[Farmpunker]

I'm completely scoobied by stem rise. I searched back through the archives and only got more confused.
So here's my dumb question: my current stem is a little below horizontal. Flipped, it's way over. I'd like to be at or a little above horizontal. There's a nice stem on ebay, a -10 rise. Where will that stem put me?

 

[Spunout]

-10 would be something less than what you have now...

I'm completely scoobied by stem rise. I searched back through the archives and only got more confused.
So here's my dumb question: my current stem is a little below horizontal. Flipped, it's way over. I'd like to be at or a little above horizontal. There's a nice stem on ebay, a -10 rise. Where will that stem put me?

If currently your stem is below H, then you have a -17 or so. Generally, your HT will be 74. Definitely will rise alot if you flip it.

So, a -10 will be slightly above horizontal. I use a slight positive rise on a Thomson +5. So, a zero would be perpendicular to the steer tube, and would rise at the angle of the HT.

 

[MC Hammer Pants]

this post is really old, but just in case youre still wondering...

Here is the explanation I found in some thread somewhere. First the variables are explained, then the formulas, then examples... It helped me a lot to draw pictures to better understand what was happening. This is cut and pasted from an email to a friend... thats why the examples arent actually what you asked about...


SA = stem angle
--> e.g +/- 7deg = 83/97 degree
--> e.g. +/- 17deg = 73/107 degree
--> depends on whether the stem is "upside-down" or not.
--> can be measured if you have the right tools. or look it up online

HTA = head tube angle = determined by the frame of you bike, cannot be changed
--> a Trek 1500 in size 52 has a HTA of 71.5 degrees
--> a Lemond BA in size 55 has a HTA of 73.5 degrees

L = stem length = measured from center to center of clamps along the
side of the stem

Formulas:
(SA-HTA) = #
horizontal distance = COS(#)x(L)
verticle rise = SIN(#)x(L)


e.g.

(a)
--> 97deg - 71.5deg = 25.5deg
--> COS(25.5)(90mm) = 81.233mm
--> SIN(25.5)(90mm) = 38.746mm

(b)
--> 107deg - 71.5deg = 35.5deg
--> COS (35.5)x(110) = 89.553
--> SIN (35.5)x(110) = 63.877

(c)
--> 97deg - 71.5deg = 25.5deg
--> COS(25.5)(110mm) = 99.284mm
--> SIN(25.5)(110mm) = 47.356mm

 

[divve]

I can tell by that picture you take your bar wrapping seriously

 

[C-40]

sure about that??

Very few threadless stems are offered in the old 73 degree angle, which makes the stem exactly horizontal with a common 73 degree head tube angle.

The next step up is an 80 degree which raises the bars a bit less than 1cm, depending on the exact length. Flipping this stem to raises the bars another 3.5cm, which is a lot.

The next step is an 84 degree, which will raise the bars another 1cm. Flip this stem and will only raise the bars another 2cm.

 

[mness]

You need this spreadsheet

I'm completely scoobied by stem rise. I searched back through the archives and only got more confused.
So here's my dumb question: my current stem is a little below horizontal. Flipped, it's way over. I'd like to be at or a little above horizontal. There's a nice stem on ebay, a -10 rise. Where will that stem put me?

This spreadsheet was posted by Clary on MTBR a while back. You enter your head tube angle and the stack height, spacers, angle and length for two stems, and it tells you the reach & height difference and shows you a picture. Great for playing around with combinations before you lay out the money.

<a href="http://users.rcn.com/mjness/stem_and_handlebar_comparator.xls">stem_and_handlebar_comparator.xls</a>