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  1. #1
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    Bottom bracket drop for track racing

    Hi

    Hope you can help. I would love to convert my road TT bike into a track bike. Only concern I have is the fact that the bottom bracket drop is 75mm, which I know is quite high compared to traditional track bikes.

    A few questions:

    - Will I have problems with hitting the floor with my pedals given the 75mm bottom bracket drop? (I am racing with 172,5mm pedalarms - powermeter)
    - I am only doing TT on the track. Therefore I assume that I should not have any problems given the fact that I more or less stay on the lower black line all the time + I am going quite fast all the time.

    Looking forward to hear from you all.

    Br
    Garfild78

  2. #2
    Senior Member chas58's Avatar
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    Question 1) Yes, you have picked up on a big problem.
    Question 2) maybe

    Q1) BB drop in the 50s is good. Anything over 60 is going to start to cause problems.

    You have a lot more drop there, which is not unusual for the type of bike you are riding. So, the generalized answer to your question is no, you cannot use that on the track.


    As you have noted, there may be some mitigating questions.

    What type of track are you on, specifically what is the angle of the turns? If you are on one of these mini-NASCAR asphalt conversions or a long shallow 333+ meter track, it is going to be less of an issue. If you are on a track with 44degree banking, you are going to have pedal strike unless you are experienced and limit what you do.

    Q2) To answer your other question, sure, if you donít go above the black line (i.e. single bike time trial events at the black line only), and maintain speeds of over 20mph, you can probably get away with it. The real question is will the track officials let you do it? I doubt it, but the only way you will know for sure is to ask.

    One quick test is to take your bike to the banking, and hold it vertical with the outside pedal down. Does it hit? Answer: yes (on most tracks).
    Last edited by chas58; 09-17-12 at 11:44 AM.

  3. #3
    Wear One IvyCap's Avatar
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    please don't covert your TT bike to fixed. You're better off buying a complete.

  4. #4
    Elitist carleton's Avatar
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    Quote Originally Posted by IvyCap View Post
    please don't covert your TT bike to fixed. You're better off buying a complete.
    +1

    There are LOTS of off-the-shelf frames or complete bikes that would be better suited for the job...especially if you actually intend to race.

    You aren't doing yourself any favors by converting a road TT bike into a track bike. The bigger problem you will face is the fact that you won't have enough space in the dropouts to run different gear ratios without using a different chain. On a road bike, the slack is taken up by the derailleur. On a track bike, the slack is taken up by moving the wheel forward or back.

    Basically, you'll cause more problems that you'll solve by doing this...no matter how nice the road TT frame is.

  5. #5
    Senior Member bitingduck's Avatar
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    You probably won't die, but as already said, you probably won't be happy either.

    My first track races were done on a converted road bike rented at Blaine (43 deg banking, low BB, 170 or 172 cranks). It got interesting when things slowed down. There's at least one guy who shows up at HDC every once in a while with custom 185 or 190 or something. As far as I know, he's still alive. It depends on which track, but AFAIK, at HDC your equipment choice is up to you as long as it's legal for the race you're using it in. Whether it's a good idea, what the limits are is your problem.

    If the bike is only used for TTs, and you never are taking it high and slow you'll probably be ok on most tracks, though not always happy. I always ride 165s, and had a teammate who would sometimes follow on the balustrade on his TT bike in a big gear with long cranks. He'd yell at me if I slowed much (even though the speeds were fine for my equipment).

    Your big problem will likely be warmups-- you won't be comfortable warming up on a crowded track (at least not one with banking). It's not just going slow, but also moving uptrack while slowing for an exchange that becomes an issue.
    Track - the other off-road
    http://www.lavelodrome.org

  6. #6
    Senior Member chas58's Avatar
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    To be more concise:
    you should never going to ride that bike on a track with other bikes. It is dangerous. Its doubtful that the track regulators would let you on the track with that bike in the first place.

    While theoretically possible if no one "catches" you, its just a bad idea.

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