heres a strange one...

[ultraviolet]

on my front Deore hydrolic disk brake i never seem to get much power from it at the start a the ride [never seems to be enough bite], but, after a good ride it works realy well, as you would expect. now heres the thing; i then leave the bike until the next ride not doing anything to it and i'm back to square one again.
anyone have any idears why this might be happening?

 

[Steve Austin]

stiction in the cable? ie you need to lube or fit a new cable and outer..

or

pads glazing. when you next go ride. When you first get on the bike, do some sharp stops from 10/15 mph to stop. The same sort of thing you should do to bed pads in.

 

[Bigtwin]

Nope - but I have a Julie on an XC bike that does the same thing.

Changed the disk, pads and the oil, still does it.

 

[02GF74]

it won't be the cable since the OP states they are hydraulic.

Are the disc warm when they are braking better?

Have you tried new pads?

 

[tandemman]

My juicy 5's did this a while back, changed the fluid and OK since, probably due to water absorbtion, brake fluid is hygroscopic, how old are the brakes?

 

[ultraviolet]

My juicy 5's did this a while back, changed the fluid and OK since, probably due to water absorbtion, brake fluid is hygroscopic, how old are the brakes?

the brake is about 4 years old, i would of thought that if the brake had water in it it would feel spungy? mine doesn't

 

[Jonathan M]

I'd have also thought that if the fluid was old and hadtaken in water, braking was more liekly to go off as a ride progressed, and the set up got hotter. Certainly did that with some 2nd hand Formula hydraulic discs that I got. Once fluid changed then it was fine.

My thoughts would be that the OP's set up works best with some heat in the pads/disc.

 

[Ivan Ardon]

Sounds like someone's fitted high performance pads, i.e. the ones that don't work properly until they're hot.

 

[Mr Pig]

How do you store the bike?

 

[ultraviolet]

Sounds like someone's fitted high performance pads, i.e. the ones that don't work properly until they're hot.

nope, standard pads

 

[ultraviolet]

How do you store the bike?

hanging up by the front wheel

 

[ultraviolet]

My thoughts would be that the OP's set up works best with some heat in the pads/disc.

the thing is i can stop off for a bite to eat or take some photos or something, get back on the bike and the power is still there

 

[Mr Pig]

hanging up by the front wheel

Thought so.

Air is getting into the hydraulic line, resulting in the soft brake. As you ride the bike the air works its way back up the line and out into the reservoir and the brake returns to normal.

Live with it or store the bike vertically.

 

[Garz]

Nice detective work there Mr P!

 

[Bigtwin]

Thought so.

Air is getting into the hydraulic line, resulting in the soft brake. As you ride the bike the air works its way back up the line and out into the reservoir and the brake returns to normal.

Live with it or store the bike vertically.

Swot I thought with mine, but it makes no difference how it's stored.