|Is my stem too long?||castrello|
Feb 10, 2003 6:31 AM
another exciting fit question for all you people out there. I purchased a new bike about a month ago. The bike is a Caad 7, size 60 (72.5 STA, 59 cm TT) that comes with a 130 mm stem. The question is simple really; is the stem too long?
My former bike had a 73 degree STA, 57 cm TT and a 125 mm stem. This bike, however, was purchased without too much fit knowledge, although it fit me nicely (but not perfect).
The saddle-to-bar-drop on my new bike is slightly less than the drop on my old bike.
90 cm inseam
67 cm arms
155-156 cm sternum notch
72 kg (skinny)
young, no back problems
I have done two tests.
1. The bars-over-hub test. I put my hand on the hoods and face forward. When I look down (without really turning my head, I just glance), I can´t see the hub if my arms are bent.
2. I also did a "test" described in the Idiot´s guide to bike fit found on this site. I did the following
"Now just put the back of your upper right arm against the nose of the seat, with the nose touching a few inches above your elbow, and forearm parallel to the ground and at a right angle with upper arm. Your right hand should be extended in the vertical plane, with pinky on bottom and thumb on top, with the fingers touching the adjacent ones and pointed in the direction of the handlebars. Next, place your left hand in the horizontal plane with palm facing down and fingers pointing to your right, and knuckles of left hand meeting the middle fingertips of right hand. Well, here's the ballpark rule for top tube length: the pinky of your left hand should fall smack on the middle of the bar top. (Go ahead and laugh. We only need ballpark here to prevent mistakes way out of the ballpark, and this test gives it. In any case, I asked several cyclists friends, all with very different types of body build, to try this test on their bikes whose setup they are happy with and it was just about dead on for them all. I urge you to try it as well; it's scary how close it comes. Betcha most of you are within +/-1 cm.)"
And my pinky fell smack on the middle of the bar top. Am I supposed to feel happy now?
So, is my stem too long? Judging by numbers, I´d think it is. However, riding on the trainer, it feels kinda ok, but slightly stretched out. Should I change my stem? 110 mm? 120mm?
|Surgically shorten it. Lighter, stiffer, more responsive. nm||dzrider|
Feb 10, 2003 7:06 AM
|stem length is alchemy. It's trial and error and what you get||bill|
Feb 10, 2003 7:30 AM
The best test for these things in my book is miles in the saddle. If you find yourself moving forward onto the nose of the saddle, assuming that the nose is not pointed down, your stem is probably a bit long. If you find your neck, shoulders and arms cramping up, somewhat counterintuitively it's probably because your stem is too short, and you're pushing back on the bars.
Eddy Merckx believes that bikes should have a 110 stem, that 110 is the best compromise between long enough to provide some suspension effect and some steering stability, but not too long.
Just by the numbers, I'm not much at the math, but the longer TT makes some sense with the slacker seat angle, although you may have to push the saddle a bit forward on the rails.
|re: Is my stem too long?||sacheson|
Feb 10, 2003 7:35 AM
|Did you buy this bike new? (I know you said "NEW" bike, but I don't know if it's new, or just new to you). If you did buy it new, take it back to the shop. I think you've dropped enough coin on a bike to warrant them helping you out with a couple of stem fittings so you can assess the fit of the bike and increase your satisfaction with the purchase.
On top of that, there are things like the saddle choice, seat post, fore-aft of the saddle, the bars you use (some put the hoods farther out than others, others have a shallower or deeper drop), your cleat position on your shoes, the shoes you wear, the peddle system you are using that will inhibit almost everyone on this list from being able to tell you where you should be on the bike - you have to see a skilled person in person to make these determinations. Since you are young and relatively new to cycling, consider the investment in a fit kit. It will get you started on the right path, and might limit any injuries you get from an improper fit.
Second, if you didn't buy it new off the showroom floor, you don't want to pay for a shop to fit you, or you live out in the sticks and can't get to a shop, you can do some testing rather inexpensively. You have a removeable face plate stem, correct? I think you can either visit your LBS or go online and find a relatively inexpensive 120 mm stem to try out. If you don't like it, you don't have much invested - if you do like it, you can either keep the cheapo stem or look for something more Gucci.
|A couple of ideas||bigrider|
Feb 10, 2003 8:17 AM
If your other bike was just right you need to use the M&M technique. That is measure and mimic. Just set up your saddle and make sure it is perfect in height and where your knees are over your pedals then measure from you saddle to your bars for length and height in relationship to your saddle. The same saddle on both bikes make this method flawless.
If your first bike was not perfect but close implement the first idea and then make small changes from your original position.
Ride it the way it is and see what it feels like. Change it if you need to otherwise leave it the way it is.
Feb 10, 2003 3:51 PM
|My understanding of it is to have your arms at approx 90 degrees to your torso and adjust your stem length accordingly (never your saddle). Of course if you want a bit more relaxed position you can get a shorter stem but I wouldn't recommend going longer... if you want to get more aero you just have to put a bend in your elbows.