The Importance of Bicycle Fit

Discussion in 'Cycling Equipment' started by Rompinrhino, May 2, 2005.

  1. Rompinrhino

    Rompinrhino New Member

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    Throughout the past year, I have been on a search for a bike that fit me right. Along the way, I went through 1 Trek, 2 Giant's, 1 LeMond, and a Torelli. I found Antonio Ragatz on accident one day. I stopped by his shop to see what it looked like, and one of the first things that he said to me was that my bike didn't fit me. The top tube was to long, and the seat tube was to short. I was riding a Giant at the time. Since that Giant, Antonio has taught me many things about the art of sizing, and frame building. Bike fit is one of the most important things in cycling. The way a bike fits you determines how comfortable you are going to be, and how the bike is going to handle.

    One of the biggest things that affects the way a bike handles is the stem length. A bike that fits properly should have a 120mm stem, 110mm at the shortest. A bike with a shorter stem will be to twitchy, and a longer stem will make the bike to slow. There are quite a few companies out there that are trying to sell a "one size fits all" style of bike. It used to be that bikes came in 1cm increments, and were available in just about any size possible. The main reason for the new switch is capital. For a bike company, it is a lot cheaper to mass manufacture bicycle frames in 4 sizes. This provides excellent savings for the company, at a HUGE disservice to the customer. These companies say that you can fit on any bike, just put the right stem on. Often this makes the stem to short, and as a result, the bike handles poorly.

    The top tube length is another common mistake. The top tube is proportional to your torso, and any companies today are producing longer top tube lengths than the average person needs. For example, the top tube length on a Large Giant is 58.5cm. Giant states that a person 5'11"-6'1" can ride a large. The large majority of the people that are that height do not have a long enough torso to properly fit this bike. I will admit that some people can ride it, my friend rides a large with a 120mm stem... He's also 6'4.5", well over the recommended size for him. If he were to ride an XL, as suggested, the top tube would be to long. When you ride a bike with the top tube to long, it forces you to do one of two things. 1, Sacrifice the difference with your stem, but I have already mentioned the sacrifice in performance that comes from this. 2, you can try and correct it by pushing your saddle forward.

    Your saddle position is also very important. With the saddle pushed to far forward, your knees are over the pedal to much, and it causes your pedaling to be incorrect. Saddle position is affected by your seat tube angle.

    The ideal seat tube angle is 73 degree's. With a seat tube angle of 73 degrees, you can have your saddle far enough back that your pedal stroke is able to push and pull through the full range of motion, resulting is better power and efficiency.

    These are just some of the very BASICS that I have learned from Antonio, there are so many factors that affect bike performance, that there is no way I can list them all. Antonio believes that fitting a person properly on a bike is a passion, and an art, that comes from within. I have found that having a bike that fits properly makes the biggest difference in my riding. I am now able to carve corners and go on long rides in comfort.

    The bike that he has built for me is so smooth that if I knew when to turn, I could ride blindfolded. The bike has almost become a part of me, an extension of my body. I am riding a bike that fits and rides the way a bike should, and so could you.

    Antonio has VERY competitive pricing, and many of his customers are so satisfied with the bike that he builds for them, that they have him build another, if not two more. Check out his website at www.bicycleworldusa.com It has some information on Antonio, his shop, and a look at some of the frames that he offers.

    By the way, Antonio builds his bikes with Dedacciai U2 and 6110 tubing, the same tubing that Pinarello uses in their Dogma and Prince SL, but at a much lower price, for a custom bike. You can get your bike built any way you want it, with any tubing from Dedacciai, including carbon. You can check out Dedacciai here: http://www.dedacciai.com/products.asp?type=1&tid=64
     
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  2. lochick87

    lochick87 New Member

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    I was just wondering, when you are sitting on the saddle and put your feet down should you only be able to touch the ground with your tip toes? and also, how do you push a saddle forward?
     
  3. boudreaux

    boudreaux New Member

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    Where did you dredge up this nonsense and drivel? The dogma is Magnesium.
     
  4. boudreaux

    boudreaux New Member

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    Loosen the clamp bolt and push from the back.
     
  5. RC2

    RC2 New Member

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    How long does it take to post such an elaborate post and not get such things... Weird? :confused:
     
  6. RC2

    RC2 New Member

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    You can disregard B's response as a friendly, questionable attempt at humor. On the saddle, your knees (front of the patella) should generally be directly above (use a plumb bob) the pedal spindles...GUIDELINE ONLY...if you're out of that ballpark raise a flag.

    Should you be able to touch the ground with tip toes?..see above. Probably not; learn track standing or clip out. How far forward should a saddle go??...knees over spindles is again the general rule, but if you haven't already spent time with a fitter with average or above gray matter quantity and quality, that may be a moot point. Fitting involves more than rules of thumb -- it's often straightforward for 'average' humans (i.e. proportionate upper/lower body in synch with the framebuilder's assumptions, etc.) but your mileage may vary a lot. Get a good tech from a trusted LBS and pay him/her a few bucks, it's worth it.
     
  7. Rompinrhino

    Rompinrhino New Member

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    Yea, I messed up. The Dogma is MG. I know the Prince SL uses U2 tubing, and then the Paris uses 61.10 I THINK. So don’t get all excited if I don’t get that right either. Pinarello likes to call it "Pinarello Prince SL" tubing. They also use a hydro formed tubing.

    And I messed up because it was late, I haven't slept much in the past few days, and so I goofed. Big deal. You guys are quick to jump on the small mistakes and overlook the bigger picture.

    I wrote this more about bike fitting. I don't really care what the Dogma is made of. The only point in bringing up Pinarello was to point out that you can get the same tubing in a custom bike for about $800 less.

    I "dredged up this nonsense and drivell" from my own experience. By talking with Antonio, I've learned a lot about fit that I never knew. I thought I had my position perfect, and several bike fit people confirmed that. I know better now. And just in case your thinking of jumping to the conclusion that Antonio doesn't know any better, let me tell you something about him.

    He worked in Italy, with Ernesto Colnago, for almost 10 years. He learned bike fitting from the same man who fit Eddy Merckx and a bunch of other champions. In fact, he uses the exact same tools that Colnago uses. When he thinks he's stuck, he e-mails the man himself to get the answer. You can fly to Italy to get it done, or you can fly to California. Your choice.
     
  8. Rompinrhino

    Rompinrhino New Member

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    Hey, I know that when I thought I was fit properly on the bike, I was able to put my feet down when I was at lights. After getting fitted by Antonio, he raised my saddle a lot, and now I can't. The difference was in pedal stroke. He changed it from a heels down method to a heels up. I think it lets you pull through better. I know it works though. When I stand behind my bike without shoes, the saddle is almost at my belly button.
     
  9. artmichalek

    artmichalek New Member

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    I think it's ironic that someone would blast other builders for their one size fits all mentality, then go on to insist that everyone needs the same stem length and seat tube angle. I realize that a lot of builders determine seat tube angle by convenience rather than fit, especially at the outside ends of the size spectrum, but 73 degrees isn't some sacred number. If it was, you wouldn't see so many bikes with 73 degree seat tubes built up with set back seat posts. If everyone had the same thigh/shin ratio and did the same kind of riding there might be a magic number, but there isn't. Seat tube angle should be fit to a person's individual power vs. comfort balance as well as their measurements.
    As for stem length, we've been over this in other threads and it seems there's no agreement on what an optimum length is for everyone. I for one have a 90mm stem and my bike is anything but twitchy. I have a long torso, but prefer the feel of a shorter reach. My experience has been that for me a short stem and a long wheelbase feels more stable than a short wheelbase and a long stem.
     
  10. Rompinrhino

    Rompinrhino New Member

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    Hmm, Interesting. I'm not saying that everyone needs the same stem length. I'm saying that a 110-120 stem is ideal, and if your bike fits you properly, thats what you'll have to. There is a way that a bike should handle. A 120 stem is perfect because the bike responds better. I've had a 90mm stem, and I didn't think it was that twitchy either because I rode it all the time. I had to be cautious though because small movements make the bike turn quicker. I didnt say 120 was a must, I said it was ideal. And if the top tube length is correct, then you should be using a 110 or 120 anyway.

    I didn't say that 73 degrees for a seat tube angle was the magic number. I also didnt say that with the same angle you don't use a strait seat post with no setback. The seat tube angle will change when you get into smaller frames. It increases.

    You can have a long wheelbase and still have a 120 stem. My bike with a 56.7 top tube has a longer wheelbase than my Trek with a 58.5 cm top tube. The difference is that the head tube angle on the 56 is much more relaxed, and that gives it the extra length
     
  11. artmichalek

    artmichalek New Member

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    But there isn't. If you're building a bike to race crits or ride double centuries, that handling ideal is going to be completely different. Stem size, top tube length, and head tube angle all make different contributions to the overall feel. There's no ideal number for any of them because they have to be balanced.
     
  12. Rompinrhino

    Rompinrhino New Member

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    I can't argue that, I'm not an expert on it.
     
  13. Leozinho

    Leozinho New Member

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    I'm sure this is Antonio is a great guy, but by any chance did he serve you kool aid when you visited his shop?

    (You make some valid points, I think, about makers going to S, M, L frames, though.)
     
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