Tri bike sizing advice.

Discussion in 'Triathlon' started by coolny29, Nov 17, 2010.

  1. coolny29

    coolny29 New Member

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    I currently ride a 56 Size Road Bike and want to buy a Tri bike. After competing in several sprint and olimpic distance tri's I will go for a 1/2 Ironman early next year.

    My question I measure 6 ft (182cm) and have a longish torso so I am in between sizes, due to my legs I should buy a 54 Tri bike and use a 110 or 120mm stem or due to my longer torso buy a 56 Tri bike and use a shorter stem 90mm? I tried both and can obtain a comfortable position in both bikes....so any recommendations?
     
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  2. SCardamon

    SCardamon New Member

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    Whichever brand you are arming for, bike wise, go to a local vendor and have them size you out. They should have you bring your road bike and measure out your pad stack (or where your pad stack could logically be if you do not have aero bar attachments).

    I just went though this process and very glad I did. I am about to obtain a Specialized Shiv Expert and everything about my height said I should be a large (56cm) but after sizing up, it turns out my torso length and desired reach puts me in a medium (54cm). Important thing to know is that each brand of bike goes after a certain aspect of fit more than another. What I mean is that you may be a large on a Trek but a medium on a Shiv.

    BTW if you are looking at Specialized I would strongly reccommend visiting Bike Source, if you have one in your area, you can not do better than this franchise IMO.

    Good luck!
     
  3. maydog

    maydog Well-Known Member

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    You may want to consider getting a professional fit for a such a bike. The fit will be dependent on more than just frame sizes; a good fit may be more critical on a Tri bike than a standard road bike since you will want to remain aero for the duration of your event. Standing up and shifting around are generally to be avoided.

    There are plenty of resources that discuss the issues with Tri bike fitting online; do a bit of research and get a an idea of what you want out of the fit before going to a shop.

    Otherwise, if you are comfortable on your current setup or cheap (like me) and want to try to fit yourself, you could use a current bike as a starting point. I built a Tri / TT specific bike last year out of bargan bin parts using measurements taken from one of my existing bikes that has clip on aero bars as a guide.

    My position on the current bike was comfortable but more extended than the reccomended tri position. My elbows were open much more than 90 degrees. I wanted to tweak the fit on my new bike so I measured the distance between the "center" (the point where the axis of the seat post would pass) of my seat and the elbow pads. From that measurement, I figured where my elbows should be and shaved a few cm's from the stem length and brought the seat forward as well.

    My seat height was good, but I was moving it forward on the new bike and I planned to use a bit shorter cranks, so I moved it higher than my base measurement.

    Knowing roughly what the bounds for seat angle, top tube length, stem length and seat tube length I wanted. I found parts that fit. I built the bike up using the measurements and the fit was pretty good. I was able to tweak everything to my liking after a few rides.
     
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