Horizontal Dropouts and Disc Brake?- Mtbr.com
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  1. #1
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    Horizontal Dropouts and Disc Brake?

    Okay I waited and waited and finally got a new ss WITH rear mechanical disc brake now...figured it has to be better and was so excited to move from V's to discs.
    Obviously, I didn't think this through...don't get me wrong, love the bike, but got a lesson today.
    Seems that those horizontal dropouts don't let the rear wheel fall freely when you have to remove the back wheel for a flat like verticals do...duh...how did I not realize this??
    Now I have to unscrew the rear caliper from the mount to remove the rear wheel!!
    My simplicity has been ruined...
    Did anybody else get this rude awakening or am I the only one who didn't see this coming.

  2. #2
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    I have a MUSS and it has both horizontal drops and disc brakes but I don't have to touch the brakes when I pull the rear wheel. It must be the location of your rear disc?

  3. #3
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    I need to loosen the caliper (Avid mech) on my Monocog to remove the wheel. Not a big deal. I thought it would be more of a hassle than it is.
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  4. #4
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    My Spot is set up w/ horizontal drops and discs. I loosen disc brake's lower caliper bolt and that provides enough "wiggle" room to remove the wheel and keep the caliper in place.
    I guarantee I will never, ever be accused of bringing sexy back...

  5. #5
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    Yup. The same with my IRO Mia!

    Yeah, what shiggy said.

    Accounts are a bit lacking here about that little caviat with discs and horizontal drops. But the truth is, it's not a big hassle, even when changing flats on the trail.
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  6. #6
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    Ah... thanks...I will try the loosening bit and see if that works.
    Thanks for the suggestion.

  7. #7
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    My Misfit has horizontal drop and Avids discs. The wheel slides-out without any problems.
    It's only pain......

  8. #8
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    Here's my setup. The caliper lives in front of the rotor, and once it's been setup for your wheel position (determined by gear sizes and chain length) it never moves when you have to take out the wheel.
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  9. #9
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    how odd that i was only talking to someone about this exact issue this morning

    that is a much better way to mount on a horizontal dropout frame. i wonder why surly/on one/etc are still using the seatstay mounting position when they could have the mounts on the chainstay?

    what is that frame miles? a custom?

  10. #10
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    It doesn't look like that mounting arrangement would work for mechanical brakes. On a custom where you can build it to the components, it looks extremely slick, though.

  11. #11
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    Kiss Off

    Quote Originally Posted by alexb618

    what is that frame miles? a custom?
    http://www.philwood.com/kissoffflame...Detail%202.jpg

  12. #12
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    Quote Originally Posted by pinkdirt
    Seems that those horizontal dropouts don't let the rear wheel fall freely when you have to remove the back wheel for a flat like verticals do...duh...how did I not realize this??
    This issue is very caliper/frame dependant, the trick is to get the slave pistons positioned at 12:00 or slightly earlier wrt the horizontal mount. With the caliper thus positioned, you can adjust the chain tension without need to adjust the caliper.

    Here are a few things to try:

    Use a different caliper/system - I know that Magura Louise rear ISO calipers mount much farther forward than the Avid Post mounts.

    Use a different ISO to Post mount adapter - Hayes adapters place the caliper further forward than the Avid adapters.

    Use a "wave" rotor - the notched in the rotor may give you enough clearance to remove the wheel.

    Use a 180 (or larger) rotor, and select a post mount adapters that places the caliper farther forward.

    If a combination of the above still does not let you remove the wheel without lossening the caliper mount, and the interference is minimal, you can also shim the rear of the post mount with a washer to tilt the Avid caliper forward and clear the rotor. Slight misalignments of the pad - rotor will have a very minor effect on the brakes.

    Simplicity may still be withing reach...

    Cheers,

    Tom

  13. #13
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    Wow

    Quote Originally Posted by itsdoable
    This issue is very caliper/frame dependant, the trick is to get the slave pistons positioned at 12:00 or slightly earlier wrt the horizontal mount. With the caliper thus positioned, you can adjust the chain tension without need to adjust the caliper.

    Here are a few things to try:

    Use a different caliper/system - I know that Magura Louise rear ISO calipers mount much farther forward than the Avid Post mounts.

    Use a different ISO to Post mount adapter - Hayes adapters place the caliper further forward than the Avid adapters.

    Use a "wave" rotor - the notched in the rotor may give you enough clearance to remove the wheel.

    Use a 180 (or larger) rotor, and select a post mount adapters that places the caliper farther forward.

    If a combination of the above still does not let you remove the wheel without lossening the caliper mount, and the interference is minimal, you can also shim the rear of the post mount with a washer to tilt the Avid caliper forward and clear the rotor. Slight misalignments of the pad - rotor will have a very minor effect on the brakes.

    Simplicity may still be withing reach...

    Cheers,

    Tom
    Tom, Your handle is right on. I never thought that there were that many solutions. It certainly is doable.

    One other pseudo solution that I have not seen is going tubeless. This may eliminate or greatly reduce your need to deal with the rear wheel. Just a thought....and it is what I do.

    One other thought....depending on the frame you are using....You might be able to add a link of a half link to the chain and get the axle far enough back that it will put the caliper at 12:00 and solve your problems (works with a KM frame...what are you using?)

    Personally, I dont think 2 extra 4mm bolts to loosen is that big of a deal, You are already dealing with a bolt on hub...what is 2 more bolts? Either way, you are not changing a flat in record time....add to that the chain tensioner (tug nut)...Man, now that I think about it, MY SS is anything but simple!

    This is a frequently debated topic here. Basically, you either find the bennefits of disc brakes worth the added hassle or you dont. Nothing is perfect for everyone.
    My ego is bigger and better looking than yours.

  14. #14
    If you have to ask...
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    Quote Originally Posted by unit
    This is a frequently debated topic here. Basically, you either find the bennefits of disc brakes worth the added hassle or you dont. Nothing is perfect for everyone.

    Well, see, now that's the beauty of the Phil Wood setup- no hassle at all.



    miles
    It's 7:09 California time

  15. #15
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    i have a P.U.S.S. frame with avid bb7 mechanicals and i never touch my brakes, even to make gearing changes. seems that proper calliper allignment and the avid wave rotor seem to be enough to give me proper clearance to get the wheel on and off.

  16. #16
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    Quote Originally Posted by miles
    Here's my setup. The caliper lives in front of the rotor, and once it's been setup for your wheel position (determined by gear sizes and chain length) it never moves when you have to take out the wheel.
    This solution is so obvious yet have not seen it implemented on many bikes. THis would solve the entire EBB and paragon slider dropout for good. BTW what brake is that?

  17. #17
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    Quote Originally Posted by crux
    This solution is so obvious yet have not seen it implemented on many bikes. THis would solve the entire EBB and paragon slider dropout for good. BTW what brake is that?
    Not sure how this "solves the entire EBB and paragon slider dropout", but all solutions are not without thier disadvantages. Hayes is the only caliper made with the R22 mount used on the KissOff. However, an ISO or Post mount can be used by modifying the seat & chain stay Junction, like in this setup:

    Post mounts require more clearance on the seat stay, but you may not be able to use all the available calipers.

    The main issue I've had with seat stay calipers is that reverse braking manouvers tend to pull the wheel out of the dropout unless you have the QR set really tight. It's not an issue for most people, but if you like rolling back on your rear wheel and doing a rear wheel hop (trials like manouver), that's often enough force to make the rear wheel shift in some frames. There is a reason why ISO mounts are placed (within a few degrees) in-line with the dropout.

  18. #18
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    One clarification is in order. When refering to horizontal dropouts you need to specify conventional (forward facing) dropouts vs. track style (rearward) facing dropouts. Both are referred to as horizontal dropouts. Track style dropouts don't have the brake interference problems as you can see in Miles Kiss Off. It wouldn't matter if the Kiss Off had a seat or chainstay mount. With track style dropouts the wheel exits to the rear and never interferes with the caliper no matter where it's mounted. If you use a quick release instead of nuts in this setup you don't need a tool of any type to take the wheel out. I know you'll probably need a tugnut and some don't like to use quick releases but it makes wheel changes easier, especially on the trail.

  19. #19
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    Quote Originally Posted by meloh1
    One clarification is in order. When refering to horizontal dropouts you need to specify conventional (forward facing) dropouts vs. track style (rearward) facing dropouts....
    Technically, rear facing track mounts are NOT dropouts (sometimes called track forks), while the forward facing mounts are considered dropouts - the term "dropout" meaning the ability to remove, or drop out your wheel without removing the chain. But that's semantics & etymology, or a pet peeve, depending on your bent.


    Quote Originally Posted by meloh1
    ...With track style dropouts the wheel exits to the rear and never interferes with the caliper no matter where it's mounted...
    Depending on your caliper, seat stay angle, seat stay mounted calipers can interfere with with rear entry track mounts, as many people here have found.

  20. #20
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    I don't think you're going to see many conventional dropouts with discs.

    I think it's fair to assume most people are talking about track dropouts. Track dropouts with the now-standard 51mm mount calipers can be a problem. The caliper sort of wraps around the disc. I have a PUSS with rear facing dropouts and Shimano brakes. I have to loosen the bolts and twist the caliper to get the wheel out. The mounts are slotted to allow this so it's not too big a deal and if I had the wheel further back in the dropouts the caliper would already be twisted a bit and probably allow the wheel to slide right out.

    The reason the KISS OFF works is because it uses a mount style developed by Hayes and Trek (I don't think brakes with this mount are available anymore) that sits on the chainstay in front off the disc. It's not entirely perfect though. The thing that says "Phil" under the caliper is a slider that has to be used to make sure the pads cover enough of the disc. On the Roloff bike above, you'll notice that,while it uses sub11 dropouts, the drop outs face down, not back, making them really just super deep vertical drops that don't offer much chain tension adjustment. I imagine this was done to keep the wheel from being so far back that the disc is pulled out of the caliper. That design with true horizontal drops would only give you a few millimeters of adjustment at best.

    I think the best design for rear facing dropouts with disc brakes is the slotted mount used by Bianchi, Surly and Spot. It's fairly simple and allows for a significant amount of adjustment. The only problem is the long tabs can bend under hard braking, but I've only seen that happen once.

  21. #21
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    Quote Originally Posted by dannybob
    ...On the Roloff bike above, you'll notice that,while it uses sub11 dropouts, the drop outs face down, not back, making them really just super deep vertical drops that don't offer much chain tension adjustment. I imagine this was done to keep the wheel from being so far back that the disc is pulled out of the caliper. That design with true horizontal drops would only give you a few millimeters of adjustment at best....
    The sub-11 on the Rohloff bike above was used for the OEM-1 torque arm, chain tension is supplied by an eBB. The Sub-11 also allows you to drop the chainstay lower to make room for an ISO mount.

    Perhaps I should have put this up:

    Cook Bro's cruiser solution.

  22. #22
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    Quote Originally Posted by itsdoable
    The sub-11 on the Rohloff bike above was used for the OEM-1 torque arm, chain tension is supplied by an eBB. The Sub-11 also allows you to drop the chainstay lower to make room for an ISO mount.

    Perhaps I should have put this up:

    Cook Bro's cruiser solution.
    Now that's slick. Best way to run discs with horizontals for sure.

  23. #23
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    Damn right!

    I like it!
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  24. #24
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    That's BRILLIANT!!

  25. #25
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    Quote Originally Posted by dannybob
    I................................................. .....
    I think the best design for rear facing dropouts with disc brakes is the slotted mount used by Bianchi, Surly and Spot. It's fairly simple and allows for a significant amount of adjustment. The only problem is the long tabs can bend under hard braking, but I've only seen that happen once.
    as far as the Bianchi goes, the slots only seem to allow the calliper to pivot, not slide fore or aft. At least thats how it is with my brakes/frame. (BB7 brakes and a PUSS frame). I really dont see why they made them slotted at all since i have yet to adjust the position of my calliper since i assembled my bike. I could have made that adjustment with shims. I have zero issues, even when i go from an 18t to a 16t on the rear. is this odd for these frames? or did i just find the sweet spot with the calliper? I have wave rotors so i dont have to touch the calliper to pull the wheel either.

  26. #26
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    I've got a Spot running horizontal dropouts with a Marta 160mm in the rear and Paul disc hubs. My rear wheel comes right out without touching the calipers: I just loosen the bolts, punch the wheel forward, derail the chain off the ring, and pull the wheel straight back. I run the hub right at the mid-point of the dropouts and the calipers at the end of the sliding disc tabs, although I guess I just Iucked out with chain length. This is my first experience with disc brakes on any bike, and I keep trying to convince myself that they are better than the Paul Motolites on my other SS...

  27. #27
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    Yep

    My Karate Monkey has 185mm Avid BB7s, and for most axle positions I have to loosen the caliper to remove the rear wheel. I did not enjoy having to realign the caliper after changing a flat on a dark road on a very rainy night riding home from work. I started running the wheel further back in the fork ends, allows the caliper to be rotated into a position that doesn't require loosening to remove the wheel.
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