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Got a pair of these on a hardtail that I've just changed the frame on. I broke the pads in a while ago commuting and they're ok used in combination. The rear brake will lock the back tyre, but the front brake is disappointing.
The front has the factory bleed - so does the back although I shortened the hose without re-bleeding it. When trying to endo the bike the front brake isn't strong enough to really lock the wheel.
Discs are 160mm and pads are standard organic.
Are these brakes just not that strong -
or can anything be done to improve power?
Better brake pads? Bigger front disc?
My other bike has Sram Guide R's so they don't do the Shimano Deore brakes any favours (running 200/180 discscwith sintered pads).
Better brake pads? Bigger front disc?
Bigger discs will definitely improve things...
Other brake pads might help - kinda difficult to tell without buying some and finding out.
HTH 8)
something is wrong. contaminated discs is my guess.
A poor bleed leads to a soggy lever feel with a lot of travel. Lack of powers is another fault
The bleed feels ok, there's not loads of travel in the lever. The lever is pretty firm too, it's not spongey.
The brakes aren't that old, and I'm pretty sure I've not contaminated them.
I guess I'll clean the rotor and sand the surface of the pads then re break the front brake in and see if that helps.
Leaking piston would be my guess. Common fault I think.
as Raveydavy say. Many folk myself included don't like shimano brakes but lack of power in a properly working one is not a usual complaint. My bet would be the leaking piston seal
It's an older style of Deore disc rather than the newer ones that have had problems I think - but I'm ot a Shimano fan in general.
Only bought them as new (old) stock as they were a bargain and I thought they were a better bet than the cheapie Clark's brakes.
I'll have to pull the pads out and see if there are any obvious leaks if there are then it's quite disappointing given how little use they've had. I guess I'd look to replace with Guides or maybe some kind of ludicrously powerful magura 4 pot. Whichever I can find as cheap as possible as it's just a muck about hardtail,not my main one.
Had the seals on mine fail at the caliper. There was no obvious sign of a leak but I guess they sprayed out a fine mist of oil when compressed. Diagnosed it as they made an awful squeal and lacked power.
Same as mine. Were replaced under warranty then failed again after a months use.
Lever feels fine but just no power, and an awful squealing noise. New pads and a change of rotor made a difference for a couple of rides then back to same again.
Binned them and bought a set of Guide RS.
This isn't sounding good! Will have to put them in the work stand and have a closer look. Poor if they've died this quickly.
Noticed the rotors say 'organic pads only' on them so can't even give Sintered pads a go in them at any point.
Think I need to clean the pads up and see what happens. Was hoping not to need to spend anymore money on this bike as it's just for a bit of playing on.
Lack of power due to contamination from brake fluid is usually accompanied by a truly awful squealing. If you've not got that then I doubt it's leaking.
I'd have another go at bedding them in. Find a big hill and get them really hot.
It's normal that it takes a lot more force to lock the front than the rear, so the fact that you can only lock the rear doesn't necessarily mean that the front is worse than the rear.
Front should lock easily with not too much pressure.
No squealing at all. Just thought they should lock easier. The magura hs33s that were on there before did (but were a pain with getting wheels out / needing adjustment).
I'll have another pop at bedding in and see what happens. Not had Shimano discs before so not sure what to expect. The levers are quite long 2 finger jobs.
I guess I'm comparing low end few years old Shimano 2 pot brakes with 160mm rotors against Sram Guides 4 pots with 200/180mm rotors. I could quite happily throw myself over the handlebars with a 1 finger brake on those.
take the pads out and give the caliper and pads a good clean. Put a piece of tissue paper between pads and pistons on rebuilding and hold the brake on hard and tie the lever back with a cable tie or strap. after a couple of hours of the brake on hard strip it again and look for signs of fluid on the tissue paper. Only needs to be drop to contaminate the brake and to show the caliper is scrap. Calipers can be replaced for not very much at all
Thanks TJ, I'll try that to see if I can rule out a problem calliper.
Are these brakes just not that strong -
That's your answer the lower end , cheaper than Deore 615 Shimano brakes are not very powerful , the higher end brakes are very powerful .
Thanks TJ, I'll try that to see if I can rule out a problem calliper.
The lack of squealing should have already ruled out contamination .
Surely a low speed endo shouldn't be out the question with a hydraulic disc brake? It's a Deore brake - just a few versions before the current one.
I had Hope C2's that would lock a wheel for an endo in the late 90's. And even LX v brakes did that job mid 90's!
Something is definitely up. I used to have these and they did malfunction at one point. Never got to the bottom of it despite replacing a caliper, pads, multiple bleeds.
If it's not contaminated pads (which filing doesn't help btw) then the easiest option is to replace the entire system with 615 probably, they're only 35 quid per end last time I checked.
Never ridden a sram guide but if it's anything like an avid I'd stay well clear.
The Deore has the same hydraulic ratio as the SLX and XT. The SLX & XT have ceramic pistons which helps prevent heat transfer and the XT has additional bite adjust as well as the toolfree reach shared with teh SLX. I wouldn't expect a massive short term power difference unless it was due to the pads and rotors in use.
Note it's the older style Deore rather than the current one hats like the Slx / XT but with less adjustment / slightly less fancy material. Like these:
I've got Guides on my other bike - they're nothing like old Avids - they're amazing.
If I have to replace the Shimano it won't be with more Shimano that's for sure. Either Guides or perhaps some kind of Magura. Whatever o can get the cheapest deal on that'll be an improvement on what I've got. Hope probably too expensive.
I know what you mean about the Guides. I’ve got Guide RS’s on two bikes and a third set for my next build. Got rid of all my Shimano brakes as Just sick of dealing with them. 😀 Obviously other opinions are available!
I’ve had half an eye on the cheaper less exotically built MT Trails as a possible alternative, tbh the fact I have the spare Guides already is what has stopped a purchase. The Maguras play nice with MMX which is important to me, too.
I had the later Deore brakes and they were very good until I used non-Shimano fluid and killed them, but they don’t have piles of power (but a week in the Alps didn’t kill them or me).
They’re not very powerful out of the box, they’re quite old now (I think the design is at least 10 years old now) and they have small rotors. A leaky claiper isn’t a stealth fault, it goes everywhere and they just stop working.
Buy bigger discs I would say.
Going to pop out to the garage and have a poke round the front brake and see if I can find any moisture / leaks this afternoon. If not I'm going to file the pads a little and clean the rotor and try and break the pads in again.
If that doesn't work I either try better pads /
bigger rotor - or swap them out for something different.
Pads and pistons are dry as a bone. Tried leaving some tissue between the pads and pistons and no residue at all.
Have roughened up the pads and cleaned the discs. Will have another go at wearing in he pads next time I take the bike out.
If that doesn't do it then it's either try a bigger rotor / more aggressive pads or swap the brakes for something else.
Wondering if I can sell the brakes plus some other bits of bike I've got to fund some secondhand eBay Guide Rs. If so it might work out about the same as a new rotor and pads for the existing brake.
Not sure if my current Shimano discs could be used with guides (with organic pads)?