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Thanks for all the help C-40(4 posts)

Thanks for all the help C-40Mr Nick
Sep 23, 2003 9:08 PM
You explanation brought everything together with the stem angle. For that I thank you. Maybe you can help me with my real problem and why all this arose. I want to be in a more aero position. I have become more flexible since I started and I tend to ride in my drops more now to get a lower position. I flipped my 107 degree stem so that is was a 73 like you stated, which makes it almost parallel on my Lemond Zurich which is a 57cm and has a 73.5 degree head angle. With my current 3.5cm of spacers this gives me a saddle to handlebar drop of 9cm. I also measured the reach from the tip of my seat to the top of the handlebar with the stem in both positions and turning the stem over has increased the reach by about 3cm. This is obviously a problem because I am pretty comfortable with the reach, I just wanted to go lower. So how do I figure out what length stem to use if I go to an 80 or 84 degree stem? By the way my current 107 degree stem is 110mm long.

Once again I appreciate your advice.
calculations....C-40
Sep 24, 2003 4:53 AM
When you flipped the stem, the HORIZONTAL reach only increased by 2cm (trust me, it's simple trig), but if you are measuring the reach at an angle from the tip of the saddle to the center of the bars, this distance will increase by about 2.5cm.

The short answer on the stem length is that you could use either an 80 or a 90. With the saddle as far forward as you have yours, it would be unusual to need a stem shorter than a 90. With the shallow 80 and 84 degree stems, the reduction in the horizontal reach due to the angle is only 1-2mm, so it is ignored. When you progress to a 90 degree stem the horizontal reach is about 5mm shorter, and the stem length is actually in-between the standard lengths.

Before making any more radical changes, ride the bike for a while and see if it's tolerable. Also check for knee to elbow clearance when riding in the drops, with you fingers in reach of the brake levers and the upper back horizontal. In this position, any amount of clearance is enough. If you have 2cm of clearance, for example, a 90cm stem would reduce this to zero, which is still OK.

If you want to see what the reach of a 90mm stem is like, simply move your saddle forward by 2cm and try riding it. If it feels good and you have knee to elbow clearance, you can then get the new stem and move the saddle back where it was.
Flipping a 110cm stem means roughly 4cm of dropelviento
Sep 24, 2003 9:39 PM
which is pretty dramatic by any standards. Maybe you should start by not flipping the stem, but moving some spacers above the stem, and drop the height by maybe 5mm at a time.

You will probably be able to adjust to the longer reach, because when you go lower, your upper body naturally rotates forward so the longer reach in handlebars actually is normal.

Many people have a position that they think is ideal for them, but what's ideal changes along with many factors.

And it takes much tinkering to find the illusive ideal position. DOn't be in a hurry to spend that money...
Actually I take that backelviento
Sep 24, 2003 9:42 PM
since yours is a 17 degree model, the drop is more like 6-7cm. The rest of the analysis still stands.