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Frankenbrakes and brake improvement discussion

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Nick

My name is Nick
Sep 21, 2001
24,933
16,537
where the trails are
What's up with the curas?
I canNOT keep them from rubbing. Perfect flat, true rotors, good bleed, and they'll start squealing randomly. Shit they even sing when I'm climbing (a rare moment i'm not riding my brakes) and once I start downhill they scream nonstop.

Pistons don't seem to be retracting. I've tried cleaning them but no change. I haven't given up on them entirely, but I didn't want to deal with that shit all weekend so I threw a known-good pair of Saints back on for the time being.
 

Sandwich

Pig my fish!
Staff member
May 23, 2002
21,858
7,106
borcester rhymes
I feel like shimanos are cheap enough to run for a season then just throw away. That's like four seasons before you've matched a set of directstuff, and at that point they might be ready to ship.

Sounds like most people like their maguras, except for weird euros ascared of big jumps
 

Nick

My name is Nick
Sep 21, 2001
24,933
16,537
where the trails are
well, I've never had a Shimano warranty claim answered any way other than a replacement brake. (knock wood)
so long as they continue that until they fix their flaws ....
 

HAB

Chelsea from Seattle
Apr 28, 2007
11,592
2,028
Seattle
I canNOT keep them from rubbing. Perfect flat, true rotors, good bleed, and they'll start squealing randomly. Shit they even sing when I'm climbing (a rare moment i'm not riding my brakes) and once I start downhill they scream nonstop.

Pistons don't seem to be retracting. I've tried cleaning them but no change. I haven't given up on them entirely, but I didn't want to deal with that shit all weekend so I threw a known-good pair of Saints back on for the time being.
2 or 4 pots?

I still really like the RORs. They're not quite up there for power with the big 4 pot guns (e.g. Saints) so maybe not great if you're on a 29er DH bike doing park laps all day, but they're powerful enough for my purposes and everything else about them is awesome.
 

kidwoo

Artisanal Tweet Curator
I canNOT keep them from rubbing. Perfect flat, true rotors, good bleed, and they'll start squealing randomly. Shit they even sing when I'm climbing (a rare moment i'm not riding my brakes) and once I start downhill they scream nonstop.

Pistons don't seem to be retracting. I've tried cleaning them but no change. I haven't given up on them entirely, but I didn't want to deal with that shit all weekend so I threw a known-good pair of Saints back on for the time being.
hmmm

I have a 2pot caliper that seems to be leaking now. I need to try some fresh pads to be sure.

This may be the point where we realize that cheap shit is cheap.


I did notice on my saint lever/2pot cura setup I had on my dh bike, that the rotor would deform after some really really hard brake dragging...to the point where they would temporarily rub until they'd cooled back off. The super tight spacing on formulas definitely contributes.
 

jonKranked

Detective Dookie
Nov 10, 2005
88,897
27,089
media blackout
I feel like shimanos are cheap enough to run for a season then just throw away. That's like four seasons before you've matched a set of directstuff, and at that point they might be ready to ship.

Sounds like most people like their maguras, except for weird euros ascared of big jumps
maybe i'll just start using my saint M800 brakes on my trail bike.
 

HAB

Chelsea from Seattle
Apr 28, 2007
11,592
2,028
Seattle
I feel like if you've had brakes go to the bar at inopportune moments, you're gambling with your face.

I've almost gone over an 80ft cliff before. it's not cool.
I had a Saint 810 go to the bar in Whistler, when I was trying to stop because there was a bear in the middle of the trail. Some poo came out. :rofl:
 

Flo33

Turbo Monkey
Mar 3, 2015
2,139
1,367
Styria
I did notice on my saint lever/2pot cura setup I had on my dh bike, that the rotor would deform after some really really hard brake dragging...to the point where they would temporarily rub until they'd cooled back off. The super tight spacing on formulas definitely contributes.
That's why I bought Formula 2 piece rotors in July. It seems to help, a bit.
 

Lemke

Chimp
Aug 22, 2019
16
14
The Magura and Shimano hoses mic out at the same OD, and their respective olives have the same ID. I had the same mind-set as Sandwich... matched the interface pieces with the lever/MC. We'll see...
Update: Well, the Magura hose with Shimano barb and olive have a slight leak at the lever, dang it. Next up, Magura barb and olive.
 

Boozzz

Chimp
Sep 12, 2019
81
85
Amsterdayummm
Signed up here specially for this thread, love the spread sheet, seems like the ultimate disc brake knowledge zone on the net :)

I was thinking about the Magura MT5/7, and how it compares to the Hope V4. Magura uses 17/17 mm pistons in the caliper, Hope 18/16, so the slave area is the same. Now the Hope Tech 3 lever uses a smaller master cylinder diameter than Magura by .5 mm. I take it the mechanical leverage in the sheet for the Magura's is with the longer lever. So if I use them with the shorter HC lever, this will be slightly less, maybe comparable to the Tech3.

Anyway, I actually own the V4 and they're pretty good, but everyone always keeps raving about how crazy powerful the Magura's are, while they in theory should actually be about the same or even slightly less? Or does the 18/16 mm piston combo make for more modulation and a less instant power feel, or does Magura just use softer pads?

P.S. I use the Hope Trial Zone brakes on my trials bike, so anything you want to know, just shoot.
 

Sandwich

Pig my fish!
Staff member
May 23, 2002
21,858
7,106
borcester rhymes
The one-piece are the way to go. Four-pieces defeats the point of having four pots, it's more like having 2 calipers
So Magura's take is that four independent pads makes for double the bite as you now have four leading edges rather than two. I don't know how grounded in reality that is, but I will say that when I switched from single pads to dual, I got more bite. I also got a different pad compound, so my data is irrelevant.

For what it's worth, Trickstuff (whose mantra seem to be "more powerful everything") makes their power-pads as one piece, like for the MT5.
I can see the logic of a one-piece pad if that single piece was filled with pad material, but it's not. You get identically sized pads but they're attached rather than separate. So you're kind of throwing two stones to kill one bird here. No dual "bite", no extra pad material for heat mitigation. It is nice to not have to run pins, but I'm not sure that's a real concern.
 

maxyedor

<b>TOOL PRO</b>
Oct 20, 2005
5,496
3,141
In the bathroom, fighting a battle
I'd still love to try the Trickstuff brakes, but honestly, for for the price I'd at least hope for non-finicky bleeding. They really should have a fitting on the lever cap for a cup like Shimano has, all brakes should have that thing. Still tempted to buy them, for the same reason I want eeWings cranks, so damn good looking.

On the subject of Trickstuff, anybody have a US source for the powerpads to fit Cura 4s? Still have too few miles to declare them a complete success, but so far the Cura 4s are great, more than enough power with the organic pads, but they have been wearing kinda quickly, curious how much extra power they have with the Trick-stuff pads.
 

Nick

My name is Nick
Sep 21, 2001
24,933
16,537
where the trails are
ok brake nerds ... riddle me this,

what would be the real fix to making a set of 820 Saints consistent and issue-free? (or any shimanos for that matter)

piston material? (stainless vs ceramic?, something else?)
piston seal material?
MC seals?
 

HAB

Chelsea from Seattle
Apr 28, 2007
11,592
2,028
Seattle
I think they need to do two things:

1) address MC bore wear somehow. Some combination of anodizing the inside of the bore post-machining so it's harder, and/or better material selection for the piston.

And 2) make the caliper pistons stop leaking. The ceramic ones make sense from a heat management/insulation perspective, but it seems like they can't keep the surface of them smooth enough to make a good, reliable seal.
 

Rockland

Turbo Monkey
Apr 24, 2003
1,880
286
Left hand path
Have you taken apart your used Saint lever yet?

ok brake nerds ... riddle me this,

what would be the real fix to making a set of 820 Saints consistent and issue-free? (or any shimanos for that matter)

piston material? (stainless vs ceramic?, something else?)
piston seal material?
MC seals?
 

chris_f

Monkey
Jun 20, 2007
390
409
Signed up here specially for this thread, love the spread sheet, seems like the ultimate disc brake knowledge zone on the net :)

I was thinking about the Magura MT5/7, and how it compares to the Hope V4.
I made the very same switch. I run my MT7s with the shortest lever, the HC3 adjustable one, and let me tell you... even with the lower mechanical leverage than the "normal" Magura levers, the power on the MT7 and the Hope V4 are in no way comparable. The V4 is possibly the weakest Actual DH brake I've used, and the MT7 is the most powerful. I've not used any of the Formula brakes, and I've not used any Trickstuff brakes, but I've tried a fair few different systems.

Oh, I also used the MT7 for a few weeks with the long-ass lever the normal version comes with, and the power difference between that and the HC3 was not something I felt was worth taking into consideration when faced with the far superior ergonomics, adjustability and lever feel.

Make the switch.
 

Boozzz

Chimp
Sep 12, 2019
81
85
Amsterdayummm
I made the very same switch. I run my MT7s with the shortest lever, the HC3 adjustable one, and let me tell you... even with the lower mechanical leverage than the "normal" Magura levers, the power on the MT7 and the Hope V4 are in no way comparable. The V4 is possibly the weakest Actual DH brake I've used, and the MT7 is the most powerful. I've not used any of the Formula brakes, and I've not used any Trickstuff brakes, but I've tried a fair few different systems.

Oh, I also used the MT7 for a few weeks with the long-ass lever the normal version comes with, and the power difference between that and the HC3 was not something I felt was worth taking into consideration when faced with the far superior ergonomics, adjustability and lever feel.

Make the switch.
Good input, but I'm also trying to nerd it out a bit by looking at the hydraulic leverage, which is greater on the V4/Tech3 combo than on the MT5/7. Which gives me to wonder if it's just the stock pads that are better/softer/grabbier on the Magura? Or does an unequal/equal piston size matter that much for the feel of a brake?