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i sold all of my bikes that I couldn't afford to set up correctly.
I don’t think that’s as impressive sounding as you think it is.
I think its a good idea, No point owning mediocre bikes when you can have 1 or 2 with the parts you want.
Yeah it’s a bit tongue in cheek
Thanks for the advice. I’ll hold out for the hope evos.
Double tap the brakes when you're riding shimanos... first tap will tell you where you're at, second pull will have full power. Most of my bikes have some form of slx, xt, xtr, or saint variant. I don't know how, I don't know why, but double tapping when riding them has kept me from having those oh shit moments.
If I had to double tap my brakes every time I pulled them, I’d throw them straight in the trash. That’s not acceptable brake operation.
more info being released on instagram from Brembo. Sound solid! Hope they are available soon...
1. Dbl/Trpl check your bleed. Easy to do. Flip the bike upside down and see if the brake starts going to the bar. If so, bleed, baby bleed. We're human. We err. It's part of being in this divine comedy. 2. If no bleed needed, do the piston massage trick as done on the Mavens. Those ceramic caliper pistons generate a lotta stiction due to the porous nature of the material. I posted about this sometime ago, here and elsewhere. It does help with, but not get rid of, the wandering bite point. Side, I'd like to thank Sram for introducing something I started blabbing to people about back in my industry days way over 15 years ago and making it seem like I'm not a kook. The things co's do to not have a 'leaky caliper' new out of the box. 3. and pretty much last resort. Swap the caliper pistons with aftermarket phenolic units found on Amazon/Ali/eBay. Since Shimano refuses to offer service kits and would likely not look at this as a warranty issue you may be on your own. We can leave the 'should I have to do this on new/near new brakes?' debate behind since we all know the answer esp in light of the new and improved brakes. I've used the Xnavi ones without issue. Downside/upside (depending on perspective) is pad gap decreases, so the brake engages way quicker. I loved it and so did the other 2 guys I swapped em out for.
Things to watch for. 1. torn reservoir diaphragm. If you're using 2 syringes to bleed the brakes it is way easy to tear the diaphragm. I learned that the hard way and I didn't even think I was pulling a big vac. As Shimano doesn't provide spares, you'll need to source the aftermarket ones from the same sites as the phenolic pistons. I did, it worked. 2. Ruptured hose or MC piston primary seal. Both can behave like there's no problem, both can give the same lever to the bar feel under a slow, easy pull of the lever. Diagnosing em requires a bleed block and the bleed cup. It's long-winded to write in an already long-winded reply. If it comes to that, lmk.
Bleed is good. Done with syringe and cup. It was very dusty and there are no signs of fluid anywhere. All 4 pistons move and retract equally and visually appear to be all extended the same at rest and while clamping the rotor.
You can double tap the brakes in your car as well for a different pedal feel, and drivers do it all the time for different reasons.
Did you actually flip the bike upside down to check?
About the caliper piston engagement, good, but that's what I'm not referring to. The ceramic pistons bring a lot of retraction to the table. Equal actuation may not be correct actuation. Pumping em out, pushing em in a few times can help generate more seal slip, which means the seals can behave properly under heavy use. I had seal roll issues on my old SLX brakes and that trick worked for a good while to address wandering bite point. Replacing the caliper pistons solved it outright, at least until the MC pistons crapped the carpet.
You are correct however in those moments where the pedal is hitting the floor with no stopping action, the brake ain't working the way it's intended to.
in a Modern Everyday road car, that should not happen unless something is loose etc causing the same as below.
However in race cars, especially such as 'supercars' in Australia, Drivers will tap the Brake pedal at the end of a long straight before brake zone to ensure the Pads are close to the rotor/disc, This is often because of the lead up corners putting side stress/flex though the carrier/hub pushing the pistons back.
It wasn't clear to me in the OP that there was no stopping power, so I assumed the oh shit moment was caused by a gap in the expectation of brake force given the lever pull and the amount of brake force delivered.
Besides bleeding again, my only other suggestion on the shimanos is to back out the free stroke screw when bleeding, and then screw it all the way back in when the system is closed.
Alright this is getting a little off topic - just trying to add color to a guys comment about crappy lever feel on some shimanos. Hope you find a solution, please let us know what works incase my shimanos decide to start acting up on me.
Any car with ABS will give you a different pedal feel when you prime the brakes before a braking event. It's especially noticeable in pickup trucks. Try it on your way home.
It's been a while since this thread has gotten derailed. Maybe we're overdue :D
I'm curious what the discovery is too. I got hypercritical of brakes a long time ago and thought going with Shimano would end my search. And it did until they started developing all sorts of issues. I am cautiously optimistic on their new lineup but as it seems they're still using plastic MC pistons, at least on the high-end wares, they're still off my braking diet.
Hey @HexonJuan I finally found out the issue with my Dominion A4s and it was a leaky caliper. During fatbiking your bike is constantly getting washed so I guess the smallest amount of leak would get washed away going unnoticed. Hayes warrantied the front caliper and I has to rebuild the rear as it also started leaking after spending a few months in storage. So both calipers started leaking in under a year. Could it be that the sub zero temps are bad for these caliper seals? I never had issues with SRAM brakes in the winter before so this is interesting. According to my local shop, the dominions are notorious for leaky piston seals so maybe it is just crap quality.
During this process I also found a way to get the best bleed I managed so far:
1) Push-push only. Send fluid from caliper to lever and then back until no bubbles can be seen. Don't create vacuum at lever.
2) Close the system and zip tie the levers to grips for 24 hours
3) Attach the syringes again. Tiny pull of caliper syringe to remove that small air bubble introduced from fitting. Then one long push to remove the air accumulated in the lever.
The numbers are promising it could possibly be the most powerful brake so far
Curious about the aluminum pistons tho, they should transfer lots of heat to the pads 🧐 but I’m sure they know what they’re doing.
Regardless, I’m curious what kind of price and claim they will give us
Absolutely! That part excites me. I am just eager/optimistic about their take on things and how they may perform.
Aluminum pistons will be interesting but at least they do have a pretty solid background with high performance brakes so we shall see...
Price has me on my toes however based off their original take 20 ish? years ago.. ha.
But I would assume around the $1,000 realm.
I am excited to try them and hope they become available soon.
Interesting! I've a few friends riding fatties on A2s and no issues to speak of. Hayes have a 2yr warranty so the other brake (I think) should still be under warranty. I wouldn't think the onus of a rebuild would be on you.
Yes it would also be covered but that would have me out of a brake for maybe 2-3 days while the shop submits warranty claim etc. It took me a short drive and $34 CAD to get the rebuild kit and 1 hour of labour to fix it. Good to know your friends' A2s are going well. Maybe just crappy luck on my end. I'll give them another shot.
Sad to see Brembo is all red. I know they want to enter hard, but a color like that will simply crash with so many bikes. Why couldn't they just sticked to their usual color combos...
Hopefully they introduce more color options.
Personally I'm still curious to see when somebody will review the HEL Advocate brakes, because it's been awefully quiet about those.
wouldn't the opposite be true as well? that the pad will be better coupled with the caliper body for better heat dissipation? this could also lead to overheating the fluid i suppose...
The heat in the brakes is coming from the pad/ rotor contact. Aluminum pistons could transfer that heat to the caliper/ fluid. The caliper hopefully is designed to handle/dissipate that heat.
My car has Brembo brakes and they are super easy to work on, I hope that carries over to their MTB brake designs.
The main issue is, regardless of the performance, if they price them at 1k other than to fanboys they’ll be hard to sell, the ugliness is unreal for the brand, compare them to Hope/Intend/Trickstuff and others in the price range, these are in the same aesthetic level of TRPs at best
https://www.instagram.com/reel/DLzNdUqsUkf/?igsh=ZWdmNm44cHQwYmFh
Aluminium pistons? That's a surprise, I thought manufacturers wanted to isolate the heat from the rotor from the fluid in the caliper (ceramic, steel, phenolic, ...), but with aluminium, that would be kind of the opposite?
But we learn it's a 9mm MC piston and 4x18mm caliper, which should be on the higher end of power (just accounting the hydraulic ratio)
It’s the highest so far, higher than the mavens. One thing to keep in mind is that regardless of how much heat is being transferred to the fluid, hydraulic fluid, like dot or petroleum based mineral fluid, those fluids have some of the lowest thermal conductivity of any component in the brake system. It’s an order of magnitude lower than that of SS or AL. It’s going to take more BTU’s than one would ever be able generate in a mtb brake system to get any fluid to boil, especially under pressure, when the brake are applied. I can’t remember off the top of my head but DOT fluid at 1500 psi has a boil temperature of well over 800°F, or something similar to that, feel free to fact, check me I could be off. There’s not enough mass in a mountain bike brake system to sustain those system temperatures after someone lets off the brakes when the pressure subsides. Thermal degradation near the boil point is a completely different story, that is one area where DOT fluid has the upper hand compared to mineral oil.
We've seen the Brembo brakes on a grand total of what, two or three bikes so far? They aren't a consumer retail product and we don't know what they'll look like when/if they are.
Post a reply to: Nerding out on Brakes shall we? Not another tech deraliment