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fit, handling and stems(6 posts)
|fit, handling and stems||colker|
Sep 13, 2001 2:07 PM
|hmmm... i'm new to road riding but i'm already doin it every day. got myself a 54 pinnarello cadore. i should ride a 53 and i would have a 1/2 degree steeper seat angle, 1/2 cm shorter top tube and 1cm shorter head tube (on pinnarello and other italian frames). nothing drastic. actually some american 53's have almost all the same numbers (but s.o. height) as my 54. |
well, the question: which stem is right for me? i've tried a 12cm, a 13cm and a 11cm.
with the 11cm the bike handles much better while commuting (braking accelerating cornering all done quickly). the front feels right! the problem is: i don't achieve the flat back i see on race photos. nope.i'm cramped.
on the 13cm, i'm on the right spot for speed in the drops but ridin wiht the hands on the hoods is bad.very bad.
the 12cm stem resumes the worse of both worlds.bad handling and slightly cramped for speed.
isn't stem length related somewhat to front angle? is it the reason why the longer stems are giving me bad handling?
ahh.. i got the sizing from lemond's formula and colorado cyclist's fit system.
|Do a search.......||Len J|
Sep 13, 2001 3:04 PM
|of this site for "idiot's guide to bike fit" by a poster named "E T" it's a good place to get your answer.|
|I think that stem length probably does affect handling, but||bill|
Sep 13, 2001 3:05 PM
|not too critically. I've noticed some difference in handling with stem length, but I wouldn't say that it's inherent to the bike's ride, if that makes sense. In other words, I think that you can get used to the difference and compensate, unlike head tube angle, rake, and trail, which will affect the bike's ride despite all efforts to compensate. |
A longer stem will do two things - place your bars at the end of a longer lever, so that the bars will turn in a wider arc, and place your weight a little farther out front. You can adjust for both by (a) getting used to the steering, and (b) lightening up a little.
I think that one of the better tests for proper stem length is, how do you feel? Sounds silly, but it's true. If you are too cramped in the cockpit, your neck and arms will hurt (as well as your hands), because you're effectively pushing back on the bars instead of laying over comfortably. If you're too long, you immediately will feel just too stretched out, but, I still would try to work with it a little to see whether you can get used to it. The right length, the length where all those pains go away, can feel awkward at first if you've become used to something else.
Stem length is not a terribly critical measurement, in my opinion, because your comfort at different lengths can change, because you have different hand positions, because it doesn't much matter to the repetitive motions, etc., but the right length can be more comfortable.
The ol' can you see the hub actually works fairly well, IMHO. The other one that's sort of intriguing is to lay your forearm (elbow to pointed fingers) from the point of your seat toward the stem. Then lay your outstretched hand sideways. The sum of the two is supposed to reach to your bar. I don't know why this one would work, but some people think that it does.
A far more critical measurement to how you feel in the drops versus the hoods versus the tops is the angle of the bar in the stem. Check to see that the angle is consistent as you try the different lengths (rolled neither too far forward or backward, with the ends of the drops pointing, in my opinion, midway between the rear axle and horizontal).
Sep 13, 2001 5:07 PM
|One of the things to check is knee-to-elbow clearance when pedaling in the drops, with the fingers in reach of the brake levers. Major knee and elbow knocking is a sure sign of a too-short stem. More than 1cm of clearance is unnecessary, but won't hurt anything.
You will find that regardless of how long the stem is, it's always possible to create interference between the knee and the back of the arm (above the elbow) if you crouch low enough.
The idea that a longer stem or top tube will produce a flat back when riding in the drops is a misconception. All it does is pull the arms further forward. When you're in the drops, the arm will have more knee-toe-elbow clearance. If your back isn't flexible, it will never be very flat. Stretching exercises are the key to developing this flexibility.
A stem that is too long can put additional strain on the shoulder muscles, when riding on the brake hoods. From your description, you have experienced this. If you need the longer stem for knee clearance, you need to have patience. It may take a lot of miles to get comfortable with a long stem.
As for the effect on steering speed, each additional centimeter of stem length only lengthens the distance from the center of the steering tube to the brake hood by 2%. A 2-4% change in steering speed or leverage is such a small amount that you will quickly adjust to it. You can't blame stem length for bad handling. I've used stems from 90 to 120mm in length with success. In my early days, I rode with a little knee-to-elbow overlap, but as I became more experienced, I gradually became able to comfortably use longer stems and a lower bar position.
|glad to see the responses include comfort||ishmael|
Sep 14, 2001 5:33 AM
|its the most important thing...if you want to get aero you can always go to the drops or lay out more..if you are comfortable you will handle the bike better and have unfatiged arms, shoulders, back and neck...over time you might want to go with the longer stems if you get more flexable but id say deffinately go with what is comfortable...youll probably go faster too|
|re: fit, handling and stems||VW|
Sep 14, 2001 8:48 AM
|I noticed you kept saying longer stems gave your bike bad handling. I also read other post here saying the change from 11cm to 13cm shouldn't affect handing that much.
I think when you are trying to achieve the "flat" back, you are reaching forward hard to get to (for you) an unnatural position. Your back is fighting to not get flat, and your arms are trying hard to pull your back flat. Your arms are stretched straight and working hard to keep your flat back position. Naturally, you will have a difficult time with steering.
I would go with the 11cm until you gain more flexability before switching to a longer stem to flatted your back!