motorambler

Quick backstory: I own a 2020 Surly ECR that's equipped with Avid BB7 brakes (180/160mm f/r) and Avid FR-5 levers. My wife owns a used Surly Ogre that was custom built and has an XTR brake setup.

I've always loved the way her brakes felt and also the great feel of the levers. Anyway, she surprised me today with an early Christmas present by having our local Surly dealer replace the cable actuated Avid brakes on my bike with a Deore hydraulic brake setup (front and rear).

Initially, I was thrilled -- the brake feel at the levers felt much better than the oem Avid brakes. However, I'm really disappointed in the stopping power of the new brakes. Front brake stopping power is about the same as the Avid cable brakes. Sadly, the rear brakes feel even weaker -- I can barely skid the rear wheel on pavement when in the seated position unless I unload weight by standing. This is even when pulling the lever really hard with two fingers.

This "upgrade" cost $600 (including labor and taxes) and at this point it has improved brake feel at the lever, nothing else.

I understand Deore isn't XTR. Am I out of line by expecting a night and day difference between the oem Avid cable brakes and Deore hydaulic brakes or could something be amiss?

cobba

Did you attach the Deore brakes with the same bolts and washers that the BB7 brakes were attached with?

motorambler

I'd have to ask the shop. Why do you ask?

cobba

Unlike standard disc brake calipers, the BB7 is a CPS caliper that needs a 5mm stack of spherical washers beneath the caliper for proper spacing over the rotor.

If the Deore calipers were attached the same way as the BB7 calipers, the pads in the Deore brakes wouldn't have full contact with the rotor, they would overhang it by 5mm.

I have seen people make this mistake when changing from a CPS caliper (BB7) to a standard caliper.

You can see the washers I'm talking about on here: https://www.sram.com/en/sram/models/db-blbg-7m-a1

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mr_pedro

Hydraulics allows you to apply less force on the lever for same force on the brak pads. Perhaps previously the limiting factor was not handgrip strength? In that case switching to hydraulics would not increase stopping power as it is still the same brake pad.

cpach

Your experience is not normal; Deore brakes work very well. Did they use the same rotors? The new pads may have a different composition than the old, which will have bedded in some pad material onto the surface of the rotor. Or they contaminated your pads slightly. Or something. I really doubt this is right.

dsaul

I have Deore brakes on my MTB and they have lots of stopping power. The pads are contaminated with oil or you just haven't ridden them enough to bed them properly. They always feel weak for the first few stops until some pad material gets deposited on the rotors.

AeroGut

In my experience, the performance of hydraulics is not a huge improvement over cable-actuated, but the big advantage (for me at least) is in not having to adjust them frequently. The hydraulics move both pads towards the rotor rather than having one pad fixed and one moving in the cable-actuated. That makes the whole system less finicky with respect to slightly out-of-true rotors (and maybe the required rotor flexing of the cable-actuated increases rotor warping? I'm not sure about that). The hydraulics also self-adjust the distance to the rotor. So once I got over the learning curve of setting up hydraulics, I have found that I rarely have to do any kind of adjustment, whereas I frequently have to make minor tweaks on the cable-actuated to keep the fixed pad in a position where I get good braking but no rub when the brake is released.

Iride01 

I was disappointed with the stopping power of my new hydraulic disc brake bike too. I felt my rim brakes of the previous bike just as good or better. But after 300 or so miles, they started really stopping quick. In fact the rear has almost too much stopping power and I have to be careful not to lock up the back while stopping in a turn.

So if everything else seems correct and you don't have spongy levers from air in the lines, then wait for them to wear in.

Geepig

I would agree. When I got my first hydraulic brakes they were not up to much. Because the roads were slippery at the time I generally used the rear brake, and after a week I could see that the rear braking had improved a lot, compared to the front.

Amt0571

A few things:

1. Have you bedded in the new brakes? disc brakes have little power until you bed them in. I usually descend a steep incline while braking and letting go of the brakes until they start to bite with decent power.

2. If it's not a bed in problem, you have something wrong there. I've used both BB7 and Deores and Deore brakes are vastly superior in all departments. Did you replace the rotors? Maybe they're contaminated. I've had this happen and only solved the issue when I replaced them.

3. $600 for a couple of Deore brakes seems like a scam. I bought a set of MT520 (4 piston Deores, basically) a few months ago for 112€. Deore were even cheaper at 90-something. I installed them in less than an hour, including shortening the hose and bleeding them. So $600 sounds me like a lot of money for that,

Trevtassie

Yep, $600 is a lot, for that you should have got new Icetech Rotors and Deore XT grade calipers. Definitely should kick BB7s butt, braking wise and feel. If they didn't replace the discs you definitely got dudded, BB7s create weird wear patterns on discs because of the single moving piston.
As a lot of other posters have said, first port of call might be to re-bed in the brakes. Clean the discs with isopropyl alcohol and sand the pads lightly then re-do the bedding in process as per the Shimano instructions.
Find somewhere flat. accelerate to a moderate speed. Apply one brake until you are nearly stopped. Release the brake before you actually stop. Repeat around 20 times until the brake bites properly.

jgwilliams

What he said.

hokiefyd 

You may be able to hasten the break-in by THOROUGHLY cleaning the rotors with alcohol to remove any pad material that was there, so you're starting with as fresh of a surface as reasonable. Then ride the bike for 10 or 20 miles concentrating in brief but moderately intense braking sessions. This should quickly transfer pad material to the rotors and get your system stopping well. I have a set of Deore M615s on my Surly Pugsley and, even on 160mm rotors, they stop WELL.

Amt0571

10 or 20 miles are not needed in my experience. I just get down a 300m 20% street near my house while braking and letting go. If it doesn't brake well when I reach the bottom, I repeat the operation. I've not found a brake/pad combination that requires more than 3 tries to brake at maximum power.

Ryan_M

This is what I was going to mention. I upgraded my brakes from MT200 to M6000 w/J03A pads and there's a BIG difference in brake performance, once I got it worked out. Initially it felt kinda meh then started squaling a ton. I resurfaced the pads and rotors and almost no improvement. Putting in the old pads made everything work normal again. I then ordered new RT66 rotors and after bedding in there's easily enough power to send me over the handle bars. I suspect I wasn't aggressive enough on resurfacing the rotors to get out the previously bedded in material. If they used different pads I'd get new rotors. Check for conatamination first though.

rosefarts

I ran nothing but rim brakes until this spring. I had no complaints. I never failed to stop and my hands never hurt.

I got a used mtb that had basic shimano hydro's on it and it spoiled me. It's not about braking power but about feel.

I did test ride mechanical discs in a single speed for a few days a couple years ago, they were no better than rim, and a lot more finicky. I wouldn't bother with those.

At first I hated them because they seemed tricky to adjust but once I figured it out, I'm in love. They are so nice that I upgraded my gravel bike pretty much just for the brakes. 1996 steel CX bike with cantis vs 2020 steel CX bike with discs. Basically the same thing with new brakes. I feel like it is worth it.

So yeah, something is wrong with your setup.

rosefarts

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