Bleeding hydraulic brakes after 1 year - worthwhile?

[schred]

What year/series are yours out of interest?

The saints/zees are not without issues so don't plan on a perfect solution there. Given one issue is the lever shifting all over the place, the lack of adjustment on zee would concern me.

If it were me I'd put sintered finned on the front and an icetech 203 and take it from there. If you need more then consider putting more pistons on the front. From memory the master cylinder of Saint/zee is different too so not sure a caliper only swap would be ideal.

Semi-relevant thread hijack....

I am very fussy about brake performance & lever feel so I check, adjust & bleed often.

I can confidently say I have my XT/SLX brakes working to best potential - they usually haul my near 100 kilos up pretty well.
I'm running 180mm rotors front & rear & I recently added new finned pads (resin).

But....
All this talk about Maydena & the strain on brakes has me thinking I might be bringing a knife to a gun fight when I break the seal on my shiny new maydena collective membership...?

So, are Zee brakes any good?

(I've read mixed feedback here & there )
Are they good bang-for-the-buck? Value for money is my priority....not bling for blings sake.

Alternatively, I could add a 203mm disc to the front & switch to metallic pads (with fins) & I might be OK with the M675's....?
I'm no Richie Rude....and maybe the Zee's would be overkill for all the other days I'm riding regular trails...?

Bike is a modded 140mm Trance
that needs to be jack-of-all trades....





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[Tubbsy]

I switched from 180 to 203 on the front when I moved my old brakes onto my new bike, and the difference was quite noticeable.

It's relatively cheap thing to try first before splashing out on new brakes.

 

[born-again-biker]

Yeah you make a good point too...

Currently the bike has:

Front - brm675 lever & caliper with 180mm resin-only disc & finned resin pads.

Rear- brm785 XT lever with recently upgraded shimano hose into brm675 caliper, cheapo stainless 180mm disc & finned resin pads.

At Derby / Trevallyn / Hollybank etc this set-up is completely adequate...even considering that I am the wrong side of 95kilos kitted up.

I am usually an incremental parts improver...rather than a buy-the-best-no-matter-the-cost kinda mtn biker, so maybe your bigger front rotor + metal pads route is smarter?
....but I won't know until I'm half way down maydena with boiled stoppers!

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[Tubbsy]

I'm a similar weight to you, and I reckon try the 203 first. Maybe try it down a steep road?

Not sure about the pads, I thought that was more about longevity than performance?

You could just get a cheapo used one off here (I've got a 6 bolt hope rotor you can have for nix), but you'll probably need an adaptor for your caliper.

 

[Oddjob]

What year/series are yours out of interest?

The saints/zees are not without issues so don't plan on a perfect solution there. Given one issue is the lever shifting all over the place, the lack of adjustment on zee would concern me.

If it were me I'd put sintered finned on the front and an icetech 203 and take it from there. If you need more then consider putting more pistons on the front. From memory the master cylinder of Saint/zee is different too so not sure a caliper only swap would be ideal.

The physics dictates that the Saints/Zee caliper will have more stopping potential. The pads are about 30% bigger than the m785/m8000 pads.

In terms of the moving bite point, I think that is more to do with heat management than the levers. The shimano lines tend to swell when they get hot. The solution is to get metal braided lines that don't swell.

Also keep in mind that the resorvoir system needs the master cylinder to fully retract to balance system pressure when the fluid gets hot. So its better to hit the brakes hard on short bursts rather than feathering for long sections.

Finned metal pads are good but I don't think the ice tech rotors are a good idea. The alloy core and pinned construction can lead to warping. Better to get Hope or another brands floating rotors with the proper interface between the alloy carrier and steel disc.

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[Oddjob]

Not sure about the pads, I thought that was more about longevity than performance?

Nope. Sintered pads are pretty much superior to organic in every way. Higher friction, longer life, better performance in the wet, more progressive bite. They chew out disc rotors faster but I've never actually replaced a rotor because it was end of life. The heat they produce is just a by-product of their higher friction.

Even amongst sintered pads there are some big differences. Nukeproof sintered pads are ok for commuting but I wouldn't use them for dh/enduro. At the other end of the scale are the EBC gold, Clarks VRX, Shimano metal compounds. The best I have used were Alligator sintered ceramic, but they are hard to get.

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[link1896]

Nope. Sintered pads are pretty much superior to organic in every way. Higher friction, longer life, better performance in the wet, more progressive bite. They chew out disc rotors faster but I've never actually replaced a rotor because it was end of life. The heat they produce is just a by-product of their higher friction.

Even amongst sintered pads there are some big differences. Nukeproof sintered pads are ok for commuting but I wouldn't use them for dh/enduro. At the other end of the scale are the EBC gold, Clarks VRX, Shimano metal compounds. The best I have used were Alligator sintered ceramic, but they are hard to get.

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Only thing organics do better is initial low speed bite is superior. But crap in the wet.

 

[schred]

Maybe the 30% means the threshold between two and four pistons is tangibly different, but I haven't found that, and it doesn't mean much when they are both heat soaked down there, I'd rather the larger disc at that point. I also get the stab vs feather argument and have read journal articles that back it up. Respectfully I don't care tbh, I expect the brakes to be there whenever I need them, and (on a poxy Shimano system) a larger rotor shedding heat nonstop makes more sense to me to achieve that. More importantly for me, I've tried both setups and the xt 775, sintered pads with 203ice tech, and now m8000 with same, and they both blow the saints away for trail riding, for dh I can't comment on the m8000 but wouldn't expect them to last one run truthfully.

I dont like icetech either as they are made of butter, but I've only heard and seen ice tech failures OS, none on Aussie hills, have you? At the limit I don't trust Shimano anymore after being caught out previously, I don't think they design a wide enough envelope into their brakes. But everyone's expectations and demands of brakes are different so it prob doesn't add anything other than they obv work for most people. So I still suggest cheapest first before tossing it out the window and dropping big big money on purple ano (what's the full cost incl rotors and going to dot long term).

Sintered also more fade resistant and once hot still operate more predictably long after resin has gone home.

 

[born-again-biker]

OK, good debate/input fellas.
Based on some of your experience, I'll prolly choose Hope/Clarks/other rotors & give ice tech a miss, regardless of what system I end up with.

Without having any way to benchmark any of the relative pros & cons of brands/diameters/no. of pistons etc, the big question for me still remains:

How undergunned will my current set-up be at Maydena?
Others were struggling with much tougher set-ups than mine....but how much faster do they descend compared to me?

There's so many variables with braking performance for each person & bike.

Does my set-up need an incremental upgrade OR is it so far below 'adequate' it will be dangerous and a full overhaul/upgrade is the only way forward for shuttle days??

(Well, only one way to find out sonny boy!)

Sadly work, & other stuff going on means my first Maydena visit won't likely happen 'till late Feb, or failing that, early April.
...and then maybe a few visits per year after that.

So I think I'm gonna go with this first:
- Finned & sintered pads f & r.
- Hope (or Clarks?) 203mm front rotor (floating)
- Stick with SLX / XT calipers & levers for now.
- And stay off the fuggen brakes!!!

After first visit I'll have more answers

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[Oddjob]

I agree that the larger discs are a must but not for heat. The larger discs simply give a higher angular velocity for the disc surface and maximise the available stopping force.

If you look at the infrared videos of disc brakes, the disc rotors themselves cool very quickly. The problem is the heat soaking into the calipers and lines. If the lines are plastic they swell. Contaminated dot fluid will boil and old mineral oil begins to 'crack' and breakdown. These are the things that cause spongy brakes on long steep runs.

Maybe the 30% means the threshold between two and four pistons is tangibly different, but I haven't found that, and it doesn't mean much when they are both heat soaked down there, I'd rather the larger disc at that point. I also get the stab vs feather argument and have read journal articles that back it up. Respectfully I don't care tbh, I expect the brakes to be there whenever I need them, and (on a poxy Shimano system) a larger rotor shedding heat nonstop makes more sense to me to achieve that. More importantly for me, I've tried both setups and the xt 775, sintered pads with 203ice tech, and now m8000 with same, and they both blow the saints away for trail riding, for dh I can't comment on the m8000 but wouldn't expect them to last one run truthfully.

I dont like icetech either as they are made of butter, but I've only heard and seen ice tech failures OS, none on Aussie hills, have you? At the limit I don't trust Shimano anymore after being caught out previously, I don't think they design a wide enough envelope into their brakes. But everyone's expectations and demands of brakes are different so it prob doesn't add anything other than they obv work for most people. So I still suggest cheapest first before tossing it out the window and dropping big big money on purple ano (what's the full cost incl rotors and going to dot long term).

Sintered also more fade resistant and once hot still operate more predictably long after resin has gone home.

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[Tubbsy]

Good info here, thanks fellas

 

[born-again-biker]

I agree that the larger discs are a must but not for heat. The larger discs simply give a higher angular velocity for the disc surface and maximise the available stopping force.

If you look at the infrared videos of disc brakes, the disc rotors themselves cool very quickly. The problem is the heat soaking into the calipers and lines. If the lines are plastic they swell. Contaminated dot fluid will boil and old mineral oil begins to 'crack' and breakdown. These are the things that cause spongy brakes on long steep runs.






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Hmm....so maybe if I add Jagwire Pro hoses to the aforementioned mods I'll get better fade resistance?

(But there is a point where the incremental upgrades cost almost as much as a complete quad piston system...)

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[born-again-biker]

Come to think of it...I upgraded the front brake hoses to steel braided on my road motorcycle a few years back.
Definitely improved lever feel & bite.

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[stirk]

Hmm....so maybe if I add Jagwire Pro hoses to the aforementioned mods I'll get better fade resistance?

(But there is a point where the incremental upgrades cost almost as much as a complete quad piston system...)

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Given you really only need a front upgrade zee Germans have what you need.

https://www.bike-discount.de/en/buy/shimano-zee-disc-brake-br-m640-b-front-with-d01s-resin-86995

 

[born-again-biker]

Just been watching Nathe Fertes Maydena vids.
You can definitely see why people are cooking their brakes!
So steep & fast.

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[Flow-Rider]

I think you'll find it's a misconception that mtb braided brake hose is better than a standard mtb brake line because they both run teflon inner hose which doesn't expand much much with pressure. When people generally say that braided lines are more direct, they are referring to comparing the difference between automotive brake hose from factory that is made of rubber. Stainless braid on the outside is mostly used for a high quality mechanical shield against the brake line from being damaged and it's really not designed to stop the brake line from swelling under pressure.

 

[Scotty675]

Have to agree with flowrider here. I can’t see the point of upgrading to braided line on a mtb. I ride sports bikes street and track and there is no doubt they make a difference on a motorcycle. On a mtb I have done no more than change pads and rotor size and a regular bleed. I am only a featherweight and maybe a heavier rider can argue this.

 

[Delazy]

Just been watching Nathe Fertes Maydena vids.
You can definitely see why people are cooking their brakes!
So steep & fast.

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Watched his videos last night...they don't nearly show how steep it is!

King Brown is a brown pants moment if you aren't expecting it, while even colour blind has some pretty quick elevation changes!

Heading back on the 15th for another crack and I'll decide then what to do about my hope e4 brakes...might even try and change to metal pads before then...

 

[scblack]

I've got a brake bleed question:
I have Saint M820 brakes F&R. Front bled ok, with plenty of bubbles and now works well. Simple bleed, just pushing the bubbles out really.

Rear has not gone so easy. Still pulls to lever and now dirty fluid is coming up to the cup on lever bleed port. I bled second time, still crappy. Again just pushing bubbles, not full bleed.

Question is: I have 25ml left in my container - is that enough to fully bleed the rear brake - push ALL old fluid out and refresh completely so all new red fluid. How much fluid does the rear take for that? Is 25ml enough?

 

[wkkie]

I just did front and rear, and for a good flush of the rear, I'd say no. You'll probably need at least 40 for a proper flush.

Best if you take the brake off the bike as well if possible, that'll get you a better bleed with the line vertical.

If your around the west of Vic, I'm happy to donate mineral oil.