Avid BB7s in the modern world.

Retrorockit

Old School Hero
My 2004 Gary Fisher Solstice 26" comfort bike ahd Avid BB7s added to it when new. It's also had a 1500W motor a few years ago. The BB7s are still there. But the stress of the motor led me to a few upgradesthat I feel keep them on par with all but the be$t hydraulics. First off there are 2 series of BB7. The original AVID with small knobs, and the newer SRAM BB7 with larger knobs and an opening above the pads that the older ones don't have.
The first thing I do is run metallic pads. They never come with the brakes. But they cut way down on the frequency of brake adjustment ( about 5x) and last much longer. If you've run organic pads before, sand the rotors to remove the coating. I've found that in the rain they howl until the whole brake is wet then they settle down. But hey do work wet. Quality varies. I use SRAM. Off brand stuff will wear out your rotors. If you're ever stopping with BB7s and you need to increase pressure as you slow instead of backing off you need metallic pads.
Rotor size matters. I use offset sizes 185f/160r for 26". and 203/185 or 200/180 for 29". Skinny 770c tires I don't think it matters much. For the 26" Ebike it's 203/180.
Avid still offers their Speed Dial adjustable ratio levers in metal. The old 9.0 levers also had this and were all plastic. I use them on my XC bike. They protect the carbon handlebars.
Brake noise. I found that this happens under light braking when just one pad is touching. The rotor is free to ring like a gong. I found a solution, and it may be overkilll for most pedal bikes but it definitely makes the brakes run much cooler. Shimano Icetech rotors have an alloy rotor with stainless facings. This dampens any vibration. So no need to adjust for noise.They run 100*C cooler. Supposedly they won't work with BB7s. Just cut the extraction tab off of the inner pad. Removing the other pad first allows it to be pulled out easily. RT86 is the 6 bolt Icetech, RT76 looks the same but isn't.
For extreme use like loaded touring there are 220/223mm rotors and thicker rotors that he BB7 can open up to accept. But no Ictech option. Keeping the inner pad adjusted quiets them down.
BB7s get installed slightly off center. Read the manual when installing them.
Brake cable setup. BB7s will work with just about any thing for cables. But if you want them to feel as close to hydraulics as possible then you have some wrok to do.
1- Get good cables. Prestretched Stainless Steel, swedged smooth and round. Jagwire is one brand.
2- Get all extra slack out of the cable housings. When you pull the lever nothing should move except the brake lever, and the caliper arm. This can be tricky with internal cable routing. I've seen rear brake performance ruined by this.
3- High end cable housings. This is optional but fun for bodgers. You can get assorted compressionless cable kousings. But king of the hill is Jagwire Elite Link housing kits. SS cables as above, with a Teflon sheath, inside alloy beads for outer houisng. Tight bends are not a problem. Unfortunately this costs alomost as much as the brakes (but much less tha high end Hydros). One trick is to use 1/8"/3mm ID automotive metal brake line over the Teflon sheath for up the fork leg, or the seat stay for no compression, no slack housing. Alloy tubing can be found. The OD fits inside regular bicycle cable end ferrules. I've run it inside of the frame also. Shift cable can be done this way too.
If you get this far the BB7 has a little used return spring tension adjustment inside the caliper arm. You can adjust this until it balances the brake lever return spring. This gives much better feel of what the brake pads are doing.
4- Just for fun, the alloy cable beads come in different colors. You could match the bike , or even alternate different colors for a strobe effect that hydraulic brake hoses don't have.
So for no leaks, no bleeding, no water contaminated fluid, no popped pistons with the wheel removed, no boiled fluid when you least expect it. no melted plastic tubing at the caliper fitting......
 
A few words on rotor sizes, and brackets.
The original AVID rotors sizes were 160,185, and 203mm. The uneven size steps and 160mm f/140mm r bases sizes made different bracket for each size, and each end of the bike necessary.
Modern SRAM rotors come in 160mm/180mm/ qnd 200mm (220/223mm do exist). The base size is still 160f/140r. Brackets now come in Std., +20mm, +40mm and +60mm sizes and interchange between front and rear. So the same +40mm bracket is 180mm rear and 200mm front
Shimano Icetech is mixed here with 160/180/ and 203mm options.
 
Rebuild kits are available for the SRAM BB7s, but not the Avids. There are now road BB7s with a ratio for drop bar brake levers, and MTN-S versions with stainless bolts and an anodized finish. The Ebike can damage the paint on the normal versions. Or at least it did before the Icetech upgrade.
 
When setting up the cables (any cables) on BB7s you want zero slack in the cable. The brake lever and caliper arm should both move as one. This helps keep rattles out of the brake levers when not in use. Once you have this don't use the barrel nut adjuster at the leverss again. Do all wear adjustments at the brake pad dials. The caliper arm doesn't need to be fully resting on it's stop. It can be slightly applied to keep slack out. With metallic pads you shouldn't need to stop and adjust for wear in the middle of a ride. With Icetech bimetal rotors I'm out to almost a week for adjustments. The need to keep the inner pad almost touching the rotor at all times to avoid light braking noise goes away.
 
Here are a couple links to the Icetech pages.
https://bike.shimano.com/en-EU/technologies/component/details/ice-technologies-freeza.html
https://bike.shimano.com/en-EU/technologies/component/details/ice-technologies.html
The Icetech rotors are easier to bend than other rotors, but easier to straighten too. The alloy spider helps make them stiffer, and the Freeza versions, which are much more expensive have more metal, so should be stiffer due to that. The upcharge for the RT86 is about $20USD.per rotor. The Freeza MT905 are much more expensive. I've never used those.
 
I'm hearing on MTBR that Shimano rotors sourced form China instead of japan are stamped instead of laser cut and not being as flat don't work nearly as well. I haven't experience this myself/ But I would ask a vendor about this. This is not just the Icetech versions., solid steel rotors have the same issue.
 
Just an update on my experience with the BB7/ Icetech rotor setup. I picked up a pair of the latest BB7 Mountain S calipers on closeout. I didn't really need them, the 20yo ones are working just fine. But I pulled the original Avids off of the Ebike to get them back on my 2004 softtail XC bike instead of the TRP Spykes I left on it after testing them there.
Swapping the new vs. old calipers was no problem. I had to cut the bent tab on the inner pad as expected. I did find that the Icetech rotors run so much cooler than normal ones that it took a lot more effort to bed in the new SRAM metallic pads. Much harder to get sufficient heat into the pads to burn the oils off the surface. It took a few runs down a hill using the Ebike power going down to heat them enough. I already had the pads bedded in when I added the Icetech rotors, so I didn't notice this before. I may bed in an extra set of pads on the Ebike before putting the BB7 calipers on the XC bike.
I also found that the Avid F203mm brake adapters neeeded a 1/8" spacer (and longer bolts) with either caliper. Looking in my parts bin I found a vintage Avid R185mm adapter. Doing the math this would be a +45mm adapter in the new SRAM sizing scheme. So 205mmF theoretical size. It worked perfectly with the 203mm rotor. So there are some off sized Avid 203F brackets being sold. The 203 rotor was a recent addition, so the bracket was too.
If shopping for BB7 brackets be sure they're for BB7 specifically. Avid used 203mm, but SRAM has gone to 200mm. SRAM is still calling the new brakes Avids. But the calipers are not the same as the original ones. The pads, calipers and brackets interchange, but the rotor sizes have changed also and the required brackets with them. So actual Avid BB7 203mm/ 185mm brackets might require a little extra effort to acquire. Those sizes are obsolete with SRAM. Shimano Icetech is 180mm, and 203mm so mixed sources may be required.
 
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