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  1. #1
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    Aero bars on a mountain bike.

    I am going on an all-road bike tour. Approximately 1100 miles. I would like to install aero bars on my bike to reduce drag while riding with roadies.

    Bike: Cannondale Bad Boy Ultra
    Drive Train: Full XTR
    Bars: Bontrager Race XXX Lite OS Riser
    Bar Ends: Bontrager Race X Lite
    Wheels: Mavic Open Pro 700c with XTR hubs



    I'd like two-piece aero bars like these, but with spring-loaded pads:



    My questions are:

    1) Will I be able to find clip-on aero bars that will fit the diameter of my riser bar?
    2) If I can find aero bars that work, will they have to clip too far apart to be comfortable?
    3) If I can find them and they are comfortable, will the carbon bar itself be strong enough to hold the weight?
    Last edited by Safeway; 02-12-2008 at 12:41 AM. Reason: Formatting

  2. #2
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    I'd like some opinions so I can shop around the LBS and online!

  3. #3
    local trails rider
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    Have you considered going for more hand positions instead, to reduce tensing during long hours on the bike?

    An On-One Midge, for example, or whatever Shiggy is running.
    A Drop Bar 29"er Takes Shape
    http://www.mtbtires.com/features/bik..._dropbars.html

  4. #4
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    I have bar ends for more hand positions, but I'd really like aero bars if possible. I can shim the clamps with rubber gromets.

  5. #5
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    If you are riding with roadies in a pack, I would go more with what Pertime suggested - midge bars. More hand positions, brakes accessible on the hoods and if you want to duck the wind you go low on the drops where brakes are still reachable. I believe aerobars are meant for solo riding like time trialing or triathlons where you cannot draft from other riders. Taking a corner at high speed with aerobars is a bit of a challenge and a concern with fellow riders riding beside you.
    Just my thoughts.
    Last edited by older guy; 02-12-2008 at 04:14 PM.

  6. #6
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    The riders are very spaced out. There is no pack. We do 70 to 80 miles per day, and only 150 riders. Some old, some on knobbies, even 10 year old on tandems. It's a family-oriented long distance ride. The roads are mostly straight, and turning would be done on the risers.

    I am fairly set in having the aero bars, I just want some advice on implementation. Since I have nice bars and ends, and hydraulic brakes, I don't want to have to go out and buy very specialized equipment like drop bars, new cables and routing, new levers that work with XTR and hydraulic brakes, etc.

    So how can I get this to work?

  7. #7
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    Okay then.
    Since your bar is OS, I would take that as 31.8 bulge, click on the link, this aerobar might work:
    Give them a call

    http://www.excelsports.com/new.asp?p...jor=1&minor=15

  8. #8
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    Quote Originally Posted by older guy
    Okay then.
    Since your bar is OS, I would take that as 31.8 bulge, click on the link, this aerobar might work:
    Give them a call

    http://www.excelsports.com/new.asp?p...jor=1&minor=15
    If I mount the aero bars just outside the taper (31.8mm to ~22.2mm), I will need to shim the clamp somehow. I can use the 26.0mm clamp, which seems very common, and cut a piece of rubber to fill the gap. Do you think this is a good or bad way to mount the bars?


  9. #9
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    22.23mm to 26mm is huge to shim. Sometimes you pull on the aerobar, sometimes put your weight, I wouldn't do it. Any slip or rotation and you go down. If you can fit your levers and shifters and to erase any apprehensions, I'd rather buy and use this bar:
    http://www.excelsports.com/new.asp?p...jor=1&minor=15

  10. #10
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    Quote Originally Posted by older guy
    22.23mm to 26mm is huge to shim. Sometimes you pull on the aerobar, sometimes put your weight, I wouldn't do it. Any slip or rotation and you go down. If you can fit your levers and shifters and to erase any apprehensions, I'd rather buy and use this bar:
    http://www.excelsports.com/new.asp?p...jor=1&minor=15
    I just created a mock-up of what I have in mind, and it looks a lot like the bar you linked me. I'm not sure if I can handle bars that narrow on my mountain bike. I have two wheel sets that I switch out: XTR UST mountain and 700c Mavic. I'd rather not have to also switch out bars and bar components.

    I need to see how wide my bars are, since I don't know off the top of my head.


  11. #11
    conjoinicorned
    Reputation: ferday's Avatar
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    i really believe clamping those to your carbon bar is asking for trouble. really though. that mountain bar isn't made for those attachments.
    what would rainbow unicorn do?

  12. #12
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    Quote Originally Posted by ferday
    i really believe clamping those to your carbon bar is asking for trouble. really though. that mountain bar isn't made for those attachments.
    Profile Design Ergo Carbon Bar Ends are safe to clamp on the bar.
    http://bicyclesource.us/itemdetails.cfm?ID=17506

    Bontrager Race X Lite Bar Ends are safe to clamp on the bar.
    http://penncycle.com/itemdetails.cfm?ID=13405

    I don't see why identical clamp mechanisms would be any different.

    Edit: I am not trying to knock down everyone that says I am wrong, but I want actual reasons! As far as I can tell, it would be safe. There are tons of carbon drop bars with carbon aero bars attached.

  13. #13
    conjoinicorned
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    because the ends of the bar usually have reinforcement (whether an aluminum sleeve or extra carbon)

    the bars were not made to be clamped in that location.


    it's your face.
    what would rainbow unicorn do?

  14. #14
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    I think if you place the aero clip bars where you show them, they will be too far apart. I believe your elbows should be closer. Plus, you want to make sure you are comfortable. Why not buy a cheap set of drop bars for the ride?

  15. #15
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    Quote Originally Posted by ferday
    because the ends of the bar usually have reinforcement (whether an aluminum sleeve or extra carbon)

    the bars were not made to be clamped in that location.


    it's your face.
    What about aluminum risers?

  16. #16
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    Quote Originally Posted by tron
    I think if you place the aero clip bars where you show them, they will be too far apart. I believe your elbows should be closer. Plus, you want to make sure you are comfortable. Why not buy a cheap set of drop bars for the ride?
    I may end up geting drop bars and aero bars for the ride, but I'd have to mount my XTR dual-action levers on the flat and then tape them. With clip-on aero bars and my XTR levers mounted, I'm not sure how much flat room will be left for my hands.

    When I am done with the ride, I will have to rip off the tape to get my levels back off.

    As for comfort, that I why I want the aero bars. I want to be able to relax my upper body with the pads spaced wide. It isn't actually for aero tucking and triathalon time trials.

  17. #17
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    Well. Be sure that you will be comfortable in that position. I know if I added aero bars to my mountain bike, I wouldnt be very comfortable. My road bike would be a different story. I think it wouldnt be too bad having the lever on the flat. That is how a lot of cross bikes are set up. The tape is pretty easy to take off and put back on so I wouldnt worry about that.
    I take a ride on your bike and try to put your elbows near your bars, I think you would be too far forward. But it might be comfortable for you.

  18. #18
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    Quote Originally Posted by tron
    Well. Be sure that you will be comfortable in that position. I know if I added aero bars to my mountain bike, I wouldnt be very comfortable. My road bike would be a different story. I think it wouldnt be too bad having the lever on the flat. That is how a lot of cross bikes are set up. The tape is pretty easy to take off and put back on so I wouldnt worry about that.
    I take a ride on your bike and try to put your elbows near your bars, I think you would be too far forward. But it might be comfortable for you.
    I just sent an email to Bontrager asking if that section of the bar was reinforced enough (normally for lever and shifter clamping) to safely mount clipon Aero bars.

    We will see what they say.

  19. #19
    No, that's not phonetic
    Reputation: tscheezy's Avatar
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    We cycle toured NZ a few years ago and used some older Profile clip-on aero bars on our handlebars. The inside of the clamp are for the aero bars was not round to follow the contours of the handlebar, but rather somewhat diamond shaped. This allowed them to clamp effectively on a bar of a diameter other than road size. I would NOT put any aero bars on a carbon bar. That would be crazy and I fear you would crush the bar. The clamping force needed for a shifter or brake is far lower than you need to keep an aero bar from moving around. If I were to tour again I would consider one of the Jones-style bars like Titec also makes now along with aero bars. Aero bars with multiple axis adjustments like the Profile GT Jammer allow you to change the reach, width, and position of the components easily to accomodate the non-traditional setup on a mountain bike.

    My video techniques can be found in this thread.

  20. #20
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    What about aluminum riser bars? Would you mount Aero bars on them?

  21. #21
    conjoinicorned
    Reputation: ferday's Avatar
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    Quote Originally Posted by Safeway
    What about aluminum riser bars? Would you mount Aero bars on them?

    yes, for the most part. (ie. not the super light racer boy bars)

    tscheezy hit an excellent point with the h-bars...you may love them so much you ditch your carbon risers all together!
    what would rainbow unicorn do?

  22. #22
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    Alright, I will get either:

    Profile Carbon GT
    http://www.profile-design.com/products/aerobars/cgt/

    or

    Profile Jammer GT
    http://www.profile-design.com/produc...ars/jammer-gt/

    I had non-racer-boy aluminum riser bar sitting unused. The will mount each aero bar in the flat between the stem and the rise, on either side. I measured the clamp width, and it is a perfect fit. The diameter is 31.8mm there, and it will be a very solid mount.

  23. #23
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    Aero bars on a mountain bike. Final results?

    Safeway, did you end up going with one of the final set ups you referenced?

    I'd be interested in seeing pictures of what you ended up with as I am having the same thoughts of putting an aero bar on my mtn set up...there is a 10-15 mile stretch of highway before I get to the trails and it would be nice to have a more aerodynamic position to ride it.

    Also, I want to be able to mount some sort of light system as well. Did you have headlights mounted with your setup?

    Finally, you seem set on riser bars and I was wondering why. Did you want that extra height for some reason?

    I was thinking about rising bars, too, as I feel like I need more height in my handlebar set-up. I was thinking of a different stem, but risers may work as well. Basically, I feel like my bars are too low and that I am too far over them. I think the top tube on my bike (2001 Spec. Stumpjumper) is too short for me. It feels pretty squirrely. Good for climbing, but very (too) responsive in most other situations (flats, downhill, etc.).

    Any feedback to correct handling would be much appreciated.
    Thanks for your posts. very interesting.

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