BH59 connected to a BH90 hose via easy hose joint system
04-03-21, 11:47 AM
#1
Junior Member
Thread Starter
BH59 connected to a BH90 hose via easy hose joint system
I just bought a set of Shimano ST-R785 levers that came with a set of BR-R785 calipers and I planned to install them on my tandem. The problem is the BR-R785 calipers utilize the BH59 hoses with a banjo and those hoses have a max length of 1700mm and the banjo appears to be a crimp on that isn't sold individually.
The set came with a shimano easy hose joint system which basically looks like a hose coupler. Since the outer diameters are exactly I'm thinking I'm just going to buy a 2500mm BH90 hose with a banjo connected to the caliper and insert the other end into the easy hose joint system.
As I understand it the internal diameter of the BH90 is 2.1mm vs the BH59 at 2.3mm. So at the easy hose joint system I'd be going from the 2.3mm internal diameter hose from the lever down to the 2.1mm internal diameter hose that would run to the brake caliper.
Is there a problem with this other than not recommended by shimano (don't think any of their brake calipers are recommended for tandem use)? Reading online I've only seen good things about having a smaller internal diameter on the hydraulic brake (especially important given the long length of the hose for the tandem).
The risk of trying it is only 40ish dollars plus the risk of a failing rear brake during a ride.
Other options I'm considering:
1) Get ride of the easy hose joint system and run a BH90 hose the entire length from lever to caliper.
2) Buying a TiCycles hydraulic line coupler. This would allow me to stick with the entire length of BH59 that shimano recommends.
3) Spend a lot more money and get new levers and calipers that are both BH90 compatible.
The set came with a shimano easy hose joint system which basically looks like a hose coupler. Since the outer diameters are exactly I'm thinking I'm just going to buy a 2500mm BH90 hose with a banjo connected to the caliper and insert the other end into the easy hose joint system.
As I understand it the internal diameter of the BH90 is 2.1mm vs the BH59 at 2.3mm. So at the easy hose joint system I'd be going from the 2.3mm internal diameter hose from the lever down to the 2.1mm internal diameter hose that would run to the brake caliper.
Is there a problem with this other than not recommended by shimano (don't think any of their brake calipers are recommended for tandem use)? Reading online I've only seen good things about having a smaller internal diameter on the hydraulic brake (especially important given the long length of the hose for the tandem).
The risk of trying it is only 40ish dollars plus the risk of a failing rear brake during a ride.
Other options I'm considering:
1) Get ride of the easy hose joint system and run a BH90 hose the entire length from lever to caliper.
2) Buying a TiCycles hydraulic line coupler. This would allow me to stick with the entire length of BH59 that shimano recommends.
3) Spend a lot more money and get new levers and calipers that are both BH90 compatible.
04-29-22, 09:34 PM
#2
Junior Member
Join Date: Jul 2020
Location: New Hampshire
Posts: 196
Bikes: 1984 homemade 531SL road bike; 1988 Ritchey TimberComp; 1997 Nashbar tandem; 1998 Kona Explosif; Specialized Epic, Scott CR1 Pro; Salsa Beargrease; Curtlo custom Tandem, Curtlo custom S3 steel gravel bike.
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I have the same levers and brakes on my tandem. If I recall correctly I found a longer BH59 hose with a banjo and connected it to the Easy Hose coupler they came with.
I've now decided those brakes are not up to the task for a tandem on hills and am switching to Shimano Zee calipers. Those take BH90 hose and banjo so I'm planning to leave the BH59 at the lever and transition to BH90 using a coupler (TRP makes one as well) IF the BH59 banjo is not compatible with the Zee calipers.
I'm curious what solution you used and surprised no one answered previously!
There is a similar thread on the tandem forum.
https://www.bikeforums.net/tandem-cy...dem-use-2.html
I've now decided those brakes are not up to the task for a tandem on hills and am switching to Shimano Zee calipers. Those take BH90 hose and banjo so I'm planning to leave the BH59 at the lever and transition to BH90 using a coupler (TRP makes one as well) IF the BH59 banjo is not compatible with the Zee calipers.
I'm curious what solution you used and surprised no one answered previously!
There is a similar thread on the tandem forum.
https://www.bikeforums.net/tandem-cy...dem-use-2.html
