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Stem Rise/Fall?
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I am looking to get into a more aggressive aero position. I was wondering if I could use a stem that drops the aero bars to a lower position? How much would the handling of the bike would be affected by such a stem that drops the aero bars to a lower position, creating a virtual shorter head tube? If so, how much do you think would be too much, I'm considering a 2cm drop. My current set up has my stem level with the ground, i.e -17 I think? thanks
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Re: Stem Rise/Fall? [Luntzy] [ In reply to ]
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Getting lower may not always be the best thing to do. Read Slowman's take on this. He provides a theoretical formula for determining armrest drop http://www.slowtwitch.com/...techctr/bikefit.html

I assume you're using a -17 quill stem. The only thing that I'm aware of that angles lower is a "track" stem used on older track bikes. They show up on ebay ever now and then.
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Re: Stem Rise/Fall? [cerveloguy] [ In reply to ]
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Salsa, Deda, Nitto all make "track" drop stems greater than horizontal (<-17 or 73 degrees) currently.

Low is slow, narrow is aero.

-SD

https://www.kickstarter.com/...bike-for-the-new-era
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Re: Stem Rise/Fall? [Luntzy] [ In reply to ]
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You can always just flip a 45 degree mountain bike stem upside down (threadless, that is). I did that before on a bike with at tall head tube. The position was ok, but the handling was less than ideal.

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Re: Stem Rise/Fall? [Luntzy] [ In reply to ]
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I'm going to assume that the headtube on your bike isn't particularly short, therefore, you are just trying to get a virtual headtube that is as short as some of the shorter out there like Cervelo with an integrated headset. I'm assuming you aren't really trying to pull a Jan Ullrich and go even lower than that.

Profile makes an H20 stem that is 115 degree / 65 degree. That gets you roughly 12 degrees lower than horizontal. They have a range of stem lengths and it costs about $40. I put one on my bike recently, switching from a 73 degree horizontal stem. The handling isn't any different, except it is actually better because I got a shorter stem and moved the seat back the same amount which got some weight off the front end. trisports.com sells all sizes, angles, and colors of the H20.

Physically/mechanically there is no difference in steering between a longer headtube offset by a down angle stem and a shorter headtube with a horizontal stem.

I went to the 65 degree stem because the headtube on my bike is fairly tall. So even with the new stem and a 77 degree virtual seat tube angle, I'm not even close to pushing the limits of aeroness or making the angle between my legs and torso too small. I'm in a good, comfortable position that I can ride all day long.

Hope that helps.


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Justin in Austin, get it? :)

Cool races:
- Redman
- Desoto American Triple T
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Re: Stem Rise/Fall? [Luntzy] [ In reply to ]
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Remember that by flipping your stem over will reduce ur drop quite substantially.

To calculate the absolute drop in handlebar height (disregarding the change in length), the change in height will be the stem lenght multiplied by Sine of the twice the stem angle.

Assuming if you are using a 17 deg stem with a 10cm length. The drop will be 10xSin(17x2) = 5.6cm

Unless your original position was completely too high or u are planning for an overly aggressive drop, lowering the handlebar via spacers will be better, assuming that there are still spacers underneath.


*You're no good to me dead*
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