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Have you checked the torque on the hose nut? I've had that be the cause of that behavior on various brakes in the past. Refer to the "Dumb Bike Problems" thread... it's more than you think, but you should use a torque wrench because it is possible to crack the nut or hose olive if you go too far.
Yeah I would start looking at the connections at MC if there's something wrong, I for one have managed to install olive or two crooked.
have you checked torque on the banjo? There have been some comments similar to yours almost exactly and a few have found the cause to be loose banjo
It is really hard to get all of the air out of the maxima mineral oil with how thick it is. If you airate the mineral oil when you pull it into the syringe, you're almost guaranteed to have micro bubbles in it that are impossible to deal with. I am really deliberate about letting the syringes sit for 30 minute after filling them to let the air fully come out of the fluid. Also advisable to lubricate the plungers on your bleed syringes before you start so you don't have to yank them super fast to break the stiction when filling the syringes up.
For this reason, I do have a better success rate bleeding maven's with a bleed cup vs two syringes. Between the risk of pulling too much vacuum and pulling air past the syringe o-rings and air bubbles trapped in the mineral oil, the bleed cup is way easier. I'm about 80% successful in bleeding maven brakes on a 1 and done method. 1/5 times, I need to do at least a secondary lever bleed to get some air bubbles that come out on the first ride, or after the brakes have sat over night.
My red splatter Mavens were like this, every 3 months on the dot. I replaced pretty much every part but the pistons and seals and nothing helped. Changed to the teal splatter and they've been flawless for going on 9+ months. I have no explanation or helpful input, just commiserating
What helped me in the same situation is to overtighten the caliper bolts way past their stated torque setting.
Also, check if the hoses are tightly screwed in.
(Based on my experience with A1 Red splatter and A1 regular ultimate)
Which bleed cup fits?
Ezmtb like this one
https://a.aliexpress.com/_EGq0nVy
Pinner Machine Shop also makes an adapter for the Shimano bleed cup to fit on SRAM mineral oil brakes. Once you have the adapter, you can use the fancy billet aluminum Pinner bleed cup or a standard white plastic Shimano cup.
The adapter is only $13 USD. Worth it's weight in gold: https://pinnermachineshop.com/en-us/products/bleed-cup-adapter?variant=41552493150305
I agree with others about the efficacy of the lever bleed method to get any tricky air bubbles out of a Maven bleed, especially when they emerge over the course of a ride or two after a bleed. I've found a lot of luck doing the overnight lever ziptie/bleed cup method as a way to get any final air bubbles out. And I agree that there's something going on with the SRAM bleed kit, the Maven architecture, or Maxima's mineral oil that makes it really hard to get a consistent air-free bleed. Maybe it's all three.
The SRAM Maven/Motive/DB lever fitting is M4 threads. The Shimano bleed cup thread is M5. I use the Park Tool fitting adapter (part 2600A, $6 each) included in their mineral bleed kit to go between the two.
I also use the M5 adapter w/ the bleed cup for Shimano brakes because the plastic bleed cup threads wear out really fast when you are bleeding multiple brakes per day.
I spent about 2 1/2 hours installing 1 maven caliper/lever and bleeding the other on a DH bike because I really wanted to get it right the first time. Will see what they say when they ride it. The lever had to be replaced because it seems like someone installed the olive backwards, I couldn't get the hose out of the lever even with pliers/twisting and the compression nut had been overtightened and turned oval.
Real interesting review on the Die Bremses. I would just skip to the performance section of the video. Claims they've got a lighter lever pull than Dominions with more power than Mavens and Hope V4s.
Can confirm, Felix is a mega rad dude.
This is a great tip! Park calls it the "Park Tool 2600A – Mineral Oil adaptor for Campagnolo" but apparently it works for SRAM DB8 and Maven, Trick Stuff, and Campagnolo mineral oil brake systems.
Link for just this adapter: https://www.ultrabikeworks.com/product/park-tool-2600a-mineral-oil-adaptor-for-campagnolo/
Link to the Park Tool site with the mineral oil upgrade kit that includes this adapter: https://www.parktool.com/en-us/product/hydraulic-brake-bleed-kit-upgrade-set-bk-uk
After watching a couple of his reviews I found the biggest caveat to be that we just don't weigh the same. Iirc Dale weighs 130-ish pounds. What works for his weight and his type of riding is not likely to translate over to the viewer. I do believe he is very transparent on what he thinks, while also being a very solid rider - but some of the info just doesn't apply to some of us, like me, who is a lot heavier.
Stronger brake is stronger brake regardless of who is riding it, just like lighter lever action is lighter no matter who pulls the lever. They are brakes attributes, not riders attributes.
Yes and no. The amount of brake torque applied to stop a rider from a given speed to a desired speed is not the same for different weights. We are going to massively simplify here and assume everyone rides the same on the same tires, rotors, pads etc..
In the graph below the 3 horizontal lines are a gross simplification representation of the torque needed to slow a rider of that weight down. The 3 lines represent 3 styles of brakes - the black line needs a very heavy initial pull but ramps extremely quick ; the red line needs somewhat firm pull that ramps fast at start but slows towards the end, and the green line which requires very little force to get moving but ramps slowly. For each rider which brake has the "lightest" lever feel is going to be dictated by how much they need to slow down and how much they weigh (among other conditions like tire/dirt/etc) As you can see, the lightweight rider is going to feel the green brake is the best for this scenario as it requires the lightest pull for the force they need. Think the black as a maven. Dale is not going to like it since it requires a massive pull for what he needs. I think it's pretty damn good since it's the lightest for what I need. Again, this is a very gross simplification.
Also grip strength is, like most things, strongly correlated with body weight. A “light pull” for Dale is probably not a “light pull” for me. (Hence all the forum hoo-hah about how the A1 Mavens are either unridable due to an inhumanly stiff lever feel or just fine.)
Do you have any real measurements to back up your graph? Without actual data the graph is just theory.
If you are shopping for DH brakes the tester needs to be able to replicate similar conditions. Brake fade is an entirely different thing for someone 200+lbs vs. a 130lb rider. Some things transfer, some don’t.
Not sure what "actual data" is required but...let's use maven (noted red) and motive (noted green), both sram brakes, as an example. At the start of the stroke, the motives have a lighter pull to start biting, so there's a data point for that (bottom left green).The mavens are going to take a bit more to get going, so bottom right red point notes that. At an arbitrary high force, the mavens will generate more braking force than the motives - you can base that either on many of whom have rode both, or the simple fact that motives have a much lower leverage ratio compared to the mavens. The 2 braking formulas f(x) maven & g(x) motive must both be consecutive. They could be close to simple straight lines if there were no leverage links, but most brakes today incorp some kind of changing leverage ratio. If there exists p that f(p) < g(p) & q that f(q) > g(q), then there must be r which f(r) = g(r). So if you are a person who often does not need a braking torque more powerful than x = f(r) = g(r), then the motives are a better brake for you. If you are a person who often needs braking torque more powerful than x, then you will be leaning towards the mavens. Why do heavy people need more braking force to slow down in the same amount of time for a given velocity? ft=mv, m being the mass, and v being velocity - if m is being increased then f must be as well for the same t(ime).
Brake fade is pad and rotor dependent, both of those are interchangable, no one is boiling braking fluid in MTB, mineral or DOT.
He was comparing it to dominions, there is your reference point. They are known to have the lightest lever action and it was also objectively measured before. 612 brake was not part of any group tests I have seen so it's possible they are actually the best in this regard.
Brake fade is also caliper dependant, a more closed off caliper will make cooling the pads harder than a more open caliper design.
As for lever pull, Die Bremse and Dominions, as per this topic Dominions have one of the lighter lever pulls before the pads contact, but apparently require quite a lot of finger force (relative to other brakes) to generate adequate braking force.
This just confirms to me a light lever pull really should NOT be a metric that we judge brakes on. It's the definition of a parking lot test issue. You brake with a considerable force in your finger, a much higher force than what is needed to start piston movement where this light lever pull comes into action.
The new Hope Evo brakes also use the same size threading as Sram Mineral Oil brakes. So you could order a Hope bleed cup and the Evo adapter if you wanted to bleed Mavens with it.
I know because I did the opposite and used a new Sram mineral oil syringe as an improvised bleed cup for my GR4’s.
My only concern would be fluid compatibility of bleed kit seals and o-rings. I used a well-cleaned SRAM DOT fluid syringe on a mineral oil brake, and the o-ring at the bleed fitting swelled and failed. In contrast. A Reverb syringe with the same M5 thread but a red o-ring did fine with mineral oil.
I’m not sure if you would have similar issues using a mineral oil bleed kit with DOT fluid.
This doesn’t seem to have anything to do with what I wrote?
For the same pad, same brakes, same rotors, same downhill, same tire/dirt/bike/you name it etc, a 200lb rider will fade a given brake faster than a 130lb rider, this is just physics. Yes they are interchangeable, no that does not make any difference whatsoever in the statement made by 63expert. This has nothing to do with the fluids boiling or not.
The light pull thing isn't a non-issue, it's just not an issue for everyone.
Aside from avoiding a lot of arm pump with light pull levers, i also much prefer the feel and control, so i'd prefer to know what brakes are heavy to pull and what ones are light. Is that okay with you?
Of course you would. DOT fluid basically dissolves mineral oil (usually NBR) seals while mineral oil swells DOT (usually EPDM) seals. This has been known since forever.
Everybody says different mineral oils are not cross compatible and there have been some claims about seals degrading by using a mineral oil from another manufacturer, but comparing mineral oils is still like comparing different fresh water sources as opposed to DOT being something completely different than water.
Completely okay, whatever floats your boat.
My concern is missing the forest for the trees. Are you sure a light lever pull will give you less arm pump? What I'm reading from you is that closing the pad gap is what gives you arm pump. Not the fact that you then need to pull the finger orders of magnitude more strongly when actually applying the braking force.
I.E. Dominions with their apparently high lever force required to get enough braking force from them would give you less arm pump than a Brake requiring less lever force but a higher starting force. To me that makes no sense at all.
Post a reply to: Nerding out on Brakes shall we? Not another tech deraliment