Hydraulic disc brakes

[Darryl Gunson]

Hi folks

 

Anyone ride hydraulic discs?

 

Just got a new bike with Rival hydraulic disc brakes. All good but I notice that you have to pull the lever much further in before the brake engages, compared to normal rim brakes.

 

They work fine but I like the brakes set without much slack. Does anyone have these or similar? Is this normal with hydraulic discs?

 

Cheers

 

Darryl

[al yuille]

Darryl, when set up well there should be very little travel in the lever.  If the feel is spongy then it is probably air in the hydraulic line. This can be bled out. With my Avids this is easiest using a retail syringe kit. Some levers have an adjustment for reach but don't see how  that can be the problem. 

 

I didn't know you were a mountain biker ?!

[Darryl Gunson]

Hi Al

 

Thanks for the advice. These are road levers on a cross bike. They don't feel spongy though, just a but too much lever pull required for my taste. The reach adjustment doesn't address this, as you say. Will try bleeding them at some point but would have thought hey'd be set up right from the start with it being a brand new bike.

 

Discs - it's all new to me:)

[XXX]

Daryl

 

There may be a pad adjustment somewhere go on line and see

[XXX]

Daryl

Ignore that didn't read hydraulic part , it sounds that they need bled

[Darryl Gunson]

Thanks Billy. As far as I can tell from online info and looking at them, there is no way to adjust the pads. I think this has to be done when they are initially set up.

[alexb]

I've got a bleed kit for mountain bike hydraulic discs if you want to borrow it.

[Darryl Gunson]

Thanks Alex, yes I would like to borrow it.

[alexb]

I'll dig it out and PM you when I find it!

[LenMcD]

Darryl, I'm no expert but in my experience, as Al said, they would only need bled if spongy. If there is no lever adjuster then I'm stumped. For your info the Hayes brakes on my MTB have a bit of lever pull before they start to bite properly. Certainly more than any of my road bikes

 

Bleeding hydraulics can be a pain unless you have the correct kit.

 

Try removing the wheel and pumping the brake once then refitting the wheel. This may adjust the gap between the pad and rotor automatically. If too tight then just prise the pads apart again and try again .

[Darryl Gunson]

Thanks Len. Think I'll try that

[al yuille]

As you know Darryl, a fluid is not compressible ( by hand ) , so either the lever is not activating the piston in the master cylinder ie you need to make a mechanical adjustment , or there is air ( which is compressible (by hand)) in the system.

 

https://en.wikipedia.org/wiki/Fluid_dynamics

 

Profesor Brainstawm

[DavieB]

Academics don't cite Wiki references Prof.

 

There should be no mechanical adjustment necessary and as far as I can see there is no mechanism on the SRAM Hydro brakes to feather adjustments as has been suggested. I have just fitted a set but confess did not read instructions apart from hose cutting / bleeding so may be mistaken on this but the nature of the actuators would suggest a defined return point as opposed to an adjustable one.

 

My advice would be to start again and charge the system from scratch - not difficult but need some brake fluid and kit which is specific to the bleed ports, Youtube instructions do the rest. I can lend you the stuff if required.

 

Note - if your supplied pads are organic they will be eaten by grit in jig time, change out for sintered (metallic) pads. Swiss Stop do a SRAM road compatible pad. Pad wear and (current) post market SRAM compatible pads are my biggest concern with the switch to hydraulics but presumably choice should increase over time.

[Darryl Gunson]

Thanks Davie (and Al, I think ). I will bleed em when I get my hands on a kit. In the meantime I removed the wheels and pulled the levers. This pushed the pads in a bit. I then refitted the wheels and centred the calliper, and this has reduced the lever pull required to actuate the brake. Not perfect but better. Hopefully better still after a bleed and fluid top up.