Do all disc brakes rub?
Discussion
I have only delved into bikes with hydraulic discs lately, and only more recently ridden said bike in the woods. This weekend i went to both Wendover Woods and Swinley Forrest for a ride, on Saturday i found that my front brake was binding a bit and fighting my efforts, and after Sunday at Swinley with all the sand my rear disc is now really graunching, I know hosing down is bad but i just wanted to get the worse off, what do i have to do to prevent this and fix it now, shall i just take it apart and clean it? I havent a clue how to adjust hydraulic brakes on a bike! Whilst at Swinley i noticed i could hear practically every bikers brakes binding, why is this? i think i might just stick some XT V brakes on my other bike as discs seem like real aggro!
I need to get a good clean down regime set up!
I need to get a good clean down regime set up!
Binding or just a loud "shing..shing..shing" sound?
The tolerances are so tight that a slightly out of true disc will make this sound. Also you may have one piston not retracting enough to clear said disc.
Even though discs look cool, they seemed to be a solution to a problem that did not exist especially on XC bikes where V-brakes are lighter and better.
The tolerances are so tight that a slightly out of true disc will make this sound. Also you may have one piston not retracting enough to clear said disc.
Even though discs look cool, they seemed to be a solution to a problem that did not exist especially on XC bikes where V-brakes are lighter and better.
Pupp said:
LRdriver II said:
Even though discs look cool, they seemed to be a solution to a problem that did not exist especially on XC bikes where V-brakes are lighter and better.
Hmmmm.... ever tried wet weather rides in the peaks? I've killed rims in a single afternoon with V brakes...Im pretty sure its actually binding, the back disc actually sounds kinda gravelly now, some of the sand must of washed into the calliper, i hope this doesnt happen every time i go out in harsh conditions.
its a shame not a lot of good susp forks come with v brake mounts now.
It could be connected to me taking the wheels on and off with the QR to put in the car, but i dont see how that should effect it surely they should locate themselves correctly?
its a shame not a lot of good susp forks come with v brake mounts now.
It could be connected to me taking the wheels on and off with the QR to put in the car, but i dont see how that should effect it surely they should locate themselves correctly?
Edited by porka944s on Monday 15th November 13:25
porka944s said:
I have only delved into bikes with hydraulic discs lately, and only more recently ridden said bike in the woods. This weekend i went to both Wendover Woods and Swinley Forrest for a ride, on Saturday i found that my front brake was binding a bit and fighting my efforts, and after Sunday at Swinley with all the sand my rear disc is now really graunching, I know hosing down is bad but i just wanted to get the worse off, what do i have to do to prevent this and fix it now, shall i just take it apart and clean it? I havent a clue how to adjust hydraulic brakes on a bike! Whilst at Swinley i noticed i could hear practically every bikers brakes binding, why is this? i think i might just stick some XT V brakes on my other bike as discs seem like real aggro!
I need to get a good clean down regime set up!
Mine don't bind, but they squeal when wet (until the heat from a decent-speed slow-down dries them) and there is a little shing-shing on occasions from the disk being a micrometer out of true. But they don't bind at all. In fact, the pads seem to spring slightly clear of the disk (we're talking paper-thickness distance) which is enough.I need to get a good clean down regime set up!
It doesn't have to be this way, generally 95% of rub is down to set-up procedure or a bent disc.
If the disc is not true it will rub, if the placement of the wheel in the drop-outs is not right or done with too much or too little torque then it will rub.
Any adjustment opportunities on alignment (if available) to widen the distance between the pads is just dialling out these opportunities for discrepancy, and will decrease your braking performance, in terms of more lever travel for same stopping power.
If you know how to align your calliper rather than widening the gap between your pads then you can circumvent some of these issues, if you ensure your wheel is always in the axle at the same position with the same torque then you get round most of the issues. Only thing for a bent disc is to unbend it or get a new one.
If this doesn't fix the issue then your calliper is not working properly and that will require further investigation.
With regard to sand on your rear, take out your disc & pads wash it out gently with some water and degreaser if needed, then give your pads & disc a clean with meths. Then bed in your pads again, 10-20 fast stops using just that brake will be fine.
If the disc is not true it will rub, if the placement of the wheel in the drop-outs is not right or done with too much or too little torque then it will rub.
Any adjustment opportunities on alignment (if available) to widen the distance between the pads is just dialling out these opportunities for discrepancy, and will decrease your braking performance, in terms of more lever travel for same stopping power.
If you know how to align your calliper rather than widening the gap between your pads then you can circumvent some of these issues, if you ensure your wheel is always in the axle at the same position with the same torque then you get round most of the issues. Only thing for a bent disc is to unbend it or get a new one.
If this doesn't fix the issue then your calliper is not working properly and that will require further investigation.
With regard to sand on your rear, take out your disc & pads wash it out gently with some water and degreaser if needed, then give your pads & disc a clean with meths. Then bed in your pads again, 10-20 fast stops using just that brake will be fine.
ribbit said:
I would also note from experience that MTB discs warp very easily so the shing-shing-shing is largely unavoidable.
It is avoidable either a large adjustable spanner or one of thesehttp://www.chainreactioncycles.com/Models.aspx?Mod...
Apply some suitable leverage in the right place, easily found by running the disc through the calliper and finding where it is out of true and the jobs a goodun. If it's trueable then 5 mins work max, if not you know you need a new one.
Not saying how long it will stay in true for but at least you can start in the right place.
ribbit said:
It's true that you can try flattening the disc, but I'd question the value of making the effort. One more moderate descent and it'll be hot enough to fry your breakfast and will assume a new shape.
agreedOneDs said:
Not saying how long it will stay in true for but at least you can start in the right place.
I would imagine that the bigger the disc and the more it is asked to do the more prevalent the problem is.On my 160mm fronts & rears on general easy xc and singletrack I've found that I have to true them or reseat the calliper about 3 or 4 time a year.
My bike is relatively new and started to "shing..shing..shing" as soon as I'd had the wheels off. Sometimes it's worse than others and I can lessen it if I fiddle with the way the wheels sit in the drop outs. It doesn't bother me too much and I doubt the amount of friction generated makes any difference. Saying that any quick and dirty tips to stop the rub would be most appreciated!
BalhamBadger said:
My bike is relatively new and started to "shing..shing..shing" as soon as I'd had the wheels off. Sometimes it's worse than others and I can lessen it if I fiddle with the way the wheels sit in the drop outs. It doesn't bother me too much and I doubt the amount of friction generated makes any difference. Saying that any quick and dirty tips to stop the rub would be most appreciated!
When you re-fitted the wheels did you loosen then re-tighten the calliper bolts while holding the brake on? If you can improve the noise by moving the wheel it suggests that the calliper may be out of alignmentDoubt you'll get the slight shing noise to disappear without holding the pads so far from the rotor that the lever travel will be unacceptable
OneDs said:
ribbit said:
It's true that you can try flattening the disc, but I'd question the value of making the effort. One more moderate descent and it'll be hot enough to fry your breakfast and will assume a new shape.
agreedOneDs said:
Not saying how long it will stay in true for but at least you can start in the right place.
I would imagine that the bigger the disc and the more it is asked to do the more prevalent the problem is.On my 160mm fronts & rears on general easy xc and singletrack I've found that I have to true them or reseat the calliper about 3 or 4 time a year.
One of those things it's best to simply put up with I think. Not worth fiddling with the brake setup to make them silent and running the risk of reducing the effectiveness of the brakes.
the_lone_wolf said:
BalhamBadger said:
My bike is relatively new and started to "shing..shing..shing" as soon as I'd had the wheels off. Sometimes it's worse than others and I can lessen it if I fiddle with the way the wheels sit in the drop outs. It doesn't bother me too much and I doubt the amount of friction generated makes any difference. Saying that any quick and dirty tips to stop the rub would be most appreciated!
When you re-fitted the wheels did you loosen then re-tighten the calliper bolts while holding the brake on? If you can improve the noise by moving the wheel it suggests that the calliper may be out of alignmentDoubt you'll get the slight shing noise to disappear without holding the pads so far from the rotor that the lever travel will be unacceptable
The easy tips are:-
Put your wheels in with the bike upside down, helps ensure the hub/axle is square and fully in the dropouts, rather than leaning over the bars at an angle to get it in quickly on the trail.
Once the wheel is in the dropouts, pull the relevant brake lever (or wrap an elastic band round it) then tighten the axle, this also helps hold the disc/wheel in the right position
Give a spin if it rubs try a little more or little less torque on the axle.
After that your into adjusting gap width, retruing discs, realigning callipers and possibly cleaning/rebuilding calliper pistons and bleeding if they are not working as they should.
EDIT:- They certainly aren't completely maintenance free, but they are relatively easy to service. Pads are generally easy if not a bit fiddly to change, rotors unless completely buggered do last along time and are easy to change. Bleeding the system is generally straight forward as well with the right kit. The rear with the longer hose length tends to increase travel first as depending on the fluids used can absorb water over time.
Put your wheels in with the bike upside down, helps ensure the hub/axle is square and fully in the dropouts, rather than leaning over the bars at an angle to get it in quickly on the trail.
Once the wheel is in the dropouts, pull the relevant brake lever (or wrap an elastic band round it) then tighten the axle, this also helps hold the disc/wheel in the right position
Give a spin if it rubs try a little more or little less torque on the axle.
After that your into adjusting gap width, retruing discs, realigning callipers and possibly cleaning/rebuilding calliper pistons and bleeding if they are not working as they should.
EDIT:- They certainly aren't completely maintenance free, but they are relatively easy to service. Pads are generally easy if not a bit fiddly to change, rotors unless completely buggered do last along time and are easy to change. Bleeding the system is generally straight forward as well with the right kit. The rear with the longer hose length tends to increase travel first as depending on the fluids used can absorb water over time.
Edited by OneDs on Tuesday 16th November 16:37
BalhamBadger said:
the_lone_wolf said:
BalhamBadger said:
My bike is relatively new and started to "shing..shing..shing" as soon as I'd had the wheels off. Sometimes it's worse than others and I can lessen it if I fiddle with the way the wheels sit in the drop outs. It doesn't bother me too much and I doubt the amount of friction generated makes any difference. Saying that any quick and dirty tips to stop the rub would be most appreciated!
When you re-fitted the wheels did you loosen then re-tighten the calliper bolts while holding the brake on? If you can improve the noise by moving the wheel it suggests that the calliper may be out of alignmentDoubt you'll get the slight shing noise to disappear without holding the pads so far from the rotor that the lever travel will be unacceptable
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