break discs and how they suck.

[jimmyhackers]

just bought myself a whole bike from my local charity shop. with front and rear wire operated disc brakes.

spent an hourish swapping the fronts over. looked pretty cool

however it was literally the worst braking capability ever. tried tightening the hell outa them. no avail. tried roughing up the disc and pad surface. no help. wouldnt lock up or even come close to stopping me in any kind of hurry.

i think just by design they were crap as hell.

i had switch back to my original vbrakes and pads which are leaps and bounds better braking force than my disc ones.

not sure where im going with this thread, its either a warning to others or a question about wether disc brakes are actually meant to have more stopping power over v-brakes??

 

[Deleted member 4366]

You probably didn't have them adjusted properly. Did you adjust the stationary pad? Was the disc properly lined up with the caliper? Cable disc brakes are often given a bad name because they're not adjusted properly.

I've seen some so badly adjusted on a new bike that the caliper arm came all the way until it touched the cable stop before the disc was clamped.

It's a shame you didn't ask before you took them back off. We could probably have put you straight.

 

[Emo Rider]

just bought myself a whole bike from my local charity shop. with front and rear wire operated disc brakes.

spent an hourish swapping the fronts over. looked pretty cool

however it was literally the worst braking capability ever. tried tightening the hell outa them. no avail. tried roughing up the disc and pad surface. no help. wouldnt lock up or even come close to stopping me in any kind of hurry.

i think just by design they were crap as hell.

i had switch back to my original vbrakes and pads which are leaps and bounds better braking force than my disc ones.

not sure where im going with this thread, its either a warning to others or a question about wether disc brakes are actually meant to have more stopping power over v-brakes??

Mechanical disc brakes, properly adjusted and free from contamination, are better in many ways to caliper and v brakes. Properly set up caliper and v brakes can have excellent stopping power but wear out quicker, require more frequent adjustment and are not as good in the wet or muddy conditions. I agree with the previous poster when he said that they probably needed to be adjusted.

 

[D C]

The other possibility is that the pads where contaminated with oil before your ownership, easily done by badly aimed spray cans. You can't get the oil out and they will never work, I found this out after getting fork oil on mine!
I would try new pads as disc brakes when working are well worth having.
Dave.

 

[selrahc1992]

just bought myself a whole bike from my local charity shop. with front and rear wire operated disc brakes.

spent an hourish swapping the fronts over. looked pretty cool

however it was literally the worst braking capability ever. tried tightening the hell outa them. no avail. tried roughing up the disc and pad surface. no help. wouldnt lock up or even come close to stopping me in any kind of hurry.

i think just by design they were crap as hell.

i had switch back to my original vbrakes and pads which are leaps and bounds better braking force than my disc ones.

not sure where im going with this thread, its either a warning to others or a question about wether disc brakes are actually meant to have more stopping power over v-brakes??

take this from a complete noob: bin the mechanical discs - i dont know who still uses it, but in a world in which you can pick up a good set of hydraulic discs for thirty quid it's absurd. the thig about hydraulic discs, i found - is that simol;y loosening teh bolts on teh caliper and squeezing teh brake and retightening does not work - one has to manipulate the caliper (soome uses an elastic) until it doesnt screech and then tighten, then you should have trouble free cycling for a thousand miles.

 

[trex]

the problem with mechanical disc brakes is that most have single caliper, forcing the rotor to flex before contacting the fixed pad. This operating mode loses huge amount of braking efficiency due to uneven contact between rotor and pads. However, the power of disc brakes is huge, they remain efficient and progressive even only active one side and in rain. Most problems with mechanical disc brakes seem to come from poor quality, spongy outer cables.
If you can afford it, go for dual caliper models like the Spyre. You don't have to faff about with hydraulic disc brake sensors.
http://www.wiggle.co.uk/trp-spyre-mechanical-disc-brake-caliper

 

[Alan Quay]

My experience with mech disk is that they need a lot of adjustment, and new pads (£15 a set) every 500 miles or so. In that time they will need to be adjusted every 100 Miles, involving re-alligning the calliper, adjusting the cable, and all sorts of nonsense.

V-brakes however, pads last 2000+ Miles and need slight adjustment (perhaps twice) in that time.

I don't often ride in the wet, so perhaps that why I don't see the benefits.

 

[Emo Rider]

My experience with mech disk is that they need a lot of adjustment, and new pads (£15 a set) every 500 miles or so. In that time they will need to be adjusted every 100 Miles, involving re-alligning the calliper, adjusting the cable, and all sorts of nonsense.

V-brakes however, pads last 2000+ Miles and need slight adjustment (perhaps twice) in that time.

I don't often ride in the wet, so perhaps that why I don't see the benefits.

I certainly am not discounting your experience with brakes. However my experience has been just the opposite. My non electric 2010 model trekking bike has over 1500 miles on it and still has the original pads. I adjusted the brakes at three months and never touched them again until about the 1200 mile mark. They are far, far from worn out and the best brakes I have had on a bike in my life.

My two year old BH Emotion with five thousand miles on it uses up a set of front brake blocks about every three months and the rear ones last about five. I adjust every couple of weeks as I have a work stand.

Like all brake systems , regardless of the type, there are some pretty nasty units out there. As in most purchases quality cost and I have seen some pretty nasty and poor quality mechanical disc brake set ups. I will agree with those that prefer hydralic systems. They are the best of the lot. When they all go wrong, they all go wrong

 

[jimmyhackers]

they were set up properly, they might of been a terrible quality brand in the first place. i gave them every chance i could in terms of resurfacing and setting them up and......in comparison the disc brakes i got from the chairty shop suck compared to the vbrakes (all be it with new brake shoe cartridge pads in them) i got from the same place.

there are probably better ones out there, but without a much larger pad area i cant see them being any better.

im going upto 40mph now and im still using vbrakes to great effect.

when i switched back from the discs the first time i used my v brakes again i nearly went over the handle bars.

no heat and reasonable wear on pads with great stoping power. the bike has me and 28kgs of lead batteries on it.

 

[trex]

disc brakes are hard wearing, progressive and more controllable but you need a model with large size pads to suit the power of the bike, like Shimano XT:

 

[the_killjoy]

Must admit I have always found the mechanical disk brakes on my Wisper to be disappointing, keep meaning to replace them with hydraulic.

 

[Deleted member 4366]

They probably need adjusting. Look from the top. Does the disc move a bit sideways when you apply the brake? When the brake is fully on, how close does the arm come to the cable stop, i.e. what's the gap?