Mechanical disc brakes

[Lurkin]

Putting together a bit of a beater bike, was thinking of trying out mechanical brakes seeing as others on here think they are the bees knees and they seem pretty simple to service without the requirement of bleeding.

Just trying to work out a cost effective option to get decent braking power, Google revealed that BB7 is the preferred option, ahead of BB5 due to the brake adjustment knob.

BB7s can be obtained here:

http://www.ebay.com.au/itm/AVID-BB7-Mountain-Fahrrad-Scheibenbremse-Mechanical-160mm-HS1-Scheiben-SD7-Hebel-/371519795152?hash=item56804e2fd0:gzEAAOSwv-NWVWDl

BB5s can be obtained here:

http://www.ebay.com.au/itm/BB5-Mountain-Mechanical-2x-Disc-2x-Brake-Calipers-Set-Kit-HS1-rotors-160mm-White-/161398588671?hash=item25941b04ff:g:2foAAOSwxH1T8sV8


Both are with tiny discs, but they are probably sufficient for what I am using them. The BB5s is probably the better kit for money given it includes cables and is cheaper anyway. However it is from Hong Kong and is probably counterfeit.
for.

Is there any other mechanical disc brakes I should be considering?
Is there any other mechanical disc matters I should be thinking about?

 

[Leebolectric]

BB5 and BB7 are the only worthy mechanicals, all others are a joke in my experience.
The speed dial 7 levers are really nice, because you can adjust the leverage to each, and make the front and rear match in feel nicely.
I usually run them with high leverage to the rear, for max power and to compensate for the housing compression.
I run low leverage in the front, for more modulation and control and less housing to compress.

The smaller the disk, the less the modulation and power both.
the larger rotors will have a better feel, not just power.

 

[WoodlandHills]

I would go with the BB7s, I replaced the calipers and rotors on my bike with BB7s and Avid G3 160mm rotors and it was a very noticeable change. The feel was much improved as well as the absolute stopping power. I was replacing a set of OEM Chinese Tekro cable brakes. Since I ride mostly on dirt 160mm all around is enough, but if I was spending more time on pavement, I would be looking at a 200mm rotor in front and a 180 in back. Hydraulic disc brakes are the gold standard, but are a bit harder to interface with a drive system: if you chose cable discs, you can use the brake levers from your kit with the electric plugs for the motor wiring harness already built in. Your don't want the motor to continue run after you grab the brakes!

 

[nutnspecial]

BB7, not sure if genuine or knock off make a difference tho.

I went from great avid linear pull to knockoff bb5's on 160's and they absolutely suck, although the 'ceramic' pads help the crap brakes slightly. I nearly bought the dam farm once or twice now, and did buy a telephone pole, but that one might not have been juuust the brakes

 

[Lurkin]

This bike isn't going to be electrified (for now :lol: ).

Hmm. Anyone come across multiple pot (i.e. four pot) mechanical disc brakes?

None of the super cheapo kits have bigger rotors. Might be a secondary thing I'll do at a later date.

 

[nutnspecial]

I personally wouldn't be opposed to used, and would/ should try something like this:
http://www.ebay.com/itm/COMPLETE-AVID-ELIXIR-R-SL-HYDRAULIC-DISC-BRAKE-SET-185mm-203mm-ROTORS-MOUNTS-/291649794469?hash=item43e7aeb1a5:g:ibIAAOSwJcZWhCTd
avid elixir and 8" for 80$ used - cant beat it, and just how much service do they need?

 

[Lurkin]

These are kinda neat, look to be a hybrid between mechanical and hydraulic:

http://www.wiggle.co.uk/trp-hy-rd-cable-actuated-hydraulic-disc-brake-caliper/

Unfortunately well out of the price range for a beater!

 

[Chalo]

BB7 brakes are unsurpassed among mechanical discs. They feel different, but work as well or usually better, than any hydraulic discs I've tried (many). They are reasonably priced, for discs. You don't need to look any farther.

BB5s suck. Apart from the lesser build quality and more limited adjustment, they have sorry pads. There are no good aftermarket pads I have been able to find for BB5. If Avid would just make those brakes to fit the same pads as the BB7, they'd probably be fine. But no.

I have heard praise-- but not from anyone whose judgment I respect-- for the TRP Spyke dual-piston mechanical brake. I haven't been able to try one for myself.

The BB7 Road and TRP Spyre are versions of the above brakes designed for short cable travel road bike levers, meaning they should be compatible with typical e-brake levers if that matters to you.

 

[Lurkin]

The reviews on the internet applauding BB7 go back quite some time! I think they will be the winner, the TRP stuff has good reviews but is well out of the price range of this beater bike. 8)

 

[Chalo]

These are kinda neat, look to be a hybrid between mechanical and hydraulic:

http://www.wiggle.co.uk/trp-hy-rd-cable-actuated-hydraulic-disc-brake-caliper/

Unfortunately well out of the price range for a beater!

Those are reminiscent in principle of the Mountain Cycle Pro-Stop cable/hydraulic discs I got back in the early '90s. With full floating 9" hard anodized aluminum rotors, no less.

The same fundamental problems apply: When you put the master cylinder and slave cylinder right next to each other, right next to the brake pads, the whole system gets hotter quicker than when the master cylinder and reservoir are elsewhere. The fluid doesn't get to flow in and out of an exposed hose to cool. That means less braking n before the brakes fade, lock up, or both.

Plus, you combine all the tradeoffs of cable brakes (adjustment, routing, cable and lever lubrication) and hydraulic brakes (fade, leaks, hose damage, self contamination, bleeding, lack of field serviceability), without adding any virtues.

If beater pricing is one of your criteria, see if you can find some used or new-old-stock Hayes HMX-1 calipers. Those work as well as BB7 (not as many degrees of adjustment, though) and there are excellent pads available for them.

 

[Raged]

I actually run avid BB7's road for my cyclocross 29er. Theyre good but as expected, you need more effort to press to match the clamping point of mid range hydraulics (eg tektro). That said, im atill on the stock pads, so maybe i need to move to some nukeproof enduros.

I run 180mm front and 160 rear. I think theyre fine for road/commuting but if youre doing a serious mountain where you will be on the brakes alot. Your fingers might tire faster.

 

[dogman dan]

I get reasonable performance from the bb7s. I got similar performance from cheap tektros too, but two things have me switching to bb7. One is the allen screw to adjust the tektros cannot be adjusted with a hub motor in the way. So for the rear wheel, bb7 for sure, for the no tool adjuster.

The other is that the pad for those ancient tektros seems to be unobtanium. I have modified others to sort of fit, but they squeal. BB7 pads I can get, expensive genuines at the LBS, or all kinds of knock offs on ebay. The genuine pads work quite well for me.

FWIW, I never changed handles, so I'm getting tolerably good performance with those brakes using the wrong handles. If I keep them adjusted. I'm not going to say they work fantastic, but the brakes work fine for planned stops, and lots of velocity changes riding off road. Obviously if you hit shit, you just rode past the line, and that line might be way too close if the brakes truly don't work well.

Some of my bb7s are genuine, and some obviously knock offs. The knock offs noticeably lower quality, but quality of the stop itself seems about the same.

 

[waynebergman]

I like the avid mechanicals a lot. One tip if you go this route is not to use the barrel adjuster on the levers for anything other than adjusting cable slack. If you use this adjustment for setting your pad to rotor spacing you loose the ideal leverage coming from the lever arm on the calipers. So in other words this leveraging arm (not sure what its called) that the brake cable is attached to is meant to be in its resting position when all the cable slack is out of the system. As your pads get worn down you need to adjust for this at the caliper, not at the brake lever or you mess things up and loose a lot of the leverage the system needs to work properly. I think lots of people that bad mouth cable brakes don't understand this and have tried bikes that have not been set up properly. The Avid instructions from my first set bought in the early days I think recommends this also. Clean pads and rotors with proper simple adjustment procedures and these brakes work super good. The avids shown on my trike build are from the very first year Avid came out with the mechanicals and they have given me zero greif for well over 10 years maybe 15, I can not remember when the fist Avids came out. Best bike component I have ever bought for value!

 

[Leebolectric]

I agree with the barrel adjuster comment....very true, but I take it further.
Any wobble or flex in the system will diminish performance....so I don't use the barrels AT ALL.
When the system needs tightening, I just pull about 1/4" more cable through the anchor on the caliper.
I like the caliper arm to be about 15% engaged when the cable is at it's slackest, so that the sweet spot engages sooner and more firmly.
This also takes advantage of the stronger range of the spring in the caliper, so the levers snap back quicker too

 

[Leebolectric]

P.S....they just came out with a much lighter version of the BB7, still reasonable price around $100 per wheel.

 

[shadetree]

The tried and true stand-by is the BB7. Can't go wrong with this set-up. These have been out 15 years or so, and for years was the best cable option available.

The best mechanical cable disc out now is the TRP Spyre. Both pads move, instead of only one side like BB7's/pretty much every other cable disc out.
http://www.jensonusa.com/Road-Bike-Brakes/TRP-Spyre-RoadCx-Mechanical-Disc-Brake

http://www.jensonusa.com/Road-Bike-Brakes/TRP-Hy-Rd-Disc-Brake
The TRP Hy-Rd uses cable to activate hydraulic caliper. This brake makes way more sense for a cyclocross or gravel road bike with drop bars and integrated STI brifters. If you have mtb bars, going to full hydro makes much more sense... lighter, cheaper.

Shimano is tough to beat for inexpensive hydro's.
http://www.chainreactioncycles.com/us/en/shimano-deore-m506-disc-brake/rp-prod119951
http://www.chainreactioncycles.com/us/en/shimano-deore-m615-disc-brake-rotor-bundle/rp-prod124962
Deore's are best bang for buck, $60 including rotor and adaptor, $45 without rotor/adaptor. These are extremely similar to the SLX and XT brakes, though have normal pads, instead of the fancy finned heat sink pads on slx/xt. You can run finned XT pads on deore's and get pretty much same performance.

Chainreaction, bikediscount.eu, wiggle.uk usually has best prices on Shimano. Pricepoint, Jenson is usually better for SRAM/avid stuff.

I would avoid used Avid hydro's, Elixers in particular. This brake is prone to ingesting air at the lever, especially the ones with all the knobs. They are also finicky to bleed properly, and seem to require bleeding much more frequently than other brakes. The Elixer was problematic, and actually killed Avid's reputation for hydro brakes. Their newer, improved Guide brakes are now branded SRAM, not Avid. Elixer made Avid name synonomous with SUCKS.

 

[nutnspecial]

I would avoid used Avid hydro's, Elixers in particular. This brake is prone to ingesting air at the lever, especially the ones with all the knobs. They are also finicky to bleed properly, and seem to require bleeding much more frequently than other brakes. The Elixer was problematic, and actually killed Avid's reputation for hydro brakes. Their newer, improved Guide brakes are now branded SRAM, not Avid. Elixer made Avid name synonomous with SUCKS.

Really appreciate the mention, I had no idea. I actually already have a set circa 2005 and am planning to use on another build. There are no knobs, but I'll check deep into the reliability and workings for a better understanding. I'm sure there must also be alot of bad reviews floating around if they (avid) are so bad?

 

[drew12345]

Using bb7 now on my alpha flux. Enough stopping power even for heavy bike. Very adjustable with knob for each pad.

 

[Chalo]

If you have mtb bars, going to full hydro makes much more sense... lighter, cheaper.

Hey, how else are you going to have the chance to lose 100% of your braking when you're out in the middle of nowhere, with nothing you can do about it?

To this day, I have never had a cable leak out of my bike.

 

[shadetree]

Really appreciate the mention, I had no idea. I actually already have a set circa 2005 and am planning to use on another build. There are no knobs, but I'll check deep into the reliability and workings for a better understanding. I'm sure there must also be alot of bad reviews floating around if they (avid) are so bad?

The cheaper/no knobs versions are the more reliable ones. The "fancy" ones are the problematic ones, with the rotating piece where the brake line enters. http://www.sicklines.com/gallery/data/529/elixir_rear.jpg
Those CR's were really popular OEM spec on tons of $3500-5000 serious MTB's, and lots of serious MTB guys had issues with them. Part of the issue with the brakes is they are tricky/finicky to bleed right, and get all the air bubbles out. So lots of people ended up bleeding, not getting all the teeny bubbles out, 2-3 rides the bubbles migrate up to the levers and consolidate in one bigger bubble, and yer brake works like shit again. Rinse, repeat. Also, some of their rotors have a tendency to warp, and makes your brakes garble like a turkey. When they are bled right, and don't have warbley rotors, they work good. If you are gonna bleed them, do yourself a favor and get the $50 pro bleed kit, and watch the Avid how-to bleed video on youtube, with the degassing the fluid first, proper procedure of bleeding up vs down, when to have lever squeezed vs open, etc. It's a procedure :/
http://www.jensonusa.com/Avid-Professional-Bleed-Kit
The $35 one works, too, way more likely to have hose pop off while you're bleeding. http://www.jensonusa.com/Avid-Disc-Brake-Bleed-Kit

By comparison, for Shimano's, you need one little $5 cup that threads into your lever, and a drain tube at the caliper. You bleed it just like a moto brake, just squeeze the lever, easy peasy.
http://www.chainreactioncycles.com/us/en/shimano-bleed-kit-m575/rp-prod34710

Also, Shimano uses mineral fluid. Avid uses DOT4 or 5.1 depending on model. If you use wrong DOT fluid, it eats the seals :/ 5.1 is tricky to find at autoparts stores sometimes people mix them up. DOT fluid absorbs moisture from the air. If you have a half empty bottle of DOT, it will go bad with time. If the bottle is 100% full, it lasts longer. Mineral oil doesn't have this issue. Get a liter bottle, set it on the shelf, be good to go for 10 years. DOT, you're better off buying small bottles when you need to bleed vs. big bottle that sits on shelf for years. The DOT is also caustic, bad for your skin and paint. Mineral is not.

 

[Chalo]

That reads like a good summary of why hydraulics have no business on bicycles. Include an anecdote about accidentally pulling your brake hoses out and I think you've got it covered.

 

[nutnspecial]

Thanks, all valid shade. Sounds like a huge win for shimano, tho I'm surprised avid has seemed to make such novice mistakes. Who wouldn't want the easiest/cheapest bleeding and use of mineral oil over dot fluid?

Yes, mine are elixir one, and look simple like the new take off's (elixir r sl) I linked above. But I guess they were 'new take off's' for a reason lol- somebody didn't like 'em.

Lol, we probably all kno where you stand on hyrdo for bikes Chalo. I for one am not convinced yet :wink:

Oh, PS, really dumb question?? The pic above (chalo) shows rotor mounted opposite than what I thought was preferential/optimal. I thought the angles were to be toward (sharpest) in the direction of forward travel?

 

[ScooterMan101]

I had BB5's years ago on a Mountain Bike, they made noise, it was a design and or pad flaw, most other people had the same problem with them.

I now have the BB7's on a Road/Gravel Disc 700c bike, with 29er wheel set. and I love them .
There are places in the U.S. that sells them for a good price. you do not have to take a gamble with counterfits.

Jensonusa.com has good prices on them.

Putting together a bit of a beater bike, was thinking of trying out mechanical brakes seeing as others on here think they are the bees knees and they seem pretty simple to service without the requirement of bleeding.

Just trying to work out a cost effective option to get decent braking power, Google revealed that BB7 is the preferred option, ahead of BB5 due to the brake adjustment knob.

BB7s can be obtained here:

http://www.ebay.com.au/itm/AVID-BB7-Mountain-Fahrrad-Scheibenbremse-Mechanical-160mm-HS1-Scheiben-SD7-Hebel-/371519795152?hash=item56804e2fd0:gzEAAOSwv-NWVWDl

BB5s can be obtained here:

http://www.ebay.com.au/itm/BB5-Mountain-Mechanical-2x-Disc-2x-Brake-Calipers-Set-Kit-HS1-rotors-160mm-White-/161398588671?hash=item25941b04ff:g:2foAAOSwxH1T8sV8


Both are with tiny discs, but they are probably sufficient for what I am using them. The BB5s is probably the better kit for money given it includes cables and is cheaper anyway. However it is from Hong Kong and is probably counterfeit.
for.

Is there any other mechanical disc brakes I should be considering?
Any other thoughts?

 

[Chalo]

The pic above (chalo) shows rotor mounted opposite than what I thought was preferential/optimal. I thought the angles were to be toward (sharpest) in the direction of forward travel?

For reasons I can't explain, Pro-Stop discs specified rotor installation with spokes trailing, rather than leading as today's disc manufacturers do. The picture shows the 8" size, but I used the 9" version (up until about a year ago).

Those rotors were made from aluminum and were at least twice as thick as typical rotors today, so they had more lateral and compressive stiffness than what we're familiar with. I think they'd have worked fine mounted the other way 'round, though.

 

[Lurkin]

Not interested in hydros on this bike. Horses for courses, not getting into that debate.

BB7s will be the go, easy decision as the others referred to are well out of the budget. Seems like these have plenty of support too, despite their age, so they are the go.