|picking a stem for a road bike||bonsai171|
Aug 20, 2003 6:58 PM
|is there somebody who could help me figure out what extension I should get? I read somewhere that the extension length should be long enough so that when you look down at your hub (when you're on the lower part of the handlebars) that you can't see your hub. It seems like for me 120mm would be a good length.. but i'm not sure about the rise. Should I get one which goes up or down? and how much? tia|
|Only a psychic can answer||filtersweep|
Aug 21, 2003 5:33 AM
|...more information is required. What do you have now and why do you want to change?|
|Only a psychic can answer||bonsai171|
Aug 21, 2003 8:10 PM
|the stem on the bike now is about 85mm. When I ride the bike, it is extremely uncomfortable as far as reaching the handlebars. It seems too short. The handlebars and seat are at about the same height, but my arms are kind of long so maybe a different extension will help ?|
|A couple of points.......||DINOSAUR|
Aug 21, 2003 8:47 AM
|Locate a good LBS and talk to someone about your problem. See if they have a couple of old stems you could try out until you find one that works. Stem length is related to anatomy and personal preference. I went through several stems on my old bike until I found one that worked. I was lucky as I found one on sale for $20.00, but stems can get expensive ($$$$$$$$).
They say that your front hub should be obscured by your handlebars when looking down when you are riding with your hands on your hoods or in the drops. It works for me, but some say it does not hold water.
You might consider getting professionally fitted and save yourself a lot of time and effort. But even then, things come down to preference and what feels comfortable.
You can also read stuff about fitting (Zinn's Book of Road Bike Maintenance has a whole chapter).
If you are new to the sport, or coming back (like I did) your position will change over the years. It might take a few years (or more) until you get everything dialed in......
|A couple of points.......||bonsai171|
Aug 21, 2003 8:14 PM
|that sounds like a good idea. Maybe that way it would be easier to pin down what i'm looking for. Out of curiosity, how much does it cost to be professionally fitted? There's a charity bike ride coming up next spring and the coach had suggested that too, but I wasn't sure about how much that would be. What are the benefits of that too? What exactly are they doing there? thanks|
|not enough info...||C-40|
Aug 21, 2003 8:55 AM
|To pick a new stem, you have to start with an existing stem to compare with, or dimensions from the frame (head tube length, including the headset) and your saddle height (from center of bottom bracket to top of saddle, along the seat tube). Dimensions from the frame and saddle height will only provide an estimate of the saddle to handlebar height difference.
It's impossible to predict the proper stem length without getting on the bike and performing a functional test.
Obscuring the view of the hub is a worthless standard that can be satisfied by 2-3 stem lengths.
A functional test is knee to elbow overlap. With the hands in the drops, fingers around the brake levers and back in a horizontal position, it's good to have a small amount of clearance between the knees and elbows. Beginners may have a bit of overlap. For this test to be valid, the saddle must also be in the position to produce the desired knee to pedal relationship. Moving the saddle forward or backward has a diect effect on the required stem length.
Aug 21, 2003 9:13 AM
|There are so many variables involved (frame size; fore-aft seat position; headtube height; body dimensions; etc., etc.) that it is impossible to give any meaningful advice.
If you already have the bike built up and it has a stem on it, listen to your body. Are you too cramped? Too strectched out? Go from there. The problem is that until you have a bunch of miles on the new stem, you wont know if it truly works for you. That makes going into a bike store and trying on stems tough.
My advice is to buy a really cheap stem in the dimensions that you think you need (I found a Titec for $10 that worked fine for me). If it doesn't work for you, try again. Once you are certain of the size and rise you need, then spend money on a chi chi stem if that is what you want.
Aug 21, 2003 8:19 PM
|the bike feels too cramped. I don't think it would be too much fun to ride it very far.. The extension on it now is 85mm. The bike is a Schwinn sprint that was just rebuilt with some different parts. My old bike was a Schwinn continental, and that extension was about 110mm I think? That seemed just right for me (maybe i'm answering my own question?? haha) anyways, well thanks a bunch|
|re: picking a stem for a road bike||hfc|
Aug 21, 2003 5:51 PM
|You can also use the wrenchscience website if you're starting fresh to calculate an overall reach measurement. This will be your top tube length (center of seat tube to center of headset tube) + stem length. This gives a ballpark estimate of where to start. Also remember, that longer stems (> 120 mm or so) have more flex and make the bike more difficult to control. As far as stem rise, I think it's just a matter of comfort vs. aerodynamics. The bottom line is though as others have said, the proof is in the pudding and how it feels when you ride.|| |