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Discussion Starter · #1 ·
i just set up my bike with the Avid standard Mech discs, (BB7) and i'm having a problem dialing them in. I can't seem to get rid of slack in the levers. After many tries, i still have a little play in the levers. The brakes are working...If i squeeze the lever fully, it'll work properly, stop the wheel 100%, but then if i tap them just a little, the lever just bounces back n forth loosely, w/o moving the brake caliper at all.

I've tried getting the lines super tight first, and also taking out the slack via barrel adjuster on my levers. This just moves the caliper up, and then i'm getting the pads rubbing against the rotor. I'm running avid SD 7 levers.

One thing i haven't had much luck with too is the spring adjuster, i have it turned all the way in, but still getting play in the levers...

Im also experiencing alot of chatter/vibration when stopping hard. I've only been up and down the street a few times, but still, it's pretty noticeable when stopping quickly.

Any help/advice/tips greatly appreciated!
 

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I too just installed a set of BB7's to replace a set of Hayes HMX mech's. I found the lever action too easy so I turned in the caliper tension screws in. The front required the screw to be all the way in to remove to keep the cable taught. If I removed the screw (after running it all the way in) you can see the screw has to be 3/4 of the way in before it contacts the arm. I disasembled the caliper but couldn't see anything that looked out of the ordinary. Called Avid today but they were closed. I went to the hardware store and bought some 3mm x 12mm screws to give some more adjustment but want to see what Avid has to say. I did have a set of Avids 2 years ago and didn't have to adjust the caliper tension.
 

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meh....
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dtmartin46 said:
I've tried getting the lines super tight first, and also taking out the slack via barrel adjuster on my levers. This just moves the caliper up, and then i'm getting the pads rubbing against the rotor. I'm running avid SD 7 levers.
If you've tried to get the slack out using the barrel adjuster on the lever it sounds like there's some play between the knob on the end of the cable and the lever.

M:(nte
 

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dtmartin46 said:
i just set up my bike with the Avid standard Mech discs, (BB7) and i'm having a problem dialing them in. I can't seem to get rid of slack in the levers. After many tries, i still have a little play in the levers. The brakes are working...If i squeeze the lever fully, it'll work properly, stop the wheel 100%, but then if i tap them just a little, the lever just bounces back n forth loosely, w/o moving the brake caliper at all.

I've tried getting the lines super tight first, and also taking out the slack via barrel adjuster on my levers. This just moves the caliper up, and then i'm getting the pads rubbing against the rotor. I'm running avid SD 7 levers.

One thing i haven't had much luck with too is the spring adjuster, i have it turned all the way in, but still getting play in the levers...

Im also experiencing alot of chatter/vibration when stopping hard. I've only been up and down the street a few times, but still, it's pretty noticeable when stopping quickly.

Any help/advice/tips greatly appreciated!
Sounds like you have excessive drag in the cable housing.

It must be routed as straight as possible with no tight bends even it it means bypassing the stock cable stops. Full length housing works better, too.

They do take some time to bed in and the feel will change and be more powerful.
 

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Discussion Starter · #5 ·
keen said:
I went to the hardware store and bought some 3mm x 12mm screws to give some more adjustment but want to see what Avid has to say. I did have a set of Avids 2 years ago and didn't have to adjust the caliper tension.
Hey, that's something that i was going to do too... I too thought that the tension screw had to be screwed in all the way to make any sort of difference. (i.e. kind of worthless) Let me know if putting in a longer screw works.

I managed to fiddle with the front brake more, and i think it's better. I guess i need to spend more time looking at the rear cable routing, too. It's a Full suspension bike (Weyless Single Pivot), so i'd imagine that getting the rear to be as close to perfect as possible will prob. take some adjusting.

Oops, guess i didn't mention one relatively large piece of info, i installed these with the Avid Full Metal jacket cable system, so one of the metal rods may be the culprit, too. I wouldn't say it's BENT, but i did have to zip tie it down to the rear arm of the frame (swing arm? stay? whatever, the back part of the dam frame...) Shiggy, would this be making things alot worse? The connection from the caliper to the metal rod is real tight. It is just bent down 10-15 degrees from the angle that the brake sits at.

Thnx for all the suggestions. Anyone elses input greatly appreciated.
 

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Not a cable issue (at least in my case). If you thread the tension screw in all the way then back it out the screw it is 3/4 in already leaving only a couple mm's of tensioning. The brake arm is supposed to come @ full rest - the lever barrel adjuster is used to remove cable slop not move the arm like say a Hayes or BB5. The hardware store 3mm x 12mm bolt gives enough tension to put things in proper perspective but I want to find out from Avid why this happening. Like I said, my previous Avids did not have this issue and my last bike had Jagwire Braided cables w/ some twisty routing.
 

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dtmartin46 said:
Hey, that's something that i was going to do too... I too thought that the tension screw had to be screwed in all the way to make any sort of difference. (i.e. kind of worthless) Let me know if putting in a longer screw works.

I managed to fiddle with the front brake more, and i think it's better. I guess i need to spend more time looking at the rear cable routing, too. It's a Full suspension bike (Weyless Single Pivot), so i'd imagine that getting the rear to be as close to perfect as possible will prob. take some adjusting.

Oops, guess i didn't mention one relatively large piece of info, i installed these with the Avid Full Metal jacket cable system, so one of the metal rods may be the culprit, too. I wouldn't say it's BENT, but i did have to zip tie it down to the rear arm of the frame (swing arm? stay? whatever, the back part of the dam frame...) Shiggy, would this be making things alot worse? The connection from the caliper to the metal rod is real tight. It is just bent down 10-15 degrees from the angle that the brake sits at.

Thnx for all the suggestions. Anyone elses input greatly appreciated.
I do not consider FMJ full length housing. Each cut end of the flexible housing is a friction point. Use one continuous piece and you eliminate 4 ends.

BTW how did you get the cable through a "metal rod"? Tubes work better. :eek:
 

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Discussion Starter · #8 ·
shiggy said:
I do not consider FMJ full length housing. Each cut end of the flexible housing is a friction point. Use one continuous piece and you eliminate 4 ends.

BTW how did you get the cable through a "metal rod"? Tubes work better. :eek:
Sorry Shiggy, bad use of terminology on my part...

Soo.... You're saying it's better to use one long length of good, strong housing instead of the provided "metal rods", i mean FMJ's? :D

That makes 100% sense, i can't believe I never thought of that. I already cut up the housing that came with the FMJ set to the various pieces needed, tho. Do you think i'd get better results with just buying one new long piece of housing for the rear brake, and zip tieing it down the length of the frame? (at $3 a foot, and i'm guessing 4-5 feet total isn't too bad i guess.)

As you can see, i prefer the 'home mechanic' approach to my bike maintenance as opposed to paying a shop to do it... I'd much rather risk screwing things up a little myself, pay a little more in parts to fix any errors, and learn the whole process thru trial and error.

Thanks again for your help!
 

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i just got some pretty cheap $5 a pack (one front, one rear) cable sets w/ teflon lined housings from the LBS. ran the rear full length and ziptied it under the top tube for the smoothest curves, etc. it feels like butter. really nice. so i'd recommend it.

the guy who worked there said running full housings was a dumb idea, but i went w/ it anyway. thanks, intarnet! hah. i really like the idea of a sealed system here.
 

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Yeah, first 2 weeks with my bike and I kinked the housing... then I adjusted the barrel adjuster out a bit and threw some lube on the cables and all is new. If I drilled out the stops a tiny bit, I could run full housing to the rear.

My shifter cable runs UNDER my frame so I dunno. I know it'd greatly benefit from full length housing and an Avid Rollamajig.
 

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yeh my shifter cables are still exposed under the BB too. dunno, ill worry about them later.

but as for the rear brake housing, i ran it under the top tube and held it there w/ zip ties. i found it noticably smoothed the curve of the housing compared to running it on top of the top tube where my factory stays are. the run it on top stock because the cable needs to come out high on the rear end for the V brakes. but since the housing is going down to the caliper anyway, you might as well run it lower along the top tube. makes the curve off of the brake lever to the top tube bigger/smooth and an easier angle down to the caliper off the TT.

so in short, dont worry about the stock cable stops...
 

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dtmartin46 said:
i just set up my bike with the Avid standard Mech discs, (BB7) and i'm having a problem dialing them in. I can't seem to get rid of slack in the levers. After many tries, i still have a little play in the levers. The brakes are working...If i squeeze the lever fully, it'll work properly, stop the wheel 100%, but then if i tap them just a little, the lever just bounces back n forth loosely, w/o moving the brake caliper at all.

I've tried getting the lines super tight first, and also taking out the slack via barrel adjuster on my levers. This just moves the caliper up, and then i'm getting the pads rubbing against the rotor. I'm running avid SD 7 levers.

One thing i haven't had much luck with too is the spring adjuster, i have it turned all the way in, but still getting play in the levers...

Im also experiencing alot of chatter/vibration when stopping hard. I've only been up and down the street a few times, but still, it's pretty noticeable when stopping quickly.

Any help/advice/tips greatly appreciated!
Did you ever make contact with Avid regarding this problem?

I just installed a rear bb7 and and am experiencing the same limpy slack issue.

A change in cabling/tensioning has not improved the condition, almost seems like the spring tension to too slack.

Also, does Avid have an email? Only found a phone# on their site.

Thanks for the help
 

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number9 said:
Did you ever make contact with Avid regarding this problem?

I just installed a rear bb7 and and am experiencing the same limpy slack issue.

A change in cabling/tensioning has not improved the condition, almost seems like the spring tension to too slack.

Also, does Avid have an email? Only found a phone# on their site.

Thanks for the help
Just thread the caliper tension screws all the way in. I just did this yesterday for a freinds BB7's. I still find the tension on Avids low = a longer 3mm bolt will give more adjustment. I did call Avid and they could offer little understanding.
 

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keen said:
Just thread the caliper tension screws all the way in. I just did this yesterday for a freinds BB7's. I still find the tension on Avids low = a longer 3mm bolt will give more adjustment. I did call Avid and they could offer little understanding.
Yup. The caliper tension screw is like a little grub screw on most calipers. It just puts more tension on the spring. Same concept with v-brakes.
 

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heres what I did...

I got tired of:
bad cables/housings
dirt in the housings
weak spring on the brakes
etc....

I saw this Idea on a tandem bike:

Go the the hardware and get a small compression spring. About twice the diameter of the springs in a ball point pen.

Use a couple of washers small enough to block the ends of the spring, but large enough to allow the cable through.

Put the spring on the caliper between the pull arm and the stop. Thread the cable thru it, and tighten down normally.

This 'power returns' the caliper to the full open position securely when you let go of the lever. They're great 'cause they work normally even when the cables are totally gunked up.

I know there are others out there that do this too, maybe someone can supply a picture?
 

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Depends on the lubricant ...

HuffyMan said:
i just got some pretty cheap $5 a pack (one front, one rear) cable sets w/ teflon lined housings from the LBS. ran the rear full length and ziptied it under the top tube for the smoothest curves, etc. it feels like butter. really nice. so i'd recommend it.

the guy who worked there said running full housings was a dumb idea, but i went w/ it anyway. thanks, intarnet! hah. i really like the idea of a sealed system here.
A lot of bike repair manuals instruct you to grease the cable when you install them. As it turns out, this is not the best lube. Most modern cables and housings are teflon coated. And light teflon lube will keep the cables pulling without gumming things up.

I tried a full length housing and greased the cables. The result was poor, poor action. Of course, now that I've stopped greasing the cables, I really don't feel any need to go to full length since changing would be a pain in the ass.

My suggestion is to go to the hardware store and buy a couple packet of long thing springs. Thread 2-3 of these springs between the cable stop on the caliper and the lever. These will help.

I've actually got 4 of these spring on my rear for MX-2s. What can I say? They're sucky brakes and that's what I had to do to get the pad to retract all the way.

BTW, a lot of newer bikes are shipping with "combo" cable guides. You can put an insert in there to make them a cable stops, or you can just run full cable housings. Hopefully in the future, all bikes will come this way. And hopefully, manufacturers will stop running cables UNDER the top tube so you can hang your bike on a carrier without putting pressure on your cables.
 
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