference in rollback compared to the stock piston/seal combo. Probably optimistic, but if they reduced the rollback that would be a VERY cool benefit.
 

Bikael Molton

goofy for life
Jun 9, 2003
4,010
1,146
El Lay
My XTs were mostly consistent... unless heaven forbid the bike got turned upside down or spent much time lying on its side.

My brand new Codes feel like worn out XTs in need of a bleed.
 
Last edited:

HAB

Chelsea from Seattle
Apr 28, 2007
11,580
2,006
Seattle
Update: I agree that 69mm is a better number for ROR lever blade length.

Also, for Saint 820:
62mm lever blade. Lever pivot to MC starts at 11mm and drops to 8mm as the cam does its thing.

And, because why not, an XTR m985 Race (i.e. non-Servo Wave) lever is the same 62mm lever blade with 9.5mm from pivot to pivot.
 
Last edited:

kidwoo

Artisanal Tweet Curator
Should be OK, I'm sure you remember the old M800 (and M810) pistons with a similar setup - metal piston and a polymer insert to provide thermal isolation.

Interested to hear how they go (especially if you ever fit them to one of the "throw varying" calipers), also curious if you notice any difference in rollback compared to the stock piston/seal combo. Probably optimistic, but if they reduced the rollback that would be a VERY cool benefit.

I may be on crack but it really does feel like they don't have as much piston travel. That's dictated by ring size though right? Shouldn't that be the same? The pads aren't bedded in yet shape wise so that may be part of it. I've never had a shimano brake that doesn't vary the throw. Heh.
 

HAB

Chelsea from Seattle
Apr 28, 2007
11,580
2,006
Seattle
I may be on crack but it really does feel like they don't have as much piston travel. That's dictated by ring size though right? Shouldn't that be the same? The pads aren't bedded in yet shape wise so that may be part of it. I've never had a shimano brake that doesn't vary the throw. Heh.
The amount the pistons roll back when you let off the brake depends on the geometry of the seal, so if they changed that, there could be less rollback. The result of which would be less lever throw, since you didn't need to move as much fluid to get the pad to the rotor.

My money is just on this being down to the brake actually working properly now though. :rofl: