BB7 Road - Lever Problem

16mm

Hi,
I'm building up a drop bar disk brake road bike. I've never used disks before.
Using bb7 road calipers and some tektro levers I can't seem to to get the brakes to work without either rubbing the pads or the levers hitting the bars before the brakes bite.

My rotors are new, and are pretty straight, but after setting up the calipers as per instructions (http://www.pinkbike.com/news/tech-tuesd ... brake.html ) I have to back off the adjusters about 4-5 clicks to stop rotor rub, and then the lever hits the bars before the brakes start to bite.

Have I got the wrong levers? They are from a Pompino with Cantis so I think they are OK with road calipers. Are they pulling the correct amount of cable?

Or are my rotors too much out of true? They are not totally straight, but I they look pretty close. At a guess 0.5mm at most.

I can post pics of the rotor clearances and actuator arm travel if required.

thanks.

nicklouse

1 read the avid instructions.
2 has the bike been ridden?
Do NOT over tighten the bolts. See Avid manual.

Once set up they will need to be bedded in to reduce the chances of rubbing.

16mm

nicklouse wrote:

1 read the avid instructions.
2 has the bike been ridden?
Do NOT over tighten the bolts. See Avid manual.

Once set up they will need to be bedded in to reduce the chances of rubbing.

The instruction leaflet with the brakes said the same as the video posted. Maybe there is more online.
I've not ridden the bike yet, so nothing has bedded in.

ta
Mike

ugo.santalucia

If the disc is warped, no chance. With road levers, you need the pads very close to the disc, as the cable pull ratio is low... typically less than half a mm on the inner side and half a mm on the outer. if your disc is half a mm out of true, there is no way you can use it.
Make sure the caliber is aligned to the disc, by tightening the bolts while you are squeezing the lever

16mm

ugo.santalucia wrote:

If the disc is warped, no chance. With road levers, you need the pads very close to the disc, as the cable pull ratio is low... typically less than half a mm on the inner side and half a mm on the outer. if your disc is half a mm out of true, there is no way you can use it.
Make sure the caliber is aligned to the disc, by tightening the bolts while you are squeezing the lever

I'll try to measure the deflection of the rotors. They are both new out of the packet, but neither 100% true.
Front is a slx centerlock, rear avid 6 bolt, so it's not a bad batch.
thanks
Mike

nicklouse

Get it the best you can then ride it. The rubbing will go if you have set it up right. If you have not set it up right it will reduce allowing last tweeks.

16mm

nicklouse wrote:

Get it the best you can then ride it. The rubbing will go if you have set it up right. If you have not set it up right it will reduce allowing last tweeks.

Took it for a quick spin to bed in a bit. Rear locks up easily, at the moment front is much worse than campag rim brakes.

I'll bed in a bit more and see if it will adjust closer.

nicklouse

Remember that every time you adjust,play with the front caliper mounting you will need to let the pads bed in again.