Is anyone else running Shimano BR-RS785 post mount callipers and grx 400/600 levers? I can get them working but they feel so spongy and touch the bars when being applied. There is no air trapped in the system. The hoses came with the GRX levers: sm-bk90-jk-SS. On the Shimano compatibility chart it says the br-rs785 callipers should use the SM-BH90 Hose, I thought the hose should match the lever? It’s really confusing me. Any help would be greatly appreciated. Thanks.
Those levers are BH90, the RS785 calipers are BH59. A BH90 MTB caliper like the Deore M6000 should work fine, all 2 piston calipers are same piston size last I checked.
I have used bh59 road levers with bh59 mtb calipers plenty of times and it works spot on (haven't needed to try bh90 yet)
It shouldn’t matter which hose you use as long as the inserts are correct. Bh90 is a smaller diameter. I’ve used STR785 shifters with XTR callipers for years.
What you described does sound like either air in the system or one of the pistons bending the rotor. If it’s not internally routed, I’d remove it from the bike and re-bleed.
Yes I'm running GRX 600 levers and BR-RS785 calipers. Set it up with BH90 hose (silver barb). Consensus of what i read at the time was that BH90 would give the more direct/sharper bite point.
Mine don't feel spongy or touch the bars. The only thing I did notice when doing the bleed is that the front I did with an Epicbleed kit spacer and the rear I did with the yellow Shimano spacer (I couldnt fit the Epic one in without removing mudguards & rack). Rear was marginally closer to the bar before it bit. Maybe the Epic block is thinner?
@owenh
Thanks for that. I have also heard of shaving a millimetre off the yellow bleed block, which makes sense. I am going to give it one final bleed and then look at cables etc It's good to know others have the combination working.