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-   -   Sram bb7 road brakes and in line barrel adjusters (https://www.bikeforums.net/bicycle-mechanics/1044835-sram-bb7-road-brakes-line-barrel-adjusters.html)

trail_monkey 01-12-16 10:43 PM

Sram bb7 road brakes and in line barrel adjusters
 
Why do they come with these barrels in the box when all you have to do is get cable tensioned right in the first place and adjust inboard and outboard red knobs to set the brake pads close to the rotors. Seems like something that isn't needed and I have read differing opinions about it.

Andrew R Stewart 01-12-16 10:58 PM

Why do you feel that more options for adjustment is a poor design? Andy.

dsbrantjr 01-13-16 06:30 AM


Originally Posted by trail_monkey (Post 18455532)
all you have to do is get cable tensioned right in the first place

They help you do that without having to loosen/retighten the wire until you get the right length. Yeah you can get it right but the adjusters make it quicker and easier.

trail_monkey 01-13-16 06:50 AM


Originally Posted by dsbrantjr (Post 18455822)
They help you do that without having to loosen/retighten the wire until you get the right length. Yeah you can get it right but the adjusters make it quicker and easier.

I just wondered. It seemed as if the pad adjusters (red knobs) would take the place of other adjustments regarding lever travel. Just thought I would ask. Thanks.

trail_monkey 01-13-16 06:52 AM


Originally Posted by Andrew R Stewart (Post 18455553)
Why do you feel that more options for adjustment is a poor design? Andy.

Never said it was a poor design. I was just curious. Setting up my BB7s now and wondered if they were necessary. I can see where it would be handy to have.

Andrew R Stewart 01-13-16 08:32 AM

More ability of adjusting the various aspects of disk brakes is a good thing. But these in line adjusters are easy to either install or remove for no or little cost later. So one can make their own judgment and be able to reverse their first thoughts if they find real life is different.

I would install them right from the start, picking a location with as little casing movement as possible (far away from the movement of the handle bars) and with care to not allow rattling against the frame. I find that with the greater cable movement for the lesser pad travel (hence the disk brake's greater MA) what would be acceptable with a rim brake isn't as good with a disk brake. So grind/file all casing ends as flat as possible, choose casing path ways with as "smooth" a route as possible, and start with a rotor as straight as possible. Expect there to be a seating in of all the parts that touch/compress against each other as well as a bedding in of the pad and rotor surfaces. We see far more need to revisit the various adjustments of a disk system then a rim brake one, at least initially. Andy.

trail_monkey 01-13-16 09:03 AM

Well I might have made my first mistake after reading your post but I will give it a try and see how it works. I put the barrel for my rear brake in line halfway between the first frame eyelet and where the cable comes out of the handlebar wrap. But in the bike stand I'm able to rotate the handlebars all the way both directions and I cannot see where its pulling the barrel adjuster apart even when its all the way in. I think it will be okay but I'll keep an eye on it. I don't believe when the handlebars are turned to the extreme either direction that is pulling on the rear break either which should indicate that it will work okay where I got it.

trail_monkey 01-13-16 09:05 AM

If you don't mind me asking this, where would you recommend I put the barrel adjuster for my rear derailleur? Would it be better in the short piece of housing that is right before the derailleur or in the cable before it goes into the handlebar wrap so I can adjust it on the fly?

Andrew R Stewart 01-13-16 09:19 AM


Originally Posted by trail_monkey (Post 18456080)
If you don't mind me asking this, where would you recommend I put the barrel adjuster for my rear derailleur? Would it be better in the short piece of housing that is right before the derailleur or in the cable before it goes into the handlebar wrap so I can adjust it on the fly?

So the rear der doesn't have it's own adjuster already? It's a newer SRAM or Shimano? The frame has no cable stop with adjuster?

Adjusting a cable while riding isn't my higher priority but then I don't race. So I'd place the in line adjuster as I suggested with a brake one. Most won't appreciate my approach to cable routing and fittings placement. As example I would likely not buy a bike that didn't already accommodate adjusters onto the frame. Just one more reason I don't have internally routed cables on the bikes I build. Andy.

fietsbob 01-13-16 10:04 AM

I personally use the pad wear knobs as my adjustment input, on my BB7, but My bike company did not ship a second adjuster..

{50 years of mechanics, I never missed it) BB5 uses the cable adjuster for the mobile pad adjustment, that is on the caliper, itself.


for a rear derailleur ~ indexed shifter adjustment , I like the ones on the RD itself or nearby
So I see the action the adjuster changes to the synchronizing with the lever on the other end..

There was an adjuster equipped noodle included with road, V brake long pull, levers ..

for use with ... V brakes ..

mconlonx 01-13-16 10:06 AM

My thought was that one of the main points of having inline adjusters is that you could make adjustments on the fly, without having to stop riding and make them, start riding to check, stop riding to re-adjust, etc. It's nice to have adjusters at hand while riding in order to fine tune adjustments.

And considering this, I would put them somewhere between where the cable comes out from under the tape on a road bike, and the first frame cable stop.

trail_monkey 01-13-16 10:37 AM

It is a new sram x7 10 speed derailleur and it has no barrel adjustment on it. I should have been more clear this is being used with SRAM DoubleTap Road shifter on drop bars so there is no barrel adjuster anywhere in the system. My only concern with putting the barrel adjuster in the short piece of cable housing back near the derailleur is that the housing is so short there wouldn't be much flexibility for lengthening.

Slash5 01-13-16 10:52 AM

I've never had adjusters on BB7 brakes. I would say you don't need them - you are not supposed to adjust the cable pull to compensate for brake wear. If you look in the instructions, on BB7 brakes the cable should be adjusted for full travel - for no slack in the cable but not tight enough to reduce the travel. All clearance and wear adjustments are done with the caliper adjustment knobs.

Andrew R Stewart 01-13-16 11:50 AM

As I said "Most won't appreciate my approach to cable routing and fittings placement". But I have only 40+ years of wrenching:) Andy.

trail_monkey 01-13-16 12:24 PM

I decided to call SRAM tech department and get the official word since this seems to be such a torn subject. The Tech told me that the barrel adjuster should never be used to compensate for pad wear. That is what the red adjuster knobs are for, which I think we all knew. He said the barrel adjuster was simply to take slack out of the cable. So I asked if a person was good enough and they could get the slack removed before they tightened down the Allen bolt then a person wouldn't need the barrel adjusters right? He answered correct. And I said the barrel adjuster can probably also be used to take slack out as the cable stretches right? He answered correct. So bottom line is they are not a necessary ingredient if you are good enough with your cable adjustment that you can get all the slack out before you tighten the bolt down. Hopefully this will answer a lot of questions since there's a lot of debate here.

Andrew R Stewart 01-13-16 12:30 PM

No debate, just opinions. Andy

mark2810 01-13-16 01:13 PM

On most disc calipers I've seen, one can use the barrel adjuster to move a side of the brake pad closer and farther to the rotor. This is a fact, therefore people do it. While using the knob on the other side for the other pad.

This bb7 road bike looks like it has two adjusters on both sides. So, awesome. You can use both knobs to get the centering right.

I mean you no offense but I think you're giving yourself too much credit. Good for you that you're awesome measuring your cable length lol.
But the day you get any odd, annoying bike with an annoying brake system or a bike where it's completely untuned, you'll wish you had a nice little barrel system to help you out.

My suggestion: Appreciate the barrels. Learn how to use them because they simplify life and give you perfect tuning whether its shifting or brakes. Perfect being keyword here, not "good enough."

It's not so much a debate and it's not so much as opinions as @Andrew R Stewart stated above...who is more or less a mech wise man on these forums.

I think it's more of the proper/right way of dealing with a bike. Put all your barrels wherever they should be. They make them for a reason. :fred:

trail_monkey 01-13-16 02:55 PM

Hey Mark, no offense taken but I never said I was that good lol. If you reread my post I was simply saying if a person was that good. I asked them this question just because I wanted the answer for my own knowledge not because I thought I was so good I didn't need them lol. I'm putting them in and going to enjoy having them. They're handy little devices and I've seen them on other bikes in the past.


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