can i change STI levers??

Discussion in 'Cycling Equipment' started by ILM, Mar 7, 2009.

  1. ILM

    ILM New Member

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    Hi

    I've got a hybrid bike (specialised crosstrail http://www.thetristore.com/newproductsthumbs/crosstrailsport09.jpg)
    that has Linear Pull brakes like a mountain bike.
    http://upload.wikimedia.org/wikipedia/commons/thumb/a/ac/Linear_pull_bicycle_brake_highlighted.jpg/180px-Linear_pull_bicycle_brake_highlighted.jpg

    I've been given some flightdeck STI levers and dropped handlebars and I want to try them on the above mentioned bike.
    Sounds a silly question but will these levers be ok with Linear brakes????

    thanks

    ILM
     
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  2. barrocycles

    barrocycles New Member

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    Simple answer is No, they are not compatible. But, if you are set on using them then you can use an adapter (QBP travel agent or similar product) which takes place of the noodle on the brakes and changes the amount of cable pulled. Although a pain to set up at first, they do work well.
    HTH
    JoeB
     
  3. ILM

    ILM New Member

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    hi

    thanks for your response, what are these adaptors?? I may have seen them before but not recognise them by name.

    thanks
     
  4. alfeng

    alfeng Well-Known Member

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    For the FRONT brake, you'll probably want either a TRAVEL AGENT or a Mini-V-brake otherwise modulation will be non-existent -- apparently, some people say the lack of modulation isn't a big deal, so you may want to try it as-is BUT the reason that people did endo's back-in-the-day was because they were probably using brake levers intended for cantilever calipers (which have the same pull as road calipers) with their newly acquired V-brakes.

    I've used Ultegra STI shift/brake levers with a REAR V-brake on a MARIN Redwoods (Hybrid) frame ... the cable "stretch" (!?!) provided a sense of pseudo-modulation that I prefer ... so, IMO, you probably won't need a travel agent for a rear V-brake ...

    On the particular Marin frame, I used a standard ROAD fork + standard ROAD brake caliper ... using a ROAD fork gave the frame (more) normal head tube & seat tube angles. If YOU replace your bike's suspension fork for a ROAD fork, then you'll reduce your bike's weight by a couple of pounds.

    Eventually, I eventually switched the Ultegra shifters for a pair of Campy shifters ... then, I eventually sold it to someone I knew after making some more changes which you can see in the attached picture. Before he moved, I installed a different fork + cantilever brake calipers for him because he wanted to run fatter(-than-700x25) tires ...

    If you opt for a pair of cantilever brake calipers for the front brake, you'll need to buy a CABLE HANGER.

    N.B. You will PROBABLY need to buy a different Shimano FRONT (i.e., ROAD) derailleur; but, perhaps not -- I've mismatched Shimano ROAD shifters with a Shimano MTB front derailleur when using only a DOUBLE crankset.
     
  5. barrocycles

    barrocycles New Member

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    Looks like this:

    [​IMG]


    Check with your LBS (local bicycle shop) or search the web for an online retailer.

    Happy riding

    JoeB
     
  6. artemidorus

    artemidorus New Member

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    Sorry to this respondent in advance, but this is the typical, knee-jerk answer to this question and it is wrong. (This is a hobby horse of mine.)

    You can use ordinary STI levers with a linear-pull ("v") brake, with great success and without an adaptor, as long as you are happy to make certain compromises. I have used this combination on my touring/commuter bike for some years.

    Firstly, a little background. All marketed cable brake systems use a combination of one higher mechanical advantage (leverage) component and one lower mechanical advantage component. With road brakes and centre-pull cantilevers, a high mech. ad. lever is used with a lower mech. ad. caliper. With linear-pull brakes, a lower mechanical advantage lever is used with a higher mech. ad. caliper. The net effect of any system is to give a good combination of braking force and lever travel.
    With a road lever/ linear-pull combination, you are combining a high mech. ad. lever with a high mech. ad. caliper.

    This means that, if it is set up correctly, you have a very powerful brake. The downside is that you need a lot of lever movement to give a little brake pad movement. You can overcome this with an adaptor, but you lose leverage, add friction, and also find that many of the brands don't work very well.

    The other way of managing it is to start with a very true wheel and set up the correct cable length to have the pad sitting about 1 mm away from the rim when the brake is idle. If the pad is too far away from the rim when idle, then too much lever movement will be required to bring the pad in contact and the lever will hit the bar.

    The major downsides of this system are:

    1. the cable will often be too short to allow you to release the "noodle" on the caliper, so removing the wheel from the bike will require either unfastening of the cable at the anchor bolt or letting the tyre down.

    2. You will have no barrel adjuster, so adjustment for pad wear will require moving the cable through the anchor bolt.

    3. You must keep your rims true or the pads will rub.

    Despite these disadvantages, this is the best brake set-up on any of my bikes, apart from a hydraulic disc on my MTB.

    One myth that I will dispel in advance, the "modulation" myth. This myth dates back to the days when "servo" brakes were used, meaning that the more the brake gripped, the more it tightened under the influence of the braking forces. In effect, a servo brake action becomes independent of the lever force - a very dangerous brake indeed. These brakes, indeed, lacked "modulation". Modulation in any non-servo brake system comes from the force on the lever, not the brake system itself, and a linear-pull brake is not a servo brake.
     
  7. barrocycles

    barrocycles New Member

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    In my experience, I have found that the travel agent and similar devices to work quite well when set up correctly. My answer to the OP question was by no means was “knee jerk” or incorrect. It was SIMPLE. I have tried similar methods as you have described with little success. I would not give the OP advice as to jeopardize his brake system on the account of your “horse hobby”. The system was not designed for liner pull brakes, so I would advise not using liner pull brakes with STI shifters. If the OP wants to use the brake system as you describe, and live with the major downsides as you describe….. Then so be it. I understand and respect that you are stating your opinion, please respect that I am stating mine.



    Just my 2 cents
     
  8. artemidorus

    artemidorus New Member

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    Your answer was incorrect in that you simply stated that the hardware items mentioned were incompatible, which appears a bald statement of fact rather than obviously a subjective opinion. Had you given a detailed answer listing the problems that you have had in the absence of a "travel agent", then I would have accepted your post more readily.

    Perhaps you would care to list the nature of the jeopardy to which the braking system is subjected when set up as I have described?
     
  9. barrocycles

    barrocycles New Member

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    Art



    My original post was again…. SIMPLE. I didn’t feel it necessary to go on about a modification of a system that is incompatible. If it were compatible, then why do cyclocross bikes come with canti’s and not V brakes (liner pull brakes)? STI levers were not designed to operate with liner pull brakes… As you stated, “The downside is that you need a lot of lever movement to give a little brake pad movement.” ,Which in my findings gives you poor modulation. It worked for you….Great!! In my opinion, I have tried this same modification with little results.

    :rolleyes: Can't we all just get along?:D
     
  10. youhaditcoming

    youhaditcoming New Member

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    STI levers work perfectly with cantilever brakes
     
  11. Richard_Rides

    Richard_Rides New Member

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    I just converted my hybrid to drop handlebars with Ultegra brifters using Travel Agents front and rear on my V-Brakes. Works like a dream!
     
  12. dabac

    dabac Well-Known Member

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    I've never understood that one. Over the course of a summer I'm likely to ride bikes with:
    - caliper brakes with ancient pads gripping stainless steel rims (maybe even activated by "suicide" levers!)
    - canti brakes with middle aged pads gripping aluminum rims
    - v-brakes with newish pads gripping ceramic rims
    - old drum brakes
    - a few makes & models of hydraulic disc brakes
    and maybe a coaster brake or two thrown in for good measure.

    The differences in response and linearity in the above set ups are HUGE, far greater than what you get by using "unmatched" brakes and levers.
    Yet the scary brake-related incidents just fail to appear.
    I'm perfectly capable of simply getting on the bikes and ride. No retraining required, no special skills present.

    Sure, a mismatched set WILL have other characteristics than a matched set, but ordinary rider skills will be well able to cope with that.
     
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