Rear brake noise even when not being used.....

Discussion in 'The Workshop' started by eatsrice91, Jul 5, 2012.

  1. eatsrice91

    eatsrice91 NoMoSoCal

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    Pardon my confusion. The rear is a 10mm axle with a standard qr, right?
     
  2. rojomas

    rojomas A.K.A The Oxx

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    Wow.. That was unnecessarily harsh.

    Though I do agree that frame flex could be the culprit, He has given you no reason to be a jerk.
     
  3. proraptor

    proraptor The Bikes & Brew Crew

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    is your rear axle thinner or thicker than a pencil? if thicker its a true straight thru 10mm. measure the axle in the middle
     
  4. mfoga

    mfoga Intense Whore

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    Rear dropouts will be 10mm or 12mm. With 10mm and qr skewer (2-3 mm thick) the hub sits in the dropout,with a 10mm axle the axles fills the whole dropout. The different in stiffness is huge.
     
  5. eatsrice91

    eatsrice91 NoMoSoCal

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    OK, OK. In the market for wheels. What's a good priced solid wheelset? 200/400 price range, even used if anyone has anything. I pedaled my friends stock camber wheelset, even with a qr rear, it was way stiffer than my CB set. I humbly admit I barked way up the wrong tree, sorry if I offended / pissed off / annoyed anyone. Understand, I really wanted to keep these damn wheels!

    As for the few rude comments I received, criticism of any kind its always welcome, I took absolutely no offense to it. I thank you for being quite frankly, blunt and honest.

    Take care!

    Anyone want to but some nice CB wheels? #-o
     
  6. rojomas

    rojomas A.K.A The Oxx

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    So are you saying that you tried two different wheelsets on your bike and both of them made your brakes rub, the first set being Mavics and the second set being CBs? And now you are saying you tried a third set and now the sound miraculously stopped? I don't think so... I think you're still barking up the wrong tree. Wheel stiffness has nothing to do with your brakes rubbing. Your wheel can be completely tacoed but as long as your rotor is straight it will not rub.

    Unfortunately, it probably is the frame flexing. I used to have to set up an Ellsworth that I had so the brakes would rub just a little so that when I would sit on it they wouldn't rub. Then one day the frame just cracked due to fatigue. Now that I looked back on it, I realize the frame flexing was a warning of fatigue.
    Not to sound like a d!ck but at 240lbs and plus probably a Camelbak, you're probably looking at 250+lbs and over the max recomened weight for that frame. I have a feeling the aluminum might be starting to fatigue so it is flexing.

    I have a feeling if you buy a new wheelset you are just wasting your money.
     
  7. eatsrice91

    eatsrice91 NoMoSoCal

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    the mavic cross ride setup didn't scream like the crank brothers, it was just a scrape sound every now and again. I haven't exactly bought sturdy wheels in the past either. I know the frame has some flex in the swing arm. I can't say 100% that the noise went away with the dt-swiss wheel tonight, we only installed it and flexed the hell out of the frame, etc and pedaled it in the parking lot at oaks post ride. Made my cb's look like a limp noodle! I'm still going to take the advise and ride a stiff 10mm axle wheel before I make a move.
     
  8. proraptor

    proraptor The Bikes & Brew Crew

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    you want something super strong for your weight go azonic outlaw
     
  9. eatsrice91

    eatsrice91 NoMoSoCal

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    That's one I looked at a few years ago and should have bought it! I'm gunna check out azonic, novatec or stans. Ideff want to test ride a different rear wheel saturday.
     
  10. mfoga

    mfoga Intense Whore

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    I would get something with a hub that is at least 10mm thru axle if not convertible.
     
  11. eatsrice91

    eatsrice91 NoMoSoCal

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    Do you have any suggestions on brands? Just looking to be pointed in the "right" direction. If anyone has one I can borrow for one ride, I'll buy you beer or whatever... pm me if you want to ride saturday am. Whiting/luge loop.
     
  12. Varaxis

    Varaxis Trail Ninja

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    The difference in rear end stiffness due to an increase in axle diameter isn't as huge as people make it out to be. If you are basing your logic off of stiffness gained from going from 9mm QR to 15 QR or 20mm TA, I'm sorry to say that such logic is faulty.

    1) The hub width in the front is only 100mm, compared to 135mm in the rear.

    2) The front experiences the most forces on the bike, and flex affects handling far more noticeably in the front than rear. You have steering to worry about, and your controls depend on the front. The rear, in comparison to the front, barely sees any. If modern frame designs hints anything, with their skinny stays vs 32-40mm tubes up front and massive lowers, bridge, and crown... With much more mass in the rear, it'd take a much bigger force to create an amount of flex than it would to create that same amount of flex in the front. Still, people who push their bikes hard, and don't ride with ridiculously low tire pressure, will feel torsional and maybe lateral flex, and that's something the TA helps with a little, to keep the swingarm feeling more as 1 complete unit, rather than a left and right half.

    3) Your contact with the bike are also more closely aligned to the front, with your pedals and seat being only about 60% rear biased and your grips being almost totally front biased. The more things between the forces and your contact points, the more vague the feedback. If you can feel rear end stiffness, it would have to be a really exaggerated force or amount of flex and there's still no way for the human body to detect if it's the wheel, the frame, the BB, the seatpost, or even the soles of your shoes, unless you do some scientific tests.

    4) 6mm/11mm (9mm to 15QR or 20mm TA) vs 2mm (10mm to 12mm TA) in axle diameter difference. Seriously, if there's any simple logic that can be used on this and can't be argued, it's for this argument.

    5) Rear triangle vs skinny strut. The flexier the arms, the more stiffness there is to be gained by something like a larger axle. It's like comparing a skinny rigid fork to a truss fork, or single crown to dual crown. For bikes with rear triangles that are solid (ex. dual link bikes), on top of being beefy tubed alloy or carbon, there's less of a gain there is to be seen with the axle upgrade. Believe a manufacturer when they say that their fully triangulated carbon rear triangles are stiff enough that there's no advantage to 12x142. The likes of SC are just now going that route since it seems the industry it moving to it, and they seem to like to go with the most widely accepted standards, rather than it actually being "the reason" for the stiffness of their rear ends.

    I can go into ease of wheel installation and removal, where the front is made easier, since QRs aren't exactly quick, due to the "lawyer tabs", but I simply wanted to question why people are promoting 12mm rear axles as if they were amazing. They are only amazing if you had a flexy rear end to start with (ex. FSR designs).

    For the record, the QR skewer has a diameter of 5mm. It does help to have a skewer that is stiff, mainly since it holds your wheel on with friction, as a flexy shaft could allow it to become loose and possibly shift. A standard steel shaft found on a Shimano QR skewer is more than up to the task with minimal risk of that happening--for you non-material science majors out there, steel is stiffer than Ti and Alum alloys; yes, stiffer than alum alloys (look it up). You take your chances with flimsy Ti ones. I never ridden a DT RWS skewer, but I am skeptical that it'd even offer any noticeable difference over a set of Shimano skewers. Shimano skewers just are a solid design and provides enough bite that keeps your wheel from moving; don't bother with the alternatives.

    Also TA really only help the fork and rear triangle's stiffness. They don't help the wheel's stiffness. I believe if there's any hub stiffness to be gained, it's from wider placement of the bearings. The axle inside, which the bearings roll on, is actually larger in diameter, which also increases stiffness in the hub. 10mm is only the size of the end cap part that fits in the drop out slots. Bigger end caps, to increase surface area touching between the hub and inside flat part of the drop outs also helps stiffness, but I think it's more to transmit forces in a more wider, spread out, and more manageable manner.

    On the subject of wheels, tighter tolerances of the load-bearing bearing contact points between the hub shell, axle, and bearings, and bearings that hold up to loads better will also allow for smoother and more consistent rolling. A wheel that spins forever without a load on it (in the stand), may not be the best when actually on the trail with a load on it. Hence why there's different types of bearings available. You may have heard of Enduro Max bearings, which are designed for load bearing applications. They don't spin the smoothest when you just give them a spin and watch to see how many revolutions you get, but when there's actually a person on the bike, they keep it spinning more freely than the other bearings, and you can have less of them. Having "dual row bearings" (ex. in pivots) could just mean that cheap bearings were spec'd, which cannot handle loads all that well, but will spin faster, for a weight penalty.

    Sorry for the off-topic rant. The bike industry seems to feed a lot of marketing due to the lack of educated consumers, and can seem to get away with saying simplified statements that mislead folk. Nothing personal, just a daily dose of wisdom. I can speak more about the quality of rims and spokes and bracing angles and such, but let me direct you to a great source of info:

    http://icelord.net/bike/thebicyclewheel.htm

    Best to go to the authorities on certain subjects. There are a lot of smart and wise folk on STR, but some credentials and expertise go a long way.

    135x10 vs 142x12 could very well be the biking industry's equivalent to 320 kbps cbr vs FLAC. The differences you sense between them depends greatly on the "source" (frame) and "output" (your body and trails). The results could vary from having an undetectable difference to just barely noticeable.

    ----

    On topic:

    For hubs, go Shimano for the ultimate in smooth spinning hubs, DT if you like reliable low maintenance very smooth spinning hubs with more engagement points than Shimano, go CK or i9 if you want the luxury of engagement points (CKs spin rather poorly compared to the competition, in my experience, but seem finely engineered and good for long term reliability), or go Kappius if money is no object. I'm spoiled by high engagement, to the point I am reluctant to ride on even DTs, let alone Shimanos. The only time I'd go Shimano or DT, personally, is on my pure XC bike. I know I'm not gonna win any XC races on my CK hub, but I know it's gonna last a while. My I9 hub is faster and has more engagement points, but after taking a look inside the King, I just appreciate Kings a bit more for the engineer aspect, even though my i9 wheel rides better. After being on i9 and CKs, DTs just feel ridiculously fast. Going TA at least will make it so installing/removing your wheel would help line it up with the disc brakes each time perfectly, especially if it's keyed like the Shimano system for the same tightness each time. Too tight or too loose can affect brake caliper-rotor alignment, but everyone knows that, right? I know I quickly learned that when I had to remove my front wheel to transport my bike and had to deal with trying to find that sweet spot of QR tightness for no front brake rub which I carefully tuned at home.

    Mavic wheelsets (ie. Crossmax SX for trail/AM) are a good option for SoCal and spin really fast. Their seals suck, so avoid bad weather, sloppy conditions, and water crossings, else you got to service your hubs. Yes, those loose seals are partly why they spin really fast. I'm partial to complete wheel systems, over traditional wheels, since designing it as a entire system squeezes out every last bit potential that a wheel could possibly have.

    DT rims are harshly criticized for poor reasons, such as being made of a soft alloy that dings easily, and don't have great tubeless conversion compatibily. I think they are really high quality. If you build wheels, you may come to discover how easily they build up with even tension and come out perfect round; in contrast, you might struggle with the likes of a WTB i23, to get it round, yet maintain even spoke tension, and may end up compromising one or the other just to "finish" it. Simply getting them true and not having any loose spokes results in a wheel that simply won't last long between wheel servicing, when compared to one with high tension, even tension, and are round, true, and dished perfectly without spoke wind-up and after having the spokes stress-relieved or "pre-stretched" (tensioning up the spokes, then loosening it, before dialing in the final tension to get them more settled). Wheelbuilding is an art and you will find high quality products more easily turning into quality built wheels. I guess that Swiss precision goes into rims as well. If the seam/rim joint on the DT vs WTB i23 is any indication of precise quality...

    One last thing, don't fall for the fad with wide internal widths. Wider external widths helps with stiffness, but wider internal widths affect the shape of your tire which alters the performance of the tire. If you ride high performance tires, that's typically not a good idea. DHers still use 21mm inner width rims, believe it or not. They need that rounder tire profile to get grip at all lean angles. I think the wider internal width was dreamed up by casual old men, to get a kind of "ride feel" that fat tires provide, yet allows them to use their narrower XC tires. Not like there's any XC tires that come in 2.5 or bigger, excluding the new Surly Knard 29x3.0 tire (~820g for a 29x3.0 tire, wtf)...
     
  13. mfoga

    mfoga Intense Whore

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    My logic is based on experience. There is quite a big difference especially in hard cornering. Also is makes a difference how big you are. Your not exactly a big guy so to say what some of us feel vs what you is a huge difference.

    Your forgetting that on a QR is sometimes just a cap that not solidly attached to the hub. So yes you have 10mm end cap with a 5mm axle trying to hold things together (many times going through a 10mm hole) vs a solid 10mm axle going straight through the hub.

    If I am so far off whats your great answer?



    I would seriously get something built with Hopes, DT Swiss , Hadley, Kings. I dont belive outlaws can run 10mm thru axle. Transition Revolutions if they still have 10mm thru axle option might not be a bad idea.
     
  14. proraptor

    proraptor The Bikes & Brew Crew

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    sorry varaxis i also have to disagree, i felt a difference going from a regular qrvto 20mm in front and a solid 10mm in the rear. im guessing you dont feel the difference cause you arent a clyde but as a clyde i felt a major improvement
     
  15. Varaxis

    Varaxis Trail Ninja

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    Wait, you felt a difference going from 10mm QR skewer to a 10mm screw on bolt? Do you understand why that can or can't be possible in a technical fashion? On what bike, the carbon nomad?

    Like I outlined before, there's a lot of things going on between the wheel and the rider. A person can't feel exactly what is it, but the feedback will tell them that there's unexpected and unwanted movement back there, and it's a guessing game as to what it is. In your case, I can easily deduce that there's no stiffness increase from the frame itself, which is what the TA is supposed to stiff up, and that it's some other change that's causing it:

    If you simply changed out the axle, I highly doubt that is what increased the stiffness. If you changed out a wheel (rim, hub, spokes), changed out your shoes (seriously), changed tires, tubes, and air pressure, and you turned up the sensitivity in your body (tried hard to feel for a difference), then all that would have likely made a very noticeable impact on the feedback you felt from your rear end.

    Here's what Fox had to say about their 15QR over their QR models. No change in wheelset, no change in lower design, no change in stanchion, crown, steerer, etc. As scientific as can be:

    http://www.foxracingshox.com/technology.php?m=bike&t=15qr&ref=topnav

    Some may conclude that these results are what you can expect from a TA on all forks in general, but I bet Marzocchi, Manitou, DT, etc. have other things to say. I bet they would think something like, "Wow, if you got those kind of results, Fox forks must have been really flexy before 15QR." The TA increases stiffness in the rear triangle or fork lowers, by providing a more solid connection to help the individual sides more together in the same plane, more as one unit, than 2 halves. It doesn't need to rely on a QR skewer which may flex if the legs are moving oddly, especially considering there's only a spring in one leg and you have extra weight on one side hanging off the lowers. If it's not flexing much in the first place, the QR skewer isn't stressed and there's less gain from going to a TA.

    I hope this answers Matt's inquiry as well. Basically, yes, if a rear end is pretty flexy, then a TA will do a whole lot to help, as a QR does only so much, even with quality skewers. If a rear end is already stiff, then no, the QR isn't really under any stress and a TA would just be overkill with no apparent benefit, except maybe allowing a different derailleur hanger design. Fully triangulated rear triangles, especially those made of beefy looking carbon, likely benefit very little from it. It basically turns into a matter of a stiff triangle now allowing you more confidence to put even greater forces on it, which may very well point out the QR as the weakest link. But for riders that don't push it and put forces like that one their bikes... You do have a point, such as a small guy like myself going off the same drop, the same trails, the same mtn bike park line as a bigger guy, the bigger guy will likely feel the limits of his equipment more as there's more forces being put on his frame. I understand that, but the general concept remains the same, just simply scaling to the amount of force.

    The TA only acts when something flexes. So, since 142x12 rear axles are now getting more common, do you lighten up the rear to allow it to flex and allow the TA to keep it stiff, tuned for someone my size, but too flexy under someone big, or do you increase the stiffness of the rear triangle, save weight with the axle, and go with a more cheaper, more common, and convenient wheel axle config? Or do you simply make a stiff rear end, put a 142x12 axle, just in case, and suffer the weight increase and inherent cost increase of the new less common axle config and leave it to marketing and hype to drive the new standard and accept the resistance to the "new standard" with heavy duty flame and angry customer defense, or do you do the wise choice and simply make it an option with swappable drop-outs, in case people happen to need it, and accept the extra cost and complexity in your frame? As always, it's a case of "it depends". The only way to know if it suits you, is if you understand how it all works, which I basically outlined.

    I refuse to simply say, "bro, go 142x12, you won't regret it." I refuse to be a know-nothing d-bag that just outright says "bro, get a [insert boutique name brand carbon FS trail/AM bike], you can't go wrong!" I also refuse to judge bikes by the name of their rear suspension design. I think people should be more informed, as well-informed buyers make much wiser choices. Don't rely on others' recommendations; figure it out yourself with solid factual information, as there's circumstantial conditions that others can't guess, which may affect which choice may be the best for certain people.

    To conclude, here's a bit of food for thought, not all flex is bad. In many cases, a modest amount flex is considered very good, and I'm not just speaking about "compliance" or for springs.
     
  16. mfoga

    mfoga Intense Whore

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    Ok dr google what's you fix for the problem?
     
  17. Varaxis

    Varaxis Trail Ninja

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    Try Shimano Skewers.

    Let me see if I can find some for cheap.

    http://www.ebay.com/itm/150727234748

    $10 fix?

    http://www.ebay.com/itm/380461993179

    $13.50 fix, in silver with a XT laser etched logo on it?

    The $10 looks like it's the same as the new ones, in functional design, with the steel knurled inserts. Just a bit more crude in appearance and less cutting and finishing touches on the exterior. The extra $3.50 for the XT one might give ya more peace of mind, and a polished and finished look. If it's not the solution, that's really cheap for a skewer and I'm sure it can be resold or used for something else if it's not the solution. 6.5" is the right size skewer for a 135mm hub, so don't worry about the $10 one not fitting.

    Easier to go with $10-13.50 than going the route of recommending new wheels. I can only really guess what the problem really is, without inspecting it myself. I would've first said it might need a bleed, new brake lever and/or caliper, and checked for questionable routing of the rear brake that leaves or creates sharp bends (ie as the suspension compresses). Could very well be the hub or rotor moving around or maybe some bolts are loose. Just going with the cheapest option for now and I know Shimano skewers are the most secure skewers I've used.
     
  18. F.A.D.

    F.A.D. POWERED BY MUSUBIS

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    I don't know if this have been brought up or not, but have the OP looked into the hub bearings? If that's loose/worn out, that would cause the axis of the hub shell to be in a different plane than that of the axle, therefore causing the rotor to rub on the calipers.
     
  19. eatsrice91

    eatsrice91 NoMoSoCal

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    Gents. I have a chance to buy STANS ARCH / IBIS hub oe wheels with front and rear 10mm threw axle novatec qr axles. How is this set? 445 out the door new.
     
  20. scottay

    scottay New Member

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    The front should be 9mm if your fork is qr...... did you look at Wiggle.com or Chainreaction for some Hope wheels? Sometimes they have free shipping....
    .
    And Arch's are skinny .....
    .
     

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