DIY BB7 Brake Adjuster Tool

[teklektik]

Upgrading my Yuba Mundo to disc brakes, I opted for mechanical BB7's that get great reviews for ease of adjustment except for the inside adjuster wheel. Starting with the front wheel, the brake kit went on easily but I quickly ran into a clearance issue with the inside adjuster - the BMC motor blocks the torx adjuster on the 185mm rotor (a 203 wouldn't quite get it clear either) and the adjuster itself is virtually impossible to turn by any other means.

The mechanism is comprised of a round plastic adjuster wheel that snaps into a retaining groove and engages an almost-hex shaft from the threaded inner pad adjuster that protrudes through the center of the wheel. Turning the wheel turns the shaft and screws the shaft and pad adjuster in or out. There is a torx head in the end of the shaft as well. The wheel also has 6 little grabbers that click in detents around the edge of the retaining lip to hold the setting - the wheel clicks from one detent to the next when turned.

Although the unit is optimistically designed to allow adjustment with the wheel , it's really some kind of cruel hoax - essentially impossible with fingers and no good means to do it with tools that won't soon destroy the wheel. Sadly, the torx head is the way to go.
( ...so this is source of the complaints... :-( )

I fabbed the little tool shown below from a scrap of 1/8 aluminum plate, although a similar piece of PVC or ABS plastic might do as well. The hole is exactly 1.250" and was bored with a Harbor Freight step drill that gave a perfect fit with no dressing. The six little recesses were filed to leave room for the little grabbers to move out of the detents so the wheel can turn.

The tool works great - slip it over the adjuster wheel between the brake and the motor and squeeze a bit - it gloms onto the wheel so it can be easily clicked in/out as needed. Anyhow - it's a workable solution if you find yourself with a similar clearance issue....

 

[StudEbiker]

That is awesome. You should sell those!

 

[Sacman]

That's pretty slick! Kudos on your innovative tool teklektik!

I do know full well how hard it is sometimes to turn that BB7 caliper adjustment wheel since I run BB-7's on 3 of my ebikes.
Up till now my best method to turn that adjusthent wheel was to use a torx bit on the end of a 1/4-inch drive with a universal joint. :wink:

 

[teklektik]

Thanks - the tool isn't difficult to make - it was the "Ah-ha!" moment that was long in coming... :wink:

... I run BB-7's on 3 of my ebikes.

That's encouraging news - sounds like a happy customer - this is my first foray into bike discs and I was becoming skeptical of my choice. I guess this is just an issue of the fat little BMC gear motor.

Up till now my best method to turn that adjustment wheel was to use a torx bit on the end of a 1/4-inch drive with a universal joint. :wink:

Yep, the torx adjuster is the way to go. Sadly, I don't even have enough room to slip in a short hex drive torx bit alone so I can grip the 1/4" hex body with a small wrench. I was wishing that Avid had molded a large flat hex nut shape onto the top of the adjuster wheel - a thin wrench could then turn it from the side w/o problem. They could stamp out a 10 cent shortie 17mm wrench and put it in the box. But I guess in the end this is just an ebike thing - blocked rear access is not a normal design consideration for them.

 

[nicobie]

That's pretty neat. Beats using channel locks like I do.

 

[grindz145]

Nice! I just finished mashing my hands through the spokes to reach the rear adjuster on my xtracycle monster. Very slick tool.

 

[Kirk]

Since the brakes on my trikes are on the front wheels, it is pretty easy to adjust my BB-7s, but that is one slick little adjuster you have there. Make up a bunch and I'll buy one from you, just because it makes the job that much easier.

 

[teklektik]

Hmmm - I just posted this so folks could make their own, but maybe I could get a run made up - it's only aluminum and would waterjet really easily. Never did that before and need to locate a firm, etc. I'll look into it a little later this spring when some I get out from under some other looming tasks. If it looks reasonable I'll put something on Items for Sale - New.

Thanks for the interest... :wink:

 

[gensem]

Put me on the list... but steel would be better!

 

[Sacman]

Hmmm - I just posted this so folks could make their own, but maybe I could get a run made up - it's only aluminum and would waterjet really easily. Never did that before and need to locate a firm, etc. I'll look into it a little later this spring when some I get out from under some other looming tasks. If it looks reasonable I'll put something on Items for Sale - New.

Thanks for the interest... :wink:

Put me down for one too. I don't care if it is just aluminum ... as long as it works.
You might want to post it up on MTBR forum (mountain bikers). Those guys would eat this tool up! :lol:

 

[teklektik]

Thanks for the MTBR tip. The tool needs to be a little springy so you can squeeze it and only works against plastic parts, so aluminum looks attractive. This one is made from 5052 T6 - I'll have to see if something in the 606X family would be a better choice. This is out of my area of expertise, so it'll be a bit of a learning experience.

 

[Lemlux]

Add me to the list, please.

 

[GMUseless]

That's such a good idea man. At some point, they started making the BB7's such that the knob is impossible. I've got some 2007 BB7's that turn with almost no effort. But, my 2011 set is impossible. Your tool looks perfect.

 

[teklektik]

That's such a good idea man. At some point, they started making the BB7's such that the knob is impossible. I've got some 2007 BB7's that turn with almost no effort. But, my 2011 set is impossible. Your tool looks perfect.

Interesting info about the older model. While I was trying to figure out what to do I thought about trimming off 3 of the 6 detent grabbers to loosen its grip on the caliper body. I chickened out, figuring they made it grab tightly for some good reason.

But if the old ones worked okay, maybe...

If you work carefully, you can release the retainers and pry the wheel off - it will slide up off the adjuster shaft. Trimming the grabbers would then be really easy - bend outward and nip off with Xacto blade, small dikes, or fingernail clipper. You would want to just trim off the side part of the grabber, not the top - to leave the top seal intact against dirt, etc.

You could also just trim off the inside bump on the grabbers (that drops into the detents) with an Xacto blade, leaving the top and side of the grabber intact (this sounds better...).

 

[GMUseless]

Thanks for the tips. I'll take a look at the old ones and see if I notice any differences.

 

[GMUseless]

I just took a look at the 2007's...there's not even a Torx bolt in the center. And they turn rather easily. It looks like substantially different wheel design. I'll post some photo's for you when I can. They definately over did it on the tension.

 

[teklektik]

Thanks! That would be interesting to see... I wonder when they started the current design... it would affect the models on which the adjustment tool would work. It will be a bit of a bummer if they've been monkeying around with the wheel design too much.

I just bought some 2011 185mm units - reported to be the same as the newer 2012 model except for the price.

 

[Sacman]

We all might be cursing how hard the new wheel is to turn but it might have been intentionally made that way by Avid. Brakes are mounted to the part of the bike frame that takes the most pounding and vibration. It could possibly be that the older wheel was loosening up making the brakes weaker. So if Avid made the new wheel harder to move that's probably better than having weak brakes.

 

[teklektik]

Agreed

 

[GMUseless]

So here's a couple of pics of my 2007 BB7's: (sorry about all the grime!)





I think the wheel is actually even a bit smaller...but clearly a different design. I've never had any issues with the wheels backing out or moving on their own.

 

[teklektik]

Boy, those are different... It appears as if the detents, etc are all internal - the outer rim is just for finger grabbing.
Thanks!

 

[JimB]

Nice looking tool! I'd want one for my toolbox and one for the bench even if I didn't have discs. Patent it quick!

 

[teklektik]

So here's a couple of pics of my 2007 BB7's ... clearly a different design.

I just found the Avid BB7 2008+ Pad Adjuster Knob Kit 11.5311.619.010 so it seems 2007 was the last year of the older style and the newer style hasn't changed since 2008.

 

[fatbikerNW]

If you're making some more of these, I'd love to have one.