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Old 03-28-05, 03:02 PM   #1
fitmiss
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Stems

Reasonably speaking, how much can you adjust the distance between the seat and handlebars by changing out the stem? For example, I need a top tube length of 50 CM but the top tube on my new bike is 51.7. Can you change out the stem to bring the handlebars closer so that it fits exactly?

Hopefully I've worded my question correctly as obviously, I am a newbie.

Thanks in advance.
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Old 03-28-05, 03:08 PM   #2
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Well, you can move the saddle forward and back about 2-3 inches total. Have you tried that?
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Old 03-28-05, 03:33 PM   #3
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stems range from like 30 to 120mm...so take your pick
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Old 03-28-05, 03:50 PM   #4
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I am asking because I am a Newbie about to buy a new bike. I know that based on measurements, my ideal top tube length is 50 CM. The bike is 51.7. For other reasons, the bike is the right size. So I was just double-checking what can be done to fit the bike.

There are not alot of WSD bikes around in various sizes to test ride. I'm sure once my LBS makes the adjustments and I test ride the bike, everything will be fine.
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Old 03-28-05, 03:52 PM   #5
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Yeah, you should be able to adjust yourself correctly.
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Old 03-28-05, 06:23 PM   #6
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Your ideal tt length is 50 cm, and the actual tt length of a bike your are looking at is 51.7 cm.

This is a difference of 17mm. You either need a 15 or 20 mm shorter stem. Your dealer would probably be happy to switch a stem out for you, if it meant that they could sell you a new bike.
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Old 03-28-05, 08:52 PM   #7
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I wouldn't adjust reach by moving the saddle a lot fore and aft; set the saddle to a good position for the cranks. Use stem to adjust the reach. Normal stem lengths for road bikes are something like 8 to 12 cm, but I have seen shorter ones and longer ones used. Stock bikes often come with 10 or 11 cm stems. - Jim
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Old 03-28-05, 08:54 PM   #8
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Keeping in mind that for angled stems, stem length doesn't translate directly to reach length. - JIm
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Old 03-28-05, 08:56 PM   #9
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Quote:
Originally Posted by jaldridge
Keeping in mind that for angled stems, stem length doesn't translate directly to reach length. - JIm
Nice one. I totally overlooked that.
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Old 03-28-05, 09:03 PM   #10
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I've always liked this chart from Habanero Cycles.

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Old 03-28-05, 09:08 PM   #11
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I have found that each 10 deg. rise=about 1/2" shorter reach versus a 0 degree stem. (This is assuming the nominal length [horizontal extension] of the stem (in mm) is the same in both cases.)
(I usually go shorter--that seems to be, roughly, the formula I've come up with through experience.)

This is only approximate, but it's a starting point.
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Old 03-29-05, 04:25 AM   #12
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You are right to raise the issue of length, too many women are riding bikes which are too long.

You say you need a WSD (women's) bike. How big is the frame?
If you are a newbie, how do you know that you need a 50cm TT?

For a small bike, 1.7cm is quite a long excess in TT, you have to think percentages rather than just absolute distances. If you are chosing a new frame, then pick one with the right TT length. TT is THE most critical dimension on the frame.

Although you "size" a bike by its seat tube, as long as you have standover clearance, you can adjust the saddle height. The modern style is for smaller frames with more standover, and for compact/sloping TT designs. Generally if you are inbetween 2 sizes, you should select the smaller size.

Dont adjust the length of the bike using the saddle, you need to set the saddle relative to the pedals, THEN set the bars relative to the saddle. If your cranks are excessively long, then this will affect your saddle position. You have to start the sizing process with correct size cranks and correct size top tube.

You have +-2cm of adjustment in stem length. Shorter stems will affect the steering, making it more sensitive to input, but the only way to see is to try it. Make sure you use a stem with a front-loading design and pick a bike shop that will let you swap stems around to try them whilst riding.

Most guides to fitting are more relavant to athletic males of average size who want to race. Have a read of some more comprehensive and well thought out guides at:
www.peterwhitecycles.com/fitting.htm
and
http://www.myra-simon.com/bike/tips.html

Last edited by MichaelW; 03-29-05 at 07:58 AM.
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Old 03-29-05, 08:36 AM   #13
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Quote:
Originally Posted by MichaelW
You are right to raise the issue of length, too many women are riding bikes which are too long.

You say you need a WSD (women's) bike. How big is the frame?
If you are a newbie, how do you know that you need a 50cm TT?

For a small bike, 1.7cm is quite a long excess in TT, you have to think percentages rather than just absolute distances. If you are chosing a new frame, then pick one with the right TT length. TT is THE most critical dimension on the frame.

Although you "size" a bike by its seat tube, as long as you have standover clearance, you can adjust the saddle height. The modern style is for smaller frames with more standover, and for compact/sloping TT designs. Generally if you are inbetween 2 sizes, you should select the smaller size.

Dont adjust the length of the bike using the saddle, you need to set the saddle relative to the pedals, THEN set the bars relative to the saddle. If your cranks are excessively long, then this will affect your saddle position. You have to start the sizing process with correct size cranks and correct size top tube.

You have +-2cm of adjustment in stem length. Shorter stems will affect the steering, making it more sensitive to input, but the only way to see is to try it. Make sure you use a stem with a front-loading design and pick a bike shop that will let you swap stems around to try them whilst riding.

Most guides to fitting are more relavant to athletic males of average size who want to race. Have a read of some more comprehensive and well thought out guides at:
www.peterwhitecycles.com/fitting.htm
and
http://www.myra-simon.com/bike/tips.html
Thanks for your response. I've been lurking on this site for months taking in as much information as I can. I stopped in a bike shop once and they did a preliminary measurement which is why I stated I need 50 CM TT.

My hunch is that I will probably have to order the smaller frame although I need to talk to the LBS about why he thinks I need the bigger frame. He did say something about me needing to have the seat too high with a smaller frame but I will discuss it with him further. The last thing I want to be on the bike is too far stretched because while I am in good shape, my back is my weakest point due to being rear-ended in a car a couple of times.
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Old 03-29-05, 08:58 AM   #14
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It sounds to me like you've had a "fit session" of some kind.

Don't take the advice that they gave you too literally. The top tube difference that you are talking about is less than a 1/2 inch. Being new to road bikeing, you will probably prefer a handlebar position that is a little bit higher and a bit closer to you than the racers like. My advice is to experiment a little around the parameters that they gave you and, if you find yourself doing something that's way off, it's probably wrong.

One of the other posters suggested moving your seat to adjust seat to handlebar distance. I think that's bad advice. My method is to adjust the seat to pedal position first THEN work on getting the handlebars right. Unfortunately, seats are easy to move and handlebars can be expensive to experiment very much.
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