TIL a lot of shops are setting up hydraulic disc brakes wrong

I keep seeing bikes come in where the rear caliper is bolted down with the wheel off, which puts the pads way too close together. You need to slide a business card between them before you tighten the bolts, or you'll get instant drag. I learned this after fixing the same issue on three different bikes from the same shop in Tempe. Anyone else have a trick for getting that pad gap just right?

3 comments

3 Comments

black.joel1mo ago

Actually, the business card method can still leave things a bit tight. The real fix is to just squeeze the brake lever a few times with the wheel in before the final bolt tightening. That self-centers the caliper on the rotor, which is what the hydraulic system is designed to do. Doing it with the wheel off or using a spacer is just adding an extra step that can still go wrong. Let the bike sort out its own alignment.

troythompson29d ago

Spending time sliding a business card in there seems like overthinking it for what's usually a 5 second fix. @cameronmurray if your eyeball method gave you rotor rub maybe just loosen and retighten the bolts with the wheel on and pump the lever, that's always worked fine for me. This whole thing feels like folks making a bigger deal out of a simple adjustment than it needs to be.

cameronmurray1mo ago

That business card trick is a good one. I used to just eyeball it and ended up with so much rotor rub on my own bike. A spacer from an old hub finally solved it for me.