Mediator Brake-Shifter Adapter

Each one is named brake first, then what the adapter lets you mount on it. So "I-SPEC II Brake to MatchMaker Shifter" means you have a Shimano brake lever with an I-SPEC II mount, and the adapter lets you hang a SRAM MatchMaker-style shifter or a Funn UpDown lever off it. "MatchMaker Brake to I-SPEC EV Shifter" is the other direction: a SRAM brake lever carrying a Shimano I-SPEC EV shifter. Always start from the brake you already have, because that is the part that is not moving.

They are the two rival ways of hanging a shifter off the brake lever clamp instead of giving it its own band around the bar. MatchMaker is SRAM's; I-SPEC is Shimano's, and Shimano has changed it more than once — I-SPEC II arrived around the XT M8000 and SLX M7000 generation, and I-SPEC EV replaced it from the M9100, M8100, M7100 and M6100 groups onwards. Because the two brands never agreed on a shape, a Shimano brake and a SRAM shifter will not bolt together on their own. That is the gap these fill.

No — these cover I-SPEC II and I-SPEC EV only. The earlier interfaces use a different clamp shape and are not interchangeable with either, so if your brake levers pre-date the M8000 generation it is worth confirming before you order. The reliable way to check is your brake lever's model number rather than the year of the bike, since frames are often built with older-generation brakes.

Because the adapter is a mirror image rather than a symmetrical part — the shifter has to sit inboard of the brake lever on whichever side it is fitted, so a right-hand adapter will not do the job on the left. In practice the right side is your rear shifter and the left is a front shifter or a dropper lever. The MatchMaker Brake to I-SPEC EV Shifter is right-hand only, because that pairing is only ever wanted on the shifting side.

Yes — the UpDown Dropper Lever uses the MatchMaker interface, so any of the I-SPEC to MatchMaker versions will put it straight onto a Shimano brake lever, and the left-hand ones are the usual choice for exactly that. It takes the lever off its own bar clamp and frees up the space, which is the main reason people fit one. If you would rather keep the lever on the bar but move it in closer to the stem, the 31.8mm bar clamp does that job instead.

It is a small part holding your shifter, so it is a fair thing to ask. These are CNC-machined from AL6061 rather than cast or pressed, which keeps the clamp faces flat and the bolt holes true — and flatness is what actually matters here, because an adapter that flexes or lets the shifter creep under your thumb is far more of a problem in practice than one that is simply strong. Set the brake clamp itself to the torque Shimano or SRAM specify and leave the cockpit able to rotate on the bar in a crash, exactly as you would without an adapter.