jaxgtr

So I saw this the other day and thought for $8, I'd give it a try. While I've not had issue with the gap in my brakes, sometimes I felt like I was not always getting centered. With this tool.....no issue.
Just pop it on, squeeze the brakes a couple of times, tighten the bolts, perfectly centered each time.

dscheidt

so it's tool to ensure your brakes *aren't* centered? Don't think I need to pay for that...

TenSpeedV2

Perfectly centered on what?

jetta_mike

I'd wager the rotor.

gregf83 

It's not clear that this tool helps centering any better than doing the same procedure without the shims. It just creates a small gap between the pads and disc. As soon as you squeeze the brake lever the gap will go away.

Unless I'm missing something normally hydraulic discs don't have a gap between the pads and disc. At least they don't in a vehicle. Are they different somehow on a bike?

TenSpeedV2

You don't need a specific tool to do this.

wschruba

Yes, bicycle brakes are different. On even a modest car, you have over 100hp behind the engine, and the dragging brakes means nothing significant (fractions of a horsepower?)...most people, on the other hand, would have trouble generating even 1 horsepower, ergo, rubbing brakes are bad. You should get no rubbing under normal conditions.

The tool, as far as I know, was originally designed for mechanical brakes, which would make sense, since business cards are compressible. It doesn't really do much for a properly operating hydraulic brake. If bolts are walking the caliper, drop some oil on top of the washer beneath the mounting bolts' heads.

hueyhoolihan

i think my shimano xt brake came with something similar. two plastic spacers to keep the pistons from coming completely out of the caliper when there were no brake pads present, and another, narrower, set to establish a gap when installing new pads.

gregf83 

OK, I did a little research and the XTR brakes I have include a return spring to help retract the pads a little when pressure is released which is different than automotive brakes.

wschruba

Close, but not exactly; The spring is to keep the pads flush on the pistons, any retraction is handled by the reflex action of the square-edge seal in the piston bore. On actuation, the seal deforms in a roughly trapezoidal form, and when the lever is released, it relaxes back to it's original shape, pulling the pistons with it. If the pads are worn, the piston will slip through the deformed seal, allowing the system to self-adjust (in one direction only!). Closed systems work differently, of course, but they are all but gone in the bicycle world.

In other words, the spring keeps the pads from clattering, but it doesn't retract them. The clattering has little effect on power loss, but would drive most people insane, since they are very much audible (see, people noticing the pads clanging on the slide when they apply the brakes, rocking the bike backwards/forwards).

gregf83 

Thanks for the explanation. Much appreciated.

CrippledKonaBoy

I use a business card; works every time.

SlowJoeCrow

at least it's cheaper than the Hayes tool https://www.universalcycles.com/shop...41&category=25 although it lacks the cool purple anodizing

Leebo

I don't need it for my BB7's. When setting up, just loosen the brake some. Squeeze the brakes, they are now centered and tighten the bolts. Adjust pads as needed.

rmfnla

Exactly; same for setting toe-in for calipers...

Moe Zhoost

Same for me - and they're cheap (amazing that folks just give them away).

PatrickGSR94

I used this guy's method when setting up my BB7's: adjust both pads all the way out, loosen rotor bolts, turn inboard adjustment one full turn, then the outboard adjustment all the way in until the wheel is locked. Tighten rotor bolts. Adjust outboard pad out until wheel turns freely. Adjust inboard pad by 2-3 clicks outward. Make any additional adjustments necessary to ensure the pads don't rub the rotor at any point, and to achieve desired lever travel.

Took me a couple of times to get it right initially, but after that it was pretty easy. This method also ensures that the pads are square to the rotor. Not sure if that tool will do that.