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Frankenbrakes and brake improvement discussion

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KAZHA

Chimp
Feb 20, 2015
34
6
Flat AF
From people that say things, it sounds like the brakes only last a couple of seasons before seals wear out and your brakes start sucking air. udi rants about a plastic bit in the master cylinder and kidwoo talks about a leaking, no-replaceable piston seal, so the choice is yours as to why the brakes start sucking. I have a pair of XTs that are good but the first few initial squeezes always have that pump up.

As for replacing them, I'd say you'd have a hard time finding a cheaper and better lever set than the SLX/zee levers for $24 from jenson that are always brought up. I wouldn't recommend the levers from magura but you might be able to score some sort of apparatus off of ebay. Formula makes mineral oil levers now, but it might be a challenge to get them and to make them work with the large piston surface area of your zee calipers.

It might be wiser to think about a complete set of brakes, and move on to something that people hate the least.
What about newer gen XT/SLX levers, are they any good, or same shit in different colour?
 

Udi

RM Chief Ornithologist
Mar 14, 2005
4,918
1,213
What about newer gen XT/SLX levers, are they any good, or same shit in different colour?
The second thing you said.
They changed the lever/MC but the problems remain.

I like the shimano lever ergonomics,but the build quality is very low tech, so maybe there is a "better" option, cause you can always gamble with a new shimano lever.
Just buy new Zee levers.
My buddy rides Zee brakes and buys a brand new set of levers every season. It seems to keep them working decent.

Shimano's 4-pot calipers are less prone to seal problems than the 2-pot ones (I don't know why - Shimano probably doesn't either), so Saint and Zee problems are usually at the lever end.

Definitely don't buy Magura levers, they have plasticky rubbish build quality and the ergonomics are poor.
 

KAZHA

Chimp
Feb 20, 2015
34
6
Flat AF
The second thing you said.
They changed the lever/MC but the problems remain.


Just buy new Zee levers.
My buddy rides Zee brakes and buys a brand new set of levers every season. It seems to keep them working decent.

Shimano's 4-pot calipers are less prone to seal problems than the 2-pot ones (I don't know why - Shimano probably doesn't either), so Saint and Zee problems are usually at the lever end.

Definitely don't buy Magura levers, they have plasticky rubbish build quality and the ergonomics are poor.
Thanks for information and new ZEE lever it is then.
Although maybe I have discovered something that fixes the "spongy first pull" lever issue - I put a small brass washer between the lever cap(3) and seperator(4) unit (http://si.shimano.com/pdfs/ev/EV-BL-M640-3431.pdf), then purged the system from caliper and the lever seems fine for a couple of days. But maybe I just got lucky
 
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Udi

RM Chief Ornithologist
Mar 14, 2005
4,918
1,213
Yes, I don't think that's a good idea because it's likely increasing the sealing force of the reservoir cap / bladder - which would allow more fluid to stay in the system (the bladder seal is designed to allow excess to leak out easily, it's a very low-pressure seal) which increases the risk of operating as a closed-system (i.e. no longer volume compensated under temperature-driven fluid / seal expansions).

The improved sealing may be fixing whatever issue was causing the spongy first pull, but I think on Shimano when problems start it's safest to install new lever assemblies. If it is within your budget, after 4-5 seasons I would be replacing both L/R, but up to you obviously.
 

KAZHA

Chimp
Feb 20, 2015
34
6
Flat AF
Yes, I don't think that's a good idea because it's likely increasing the sealing force of the reservoir cap / bladder - which would allow more fluid to stay in the system (the bladder seal is designed to allow excess to leak out easily, it's a very low-pressure seal) which increases the risk of operating as a closed-system (i.e. no longer volume compensated under temperature-driven fluid / seal expansions).

The improved sealing may be fixing whatever issue was causing the spongy first pull, but I think on Shimano when problems start it's safest to install new lever assemblies. If it is within your budget, after 4-5 seasons I would be replacing both L/R, but up to you obviously.
Yeah,I was just curious, because there would be a constant drops of oil under the rubber boot thing,that covers the hose entering the lever.
Anyway,new levers for new season is must!
 

Udi

RM Chief Ornithologist
Mar 14, 2005
4,918
1,213
Awesome. Testing "The best DH brakes" on an enduro bike.
Absolutely.
The real test of a brake is on a DH bike (27.5" or 29"), doing lift/shuttle runs with prolonged steep descents.

Also I like how they rated the Saint an "8" for heat management while giving the V4 a "9".
If Shimano demolishes everyone in one area (Hope included), it's heat management.
This is enough to discredit the test in my book.

At least they picked up on the part where the Quadiem has very little stopping power - however then tried to make it sound like it's not an actual issue, when it very clearly is. Why bother?

Having ridden virtually every brake on the market - both before and after a full season of chairlift riding, I really want to do my own brake writeup just so people don't have to sift through a bunch of garbage to find the facts. Every "review" and "shootout" is hindered by the fact that no one wants to step on toes.
 

PJivan

Monkey
Aug 27, 2006
157
20
Dublin, Ireland
Awesome. Testing "The best DH brakes" on an enduro bike.

In fairness it's a silly argument...I probably brake more with enduro bikes for a myriade of reasons, but more importantly while I've never experinced fading in a DH track I did doing enduro/freeride/whateveruwant2callit in the alps, hangin on the brakes in super step terrains and tyring. descending for 30 minutes no stop. It is also the only place were I saw pads get destroyed in a single day and disks singing melody that drove mans crazy!

You don't necessary need a full body armor and 230mm to test brakes, especially fading and modulation as you generally have less grip with enduro tyres, your argument it's only valid for raw power, and by that i mean decellerate in the shortest amount of time/space possible.
 

kidwoo

Artisanal Tweet Curator
In fairness it's a silly argument...I probably brake more with enduro bikes for a myriade of reasons, but more importantly while I've never experinced fading in a DH track I did doing enduro/freeride/whateveruwant2callit in the alps, hangin on the brakes in super step terrains and tyring. descending for 30 minutes no stop. It is also the only place were I saw pads get destroyed in a single day and disks singing melody that drove mans crazy!

You don't necessary need a full body armor and 230mm to test brakes, especially fading and modulation as you generally have less grip with enduro tyres, your argument it's only valid for raw power, and by that i mean decellerate in the shortest amount of time/space possible.
If you're not hauling ass into more consequential situations and braking harder on your dh bike you're just dh biking wrong. Bigger grippier tires put more stress on a brake, not less.
 
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Gary

my pronouns are hag/gis
Aug 27, 2002
8,526
6,432
UK
Bigger grippier tires shitter riders put more stress on a brake.
When a disc brake fades, eats pad material or pisses itself during a ride it generally has fuck all to do with which tyres were used.
 

kidwoo

Artisanal Tweet Curator
When a disc brake fades, eats pad material or pisses itself during a ride it generally has fuck all to do with which tyres were used.
But it's worse with grippier tires. Think about it chico, shitty tires will just slide and the brake isn't doing shit for heat generation when the rotor is just locked. Good traction lets you USE the brakes, which means not locked.
 

Gary

my pronouns are hag/gis
Aug 27, 2002
8,526
6,432
UK
You think Endurbros use shitty tyres with harder compounds?

None of them round here do. infact it's me running 60a rear semi slicks ALL year round on ALL my mtbs
 

Gary

my pronouns are hag/gis
Aug 27, 2002
8,526
6,432
UK
You're talking shit mate.

Thick downhill tyres don't grip any better than lighter versions with the exact same tread and compound. infact if anything for straight line braking traction the opposite should be true as a lighter more flexible carcus should conform to the ground better.
Thick downhill tyres just allow you to run lower pressures when pointy shit is in your path and give far better side knob support when leant over.

My point a few posts ago was that a brake dragging middle aged Endurbro weekend warrior will be putting far more stress (heat) into their brakes than a seasoned half decent DH racer/rider/ex-racer.

I can recall every time my brakes have failed through fade and every time it was because I was held up by someone lighter than me who was braking way more than I would. I eventually learned that if someone was causing me to brake drag for a significant amount of time and not letting me pass to just pull over and chill.
 

Cerberus75

Monkey
Feb 18, 2017
520
194
You're talking shit mate.

Thick downhill tyres don't grip any better than lighter versions with the exact same tread and compound. infact if anything for straight line braking traction the opposite should be true as a lighter more flexible carcus should conform to the ground better.
Thick downhill tyres just allow you to run lower pressures when pointy shit is in your path and give far better side knob support when leant over.

My point a few posts ago was that a brake dragging middle aged Endurbro weekend warrior will be putting far more stress (heat) into their brakes than a seasoned half decent DH racer/rider/ex-racer.

I can recall every time my brakes have failed through fade and every time it was because I was held up by someone lighter than me who was braking way more than I would. I eventually learned that if someone was causing me to brake drag for a significant amount of time and not letting me pass to just pull over and chill.
Why wouldn't you think that a heavier tire having more rotational mass not be harder on brakes?
 

Westy

the teste
Nov 22, 2002
56,047
22,074
Sleazattle
The best test of a set of brakes is fat chicks. Not only does the excessive mass increase the required energy dissipation, but the suspended adipose mass dampening effect improves the available traction.
 

Gary

my pronouns are hag/gis
Aug 27, 2002
8,526
6,432
UK
Why wouldn't you think that a heavier tire having more rotational mass not be harder on brakes?
Woo didn't mention mass at all. I did.

3-400g on a tyre makes fuck all difference to the grief your brakes are recieving when you're 20kg heavier than the guy you're argueing about those braking forces with. ;)


@Udi OMG... you're right. :o
I'm off to find that corner... to sit in the dark on my own.
:doh:
 

PJivan

Monkey
Aug 27, 2006
157
20
Dublin, Ireland
kinda sounds like you were downhilling.
Do you have 30 minutes race in America? To me downhill it's a race, and races course only last 4-7 minutes top, are road racers doing downhill when they are going down? are XC racers doing DH half of their loops?
 
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PJivan

Monkey
Aug 27, 2006
157
20
Dublin, Ireland
If you're not hauling ass into more consequential situations and braking harder on your dh bike you're just dh biking wrong. Bigger grippier tires put more stress on a brake, not less.
Not sure if I understand your first statement but yes I brake late, as late as I can when racing DH and therefore I brake hard, as hard as possible, and if I realise I could brake harder without loose controll, next time I'll brake later and harder, on the other side If I'm just riding with friends down the mountain there is no point for me to risk and brake as late as possible in a trail I don't fucking know and to shave few cent of seconds.

Smaller and harder enduro tyres are harder to modulate and require less power to lock down, so you feel more if a brake is not very modulable, on the other side no matter how heavy is the tyre/bike I never had a brake fading in a dh race track in the past 8 years.
 

Sandwich

Pig my fish!
Staff member
May 23, 2002
21,858
7,107
borcester rhymes
Do you have 30 minutes race in America? To me downhill it's a race, and races course only last 4-7 minutes top, are road racers doing downhill when they are going down? are XC racers doing DH half of their loops?
uh, if you're consistently descending for a prolonged period of time at a high rate of speed on a bike in the woods on rocky trails, that sounds very similar to
consistently descending for a slightly shorter period of time at a high rate of speed on a bike in the woods on rocky trails

aside from semantics, would you honestly argue that prolonged light use of brakes puts more heat into the system than shorter, high intensity pulls? I have never felt brake fade outside of riding very steep trails. I would agree that prolonged descents put more hurt on an overall system (like pad integrity) but nothing challenges performance like true downhill trails, which is where you experience fade, heat buildup, changing lever pulls, crashes, etc. If I can't reliably pull my brakes at the same lever point time after time on a 5 minute run, then that's pretty telling of a brake system.
 

Gary

my pronouns are hag/gis
Aug 27, 2002
8,526
6,432
UK
prolonged light use of brakes
sounds like brake dragging to me.

and YES. this builds up moar heat than sharp short full braking at predetermined practiced braking points. eg. on a DH race track
 

Gary

my pronouns are hag/gis
Aug 27, 2002
8,526
6,432
UK
Yeah. I do.

and a lifetime supply of 26" dual plys.

Uplifts are just about to start up here too.

You're going to have to start paying for all the corrective work I'm having to do to your #facts