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Too much to have any control? What do you mean by that?
Honestly, everything has been an experiment with the Lewis brakes and I'm willing to keep experimenting. I'm not in a rush to go larger, but open to giving it a try down the road. Ha ha
The power was coming on too fast and too much of it, it was basically like throwing out an anker behind you. That's what I've been told. Granted, it was a much lighter rider, but a very, VERY fast rider.
Interesting, I did not know that. 👍
So, for what its anecdotally worth, the overnight bleed cup has fixed wandering bite points on multiple sets of shimanos that have rolled through my garage, and provided actual consistent magura bleeds after wiggling the caliper around a bit. I've done it on pretty much every mineral oil brake I've seen on a bike build, or owned (shimano, magura, TRP, mavens) to great success. I now make it a mandatory part of all the bikes I build a season (which could be upwards of 25). I wouldn't dare try with dot fluid due to its habit of absorbing water from the atmosphere, but mineral oil doesn't have that problem.
As for the exact mechanism for why it tends to work--outgassing or over bleed. It's worked well enough for me that it might be worth a try if you have the means.
Also wanted to give Pinner machine shop a shout out, their bleed cups are awesome.
https://pinnermachineshop.com/en-us/collections/bleed-cups
Not going to lie, this intrigues me. Ha ha
Wait a tic, are you leaving the bleed cup overnight on the caliper or the lever? I'm guessing you meant lever, but said caliper, unless Mavens have a reversed procedure from most other brakes. Assuming that is the case, and you also have the levers rubber banded, it seems like it could be accomplishing 2 things. The lever compression could be dissolving any remaining bubbles in the active pressurized part of the brake system, and/or the bleed cup could be allowing micro bubbles in the inactive unpressurized reservoir to filter up slowly. Tertiarily, when you release the lever the next day, any undissolved air in the pressurized portion of the brake may have made it's way up to the lever (aided by the smaller size of the pressurized bubbles allowing freer movement in the oil column) and can then be released up into the reservoir and bleed cup when you release the lever.
Update on the Lewis levers. I contacted all Lewis dealers and none were able to offer parts. I sent an email to the Lewis factory in China and they're willing to sell the parts. All of the small parts combined for both brakes cost 108$+30$ express shipping to Finland. I have no clue how long the actual shipping time will be but hopefully I can test the setup soon.
Since the Lewis levers have the same size bearings as TS, the bite point adjuster can be retrofitted to Trickstuff levers by either swapping the part that the pushrod screws into for the lewis one or tapping the TS part for a M5x0.5mm thread (original pushrod is M4x0.7mm). I plan to first put the complete Lewis lever blades on since they seem to be a good middle ground between the Maxima and Direttissima lever.
The LH4 lever blade has a similar length to the Maxima lever but also has the same pivot point geometry of the Direttissima lever. The Maxima pivot placement gives more power than the Direttissima but also makes the lever feel spongier. This is also due to the longer overall lever blade length of course.
If they are pumping up on rapid pulls but work consistently otherwise, as a general rule, it could be due to 2 different causes.
1. If the pumping up is taking you from an excessively long lever throw to a normal one, that is usually due to a poorly maintained brake that is low on fluid and/or has excessively worn pads, and/or has stick caliper pistons. Basically, the system is at a point where a single lever pull can barely generate enough fluid volume to activate the brake fully, so you need to "stack" multiple pulls on top of each other to get enough flow to get you to a normal bite point. You're working with a newish brake and sound like you're on top of maintenance so I DON'T think this is what you're dealing with, but am just including it for general diagnostic info purposes for other thread users.
2. If the pumping up is taking you from a normal lever throw to an excessively short one, that is nearly always due to a mismatch in fluid viscosity and hose/port sizes. If the fluid is too viscous relative to the hose or ports then, after a lever squeeze, it can't flow back from the caliper fast enough to sufficiently fill the depressurized master cylinder, so as soon as the M/C piston seal crosses the timing/equalization port to the reservoir the system will draw in extra fluid from the reservoir. This would normally work itself out and the fluid would go right back to the reservoir as soon as the flow back from the caliper catches up, but in a rapid repeat pulling scenario you will be closing off the timing/equalization port and reactivating the brake before the system can catch up and return to homeostasis, so the pulls "stack" on top of each other and create what is effectively an overfilled active portion of the brake. If you have a hose or fitting that has some manufacturing defect (a piece of metal flash partially occluding the fitting, a hose with a crushed liner, etc...) then replacing it should remedy the problem, but if you are having on both front and rear brakes then it sounds like more systemic. If other Mavens behave differently, it could be you have a bad batch of fluid, but if they are all like that, and you are comfortable using a 3rd party oil, then switching to one of the thinner mineral oil options like Redline Likewater or Putoline would quite possibly resolve the problem and give you a less damped feeling lever action to boot. Many people with wandering bite point issues on Shimano brakes swear by them, so they're pretty well tried and true in mineral oil brakes.
You're totally right, I meant levers. Updating
Drilling out an M4 to an M5 thread will probably not work, I don't think there's enough material. But making a new axle-nut shouldn't be that much of a problem? You'd just have to source the pushrods
Like I mentioned, I experienced the same issue after a full rebuild or on the factory bleed on my Code RSCs. A proper bleed helped things and the lever was then consistent.
There is a third option - air in the system. The first pull compresses it and the second pull adds fluid. When you release the lever, the air can expand and pushes the fluid back.
There’s definitely enough material in the stock axle nut but I’ll give the lewis lever a test first.
I checked things and for an M5 thread the hole to be drilled is larger than 4 mm. Still, drilling out an existing hole could be problematic. It would probably make sense to make a new nut also to be able to go back to the original setup. Drilling out the nut is a one way street.
Purty much nailed that answer. Only thing I would add is work from simplest to hardest remedy. It does sound like you have excessive seal roll at the caliper to me. Given it's known that Mavens need the pistons cycled in and out a few times to develop the proper amount of piston slip, I would work that process a half dozen+ times, that's after insuring you don't have any kinks in the brake line.
If I had a dollar for every time I’ve massaged the pistons on these stupid brakes, I could buy a few six packs of beer to drown the pain these things have caused me.
The pistons aren’t retracting fast enough. I’ve tried lubricating them, I’ve tried not lubricating them, I’ve tried replacing the olive and barb, I’ve tried replacing the levers.
Replacing the levers helped, and they’re no longer bad enough that they’re gonna make me crash again but they’re still distracting.
They look like the calipers might be leaking now. Maybe this set is just cursed.
In the World cups incl world champs, Lots and lots of 'lever strapped to bar' to essentially purge the brake and keep a good solid feel..
Why is this a thing we must do? For reference Ever since I seen this years ago i've done it to all shimano/trp brakes, It gets rid of the wandering bite point for me, But i must do it every 2-3 rides.
My Mavens Once setup correctly(can be fiddly) have been fantastic. Park day after park day no worries.
Regarding the putoline I think it could be safely used on brake as Intend use it with the Trinity (and they work absolutly perfectly).
I have just realized there is a typo in the tilte of this thread. Can't unsee it now.
Ops that was me 😓
Hey lets not derale this thread like the tech rumors...
Slow retraction is a solid indicator of a fluid restriction. That can be from a deformed brake line or foreign object(s) blocking ports. Assuming you lubed the caliper pistons externally, I would not think of that as a leak but residual lube. barring a deformed brake line I would ping Sram tech support at this point. I think we can all agree you did your due diligence.
I remember watching the Trinity tech video and Cornelius said they got the idea from Shimano riders using Putoline to get rid of wandering bite point. He cited the PinkBike forums where someone used it and the idea caught on. So it technically can be used in any brake rated for mineral oil.
How was the Trickstuff/Maven combo otherwise? So the modulation was ok, the lever pull is heavier and there's more free stroke. But how was the power? Is a full Maxima setup more powerful than with the Maven caliper? When I get the Lewis parts I think the free stroke issue could be resolved with the bite point adjuster. So I'm wondering if I could get more power out of the brakes with the Maven calipers?
The power is similar, without using the same pads it's hard to say exactly.
You have to overfill them a little to work, but yes a BPA will help. I reckon a 2.3 rotor would be mint too.
Little late to this but I finally ended up pulling the trigger on a set of T4 V4's after experimenting with Code RSC's (with and without cascade cams) and a variety of Shimano setups over the past season. I appreciated the modulation of SRAM but the lack of power made them useless on any serious race runs. Kinda the opposite for the Shimano's, constantly locking them up and still didn't have the end-stroke power for big park days. After finally calling it quits on a set of XT lever+Saint caliper+MTX red pads, I ordered a set of Hope's via my employer/shop. Set them up with 203 Freeza rotors, green pads, and nonbraided lines.
At first I was a little worried due to the slightly mushy feeling in the lever, even when perfectly bled I could almost yank them to the bar with enough force. All those doubts went out the window the second I got them out on the trail. They have so much power that you never have to really pull on them. The modulation and ultralight lever feel gave me significantly better control compared to all other brakes I've used in the past, even TRP/Hayes/Magura. I would estimate my arm pump has decreased between %20-40 over a 3 minute DH run while posting consistently faster times. The only issue I've had so far is very minor rotor rub but probably due to me bleeding with the pistons pushed out slightly/brand new pads. No noise, fade, pump, or anything of that sort so far. Moving forward, I really can't see myself owning any bike over 140mm with anything other than Hope's on it (except maybe Trickstuff/Radic etc). Also, not as important, but the build quality and finish is very, very impressive. Really blew my mind compared to the mainstream brands.
pretty sure this came up on the mtb-news.de forum first…
This is exactly why I decided to keep my TS Maxima. They felt exactly as you described. "Squishy lever" doesn't mean much when you have so much power and control on tap with little effort. Some people get too obsessed with a firm bite point
Cause most people are on the stock codes or whatever, where you either have a mushy feel with no power, or a strong bite, again, with no power
So you just get hand fatigue
My Maguras are not that firm but the power is there so I never find myself pulling hard to stop or slow down
I guess that’s only elevated with superior brakes such as v4s and Maximas
Speaking of Hand fatigue, just did 2 x park days in a row... I used to suffer bad hands with shimano XT's... but now on mavens and its surprising how much of a difference they have made to my riding & hand fatigue... no sore fingers etc just sore forearms etc from the huge bomb holes.
Just full blast into a corner, quick tap on the mavens and whip around the corner no sore/very little hands vs shimanos of start earlier, rear skipping with the front odd lock and pulling hard ending up with sore hands.
My Ebike XT's with Galfer 223's & ebike pads cope pretty OK though but havnt taken to a lift access place.( no worries of weight of 223's etc on ebike)
When you say: "Why is this a thing we must do?" do you mean:
A. "Why do our very expensive brakes suck and require creative hacks to work?".
or B. "Why does strapping the lever down help our brakes work better?"
If you meant A, I can't tell you for sure, other than to say, either bike brake engineers lack the skill to make bike brakes perform consistently in real world conditions with real world maintenance programs, or they have the skill, but don't feel the consumer pressure to design the brakes with a priority on consistency, and instead are prioritizing looks, cost, profit margin, outright power, weight, etc...
If you meant B, we really dug into that topic of why strapping levers works starting on page 7 of this thread. Several ideas were bandied about, including some that were totally new to me, so I think it's worth going back to read it if you haven't yet. In short, the primary suggestions seemed to be the sustained pressure dissolves residual air into the oil, making it non-compressible, and/or the sustained pressure shrinks residual air bubbles down in size, making them float up through the system more readily, so they can ultimately reach the lever reservoir where they're unlikely to cause trouble, and/or the sustained hours-long pressure causes the pistons to slip through the caliper seals a bit more than normal, which resets them to a position closer to the rotor, leading to less lever throw required for full firm pad contact.
Post a reply to: Nerding out on Brakes shall we? Not another tech deraliment