Does SRAM/Avid make a 203mm adapter? Their rotors are 200mm - probably why you need to add a spacer for the 203mm rotor.

Where did you read that Shimano only recommends the 203 rotor with cable brakes?

 

The original (pre SRAM) AVID BB7 sizes were 160,185, and 203mm. The uneven steps requires different adapters for each rotor and each position. Mine are stamped AVID 203F.
The newer SRAM BB7 rotors are 160,180, and 200mm. These use brackets marked 0mm +20mm +40mm. with 160mmF, and 140mm R as the base sizes. There are now +60mm brackets and 220mm rotors. The vintage Avids don't have a hole in the caliper over the pads, and smaller adjusters. The SRAM BB7s are open and heavier too. The calipers,brackets,pads and rotors are interchangeable. Shimano went with the vintage 203mm size for these. Perhaps so their modern brackets for their hydraulic caliper wouldn't fit? The outer edge was touching the caliper on mine.
As far as the "cable brakes only" I would have to go look for it. The Ebike rating was only on the box they came in and not on their website. Then there is the instruction sheet, and online service manuals. Shimano sells their stuff in groupsets so they are kind of self referencing in their applications. I would guess Shimanos hydraulic leverage is somehow not correct (in their minds) for the big rotors. TRP sells 220/223mm rotors for their EVO hydraulic brakes so it's definitely not a hard and fast rule. The Shimano rotors ran big on 203mm brackets that had 203mm Avid solid rotors previously. Doesn't make sense to me. But maybe Shimano 203 brackets are different than Avid somehow?
Shimano will give you a list of all the Shimano calipers that support each rotor, but absolutely nothing on other brands. They had planned to only offer these in Center Lock to "move the world forward". I guess the world didn't move so now we can have them in 6 bolt versions.
There is also a n MT=RT905 Freeza version in 6 bolt. It runs 150*C cooler than solid. The RT86 runs 100*C cooler. The upcharge on the RT86 is not too bad. The Freezas are expensive.

 

"It also results in a longer pad life and substantially quieter braking." I'm finding this to be true.

ICE TECHNOLOGIES | SHIMANO BIKE COMPONENT | SHIMANO BIKE-EU

To Build Closer Relationships between People, Nature, and Bicycles. We believe in the power of cycling to create a better world as we move forward. We inspire all people to enjoy our products in their everyday lives and where they take them.

bike.shimano.com

6-Bolt Disc Brake Rotor ICE TECHNOLOGIES FREEZA 203/180 mm | SHIMANO BIKE-EU

The pinnacle in mountain bike braking, XTR RT-MT905 disc brake rotors deliver superb stopping power for the most aggressive riding. The ICE TECHNOLOGIES FREEZA rotors dissipate heat to maintain braking performance on long downhill stretches.

bike.shimano.com

I looked in the saint groupset with the Freeza rotors and they list the 203mm there. maybe it's just the Rt86 203mm that's for cable only? Shimano says different things in different places at different times.

 

For BB7s metallic pads reduce adjustment frequency by about 5x. Pad life is extended a similar amount, and since these brakes are pretty much immune to overheating with metal pads it's the way to go. The ICE rotors improve this even more, and are quiet too. The steady temperature of the brakes makes them very consistent in lever pressure.
I'm guessing the improvements will be there with hydraulic brakes also, in fact those may need them more. Especially with organic pads. I've seen the RT86 203mm on Ebay as low as $42.

 

I posted in a Frankenbrake thread, and everybody was shocked that cable brakes were still an actual thing. Since this is a BB7 thread from the start I will post some tips on how to get them to work. I run these ona 35mph street Ebike with sticky moped rated tires. I ride urban South Florida. I take my brakes very seriously.
For the brake end. BB7s, SRAM or EBC Metallic pads, and Shimano ICE Tech rotors. 203mmF/180mmrR. Each one solves a problem of the other.
Setting up the cables can make or break the whole thing. One cargo bike builder tried BB7s because of the good rep. and failed. The bike had internal cables. He didn't know it ,but with 5 feet of cable flapping around inside the frame there was no way they would ever work.
To get the best result you need the best cables. But if they aren't in the budget they will stop your bike first time every time anyway.
The thing about the Jagwire Elite Link cables is the outer housing is a series of Aluminum beads that you string over the Teflon liner. The advantage is that you can shorten or lengthen the housing by adding or removing beads instead of cutting things. Light weight and rigid don't hurt. You can also buy 2 or 3 colors for strobe effect housings. Take that Hydro babies!
What you want is for the only thing that moves when you pull the brake lever is the arm at the caliper. The beads allow you to shorten up the housing so that it doesn't flap around. It can make tighter turns than flex cable. At the front brake you don't need flex cable down the legs of the fork. So get rid of it. 3/16" automotive brake pipe works for this. The pads come out the bottom of BB7s. Flip the bike over and remove the wheel to change them. Leave the hard lines alone.
Don't use a tubing cutter, it will pinch it closed. The ends off of an old cable housing will fit over it. You will need to drill it out so the teflon can pass through. Do this from the caliper up to the fork brace, then the flex section. On my HT I went solid at the rear all the way up to the seat tube. On My Softtail solid up to the rear shock with just a few inches of rear flex (link) housing.
Adjusting the cable is pretty straight forward. No play between the lever and the brake arm. No free play at all. The return sping at the caliper should be holding the lever aginst the stop. This also helps with rattles. The barrel adjuster at the lever can fine tune this. But once you get it right don't ever touch it again. Do all adjustment at the brake pad knobs. There e is an adjustment for the return spring at the caliper. You can tune this so you feel what he brake is doing instead of just the spring.
Matallic pads have a reputation for being noisy. The cable brakes bend the rotor to reach the inner pad. If the outer pad touches, and the inner pad isn't touching yet, the rotor can ring like a gong. The Shimano ICE Bimetal rotors ( Aluminum core) don't do this. I f you don't have these rotors a click or 2 on the inner pads adjuster will fix it.
Adjust the inner pad first. Until it drags then back off 1 click. Then the outer pad.
I'm not saying anyone should pull good hydro brakes off of your bike and get these (but some remote touring riders will do this). But if you already have them this setup works quite well. There is a Shimano Freeza rotor option in 6 bolt also that runs 150*C cooler if long DH runs are on the menu. Shimano MT-RT905 in 6 bolt.
I've seen a recommendation from Shimano to not run the 203mm rotors with hydro brakes..... So Shimano makes these for cable brake use.

 

One other bit of BB7 folklore is that they don't get set up centered on the rotor. They install with the rotor 2/3 of the way towards the inner pad. No idea why. Adjust the pads so they hold the rotor in that position and tighetn the spherical centering bolts. Loosen the pads. You're done.

 

I should probably add that my bike has 26" wheels like most bikes in the BB7 era. If you have 29" wheels and need 220mm rotors these brake may not work for you.
The ICE stuff stops at 203mm.

 

One thing to keep in mind is that SRAM still offers the Speed Dial adjustable ratio brake levers if you need more power from these brakes.
Due to SRAM Gripshifters they have room for Ebike controls also. 3 finger levers for more power that way too.

Avid Speed Dial Ultimate Brake Lever user reviews : 4.8 out of 5 - 43 reviews - mtbr.com

Avid Speed Dial Ultimate Brake Lever user reviews : 4.8 out of 5 - 43 reviews. Read it's strength, weaknesses, find deals and pricing - mtbr.com

products.mtbr.com

For bigger wheels the leverage of the 220mm rotors may be worth more than the 203mm Freeza. But with solid cable housings the Speed dials might help bridge the gap.

Speed Dial 7 - BL-SD-7-A1 - SRAM

Speed Dial 7, BL-SD-7-A1, SRAM. Built around one of our original breakthrough designs, the Speed Dial 7 is the smooth and powerful way to control linear pull or mechanical disc brake...

www.sram.com

 

I've seen a recommendation from Shimano to not run the 203mm rotors with hydro brakes..... So Shimano makes these for cable brake use.

Where did you see this crazy recommendation from Shimano?


Shimano makes wide type rotors, narrow type rotors, wide type pads and narrow type pads.

Shimano brake calipers are made to use either a wide type pad or narrow type pad.
You can't use a narrow type pad in a caliper that's made to use a wide type pad and you can't use a wide type pad in a caliper that's made to use a narrow type pad.

Ice Tech rotors are a narrow type rotor.
Shimano recommends you only use narrow type pad with narrow type rotors.

No Shimano mechanical disc brakes uses narrow type pads.

Link to Shimano pad/rotor recommendations: 2023-2024 SHIMANO Product Information Web

Are BB7 pads similar to a wide type pad or a narrow type pad?

 

I scrolled through a lot of different pages trying to find it again. It's possible it was from an Amazon vendor and I thought it was official.
Since I'm running cable brakes I didn't feel the need to check it out further. On some of the Shimano web pages there is no mention of Ebikes, but when I recieved them it was marked on the package. But my idea of an Ebike and Shimanos may not be the same.
The BB7s are narrow pads. Since the Avid/SRAM BB7 brakes are working for my application I haven't really looked at Shimano except for the ICE 6 bolt rotors which are a huge improvement. I'm not a follow the manual kind of guy anyway. Everybody says these rotors won't work with BB7. I cut the metal tab off of the inner pad and they work just fine. Shimano isn't going to provide any info on using these with other peoples stuff. They stick it in one of their groupsets and that's it.
(I have 50 years mechanical experience, some of it modifying high performance vehicles. If you don't have a strong mechanical background=Follow the Manual.)

 

I saw a question about the BB7 MTN-S calipers. They have stainless steel hardware. But they also have a black hard anodized finish. I've burnt the paint on my Avid BB7s with metal pads on my Ebike before I had the Shimano Icetech rotors. The black finish with black adjuster knobs is probably a more modern look. So mostly cosmetic but maybe a little better for hard use.