Based on SRAM’s compatibility chart this seems like “no” so I am guessing I know the answer but I figured it wouldn’t hurt to see if anyone has had experience or knowledge of mixing an older SRAM HydroR caliper with one of the newer road levers, specifically a new E1 AXS lever like the Force AXS HRD Shift-Brake System (ED-FRC-E1)?
I have an older gravel bike with post mount interface and Force (11sp) HydroR brakes that are still working well. In my head it would be great to purchase the new SRAM E1 levers (and convert to wireless shifting) and continue to use the old post mount calipers instead of messing with adapters and a flat mount caliper.
I think it’s best to bite the bullet and buy some compatible post mount calipers along with the levers, such as the Level.
Off the top of my head I really don’t see a reason, technically, you couldn’t do this. This part of the compatibility chart has always confused me. SRAM hasn’t changed the piston diameter on any of their 2-piston calipers for a very long time so the brake lever pressure ratios remain the same. I do wonder if free stroke and piston travel has been tweaked over time for the lever side. The biggest hurdle in compatibility on SRAM braking systems, to get the system to function at all, is usually the hoses. Lever end post-HydroR is easy since it’s just a compression nut but you will need to make sure you can source the correct fitting for the caliper end.
I’ve never had the chance to try any of this myself since when I upgraded to AXS I had a complete brakeset and just used some post to flat-mount adapters, but my reasoning seems sound.
I’ve been pondering this question for years so, really, what I want is for someone to finally try it for me and give a big ‘ol thumbs up or down on the matter so I can file it away. I figure if the Hope calipers work this has got to work.