not an experienced bike guy, this is my first forray into bike maintenance/upgrades
I bought a used Specialized Crux Comp with disc brakes. My only complaint off the bat was the brakes seemed weak. Took it to a local shop, but all they did was adjust the tension, and I could still pedal through both brakes. I figured maybe the pads were old, so I replaced them, no dice. Then doing some research, saw that the installed BB5 calipers were considered sub-par. I bought a set of Spyre TRPs, and installed them with compressionless housings. There's certainly an improvement on the front wheel, but the back still feels nonexistent. I have them adjusted to the smallest big of daylight showing on either side of the rotor, and I can't squeeze all the way to the bar, but it's it's just not biting. Could it be the rotors? Everything I've read indicates most of your braking power comes from the calipers/pads, but I'm at a loss.
Are my expectations unreasonable? I'd just like to be able to lock up/skid the rear wheel, and fling myself over the handlebars if necessary. My other bike has older but higher spec rim brakes, do non-hydraulic disc brakes just not compete?
by BreazyStreet
11 Comments
Clean the rotors and bes the brakes. I remove the rotors from the wheel, spray motorcycle disc brake cleaner on a cloth and wipe down the rotors. Then reinstall and follow a standard bed-in procedure
New pads require a bit of break-in to work their best (there’s instructions all over to bed the pads in but basically you get up to 10-15mph then slow down, repeat over and over with harder braking), but overall this is how cable operated disc brakes are; they just don’t compare to hydro discs or even a good rim brake.
You’ve done everything right with the Spyre upgrade and compressionless housing and the adjustment looks good though, bed the pads in and run it! You may never lock up the front but they will function as brakes with decent modulation.
Did you read the manual on how to set them up? Pay attention to the pre load requirement. Then adjust the pads from there.
Looks like you can go a bit tighter with the pads so try that until you get to just kissing the rotor with the pad and then back it out the required amount. Do the same for the other side trying to keep them as evenly balanced as possible. Check both pads are moving and returning.
Finally make sure you follow the bedding in process. If the rotors are older they made need a cleaning or slight sanding, look online for guidance on this
https://www.trpbrakes.com/userfiles/file/SPYRE_Final_053113%281%29.pdf
Make sure you install the caliper with basically no preload on the cable. Pad spacing should be done with the individual pad adjustment, not cable tension or the barrel adjuster. Basically the spyres work best when the swing arm starts all the way back, and pad spacing is as tight as possible.
You are on the right track. If this fails, there are low cost cable actuated hydraulic brakes that would fit the bill here. Likely you just need to bed as others suggested. Hydraulic upgrade with drop bars is a bit spendy, though possible.
Looks like you only have 1 pad installed. Put the other pad in.
The sad truth is that most mechanical disc brakes are pretty weak, and messing with housings and pads can only help so much.
For the real improvement try hybrids, cable activated hydraulic brakes like HY/RD or Juin Tech / Yokozuna, or better yet switch to the hydraulics completely.
There are also high end mechanical calipers like Paul Klamper, Growtac Equal etc, never tried them personally but some say they are also almost as good as hydraulic brakes.
You should also shorten the cable to about one inch past the pinch bolt. Not likely to happen, but you don’t want the cable getting sucked into the rotor/caliper while riding.
Yeah your problem is that your brakes are mechanical and not hydraulic
You need hydraulic brakes. Trust me. You’ll be able to stop on a dime.
Get a larger rotor. That 140 is for slowing down, not stopping.