Sunday, April 20, 2008

Braking Down

The Pugsley is exactly two years old this week and until last month I have not had a single problem with it. I have been running the same chain, brake pads and tyres and I haven't even had a flat tyre yet!

I say "until last month" because I've been tearing out my hair getting my formally bulletproof braking system back on track. First my front pads lose all power with still plenty of wear left on them. I've been told it was probably oil contamination but I'm not entirely convinced. I pay $40 (rip-off) for some Kool-Stop replacements to watch my front fork resonate and shudder back and forth even under moderate braking and then last week when I'm riding under-water trails out in the forest my back brake goes all spongy at the lever and loses all power.

I finally get some XTR after lusting after it since 1993 and it turns out to be EXACTLY the same part as bottom-of-the-range Deore right down to the code number stamped on the back!

Well I spent another $40 (rip-off), on another set of pads (Shimano XTR resin this time) and put those on the front wheel. A HUGE improvement. Almost as much power, less noise, nice modulation and I don't have to watch the fork bouncing back and forth by half an inch as I slow down. 
I took out the original rear pads and they had worn down completely to the metal holder. I am lucky I don't use much rear brake or I would have totaled my rear rotor. The lever had so much travel as one of the pistons had pushed right out and become stuck. I was pleased it wasn't a hydraulic issue as I don't know how to bleed them yet and I hate taking my bike into the shop to get work done on it.

This is what passes for a work-stand in my house

The Kool-Stops behave much better in the back and a ride in the forest today with the neighbourhood crew confirmed everything is working well again. That's a relief as my big singlespeed race is only six days away.


Jeff said...

I've had spongy brakes that needed to be bled. You could feel the pressure at the lever, but there wasn't much braking going on. That's one thing I don't have the stuff or knowledge to do. Glad it was just the pads!

I have a braking problem right now, where the rear brake causes a lot of vibration. It sometimes vibrates so much that I can't even sit down because it tickles too much! It's not really a problem on the trails, just riding the city to get to the trails. I just swapped wheels and brake pads, and it still happens. Maybe it's the disc!

Antoine said...

Check that the rotor is not warped and a presume you know to centre the caliper on the rotor by operating the brake with the caliper mounting bolts slightly loose and then tightening them with the lever still pulled in so the pads are clamped tight on the rotor.

This is my first bike (sans motor) with discs and I was apprehensive about how reliable they would be. I hope this run of problems is just a "learning" experience.

I certainly like using them. One-finger braking from high speed is quite a contrast with the performance of the cantilevers on my old MTB.