Frankenbrakes and brake improvement discussion
- Thread starter Udi
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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.
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
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
@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
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
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.
I tried your advise, it didn't really help. Although I do appreciate the heads up.
@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.
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.
Thanks @Udi !
Magura doesn't seem to have this kind if spare parts, probably just to be like Shimano
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...
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.
Magura doesn't seem to have this kind if spare parts, probably just to be like Shimano
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...
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.
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?
new tormachs just came out
https://www.tormach.com/blog/introducing-tormach-m-series/
770M should be able to do what you are looking for
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
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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/
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/
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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.
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.
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.
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.
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.
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.
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.
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.
@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.
I have a spare (wrecked) Zee lever in a box, too. I can provide the measurements as long as instructions of what to measure are provided.
@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.
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.
@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
Here's another good option fornew tormachs just came out
https://www.tormach.com/blog/introducing-tormach-m-series/
770M should be able to do what you are looking for
nerds: http://www.pocketnc.com/5-Axis desktop CNC mill, would be perfect for @Udi to machine his own brake calipers, master cylinders, etc.
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.
I just want to say blowing out pistons with a compressor set at 80psi is a good time. Got the driveway of the house across the street. Try and beat it bitches.
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.
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.
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.
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.
My brand new Codes feel like worn out XTs in need of a bleed.
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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.
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.
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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.
