Monday, February 27, 2006

Interesting Juicy 7 setup tip:

On the mtbr forums, there is a post on the J7 with an interesting setup tip.
Read the whole post as there is more info than I am just copying here. I am unsure and have asked if this tip is only applicable to the 05 Polygon rotor or if it is used for the cleansweep or other aftermarket rotor like the galfer.
I am going to copy/paste it here:
By whangen
******** New to forum.... maybe this will help ********

Crucial Avid Juicy Seven Setup Tips.

Good thread everybody! Thanks for all the research and efforts by all those involved, even those who hate Juicy Sevens and love to pound me.

Topic: Most everyone is installing their Juicy Sevens wrong.

Avid doesn't help cuz their instructions leave out several important setup issues. One is a manufacturing pre-condition which I'll discuss first. The second in an almost universal setup blunder, even by a lot of LBS's... and they should know better. 'Castle'... pay attention, this will be on the test!

Avid mistakenly designed the '05 - 160mm rotor rim to be an 1/8" too far from the axle. The 185mm rotor is about 1/16" off depending on the fork or bosses. This causes the pads to rub the top of the rotor arms and produce the famous 'turkey gobble' . It's not necessarily accompanied by a squeal - that's usually a separate setup problem, discussed last. Avid is fixing the rotor designs and that is why the last year's models are selling for $129 or less a wheel.

Our objective is to move the calipers outboard from the axle a tiny bit. The easy fix for the 160mm rotor is to slip TWO .04" thick washers (each a little thinner than a dime) on each bolt BETWEEN the supplied adaptor and the inner ball and cone combo. Four washers total.

Usually the 185mm rotor takes one washer for each bolt depending on the fork or bosses. Follow Avids instruction for the rest of the setup (plus my extra setup technique below). Don't squeeze the levers with no disc or spacer in the caliper. The hard fix is to grind off an 1/8" or aforesaid bottom of the pad.. some do this, but why bother with each new set of pads you put in ?!?

The second setup issue. When you go to tighten down the loose cone and ball parts, spin the wheel VERY slowly WITH THE CRANKS --- NOT BY ROTATING THE WHEEL BACKWARDS. Slowly apply a little more force to the lever and very gently stop the wheel rotating, making sure you used the cranks for this! This slow rotation of the wheel/rotor in the correct direction the wheel naturally travels helps wiggle out the spaces in the ball and cones and align the parts correctly. Don't go too fast. While keeping the lever moderately engaged, go to each of the two bolts and tighten one a little, then the other and so on back and forth. It's kinda like the early XT linear V-brakes and the toe-in issues regarding squealing. Fractions of a millimeter make all the difference.

Okay here's the bad news, if you initially did the setup the wrong way or the way Avid advises and then rode your bike for a month or two, figuring to 'break 'em in and work out the squeals' you probably wore the pads unevenly. If so, toss 'em and start fresh cuz your old ones will make setup harder. Also, that's why your old setup sucked and you had bad modulation and noise. Constant squealing and grabbing tell me (when I'm on the trail) that someone did a bad setup on their Avids. I guarantee you'll love the results if you follow my simple tips. By the way, if it's wet, all disc brake squeal and squawk a little.

X-factor levers? Who cares. If the Sevens are setup right you don't have to be ham-fisted with the levers; one forefinger will do the trick, even in the most dire circumstance. If you prefer, scratch up the smooth blade area under your fingerpad a little with rough sandpaper.

You'll love the results if you follow my simple tips. Good modulation and powerful one-finger stops can be yours. Now, go grab some of those dirt cheap '05 Juicy Sevens before everyone figures this out.

Little known fact: Behind the lever blade, up near the brake body, is a small indentation --- your travel coffee mug's handle will hang there quite nicely while riding to the coffee shop

I am curious to try this out. The setup tip about rotating the wheel in the proper direction is something that I don't right.

If he is right about 05 Juicy's selling for $129 a wheel. Grab em. Don't buy them if you don't know how to bed in properly, and aren't willing to do a little tinkering as above. Or aren't willing to request a warranty replacement for Clean Sweep rotors.

Notice how I'm not miffed at all at Avid. It's funny, I love this sort of stuff sometimes. Finding some obscure tinkering that someone has tried and seeing what the affect is.

Actually my J7s don't have too many problems anyway. But it's fun to play around.


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