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Physics Buffs: Getting every drop out of your BB7's

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19K views 72 replies 31 participants last post by  jonshonda 
#1 ·
Guys- I know, I know, hydros are better, especially if you are doing downhills long enough to wear pads... But out of a desire to tinker, I was thinking of how to get really everything out of a set of BB7's, in terms of controllable power and weight reductions. I was wondering what you all thought of each option...
1) Take the brakes apart, and get down to the ramp that rides on the ball bearing inside and pushes the moving pad into the disc. Polish the ramp to a high gleam to reduce friction. I heard of someone doing this- he said that afterwards the brakes had significantly higher stopping power.
2) Use the road version of the BB7 with a cantilever brake lever set. The geometry of a cantilever lever is actually much more ergonomical than that of a V-Brake lever- compare, say, an XTR V-Brake lever with its pivot way near the handlebar. Now draw an imaginary straight line from the center of that pivot to the point where you pull the brakes. If you imagine another imaginary line which represents the line your finger describes as it pulls on the brake, you will see the angle between the two lines is not so flat, which means you are losing power.
Do the same exercise for, say, an old DiaCompe SS-5 lever and you will see the difference.
For a lot of people, short-pull levers are also more comfortable.
3) Use the best cables, and install them properly. One thing I have noticed on a lot of BB7 setups is that the cable housing is generally smaller than the cable housing stop on the BB7, which allows the housing to squirm some, leading to mushiness and reduced braking power. Use a bigger ferrule, and if the i.d. of the larger ferrule is too big for the cable housing, make up the difference with epoxy glue. Or use Flak Jackets with Nokon cables.
4) Use better pads. I have only ever used stock ones.
5) Use lightweight rotors. One weak point of the BB7 is its weight- and the easiest way to cut weight it seems is at the rotor.
6) Use the most powerful brake levers. The most powerful V-Brake lever is the older-style (c. 2003) Shimano LX lever, and the most powerful cantilever levers are any of the SLR-Plus canti levers from the early to mid-90's before V-Brakes took over. Both of them are a little chunky, though, compared to other choices. Another thing is that just using a more powerful brake lever will definitely give you more stopping power, but that pure clamping force is not the limiting factor anymore- when going down a long hill when you have to use the brakes a ton and the rotors get heated up, having a lever that squeezes harder is not going to help you.
 
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#2 · (Edited)
I weigh 155 pounds and I ride a 4" travel bike aggressively on steeper than average trails. Granted I'm not a big guy, but I have never felt like I need more power from my BB7's. They have always been one finger brakes with SD7 levers. I actually went to a 140mm rear rotor and organic pads to tone them down. Most of the the riders that I keep hearing complain about BB7s not having enough stoping power most likely do need some changes like harder pads or bigger rotors. They probably also need to make sure that their cable, lever, and pad adjustments are optimized to their liking. You sound like a guy that knows that you can greatly change the feel of your BB7's with these adjustments. I like my lever dialed closer to the bar and my pads as close as possible on both sides. Any high quality cable seems to work for me. I even tried derailleur cables and housing because they are lighter. I didn't care for the stiffer feel. I know most heavier riders like the extra power of the hydraulics, but I like the ease of use of my BB7's. I have ridden mine for years with no service. My Cleansweep X rotors are very nice. I may also add some titanium bolts to the caliper in the near future. I plan to throw a caliper away if it sticks, and buy a new one for forty bucks or so. I downloaded the service manual from Avid and it didn't look like it was worth my time to take a caliper apart.
 
#3 ·
I just do a clean full length housing setup with Teflon coated cables. Replace the stock pads with Galfer (discontinued) or EBC Gold pads.

Most of my bikes do use the Road version with road dropbar levers. They do seem to have more power than the Mtn setup.
 
#4 ·
Nice post - I'd have to say that the BB7's were quite good in terms of power as stock - that polishing trick sounds like it would make them a monster.

My tip - use Avid Full Metal Jacket cables if they're still around. These were astounding coming from a normal Shimano outer.

about your point 5....I thought all Avids used the same rotors. Certainly the Cleansweep rotors are not shabby weight-wise.
I'd also be a little hesitant in saying that a lighter rotor improves braking performance. All the light ones I've had have done the opposite.......in fact I chose a light rotor for my R1's for that reason, as they were way too grabby initially.
 
#5 ·
Shiggy- on your setup, are you using Shimano STI levers? These make a big difference, because they have SLR Plus inside, which makes any brake more powerful. I mean, the Road BB7's you're using may be giving more power specifically because of the SLR Plus mechanism in the lever. About rotors, yeah, lighter rotors would make them work worse. I asked about lighter rotors is because the main disadvantage of BB7's over hydros for many people is weight- they really are quite a bit heavier than most hydraulic brakes.
Actually, it's an indication of how far brakes have come that if you put together all the tips I mentioned, you would have a brake that is probably TOO powerful. My current setup- stock BB7 with normal pads, standard housing, Teflon cable, and SD-Ultimate levers (the flashiest levers with the least play, but in stopping power, inferior to the most powerful V-lever ever, the Shimano LX), could use some improving, but as it is it's already more than enough for every situation I have ever gotten into.
 
#8 ·
I get similar results with Shimano STI levers and Tekro road levers. I remove the return spring from the later as it only increases the hand effort required to pull the lever. The spring is needed in the STI lever because of the weight of the shifter guts.

AFAIK SLR is simply a less powerful return spring. It was on the mtb levers (I remove the spring from flat bar levers, too).
 
#6 ·
Using a rotor that's matched to the brake will give better performance too.

* Brake rotors such as the G3 CleanSweep and CleanSweep X are made to be used with the Code, Elixir and X model brakes, they aren't designed to be used with the BB7, BB5, or Juicy model brakes.
* The G3 CleanSweep and CleanSweep X rotors have a smaller braking track then the G2 CleanSweep rotor.
* The BB7, BB5, or Juicy brakes have pads matched to the braking track on the G2 CleanSweep rotor.
* Code, Elixir and X model brakes have pads matched to the braking track on the G3 CleanSweep and CleanSweep X rotors.

Here you can clearly see the difference in size between the BB7/Juicy pads and the Code pads.



Here you can see how far off the braking track a BB7 pad wears the G3 CleanSweep rotor.

 
#7 ·
Full length housings, proper caliper alignment, and a good brake lever is all that's needed to get BB7's to perform great. Some like to replace the brake pads with the EBC Golds, but the OEM ones are decent.

I ran this setup for 2 years on my FS bike with 180mm rotors. They could pitch you over the bars if not careful.
 
#9 ·
I changed all the bolts with TI bolts : that's 7 bolts per brake (I'm using IS-PM adapter).
That shoved just over 40 grams for the pair.
Plus the 12 rotor bolts of course.

Indeed, rotors are very heavy (in my case : CS-G2's 160 & 185mm). I'm thinking of replacing them with Formula or Hope 2-pieces rotors.
 
#10 ·
probably wont like the 2 piece rotors with the BB7's Hydro brakes move both pads, the BB7's just use one and flex the rotor. I used the Magura Venti Rotors and they were good for a bit, but the wore the crap out of the moving pad's lower edge, They just don't flex as easy as a full Stainless steel plate and make the pad twist inside the caliper. Was replacing pads every few months. and the inner pad was almost like new. but the outer pad was actually kinda rounded and lost power fast once it wore like that.
Also the light weight rotors aren't great do to the same reason. most make a taller jagged outer edge and they vibrate more than the mild wavy rotors that have more surface on the outer edge.
 
#12 ·
The most powerful V-Brake lever is the older-style (c. 2003) Shimano LX lever.
Has anyone tried the BB7's with the newer Shimano M590 levers? I've used the M590's with Shimano 415 mechanicals which was a significant upgrade over the stock combo brake/shift levers. I also upgraded two other bikes with the M590 levers which used promax v-brakes and Shimano Acera v-brakes. The M590s with the Acera v-brakes feel excellent with a surprising amount of power. The lever shape feels good too.
 
#13 ·
No, not tried this combination...
But I don't think the levers are the weaker element of the systems. Of course cheapo plastic levers will provide a crap spongy feeling... But with decent levers (Paul's), nice but not the best, I feel that the cable housings are flexible, esp. the rear one. And that's with proper large diameter Jagwire brake cables and housings.
 
#14 ·
I just recently replaced my Tektro Novelas with BB7s, G2s (thanks to cobba's post), and Speed Dial 7s. The change was significant right away (quiet brakes, what a concept) but, after bedding in the pads, I replaced my OEM cables with Jagwire Ripcords (based on comments in this forum). Wow. The difference in performance was shocking and bigger than the caliper change. I ordered some Middleburn Cable Oilers but the Jagwire cables are so well protected I may not install them when they finally get here. My take away? It's a balance of all the brake components, but you won't get full performance without installing high quality cables.
 
#20 ·
Would be awesome. Time consuming, but awesome. Then get every part chrome-plated. And shiny Ti hardware. Then do the adaptor too. Then make some metal pad adjuster knobs, and get some silver housing. And silver dust boots. Polish the cable crimp and ferrules, wax the stainless cable. Then polish the rotor too. Then do the whole freakin' bike :p
 
#22 ·
I would beadblast the parts, then clean out all residues and then polish it. Would be easier and faster then trying to scrape and sand the little corners and other small places. Just be sure to cover any holes where no sand should go and it should be fine.
 
#24 ·
FWIW, I use glass bead as the blast media. It makes a nice finish on most metals and alloy, and I find the resulting finish to be quite easy to polish using a bench mounted buffer with proper polishing paste.

David
 
#25 ·
I was a BB7 devotee for many years, I never have thought they had too little power. I do feel they lack the control that todays top hydro brakes produce. I still have one bike with BB7's they have avid rotors 180/160, flack jacket cables, Avid pads and Paul levers what can be done to add modulation?
 
#26 ·
Adjust the calipers to have the inboard pad further from the rotor, which will make the rotor bend to be able to get grabbed by both pads. The moving pad pushing the rotor will then be felt as more modulation, but will wear pads less even and might warp the rotor over time and if it gets hot too often, which a properly setup BB7 would not do.

The other solution I can think of is a custom pulling curve of the lever, allow quick pull first then degrading exponentially in the ratio of cable pull... Then you'll have a real modulation and be able to keep your BB7 setup the right way.

David
 
#33 ·
i was a long time bb7 holdout (but... well... hydros just work better), and 10 years as a bike shop manager, lead wrench, etc.

but anyhow, my tips are:

1. paul love lever, sram 9.0 lever, or shimano m952 xtr lever - best modulation and power
2. set the fixed side of the pad as literally as close to the rotor without rubbing as possible to maximize bite and minimize rotor deflection.
3. adjust the pad contact and cable pull to taste for cable pull
4. use metallic pad on the fixed side and resin pad on the moving side, this reduces noise and increases brake power
5. use teflon coated brake cables
6. use full length housing and good sealed ferrules. use the shortest housing possible.
7. use a rotor with a lot of machining (hope, magura storm sl, avid g3) to maximize bite of pads, make sure machining is lines, not circles

hope that helps someone.
 
#41 ·
Took Apart BB7's for possible Ramp polish

My interest was peaked by the mention of polishing ramp to increase leverage/ stopping power etc. Here are my results and as you can see in pictures it doesn't look possible or worth effort as each ramp that each ball bearing rides on is really small and would be tough to polish. I'm also not sure of actual physics which would take place to provide more leverage. However someone else can judge, here are pics and a link to youtube video of actual motion that occurs when disassembled.
This is a set of 2011 BB7's

BB7 Piston Motion - YouTube
 

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#49 ·
Jeff Jones uses the BB7 on his uber-bikes, and the brakes feel great - he uses a steel tube instead of housing where the brake cables run along the frame, and Nokon housing from the levers to the frame-mounted tubes. Since the tubing has virtually no compression at all, it made the brakes feel really tight. As long as it has enough room on the ID to allow the cable and a teflon or similar liner fit through without crimping against the cable (or be too large and let the liner compress/wrinkle) in the bends it may be a good solution for any hardtail bike. Hmmmm... may have to try this on a El Mariachi build I have in mind....
 
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