Author Topic: Juin Tech GT-F brake calipers (dual piston)  (Read 10833 times)

ChrisB

Re: Juin Tech GT-F brake calipers (dual piston)
« Reply #30 on: April 22, 2022, 03:55:12 PM »
I wish I could give you some long term experience but for that I did not do enough rides...

Comparing the BR-005 with the Juintech F1's:
The initial bite and break power feels very similar. I did not experience any fading on longer descents.
A 1:1 comparison is difficult since I am using different Brifters: Sensah SRX vs. Shimano 105.
The BR-005 are combined with Shimano rotors, while I am using light Oniiri rotors with the Juintech F1's.

I will try some A vs. B comparisons when I find time.
In the meantime I will try to get some more rides on the new bike.  :-)

BR Chris
« Last Edit: April 29, 2022, 10:25:28 AM by ChrisB »

kbike

Re: Juin Tech GT-F brake calipers (dual piston)
« Reply #31 on: April 22, 2022, 10:47:19 PM »
I ran the br02 and br05. The br05 bites firmer and stop much faster. They feels much closer to my Shimano hydraulic brakes. I can lock the wheels but need to pull very hard unlike hydros. The br02 feel soft and slow by comparison.  I used the same ashima rotors.

I haven't done Hills yet. I really pushed them yesterday in the city with lots of hard stops to see. The br02 scared me one time they couldn't stop me completely before an intersection. 

I either have less oil or air in my br02 or the br05 has a better seal.  I've boxed up the br02 and will be using the br05. I hope in may to hit more elevation. Wind and cold rain has pretty much described April.

ChrisB

Re: Juin Tech GT-F brake calipers (dual piston)
« Reply #32 on: April 23, 2022, 02:45:07 AM »
I ran the br02 and br05. The br05 bites firmer and stop much faster. They feels much closer to my Shimano hydraulic brakes. I can lock the wheels but need to pull very hard unlike hydros. The br02 feel soft and slow by comparison.  I used the same ashima rotors.

I haven't done Hills yet. I really pushed them yesterday in the city with lots of hard stops to see. The br02 scared me one time they couldn't stop me completely before an intersection. 

I either have less oil or air in my br02 or the br05 has a better seal.  I've boxed up the br02 and will be using the br05. I hope in may to hit more elevation. Wind and cold rain has pretty much described April.

We had a pair of earlier BR-002's in use for about 9 months and the break power was far off compared to the BR-005.
Worst of all, when checking them after a few months in use the left and right pistons did not activate simultaneously which made modulation impossible.
I would certainly not recommend getting the old BR-002 models.

BR Chris

StiffWeenies

Re: Juin Tech GT-F brake calipers (dual piston)
« Reply #33 on: April 23, 2022, 04:57:11 AM »
I ran the br02 and br05. The br05 bites firmer and stop much faster. They feels much closer to my Shimano hydraulic brakes. I can lock the wheels but need to pull very hard unlike hydros. The br02 feel soft and slow by comparison.  I used the same ashima rotors.

I haven't done Hills yet. I really pushed them yesterday in the city with lots of hard stops to see. The br02 scared me one time they couldn't stop me completely before an intersection. 

I either have less oil or air in my br02 or the br05 has a better seal.  I've boxed up the br02 and will be using the br05. I hope in may to hit more elevation. Wind and cold rain has pretty much described April.

I wish I could give you some long term experience but for that I did not do enough rides...

Comparing the BR-005 with the Juintech F1's:
The initial bite and break power feel very similar. I did not experience any fading on longer descents.
A 1:1 comparison is difficult since I am using different Brifters: Senshah SRX vs. Shimano 105.
The BR-005 are combined with Shimano rotors, while I am using light Oniiri rotors with the Juintech F1's.

I will try some A vs. B comparisons when I find time.
In the meantime I will try to get some more rides on the new bike.  :-)

BR Chris

Thank you both. Were you two using the included brake pads? the pads design looks to be the Shimano K03S standard so perhaps some more braking performance gains could be found there

ChrisB

Re: Juin Tech GT-F brake calipers (dual piston)
« Reply #34 on: April 23, 2022, 07:54:02 AM »
Thank you both. Were you two using the included brake pads? the pads design looks to be the Shimano K03S standard so perhaps some more braking performance gains could be found there

So far I am running both the Juintech F1's and the BR-005 with the original pads that came on delivery.
I am also wondering what improvements could be achieved experimenting with different pads...
Hopefully somebody can share some experience with different break pads and make some recommendations.

BR Chris
« Last Edit: April 24, 2022, 03:12:56 AM by ChrisB »

stumpym4

Re: Juin Tech GT-F brake calipers (dual piston)
« Reply #35 on: April 23, 2022, 08:51:28 AM »
Just waiting on my set to arrive :) .. I've also asked how they are on your other post , but you've answered that here so thanks for that

StiffWeenies

Re: Juin Tech GT-F brake calipers (dual piston)
« Reply #36 on: April 23, 2022, 10:46:35 AM »
So far I am running both the Juintech F1's and the BR-005 with the original pads that came on delivery.
I am also wondering what improvements could be achieved experimenting with different pads...
Hopefully somebody can share some experience with different Chicer break pads and recommendations.

BR Chris

You could try semi-metallic pads? they're certainly more abrasive that the stock resin ones. However I remember Juin support explicitly telling me to only use resin pads with the GT-F

It's a bummer Onirii didn't design the BR-05 for finned pads though. K03S is just the non-finned version of L03A which would open up a lot of cool stuff like SwissStop's EXOTherm2 or Jagwire's Elite Cooling. If you want to keep things resin and OEM, I guess you could try the K05S which is the latest in the Shimano K02S/K03S non-finned resin lineage.
« Last Edit: April 23, 2022, 10:48:17 AM by StiffWeenies »

ChrisB

Re: Juin Tech GT-F brake calipers (dual piston)
« Reply #37 on: April 24, 2022, 07:36:49 AM »
Just for fun I checked the older ZRACE BR-02 callipers lying around in the basement and shot a short video of the non symmetrical activation of the brake pistons.
Even after cleaning, the pistons do not activate symmetrical. Under these circumstances you can not expect that the brakes work correctly.
I think this is really a systematic problem due to design or quality control.

The BR-05 on the other hand activate perfectly symmetrical, so they seem to have fixed that issue.

Here the link to the Youtube video since embedding seems not to work (Youtube code: rgyoI1MuSGI):


BR Chris
« Last Edit: April 29, 2022, 10:29:34 AM by ChrisB »

1Sigma

Re: Juin Tech GT-F brake calipers (dual piston)
« Reply #38 on: April 24, 2022, 09:55:55 AM »
I've been dying to change my GTs simply for aesthetic reasons.
Given the price difference and positive first impressions, I picked up a pair as well.

Purchased on Taobao for $85CAD.
Better than average - Extra Average

stagedive

Re: Juin Tech GT-F brake calipers (dual piston)
« Reply #39 on: April 30, 2022, 01:10:48 AM »
So far I am running both the Juintech F1's and the BR-005 with the original pads that came on delivery.
I am also wondering what improvements could be achieved experimenting with different pads...
Hopefully somebody can share some experience with different break pads and make some recommendations.

BR Chris

Could you give the BR-005 a test already? Could you leave some impressions?
I'm in the planning phase of my CFR696 build and those are the brakes I'm likely going to use. Though I'm a little bit concerned that I'm not going to be that happy with the brake power. (coming from V-Brakes with compression less housings on my old-school graveler.. but I also have 4 piston brakes on my all mountain fully, so I'm kinda spoiled)


You could try semi-metallic pads? they're certainly more abrasive that the stock resin ones. However I remember Juin support explicitly telling me to only use resin pads with the GT-F

It's a bummer Onirii didn't design the BR-05 for finned pads though. K03S is just the non-finned version of L03A which would open up a lot of cool stuff like SwissStop's EXOTherm2 or Jagwire's Elite Cooling. If you want to keep things resin and OEM, I guess you could try the K05S which is the latest in the Shimano K02S/K03S non-finned resin lineage.

That's quite a good hint with the K05S, since K03S seem to be out of stock atm pretty much everywhere where I look.
Sorry for asking and kinda hijacking but the B03S would likely not fit, right? (besides they are using a splint and not a screw to secure the pads)
While I'm at it.. regarding rotor choice: there are shimano rotors designed for wide pads (as B03S) and narrow (like K03S) pad shapes. Would I experience down sides using rotors designed for wide pads but actually using narrow pads? (the other way around would make sense to me to be disadvantageous)

StiffWeenies

Re: Juin Tech GT-F brake calipers (dual piston)
« Reply #40 on: April 30, 2022, 08:26:10 AM »
Could you give the BR-005 a test already? Could you leave some impressions?
I'm in the planning phase of my CFR696 build and those are the brakes I'm likely going to use. Though I'm a little bit concerned that I'm not going to be that happy with the brake power. (coming from V-Brakes with compression less housings on my old-school graveler.. but I also have 4 piston brakes on my all mountain fully, so I'm kinda spoiled)


That's quite a good hint with the K05S, since K03S seem to be out of stock atm pretty much everywhere where I look.
Sorry for asking and kinda hijacking but the B03S would likely not fit, right? (besides they are using a splint and not a screw to secure the pads)
While I'm at it.. regarding rotor choice: there are shimano rotors designed for wide pads (as B03S) and narrow (like K03S) pad shapes. Would I experience down sides using rotors designed for wide pads but actually using narrow pads? (the other way around would make sense to me to be disadvantageous)

The Onirii BR-05/ZRACE BR-005 is the only viable hydromechanical option in its price bracket. It obviously won't be as good as the 4-piston Juin GT-F but to supposedly perform on par with the 2-piston Juin F1 while costing half as much, what more can you ask for?

I don't think that B03S/B05S will fit. Not sure about the rotors
« Last Edit: April 30, 2022, 09:17:15 AM by StiffWeenies »

planet_sammy

Re: Juin Tech GT-F brake calipers (dual piston)
« Reply #41 on: May 19, 2022, 05:04:48 AM »
„TraceVelo“ has noted in his video comparing that the disc-brakes on the cheap models is no rubber seal at the transition from the brake arm to the brake piston but there’re included in the Juin Tech F1…

Are the BR-05 brakes from Oniri with or without rubber seal?

ChrisB

Re: Juin Tech GT-F brake calipers (dual piston)
« Reply #42 on: May 23, 2022, 03:09:46 PM »
„TraceVelo“ has noted in his video comparing that the disc-brakes on the cheap models is no rubber seal at the transition from the brake arm to the brake piston but there’re included in the Juin Tech F1…

Are the BR-05 brakes from Oniri with or without rubber seal?

Some update from my side since I put some more Kms on the bike with the BR005s… all good so far but no wet weather riding.

The BR005s have the rubber seal as far as I can tell comparing to the old BR002s.
Comparing to the Juintech the BR005s need more cable pull for activation, however I have different break levers on the bikes…

I can definitely recommend  these breaks.

BR Chris

1Sigma

Re: Juin Tech GT-F brake calipers (dual piston)
« Reply #43 on: May 24, 2022, 04:52:01 PM »
Regarding the versions with exposed pistons, it seems like that was actually the 2nd generation design done by a company called IIIPRO who produced them until Onirii took over the project.

Mine just came in the mail. Interested what your take is on these.
They are branded Onirii on one side, IIIPRO on the other.
They come with pads installed, so I haven’t checked the seals yet.

For comparison, they are 37g heavier than the Juin Tech GT-F for the same 160mm setup.
So torn.  Giving up 37g and dual piston calipers for colour coordination…
Better than average - Extra Average

StiffWeenies

Re: Juin Tech GT-F brake calipers (dual piston)
« Reply #44 on: May 25, 2022, 12:17:54 AM »
Mine just came in the mail. Interested what your take is on these.
They are branded Onirii on one side, IIIPRO on the other.
They come with pads installed, so I haven’t checked the seals yet.

For comparison, they are 37g heavier than the Juin Tech GT-F for the same 160mm setup.
So torn.  Giving up 37g and dual piston calipers for colour coordination…

Yeah the quirky mixed branding (Onirii facing outwards to NDS, IIIPRO facing inwards) is normal on the Onirii BR-05.

Your GT-F is hands down the best hydromechanical option on the market, so it'll for sure be a downgrade in terms of performance.
« Last Edit: May 25, 2022, 01:59:50 AM by StiffWeenies »