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Help with stems!!!(6 posts)

Help with stems!!!Boris
Feb 19, 2002 5:41 PM
How are stem's length measured??? also, if a buy a o degree rise stem, it will actually point up because of the angle in which my fork is in, right?
stems:rusty McNasty
Feb 19, 2002 5:47 PM
Measuring reach: Center of the stem to the center of the bar-shortest distance (straight across)
Yes, a 0 degree stem will point upward slightly
Feb 19, 2002 7:13 PM
Common confusion reigns on stem rise specs. Here is the scoop: 0 degree stem means there is by definition no rise (the 0 degree refers specifically to no rise). That's the same as a 73 degree ANGLE stem (73 degrees is the angle formed by the stem base and its top). A _90 degree angle stem_ will "point upward slightly" (actually, by 17 degrees). Again, 90 degrees is the angle formed by the base of the stem and its top.
Feb 19, 2002 7:23 PM
Road stems are not advertised by degrees of rise like mountain stems often are. You will commonly see 73, 80, 84 and 90 degree angle stems which produce a "rise" of 0, 7, 11 and 17 degrees respectively. The 73, 80 and 84 degree stems can generally be flipped to produce angles of 107, 100 and 96 degrees or rises of 34, 27 and 23 degrees.
what would be helpful is rise versus inchesPaul
Feb 20, 2002 4:30 AM
I have the Ritchey 84 deg. stem which is advertised as +- 6 deg. I measured the rise (approx) in inches in reference to the top tube, and it's 1/2 to 3/4 inches depending on the flip.
Two different notationsSpoke Wrench
Feb 20, 2002 6:18 AM
Back in the olden days when men were men and stems had quills, virtually all decent quality stems had a roughly 72 degree angle which ment that the top of the stem was roughly parallel with the ground.

Many stems today continue to use the angle notation which references the ground. Consequently we have 90 degree stems, 84 degree stems and a host of others including adjustable

But, the advent of threadless systems allows a stem to be inverted to give two different angles relative to the ground. Consequently, it makes more sense today to refer to the angle of the steer tube clamp. As a result, a zero degree stem would be 90 degrees with the traditional notation and, relative to the ground, will angle upward to the handlebar.

If that's not confusing enough, there are two differing horizontal notation methods too. QBP refers to "extension" as the hypotenuse distance from the centerline of the steer tube to the centerline of the handlebar clamp. "Reach" is defined as the right angle distance from the centerline of the steer tube to the centerline of the handlebar clamp. These measurements will be equal on a 90 degree stem and will increasingly vary with differing angles.

Finally, there is one other important dimension that nobody talks about. With threadless systems, handlebar height is affected by the steer tube clamp height and where exactly the extension attaches to the clamp. In other words, a 95 degree 110mm extension stem from one manufacturer may yield a different handlebar position than a similar stem from someone else.