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  1. #126
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    Quote Originally Posted by Lombard View Post
    I can't count the number of times I have helped people change a flat and their QR was dangerously loose. Without lawyer tabs, these idiots would be dead.
    I see that as a good thing. Darwin at work.

  2. #127
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    Quote Originally Posted by CyclingLymie View Post
    They should have kept you locked up at bikeforums net. This is the kind of stupid shite that gets posted over there.
    That is spot on.

    I am a member of RBR and Bike Forums, and every time I get a notification of activity on this thread, I always assume it is from BF at first.

  3. #128
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    I wonder why, motorcycle manufacturers don't use QR???


    Why quick release is a vastly superior design to thru-axle.-20111116_2767.jpg

  4. #129
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    Quote Originally Posted by cyclostam View Post
    I wonder why, motorcycle manufacturers don't use QR???


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    go back to lurking.

  5. #130
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    I’m an occasional lurker who came across this discussion on a search of QR designs. Decided to sign in and weigh in, as in addition to being a mechanical engineer with 30 years experience, and an owner of both QR and TA bikes, I started then sold a company specializing in the design, test and Validation of bolted joints (Archetype Joint, now Peak Innovations Engineering). In addition I’ve written trade articles and testified as an expert witness in product liability cases on the subject.

    While not traditional bolted joints, the primary objective of both QR and TA are the same, both of each other and of all structural joints. The mating components (in this case forks and static hub shaft) should not move relative to one another at all during use. The reasons are related to both performance and safety. When this joint gets loaded enough that it slips, stiffness changes which in turn can impact handling. What is usually more problematic is that this movement increases the potential for loosening and component failure through fatigue fracture and other mechanisms.

    Is TA stiffer than QR? The component itself certainly is, both laterally (bending) and axially (stretching). However that isn’t the controlling factor. If one makes the assumption that the static (non-rotating) portion of the hub acts like it is welded to the fork arms, which is the objective, the hub assembly stiffness should override relative TA / QR stiffness. When cornering, the lateral (side) stiffness of the fork, wheel and tire is much less than the hub/fork interface, and therefor dominates handling impressions.

    Because the QR rod has a much smaller cross-section, it will either stretch more for a given force generated from the QR cam, or require much less force on the QR lever to achieve a given amount of stretch (two different considerations). The QR acts more like a structural bolted joint because the clamping force that holds the joint together is created by stretching the rod, just as a bolt stretches when it is tightened. On the other hand, the clamping action of the cam lever on the TA largely prevents the TA from unscrewing, rather than preventing joint slip. Slip is prevented by the close fit between the machined TA and the machined bore on one side and the mating threads on the other. If that slip fit were not maintained this joint would likely be problematic.
    But then a forum thread doesn’t go six pages over year arguing over engineering details. Who is right and who is wrong? Well, I’m not a bike engineer, am not employed in the bike industry and have never done testing on this joint, but feel I can offer the following informed opinions:
    The QR is a perfectly adequate, light and low cost approach for normal road use with rim brakes when properly designed and installed as intended. The “as intended” is important because the design leaves the operator in control of how much clamp force is generated. The “properly designed” is important because inattention to design details can lead to a greater tendency for the joint to relax after installation and reinstallation. Also poor control of friction at the lever interface can vary resulting clamp force.

    The QR’s long thin rod may be of inadequate stiffness to maintain fork-to-hub contact on side-loading and hard impacts possible off road, particularly with stiffer wheels. The reliance on a largely uncontrolled clamp load would also be dangerous with the greater forces generated by disk brakes, as the reaction force on the wheel acts in the general direction of the open slot (possible wheel ejection). The TA design better addresses these applications.

    I think the introduction of lawyer tabs has eliminated convenience as an inherent benefit of the traditional QR over the TA, leaving only cost and weight to offset the greater safety risk. I came upon this thread in search for QR designs as I have some ideas for increasing both safety and convenience.

    Based on my frustrations with bubble levels, plumb bobs and tape measures to set up my bikes when adding to the stable or changing components, I’ve just introduced a measuring device that uses length and angle rather than X and Y (distance and height) to document or duplicate setups. The cost starts at $199, so it’s accessible to the enthusiast as well as the industry. RBR has a sample for review, but not sure when it will be published. Please take a look at https://www.veloangle.com/ . Please feel free to drop me a note or give me a call.
    Dave

  6. #131
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    Many words with unsolicited product plug.

    Fyi, OP bought a thru axle bike.

  7. #132
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    This forum could use a word count limiter like Twitter. Maybe once one accumulates enough rep points, the word count goes up. But, I'm just going to read a small novel from an unknown source.

  8. #133
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    There are 132 posts on this thread with differing opinions about a subject that isn't purely opinion, but in fact is based on science. I was hoping to explain that, because I thought it would be helpful and I know what I'm talking about. The unsolicited plug wasn't necessary, but might be of interest.

  9. #134
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    Twitter is good for some things (I guess). Understanding the bikes hub/fork joint isn't one of them.

  10. #135
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    Quote Originally Posted by VeloAngle View Post
    Twitter is good for some things (I guess). Understanding the bikes hub/fork joint isn't one of them.
    Agreed. I work with a lot of engineers and have a the attention span of someone older than a millennial. I like listing to good explanations of how stuff works.

    That said, I've ridden QR bikes on and off road for 30 years and TA MTBs for about 8 without EVER having an issue with EITHER. My opinion is that this whole thread is much ado about nothing unless you're a Red Bull Rampage contestant.

    What I REALLY want to know is your opinion of whether it's necessary to replace schnorr washers when reassembling inner CV joints onto the transaxle of a VW Vanagon assuming the CV bolts are torqued to proper spec.

  11. #136
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    Quote Originally Posted by dir-t View Post
    Agreed. I work with a lot of engineers and have a the attention span of someone older than a millennial. I like listing to good explanations of how stuff works.

    That said, I've ridden QR bikes on and off road for 30 years and TA MTBs for about 8 without EVER having an issue with EITHER. My opinion is that this whole thread is much ado about nothing unless you're a Red Bull Rampage contestant.

    What I REALLY want to know is your opinion of whether it's necessary to replace schnorr washers when reassembling inner CV joints onto the transaxle of a VW Vanagon assuming the CV bolts are torqued to proper spec.
    "schnorr washer"

    I just learned something.

    Thread... success!

  12. #137
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    Quote Originally Posted by dir-t View Post
    What I REALLY want to know is your opinion of whether it's necessary to replace schnorr washers when reassembling inner CV joints onto the transaxle of a VW Vanagon assuming the CV bolts are torqued to proper spec.
    As a general statement, plain disk springs would seem to provide questionable benefit in that application, while the serrated type will help provide resistance to loosening in that kind of racking load in a joint with proper restive hardness to allow it to bite in. It's an important joint so just put them to make sure you get that 70? 80? HP to the wheels. Also eliminating a washer or changing its finish can change friction and therefor alter bolt tension for the same torque. With this reply I feel I've paid my penance for my unsolicited https://www.veloangle.com plug and will retire from Dr Joint consultation. My test company got "Whats the head bolt torque on a '85 Chevy Citation" all the time (answer - doesn't matter - get rid of it).

  13. #138
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    Quote Originally Posted by cyclostam View Post
    I wonder why, motorcycle manufacturers don't use QR???


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    Mostly because they're not very bright!

  14. #139
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    The reality is it's a lot easier for me to get the right amount of clamp force every time with a TA. With QR levers, going by feel on a set of DA skewers is a whole lot different from a set of Velocity open-cam skewers. Also I vastly prefer using my lightweight, hex TAs...minimal aesthetic, less frontal area.

  15. #140
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    Quote Originally Posted by ceugene View Post
    The reality is it's a lot easier for me to get the right amount of clamp force every time with a TA. With QR levers, going by feel on a set of DA skewers is a whole lot different from a set of Velocity open-cam skewers. Also I vastly prefer using my lightweight, hex TAs...minimal aesthetic, less frontal area.
    TAs are definitely better for disc brakes. Since there is very little clearance between the pads and disc, TA allows you to get exact positioning. Let's also not forget the torsional forces disc brakes put on the hubs. There isn't the danger of pulling the the wheel out during braking like there is with QR. Trust me, I have seen way too many people who didn't have their QRs tightened sufficiently to the point it made me cringe.
    "With bicycles in particular, you need to separate between what's merely true and what's important."-- DCGriz, RBR.

    “Statistics are like bikinis. What they reveal is suggestive, but what they conceal is vital.” -- Aaron Levenstein



  16. #141
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    never had a QR come loose on me

    my wife's rear ThruAxle on her $5k mtn bike keeps coming loose on rides. and yes I get that thing cinched properly tight. I also busted my front Maxle TA on my mtn bike last year getting it a bit too tight. Never busted a QR.

    another downside to QR is fork-mounting the bike on my roof rack, lol. easy with QR, a bit of a pita with TA. But I am perhaps a rare bird fork mounting thru-axle bikes.
    Faith is pretending to know things you don't know

  17. #142
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    Quote Originally Posted by BCSaltchucker View Post
    never had a QR come loose on me
    BCSaltchucker, have you ever owned one of the early 90s chromed rear horizontal dropout steel frames? I do, still own it in fact and ride it frequently (1994 Colnago Technos). And on that bike, there is no skewer in the world, no matter how much teeth and/or serated and/or the chrome itself roughed up, that has been able to hold the back wheel in when high sprinting/attack wattage is laid down. I've tried them all, believe, because it was the only frame I raced on in the early to mid 90s.

    I am just throwing this out there.....I have no skin in this debate/game other than the fact I own no new axle systems. Every bike (steel ones, aluminum ones, and Titanium ones) I own still has skewers. But there are instances when they fail....

  18. #143
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    Quote Originally Posted by BCSaltchucker View Post
    never had a QR come loose on me
    You and I haven't. But keep in mind that I lead some beginner rides sometimes. It's a lesson in patience.

    Quote Originally Posted by BCSaltchucker View Post
    my wife's rear ThruAxle on her $5k mtn bike keeps coming loose on rides. and yes I get that thing cinched properly tight. I also busted my front Maxle TA on my mtn bike last year getting it a bit too tight. .
    Umm, did you use a torque wrench?
    "With bicycles in particular, you need to separate between what's merely true and what's important."-- DCGriz, RBR.

    “Statistics are like bikinis. What they reveal is suggestive, but what they conceal is vital.” -- Aaron Levenstein



  19. #144
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    Quote Originally Posted by Lombard View Post
    But keep in mind that I lead some beginner rides sometimes.
    I needed a good laugh, thank you.

  20. #145
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    Quote Originally Posted by factory feel View Post
    I needed a good laugh, thank you.
    I'm glad you are so easily amuzed.
    "With bicycles in particular, you need to separate between what's merely true and what's important."-- DCGriz, RBR.

    “Statistics are like bikinis. What they reveal is suggestive, but what they conceal is vital.” -- Aaron Levenstein



  21. #146
    'brifter' is a lame word.
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    Quote Originally Posted by factory feel View Post
    I needed a good laugh, thank you.
    It's funny because?
    I work for some bike racers
    I've got some bikes, some guns,
    and a bunch of skateboards

  22. #147
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    Quote Originally Posted by BCSaltchucker View Post
    never had a QR come loose on me

    my wife's rear ThruAxle on her $5k mtn bike keeps coming loose on rides. and yes I get that thing cinched properly tight. I also busted my front Maxle TA on my mtn bike last year getting it a bit too tight. Never busted a QR.

    another downside to QR is fork-mounting the bike on my roof rack, lol. easy with QR, a bit of a pita with TA. But I am perhaps a rare bird fork mounting thru-axle bikes.
    There is zero precession happening at the TA, so why would it come loose if not for user error? Do you have other bolts coming lose on your (wife's) bikes too?

  23. #148
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    Quote Originally Posted by ceugene View Post
    There is zero precession happening at the TA, so why would it come loose if not for user error? Do you have other bolts coming lose on your (wife's) bikes too?
    Yep. Tighten to 15Nm, good to go.
    "With bicycles in particular, you need to separate between what's merely true and what's important."-- DCGriz, RBR.

    “Statistics are like bikinis. What they reveal is suggestive, but what they conceal is vital.” -- Aaron Levenstein



  24. #149
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    Quote Originally Posted by Lombard View Post
    Yep. Tighten to 15Nm, good to go.
    15n-m, damn. I use around 6-8.

  25. #150
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    Quote Originally Posted by ceugene View Post
    15n-m, damn. I use around 6-8.
    My TA says 15Nm on it, so that's what I torque it to.
    "With bicycles in particular, you need to separate between what's merely true and what's important."-- DCGriz, RBR.

    “Statistics are like bikinis. What they reveal is suggestive, but what they conceal is vital.” -- Aaron Levenstein



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