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Frankenbrakes and brake improvement discussion

Boozzz

Chimp
Sep 12, 2019
80
84
Amsterdayummm
Yeah, noticed both DRT and the Maxima is often available in inflatory quantities at some German shops lately.

Also noticed that Trickstuff has (silently? sneakily?) moved away from a hard anodised master cylinder piston to a plastic one for all their brakes. Seems a bit cheap?
 

slimshady

¡Mira, una ardilla!
Also noticed that Trickstuff has (silently? sneakily?) moved away from a hard anodised master cylinder piston to a plastic one for all their brakes. Seems a bit cheap?
Maybe they learned from Shimano's mistakes and are trying to avoid the master cylinder from ovalizing or getting scored so bad it would cause the dreaded wandering bite point...
 

Inclag

Turbo Monkey
Sep 9, 2001
2,749
437
MA
Maybe they learned from Shimano's mistakes and are trying to avoid the master cylinder from ovalizing or getting scored so bad it would cause the dreaded wandering bite point...
In the Downtime podcast with Kolb, he made reference to some issues the team had last year with the Trickstuff brakes so there may be something to your theory.
 

Boozzz

Chimp
Sep 12, 2019
80
84
Amsterdayummm
Maybe they learned from Shimano's mistakes and are trying to avoid the master cylinder from ovalizing or getting scored so bad it would cause the dreaded wandering bite point...
Maybe, but then one of their claimed features of the Maxima would be bs:

"Additional teflon support ring next to secondary seal: Prevents aluminum piston from rubbing against the cylinder bore for a wear free piston."
 

Andeh

Customer Title
Mar 3, 2020
980
962
So just a heads up. I read somewhere that you could use SRAM bleed syringes with Dominions to get a better seal for doing vacuum bleeds. This is a GREAT way to strip your bleed port. Ask me how I know... :banghead:
 

Da Peach

Outwitted by a rodent
Jul 2, 2002
13,680
4,890
North Van
So just a heads up. I read somewhere that you could use SRAM bleed syringes with Dominions to get a better seal for doing vacuum bleeds. This is a GREAT way to strip your bleed port. Ask me how I know... :banghead:
I used SRAM syringes…. Twice. Guess I got lucky!
 

marshalolson

Turbo Monkey
May 25, 2006
1,770
519
So just a heads up. I read somewhere that you could use SRAM bleed syringes with Dominions to get a better seal for doing vacuum bleeds. This is a GREAT way to strip your bleed port. Ask me how I know... :banghead:
Dude, bummer man!

did you use the old Sram ones with the flat end, or the new ones with the taper? I had heard only the old ones worked…?
 

HAB

Chelsea from Seattle
Apr 28, 2007
11,578
2,001
Seattle
So just a heads up. I read somewhere that you could use SRAM bleed syringes with Dominions to get a better seal for doing vacuum bleeds. This is a GREAT way to strip your bleed port. Ask me how I know... :banghead:
Shit, I've done at least a dozen bleeds with that kit. Sorry to hear it though, where did it strip? Caliper or lever end?
 

Happymtb.fr

Turbo Monkey
Feb 9, 2016
1,891
1,236
SWE
I barely know what kit I used when I bled my dominions... my bleed kits are a mix off older Sram, older Formula and maybe even some magura stuff. :eek:
 

Andeh

Customer Title
Mar 3, 2020
980
962
Shit, I've done at least a dozen bleeds with that kit. Sorry to hear it though, where did it strip? Caliper or lever end?
Caliper end on one bike I had to fight for a couple minutes to get the attachment off but I figured I'd just gotten the o-ring pinched in the threads, so proceeded to try again on the other bike. Lever end is fucked on second bike (used Hayes syringe on the caliper for it). The first bike seems to be holding pressure - will see when I ride today. Second one lost pressure after like 4 stops in the street - definitely fucked. I broke down and ordered a complete brake in case the first one fails too because the lever assembly is 150, the caliper is 120, or a complete brake is 250 (which comes with pads and hose too).

I think you can probably do it ok if you just use finger force to tighten them on. But I had just read a Pinkbike interview with some of the guys from Hayes who said explicitly to use some pliers or knipex to tighten up the bleed fittings so the cone-cone interface gets fully closed. They said something like, "there's a reason why we have a torque value for the ports."

My guess is the SRAM fitting has the same threads, but the cone tipped extension beyond it is a different length/cone pitch. So if you advance it until it stops (rather than just gets tight), maybe it goes past the threads so when you back out they get cross-threaded?
 

toodles

ridiculously corgi proportioned
Aug 24, 2004
5,419
4,643
Australia
some of the guys from Hayes who said explicitly to use some pliers or knipex to tighten up the bleed fittings so the cone-cone interface gets fully closed. They said something like, "there's a reason why we have a torque value for the ports."
Excuse me but did they recommend a specific brand of torque pliers for this application. I've been trying to find a set of these with a torque indicator

1688935747108.png


Being a sarcastic dickhead aside, I just looked at the bleed procedure manual. No torque spec for the syringe. The only measurement provided is for reinstalling the plug and that is specced at 1.5Nm which is fuck all. Like a jewellers screwdriver level of torque.


If they're serious about it being a torque critical application they should make the fittings compatible with some kind of normal torque wrench (evens a crows foot one) rather than a knurled nut designed to be finger tightened or with a plumbers wrench.
 

HAB

Chelsea from Seattle
Apr 28, 2007
11,578
2,001
Seattle
Caliper end on one bike I had to fight for a couple minutes to get the attachment off but I figured I'd just gotten the o-ring pinched in the threads, so proceeded to try again on the other bike. Lever end is fucked on second bike (used Hayes syringe on the caliper for it). The first bike seems to be holding pressure - will see when I ride today. Second one lost pressure after like 4 stops in the street - definitely fucked. I broke down and ordered a complete brake in case the first one fails too because the lever assembly is 150, the caliper is 120, or a complete brake is 250 (which comes with pads and hose too).

I think you can probably do it ok if you just use finger force to tighten them on. But I had just read a Pinkbike interview with some of the guys from Hayes who said explicitly to use some pliers or knipex to tighten up the bleed fittings so the cone-cone interface gets fully closed. They said something like, "there's a reason why we have a torque value for the ports."

My guess is the SRAM fitting has the same threads, but the cone tipped extension beyond it is a different length/cone pitch. So if you advance it until it stops (rather than just gets tight), maybe it goes past the threads so when you back out they get cross-threaded?
I've only ever done finger tight. Going harder than that seems suspect, though I've mostly used the SRAM kit because the Hayes one doesn't seal great at that torque...

I've got both, I can take some measurements when I get home. On the road for a few days currently.
 

Andeh

Customer Title
Mar 3, 2020
980
962
Excuse me but did they recommend a specific brand of torque pliers for this application. I've been trying to find a set of these with a torque indicator

View attachment 196740

Being a sarcastic dickhead aside, I just looked at the bleed procedure manual. No torque spec for the syringe. The only measurement provided is for reinstalling the plug and that is specced at 1.5Nm which is fuck all. Like a jewellers screwdriver level of torque.


If they're serious about it being a torque critical application they should make the fittings compatible with some kind of normal torque wrench (evens a crows foot one) rather than a knurled nut designed to be finger tightened or with a plumbers wrench.
Yeah, IDK. Here's where I saw that: https://www.pinkbike.com/news/world-series-tech-brake-tech-deep-dive-part-1-hayes.html
Looks like I misread it a little bit because the article is just a direct transcript of a conversation, but here's what they said. (The torque reference was for how much to tighten the hose nut.)
"Or if you're using the two piece olive, the barb of the olive you can visually see it's in all the way but then as you're installing it just make sure you're pushing it in to the master cylinder as you tighten your olive and then use a torque wrench, you know, we have torque specs published, we'll share them with you no matter when you ask we give them to you, just use a torque wrench and do it right. Then number two, it's a little bit less of a problem, but our syringes we don't use like an O ring or anything. It's a taper that seats into another taper. So we'll have some guys and they just thread it in by hand and then they do the vacuum pull on it, and they'll see air kind of coming in over and over and over and they'll be like, hey, like the air is getting pulled in. It's okay just take your pliers or whatever and just give it an little extra tighten and seat those two tapers and you're good to go. "
 

toodles

ridiculously corgi proportioned
Aug 24, 2004
5,419
4,643
Australia
Ah yeah fair, FWIW - a bit late now I know - it *looks* like the proper Hayes kit would be more tolerant of being over-tightened than the SRAM kit would be.

1688946631941.png


1688946647547.png


Thats just looking at the thread depth and that the Hayes kit would seem to bottom out into the taper where as the SRAM one wouldn't have a good bite into the threads.
 

sethimus

neu bizutch
Feb 5, 2006
4,775
2,066
not in Whistler anymore :/
If they're serious about it being a torque critical application they should make the fittings compatible with some kind of normal torque wrench (evens a crows foot one) rather than a knurled nut designed to be finger tightened or with a plumbers wrench.
i don’t get your problem?
t10 bit + syntace 1-25nm torque wrench (made by wera), those take a standard bit directly, job’s done.
 

toodles

ridiculously corgi proportioned
Aug 24, 2004
5,419
4,643
Australia
i don’t get your problem?
t10 bit + syntace 1-25nm torque wrench (made by wera), those take a standard bit directly, job’s done.
Nah I meant for the bleed syringes not the plug. I've always just finger tightened them and they've been fine, but if a Hayes tech wants to suggest people use a tool on them and then @Andeh strips his then they're really should decide it needs a tool, specify a limit and give the fittings a compatible interface.

I'd say however that tech has probably been flogged with a length of brake hose for even suggesting people put pliers on the syringe.
 

Happymtb.fr

Turbo Monkey
Feb 9, 2016
1,891
1,236
SWE
How strong of a vacuum pull do you guys do?
Seals on the main cylinder are made to handle a fair amount of overpressure but are also poor performers when it comes to underpressure. I see the vacuum pull as a way to motion the membrane of the reservoir and I am always afraid to suck in grit or whatever is on the other side of the seal if I pull too hard of a vacuum.
Screenshot_20230710_012341_Chrome.jpg
 

HardtailHack

used an iron once
Jan 20, 2009
6,510
5,260
Excuse me but did they recommend a specific brand of torque pliers for this application. I've been trying to find a set of these with a torque indicator

View attachment 196740

Being a sarcastic dickhead aside, I just looked at the bleed procedure manual. No torque spec for the syringe. The only measurement provided is for reinstalling the plug and that is specced at 1.5Nm which is fuck all. Like a jewellers screwdriver level of torque.


If they're serious about it being a torque critical application they should make the fittings compatible with some kind of normal torque wrench (evens a crows foot one) rather than a knurled nut designed to be finger tightened or with a plumbers wrench.
1688980129302.png
 

Udi

RM Chief Ornithologist
Mar 14, 2005
4,914
1,198
How strong of a vacuum pull do you guys do?
Seals on the main cylinder are made to handle a fair amount of overpressure but are also poor performers when it comes to underpressure. I see the vacuum pull as a way to motion the membrane of the reservoir and I am always afraid to suck in grit or whatever is on the other side of the seal if I pull too hard of a vacuum.
You can optionally hold the lever pressed in to remove the reservoir from the active system when drawing vacuum at the caliper end (useful for clearing air from the caliper when bleeding an empty system). The MC piston seal is still weak in this direction but stronger than the reservoir seal/membrane on most brakes. This is definitely more art than science to get right without drawing air into the system, in my experience it even varies across the life of the brake (more vacuum possible when brake is new). I recommend just enough vacuum to get a few bubbles into the syringe, then reverse direction to replenish fluid and repeat vacuum.

There shouldn't be much need to draw vacuum at the lever / MC end, bubbles here will escape the active system into the reservoir easily as it is near the top of the system. In any case, having the ability to do all this is a huge advantage over the archaic bleed nipple system on Shimano/Hope, especially when filling an empty system.
 

Jm_

sled dog's bollocks
Jan 14, 2002
18,766
9,486
AK
This is all fun and everything...but seriously, WTF? Why is bleeding this complicated?

In other news, using my hope buy-some-moar-shit T4 bleed adapter for my hope aluminum (because why not?) bleed kit, I figured I'd try to use it like a shimano system for the lever bleed and try to purge all the bubbles out of the lever by rocking the cup for and aft by about 30 degrees. Seemed to work pretty good. It's stupid that you are trying to fight gravity to get bubbles out the low end...but being able to use the lever to purge through the cup seemed to work pretty well, tested over the last few rides and lever working nice.
 

Happymtb.fr

Turbo Monkey
Feb 9, 2016
1,891
1,236
SWE
There shouldn't be much need to draw vacuum at the lever / MC end, bubbles here will escape the active system into the reservoir easily as it is near the top of the system.
That's actually where the design of the dominion brakes is lacking: the reservoir is on the underside...
 

canadmos

Cake Tease
May 29, 2011
19,953
18,822
Canaderp
This is all fun and everything...but seriously, WTF? Why is bleeding this complicated?
Its not, once they are bled nicely, its super easy. If you even need to bleed them...


The Hayes syringes are nice, but yeah you need to tighten them slightly past finger tight.
 

Andeh

Customer Title
Mar 3, 2020
980
962
Its not, once they are bled nicely, its super easy. If you even need to bleed them...


The Hayes syringes are nice, but yeah you need to tighten them slightly past finger tight.
Yeah on my second pass (going back to the Hayes syringes), getting them a smidge tighter with the Knipex did work at not letting in micro bubbles while pulling a vacuum.
 

canadmos

Cake Tease
May 29, 2011
19,953
18,822
Canaderp
I put Hayes sintered pads in my A4's tonight and wow, they rattle so much going over roots.

The pads that came mounted from the factory didn't do this. I reused the pin and springs, as the pads didn't come with replacements.

The rattles scared me at first. Had to pull and check that my calipers weren't loose (I adjusted them earlier).

Anyone experience this? Anyway to stop it from happening?
 

Andeh

Customer Title
Mar 3, 2020
980
962
Bend the springs back a little bit with a flathead screwdriver (in the middle, where the bolt goes through).
 

Andeh

Customer Title
Mar 3, 2020
980
962
Dominion related: I put a set of Galfer Pro pads on both my bikes as the original Hayes metallic pads were getting low. I'm pretty happy with them so far. The Hayes pads lasted forever, but they were a bit noisy towards the ends of runs. The Galfers are a *really* tight fit on Dominions with 2mm rotors though, and I had to sand them down a bit to get them to fit. It was weird though, on both of the bikes even after I sanded them, the bite was insanely quick for like 1 ride. Super short throw. Then they started feeling like a normal amount of throw.
 

canadmos

Cake Tease
May 29, 2011
19,953
18,822
Canaderp
Bend the springs back a little bit with a flathead screwdriver (in the middle, where the bolt goes through).
I'm packing the bike up for a plane ride tonight, I'll see if theres time to take the pads out. I did clean out the junk pretty well, maybe it just needs to build back up?

If they don't stop rattling after a few runs in BC, I'll have to do some work.
 

Nick

My name is Nick
Sep 21, 2001
23,818
14,174
where the trails are
I'm packing the bike up for a plane ride tonight, I'll see if theres time to take the pads out. I did clean out the junk pretty well, maybe it just needs to build back up?

If they don't stop rattling after a few runs in BC, I'll have to do some work.
have you tried greasing them?


:D
 

6thElement

Schrodinger's Immigrant
Jul 29, 2008
15,708
12,805
Hmmm good point! Would a thiccccc tractor farm type grease hold them in place? :brows:
Some of that red PM600 military stuff that SRAM used to recommend in coil forks. I still have a big tube from 10+ years ago. I'll send it up to northern Golden for you :p
 

canadmos

Cake Tease
May 29, 2011
19,953
18,822
Canaderp
Some of that red PM600 military stuff that SRAM used to recommend in coil forks. I still have a big tube from 10+ years ago. I'll send it up to northern Golden for you :p
Maybe thats the same stuff I have, but mine is labeled as use for farm equipment.

Its smells RANK. I had to stop using it, even though it seems about as tough as a cockroach.
 

Bikael Molton

goofy for life
Jun 9, 2003
3,993
1,114
El Lay
Same exact experience here going from stock A4 sintered to Galfer Pro.

I love the insane bite of the Galf Pros, but have heard they have a short lifespan.
 

Udi

RM Chief Ornithologist
Mar 14, 2005
4,914
1,198
I did not have a good experience with Galfer Pro pads, bought multiple pairs on recommendation from a local enduro expert and while they didn't do anything terribly wrong, they just didn't stop / bite all that well. Probably the most lacklustre brake pad I've purchased in a while.

I used them with new Shimano rotors, not sure if there's some kind of incompatibility but I wouldn't buy Galfer pads again.
 

Happymtb.fr

Turbo Monkey
Feb 9, 2016
1,891
1,236
SWE
@Udi
Are you sure about the quality of your rotors?

I read recently about about shimano rotors going down in quality supposedly because the production was moved to China and/or because the production method was changed from laser cut to stamped. I don't know if any of it is true and I cannot recall where I saw it... It can very well be false rumours spread on the Internet boosted by the popular false opinion that China can only produce inferior products.

For the record, I have never used galfer pads. They seem nevertheless to be well regarded by many expressing their opinion on the web. FWIW
 

Milleratio

Chimp
Oct 24, 2021
78
60
Has anyone tried using shims under the pads as the wear? My Dominion A4 have quite a much free play in and for some reason bleeding doesn't seem to help. My DH bike Saints had same issue and replacing pads fixed this little "feature".