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Bike fit question(14 posts)

Bike fit questionRode Warrior
Jun 27, 2002 9:09 AM
Having recently begun experiencing "numbness", I have been trying to adjust my seat angle to relieve the pressure. I have found that if I tip the seat down much at all, I begin to slide forward when I go over any bumps. The seat doesn't need to be tipped very far down to do this either, maybe 5 degrees, or so. I also feel stretched out in the cockpit, is it possible that my stem is too long, and a shorter stem would fix this problem? I am also considering a seat with a cutout, but I don't want to waste my money on a seat if a shorter stem would solve my problem. Anyone have an idea. I will be happy to answer any legitimate questions, and thanks in advance.

Steve
when you are on the hoods....tronracer
Jun 27, 2002 9:16 AM
you should look down and see that the handlebar blocks the hub from your sight. If the bar is behind the hub, stem too short, ahead, too long.
obscuring the hub just a rule of thumb.,..not always true (nm)ColnagoFE
Jun 27, 2002 9:53 AM
I used to think this was ....Pecos
Jun 27, 2002 10:38 AM
the proper "rule of thumb", but it is totally baseless. Picture this, you have two frames with the same TT, stem lengths and same seat tube anlgles and lengths, but the front fork on one frame has more or less rake, do you think the hub will be viewed as being in the same position from the hoods or the drops? Imagine that the head tube angles differ also, this will further throw the "blocked from view theory" out of the proverbial window. Someone in a shop pointed this out to me only yesterday. Don't use this criteria as a judge for fit. JMO and others too :o)
re: If you ride with your hands on the hoods most of the timedzrider
Jun 27, 2002 9:25 AM
Try loosening the stem and rotating the bars a little bit to bring the hoods up and toward you. It may be more comfy there and answer your question. Please remember to retighten well before riding. When you do this, the drops will be further away, so it's not necessarily a long term solution, just an experiment.
Could be that your saddle is too high. Could be that yourbill
Jun 27, 2002 9:40 AM
saddle is too far back. Either will make you ride forward on the nose of the saddle, causing numbness.
If you're not experiencing pain in your triceps from being too stretched out, I would venture that your saddle is too high. A little bit of lowering will allow you to sit back more to a surprising degree with a surprising increase in comfort.
I wouldn't mess with tipping the saddle too much. They are designed to be level (of course, everyone is a little bit different), and tipping the saddle forward (nose down) probably will force you forward on the nose, just worsening the problem. You should be able to sit comfortably with most of your weight on the rear of the saddle (your sit bones -- someone said that it should be no less comfortable than sitting on a curb, which I thought was pretty apt).
Your arms and shoulders (and hands) are pretty good indicators. Pain through the shoulders is from the cockpit's being too small, so that you are pushing back from your bars. Pain in your triceps, from hanging out too much from being too stretched out. Either way stresses your hands and wrists.
Could be that your saddle is too high. Could be that yourRode Warrior
Jun 27, 2002 10:29 AM
When I am on the hoods, my front axle is about halfway on my stem. I also feel some discomfort along my upper arm/tricep area, but only on my left arm.

I'm thinking I'm too stretched out with this setup. Thanks for the advice all.

Steve
re: Bike fit questionjtolleson
Jun 27, 2002 10:22 AM
The above suggestions are all good, and a fitting at your LBS can confirm your current setup.

You need to do things in a specified order. First, get saddle fore-aft (and height of course) correct in relation to the cranks. Generally, that means obtaining a precise Knee Over Pedal Spindle (KOPS) position FIRST, before evaluating your reach and drop to the bars.

Then, evaluate your reach. Do you need more or less length or more or less rise? All can be addressed (within reason) with a stem change.

You didn't say, but how much a height differential is there between your saddle and your bars?
KOPS is BS...opencl
Jun 27, 2002 4:10 PM
according to Keith Bontrager, the KOPS concept is baseless.
Not so fast...jtolleson
Jun 27, 2002 6:24 PM
you are misstating his position, and my abbreviated post oversimplified my own.

Bontrager (and most) say that the unwielding devoting to kops is overemphasized. Fair enough. Calling it "BS" is probably an overstatement.

But the bottom line is that for the knees of most normal humans, effecient and comfortable cycling is achieve within a few cm of vertical. Back some (a la Lemond), forward some (a la a tri setup)... cool. Too much of either gives an all-quad mash or an all-hamstring pull.

But some folks adjust their saddle exclusively for reach, without regard to what they are doing for lower body biomechanics. Would you have this rider set his fore aft based only on where he wants to be in relation to the bars? No.

Not to mention that if you've ever had a fit with a power output measurement, there is a fore-aft position at which most riders are the most efficient, and it is pretty darn close to KOPS. While we're name dropping, I'll say ... ask Ben Serotta.
re: Bike fit questionMXL02
Jun 27, 2002 10:44 AM
I agree the above. After setting the KOPS, get a comfortable saddle height, but keep the saddle tilt level. Do not tilt it forward. Adjust your reach with stem length and/or handlebar rotation. Any numbness you are having may be due to saddle shape rather than position, anyway. Agree with trying either a gel or cut out.
Skip the new seat, look to the stem.Quack
Jun 27, 2002 11:25 AM
If you feel stretched and are getting numbness, you are tipping too far forward. I would recommend as a test to slide your saddle forward until you feel comfortable and note how far you moved it from its original position. If you subtract that amount from your existing stem length and can get a stem that short, great! If you find that your stem needs to be shorter than 7cm, it might be time for a smaller frame with a shorter top tube, or just forget the magic pedal/knee/saddle relationship and ride the frame you have.

Sometimes, you can make a dramatic improvement to comfort by moving your levers up the bar a couple centimeters to shorten the reach to the hoods. There is no magic location for levers. I've seen pros with levers so high up that their levers look like guns. I personally tilt my saddle slightly up to encourage me to stay on the sit bones and not slide forward while riding. If you get on your sit bones, the numbness will go away.

Good luck!
are you having a fit about fit? :-) nmET
Jun 27, 2002 12:13 PM
.
something like that :) nmRode Warrior
Jun 27, 2002 1:38 PM
.