Adjusting hydraulic disc brakes

[ChrisV]

Got a bike online (yeah, I know, but was a massive saving so got a better bike than could have done if I'd gone in to support my LBS )

There is rubbing from the brakes. The front one is ok-ish, with a small rub every revolution, but the back is touching (disc and pads) and only spins twice before grinding to a halt (when bike is upside down).

Anyway, checked with Wiggle if this was something I could just adjust, but they said stick it into an LBS and they would refund me the small amount it should cost.

However, LBS is busy, I've to leave the bike with them, so I was thinking that if this was a very minor adjustment which 99% of cyclists would just do themselves, I should really have an attempt at it. I'm not that handy to be honest, but have watched YouTube clips and it looks straightforward.

LBS and get bike back tomorrow or Wednesday, or have a go adjusting myself?

 

[Custom24]

Have a go first, then lbs if no good
According to some, you are Not supposed to put bikes with hydraulic upside down. Any air will then move to parts of the system where it is not supposed to be. I wouldn't worry too much but I certainly wouldn't adjust upside down.

It's probably just a matter of centring the calliper. Search on YouTube.

If not that, then you can check if the disc is warped. This can be tweaked. Again, YouTube

 

[Stantheman]

Losses the two bolts on the calliper, squeeze lever and tighten bolts while keeping lever squeezed. Repeat until no rubbing.

 

[ChrisV]

But definitely not upside down?

 

[ChrisV]

I might consider a stand one of these days.

 

[Stantheman]

Probably best not to do it upside down.

 

[arallsopp]

if it rubs constantly, loosen two bolts, squeeze, re-tighten, per @Stantheman (above). No need to have the bike anywhere other than leaning against a wall for this. Correct way up. Takes literally ten seconds.

If it rubs intermittently per revolution, rotor needs truing. Could be warped, could be mounted wrong. If warped, you can normally tweak it back. If mounted wrong, remove it and put it back. Follow youtube instructions. Don't do adjacent bolts consecutively.

If it rubs intermittently per ride, it probably needs both tweaks.

 

[lpretro1]

It is normal on a new bike (and also when yuo change pads) for the pads to rub a little until they are bedded in. Best to just go and ride and really make good use of the brakes. If there is still rub/drag then do follow the advice above - if you remove wheels to transport bike you may also find you have a slight rub again when you refit - you should follow same procedure

 

[ChrisV]

The back brake is fixed after following a YouTube video. I am so amazed I may take the rest of the day off.

The front one is the intermittent one, so will ride it a bit and see if it persists. Good times!

 

[Levo-Lon]

Its a new bike too so it will need the pads bedding in which may well sort the rubbing..as the disc and pads wear to each other..

 

[Yellow Saddle]

Upside down disc brake bikes are fine. They don't suffer any ill effects unless the levers are pumped in that position. Some disc brakes - brand shall remain nameless* - suck air even when upright. Those are best avoided.
An intermittent noise is an out-of true disc. It requires some bending using a shifting spanner and a conscious technique that does not induce a local dent just beside the jaw's end but in the root of the disc.

* Since I will be overwhelmed with request to reveal my bias, they are Avid Elixir.They are absolute rubbish and I don't care that your aunt Edna has a pair that has given her trouble to date.

 

[Yellow Saddle]

Its a new bike too so it will need the pads bedding in which may well sort the rubbing..as the disc and pads wear to each other..

How do you propose bedding in will sort the rubbing?

 

[Levo-Lon]

How do you propose bedding in will sort the rubbing?

Ok....so the brand new pads and disc i just fitted made a slight noise this morning before a 2 hr ride..
i did set them up and centre them..
after the ride the guide R brakes and rt76 discs are silent...

other than that ...you can do a 1000 word post if you like...

why does a quick try this have to have a fooking big debate..

 

[Yellow Saddle]

Ok....so the brand new pads and disc i just fitted made a slight noise this morning before a 2 hr ride..
i did set them up and centre them..
after the ride the guide R brakes and rt76 discs are silent...

other than that ...you can do a 1000 word post if you like...

why does a quick try this have to have a fooking big debate..

Well, you said he should bed them in to silence them. I asked how. You then retorted by telling us how you mechanically adjusted the brakes to silence them, as if that's one and the same. Bedding in and adjusting is not the same. Bedding in is something different. That's why. Flippant throw-away guesses never help the OP understand or solve the problem.


63 words.

 

[lutonloony]

Not wishing to show my ignorance here, but shouldn't a new bike come with straight discs? I think I understand the concept of bedding in, but out of true?