Juin Tech GT

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montee
Posts: 193
Joined: Wed Apr 01, 2020 11:56 am

by montee

Has anyone here used the Juin Tech 4-cylinder brakes for long/steep (i.e. Alpine) descending? How do they perform?

by Weenie


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Marin
Posts: 4035
Joined: Wed Jan 22, 2014 11:48 am
Location: Vienna Austria

by Marin

I only used the 2-piston F1 on my gravel bike, no issues (78kg rider). A friend who is at least 10kg heavier likes them too. All on 160mm discs.

AZR3
Posts: 998
Joined: Wed Sep 12, 2012 9:00 pm
Location: Az USA

by AZR3

Here are some current users of those brakes on pace line, maybe ask over there

https://forums.thepaceline.net/showthread.php?t=273608

RDY
Posts: 2354
Joined: Thu Jul 30, 2020 10:31 pm

by RDY

I've ridden the GTF, but not down alpine passes - I.E. to potential fade. They felt excellent, and stopping power as good as Ultegra IMO ... and much easier to adjust to avoid rub.

Weasel
Posts: 53
Joined: Thu Jul 05, 2007 10:18 am

by Weasel

As RDY above - I have them on my SL7, and quite happy with the performance, but yet to take it to the mountains (hopefully next year!).
One thing I do find is the standard pads do take a second or two to warm up, at which point the braking gets stronger. I really need to try some different pads to see if it improves that a bit.

WorkonSunday
Posts: 540
Joined: Tue Jan 16, 2018 4:39 pm

by WorkonSunday

they use last generation Shimano downhll (Saint and Zee series) brake pads, don't think they can be that bad if they are rated for downhill.
Some say pour 10ml water out of your bottle to save that last bit of the weight. Sorry, i go one step further, i tend to the rider off my bikes. :thumbup:
n+1...14 last time i checked, but i lost count :mrgreen:

Weasel
Posts: 53
Joined: Thu Jul 05, 2007 10:18 am

by Weasel

WorkonSunday wrote:
Tue Sep 14, 2021 4:24 pm
they use last generation Shimano downhll (Saint and Zee series) brake pads, don't think they can be that bad if they are rated for downhill.
Same shape - yes, but not the same pads. These are Juin Tech's own (or made for them).
I did briefly try some other cheapie organic pads (Clark's I think?), which were definitely better, but about 0.4mm thicker, so I couldn't stop them rubbing.

RDY
Posts: 2354
Joined: Thu Jul 30, 2020 10:31 pm

by RDY

Don't think I tried their pads. They were Galfer or Ashima IIRC - the ones I used.

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Mr.Gib
Posts: 5577
Joined: Fri Mar 18, 2005 4:12 pm
Location: eh?

by Mr.Gib

I have a spare Di2 9150 groupset and a disc frame so I was thinking about these. I have the regular Juin Tech F1 on my winter bike and they have been fantastic. I have ridden plenty of full hydro setups and while the Juin Techs require more lever effort, the stopping power is not far off, and I think it is fair to assume that the GT will be even stronger than the F1. The biggest issue with these (or any cable actuated hydraulic caliper) is the cable routing. Full hydraulic systems hoses connect on the inboard side of the caliper, whereas hybrid systems necessitate the cable to be on the outboard side of the caliper. The problem is of course that most disc frames have cable/hose ports to suit a full hydraulic build. Inevitable the last few inches of the mechanical cable to the caliper involves some severe bends that can result in excess cable drag which will further increase lever effort. Were it not for this drawback, I don't think I would consider full hydraulics. I particularely like the control over both lever position and lever travel. Reduced incidence of pad rub is also nice. And finally 9150 levers weight 230 grams vs 320 grams for 9170 levers (although you give some of this up with the heavier calipers). Not sure what to do :noidea:
wheelsONfire wrote: When we ride disc brakes the whole deal of braking is just like a leaving a fart. It happens and then it's over. Nothing planned and nothing to get nervous for.

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wheelsONfire
Posts: 6283
Joined: Mon Jul 07, 2014 8:15 am
Location: NorthEU

by wheelsONfire

T*red sell almost all read built bikes with Juin tech over hydraulic calipers. They say because it's lighter and less rub issues. So again and i swear boys and girls, i don't want to sabotage this thread, but it seems it's great for those of use just wanting to upgrade from rim to disc with least possible expenses.
However, i do wonder for those that wish the most modern bikes with hoses (in this case wires) routed through bar, stem and fork.
How the heck is a wire supposed to handle those bends?
I have an UP /Open cycle. There is one single adapter on the frame to handle shift wire + hose. At two occasions i have leaved my bike for new hydraulic fluid. Both times to hose has been "nagged" to a degree it needs to be replaced.
Personally i could imagine (if i farted money) to buy a second Ax bike with disc brakes and a rim brake groupset with GT brakes.

Is there any groupset ( Shimano, Sram and Campagnol) for you who know, who match better or worse with respects to levers?
Bikes:

Ax Lightness Vial EVO Race (2019.01.03)
Open *UP* (2016.04.14)
Paduano Racing Fidia (kind of shelved)


Ex bike; Vial EVO D, Vial EVO Ultra, Scott Foil, Paduano ti bike.

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Mr.Gib
Posts: 5577
Joined: Fri Mar 18, 2005 4:12 pm
Location: eh?

by Mr.Gib

wheelsONfire wrote:
Wed Sep 15, 2021 3:12 am
T*red sell almost all read built bikes with Juin tech over hydraulic calipers. They say because it's lighter and less rub issues. So again and i swear boys and girls, i don't want to sabotage this thread, but it seems it's great for those of use just wanting to upgrade from rim to disc with least possible expenses.
However, i do wonder for those that wish the most modern bikes with hoses (in this case wires) routed through bar, stem and fork.
How the heck is a wire supposed to handle those bends?
I have an UP /Open cycle. There is one single adapter on the frame to handle shift wire + hose. At two occasions i have leaved my bike for new hydraulic fluid. Both times to hose has been "nagged" to a degree it needs to be replaced.
Personally i could imagine (if i farted money) to buy a second Ax bike with disc brakes and a rim brake groupset with GT brakes.

Is there any groupset ( Shimano, Sram and Campagnol) for you who know, who match better or worse with respects to levers?
Very good questions and I would never use cables in a fully integrated bike. An internal run with entry at the head tube or better yet downtube OK, but in the bars and stem? I can't see that working well. As you point out, even with hoses, fully integrated can be a challenge.

As for the best levers, my assumption is that the more cable the lever pulls, the more leeway you have as far as setting the pads further away from the rotors and/or greater opportunity to set the levers closer to the bars. I think that favours Shimano IIRC. Of course more cable pull means less leverage at the caliper, so there is a trade-off. I have used Juin Tech F1 with Sram levers and the combination works great. About to try with Shimano in a few months.
wheelsONfire wrote: When we ride disc brakes the whole deal of braking is just like a leaving a fart. It happens and then it's over. Nothing planned and nothing to get nervous for.

Weasel
Posts: 53
Joined: Thu Jul 05, 2007 10:18 am

by Weasel

I don't think it's that much worse than on most modern rim brake TT bikes though - I guess it depends on the specific bike?
I found using the cheaper coil wound cable outer works better through the handlebar/stem area, as the compressionless cable does kink easily and trap the inner wire.

Steve Curtis
Posts: 1314
Joined: Thu Jul 31, 2008 12:20 pm
Location: Hampshire UK, Dublin Ireland and Geneva Switzerland.

by Steve Curtis

I've been reading with interest. I use Juin f1 and I'm waiting for some GTs to be delivered.
They will be going on a fully internally routed bar and frame with TRP compressionless cables. ( entering though the stem and into the headset ) The f1s are on this bike right now with the same cables and they work perfectly. No issues what so ever with the cable route or tight bends.

I can only imagine that the GTs will be more powerful and a few grams lighter while enjoying the rame cable path.
I decided to go this way with RED AXS shifters as the ergonomics are nicer with the hoods than the full hydraulic AXS levers.
The system weight is also lower than with full hydraulic which is a happy coincidence.

WorkonSunday
Posts: 540
Joined: Tue Jan 16, 2018 4:39 pm

by WorkonSunday

i have TRP hy/road on 3 bikes and now building a supersix (current model) with Juin GT. I dont use the integrated stem, but vision metron 5D. I also played around with a similar setup on my friend's merida Reacto (agai, current version). I think if it is truly fully integrated like the hoses go through the stem then a D shape downtube, then yes, cable routing is a nightmare. but for those which are only a cover under the stem, then have a separate port in the head tube to receive the cables, then those system are ok. Supersix is latter and Reacto is former. My friend then switched to full hydro setup and gave me the Juin, hence my new project with supersix :up:
Some say pour 10ml water out of your bottle to save that last bit of the weight. Sorry, i go one step further, i tend to the rider off my bikes. :thumbup:
n+1...14 last time i checked, but i lost count :mrgreen:

by Weenie


Visit starbike.com Online Retailer for HighEnd cycling components
Great Prices ✓    Broad Selection ✓    Worldwide Delivery ✓

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Mr.Gib
Posts: 5577
Joined: Fri Mar 18, 2005 4:12 pm
Location: eh?

by Mr.Gib

I received my Juin Tech GT's. Installed them on my winter/wet road/fender bike, a Cannondale Synapse. Groupset is Sram Red. The GT's replaced Juin Tech F1. Cables are Jagwire Pro, although both the cable and housing for the front were re-used (just because I was lazy), rear was all new. Installation was super easy although the pistons in the rear caliper would not retract enough to allow the pad to clear the rotor. I jammed a spacer in between the pads, cracked open the bleed port and let out a tiny dribble of mineral oil, and then closed the bleed port immediately. Problem solved.

A couple of observations. They are lighter which nice. More importantly, the cable housing stop is close to a centimeter further away from the cable exit ports on the frame compared to the F1 model. This is actually a big deal in terms of reducing the cable bend that is required on most disc frames, hopefully along with the comensurate reduction in cable drag.

First ride with them today and while I didn't do any serious descending, I did perform a few good tests including multiple stops on a 15% - 20% hill, and a 65km/h to zero as fast as I could without lock up. Have to say I am very impressed. The lever action is much smoother and lighter than expected. Not quite at the level of a good hydro system but shockingly good.

I also had a high speed sweeper that I entered a bit hot, and had to feather the brakes lighly to scrub off speed. The modulation was everything I could ask for - dead smooth, no pulsing, great feedback, really excellent. I was planning on ordering some premium pads but these are performing so well that there is no need. And the brakes shipped with a spare set of pads - was not expecting that. Also they are silent although today was dry so...

I guess the big question is how is the power? Frankly it is a match for most of the hydro systems I have ridden. The only real difference is the Juin Techs, despite the nice light feel, still require more lever effort than hydro, and this is bound to limit the ability to modulate when braking very hard relative to a good hydro setup. Still, they are a noticeable step up from the very good Juin Tech F1 in terms of braking power.

My overall impression is so positive that I think I might prefer these to a full hydro for reasons of cost, weight, control of lever position, control of free stroke, and ease of maintenance and installation. Add in the fact that they are compatible with any old mechanical groupset that might be lying around and they are a compelling option. As well, they might make sense for a travel bike for my summer adventures to Europe. Alway gone with rim brakes because I just don't ever want have to do a bleed in a hotel room. (Don't ever want to travel with mineral oil FFS.) In a few weeks I will build a full hydro (Dura Ace Di2 9170) Factor O2 with XTR rotors. Then I'll have an opportunity to compare these Juin Tech GT's against the very best hydro brakes.
Last edited by Mr.Gib on Tue Oct 05, 2021 4:32 pm, edited 1 time in total.
wheelsONfire wrote: When we ride disc brakes the whole deal of braking is just like a leaving a fart. It happens and then it's over. Nothing planned and nothing to get nervous for.

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