BH90 Hydro Cable with R785 brake that uses BH59 hose

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ParisCarbon
Posts: 935
Joined: Mon Feb 05, 2007 5:39 am
Location: Winnipeg Canada

by ParisCarbon

Hi,
I have zero knowledge with Hydro brakes so here is the dilemma...

I am building my Stevens cyclocross bike up.. its a 2 yer old frame where they were still utilizing post mount, so I have R785 post mount calipers... these calipers utilize the BH59 Hose.

I have been gathering the new 8050 Ultegra components , and the only thing I don't have so far are the 8070 shifters...

I was in contact with Shimano through facebook yesterday, and was told that the Ultegra 8070 or DA 9170 shifters will not work with the R785 brakes because they utilize the BH90 cable, and I would need to use the older 785 shifter.. Is there a way to adapt a BH90 cable to fit the R785 calipers?? I read somewhere someone saying get XTR BH90 cable and snip the banjo off and insert a new olive and insert??

Im in a position here where I either just get the 785 shifter and finish by build, or wait for the 8070 and adapt the hose if possible??

Thanks

by Weenie


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ms6073
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Joined: Fri Jul 23, 2004 8:24 pm
Location: Houston, Texas

by ms6073

ParisCarbon wrote:and was told that the Ultegra 8070 or DA 9170 shifters will not work with the R785 brakes because they utilize the BH90 cable, and I would need to use the older 785 shift

Just guessing, but aside from the different size fittng that is only supplied with the applicable BH90 hydraulic hose for the DA ST-R9170 shifters, the only other thing I can imagine is that the BR-R785 post mount calipers may have a slightly larger fluid capacity. If that is the case, since the BH90 hydraulic hose has a sightly smaller inner diameter than the BH59, the result may be that the 9170 shifters might not be able to push enougbh fluid through the hose for effective braking action.
Michael - The Anaerobic Threshold is neither...

CallumRD1
Posts: 118
Joined: Mon Apr 03, 2017 2:54 pm

by CallumRD1

The BH90 and BH59 hose are fully interchangeable as long as you get the correct fittings.

ParisCarbon
Posts: 935
Joined: Mon Feb 05, 2007 5:39 am
Location: Winnipeg Canada

by ParisCarbon

Ahhhh OK.. valid points... I called a few shops and they said that the BH59 insert is 2.3mm and the BH90 is slightly smaller at 2.1 (these are numbers Im just trying to recall) But apparently you can tap the 59 insert into the 90 hose.. like you said though.. not sure of this on the braking...

Looks like the smart thing to do is just get the 785 shifters and not compromise braking..

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MayhemSWE
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Joined: Thu Mar 12, 2015 12:44 pm
Location: Stockholm, Sweden

by MayhemSWE

Aren't the R785 calipers pretty much just rebadged XT calipers? If hose compatibility between R8000 series levers and R785 calipers is anyway in doubt, perhaps you could just go for XT/XTR/SLX calipers designed for BH90 hose?

ParisCarbon
Posts: 935
Joined: Mon Feb 05, 2007 5:39 am
Location: Winnipeg Canada

by ParisCarbon

So update... just got off the phone with Shimano Canada..

Apparently with the Ultegra and Dura Ace new Hydro Di2 shifters, no changes are required at all... you just take the BH90 cable and use the BH90 insert and banjo that are supplied and thats it...

He told me the BH59 hose was used before because they were worried about the modulation of the brake and the wider hose gave the brake more of a road brake feel...

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ms6073
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Joined: Fri Jul 23, 2004 8:24 pm
Location: Houston, Texas

by ms6073

ParisCarbon wrote:Apparently with the Ultegra and Dura Ace new Hydro Di2 shifters, no changes are required at all...

Just be sure that you source the correct BH-90 hydraulic hose kits, as I found there are two variants with one containing correct fittings for the new DA/Ultegra hydraulic shifters, and the older kits for R785/R685 shifters. Referencing the image below, the fitting circled in red is required for the DA ST-R9150/R9170 and Ultegra ST-R8050/R8070 shifters:

Image
Michael - The Anaerobic Threshold is neither...

thumper88
Posts: 146
Joined: Tue Mar 13, 2012 7:27 pm

by thumper88

This is one pain in the butt I', also dealing with trying to mix and match the latest STI with older calipers.... forced into it in a way because the new flat mount calipers just can't be made to go on my post mount frame.

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ms6073
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Joined: Fri Jul 23, 2004 8:24 pm
Location: Houston, Texas

by ms6073

For the ST-R9120/R9170 & ST-R8020/R8070 shifters, the Shimano SM-BH90-JK-SSR Disc Brake Hose Kits are needed, which should allow pairing with the BR-RS505/BR-RS785 post mount calipers, and the BR-RS805/BR-R8020BR-R9120 flat mount calipers.
Michael - The Anaerobic Threshold is neither...

ParisCarbon
Posts: 935
Joined: Mon Feb 05, 2007 5:39 am
Location: Winnipeg Canada

by ParisCarbon

Thanks for the PN on the hose..
Ive managed to hunt down the RH 8070 lever, but not the LH..
Since I have everything to complete my new CX bike minus the shifter, I may just bite the bullet and get the Dura Ace 9170 ones...
CX season is already 2 races in here, and I wanna ride my new bike!!!!

ms6073 wrote:For the ST-R9120/R9170 & ST-R8020/R8070 shifters, the Shimano SM-BH90-JK-SSR Disc Brake Hose Kits are needed, which should allow pairing with the BR-RS505/BR-RS785 post mount calipers, and the BR-RS805/BR-R8020BR-R9120 flat mount calipers.

tomee
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Joined: Thu Oct 16, 2014 8:52 am

by tomee

i wonder if I was to upgrade just the hoses on my bike running r785 levers and calipers to BH90 hoses would it make any difference to feel?

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ms6073
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Joined: Fri Jul 23, 2004 8:24 pm
Location: Houston, Texas

by ms6073

The BH90 hose sets made a slight difference in lever feel (stiffer) on our CX bikes with ST-R785 shifters and BR-RS785 post mount calipers, but some of this will depend on the amount of free-stroke adjustment.
Michael - The Anaerobic Threshold is neither...

Dick
Posts: 44
Joined: Sun Jul 06, 2014 8:47 pm

by Dick

Hi there

I'm currently in the process of trying to replace R785 shifters with R9170 to have a combination of ST-R9170 shifters and BR-R785 Calipers; connected with BH90 hose.

Based on the conversations above, did @ParisCarbon manage to make these two work and what was the resulting brake feel etc?

Thanks

Hamfist
Posts: 85
Joined: Sun Feb 03, 2008 3:04 pm
Location: Bloomfield Hills, Michigan

by Hamfist

Interested as well...makes sense. New post-mount frame coming my way and I want to use the 9170 levers.

PaulH
Posts: 31
Joined: Mon Jul 10, 2017 9:50 pm

by PaulH

Yes it does work (I’m running that exact setup), feel after a good bleed is less lever throw and in my opinion. Be careful with the bleed screw on the levers as they are easily broken


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by Weenie


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