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Can someone translate stem rise?(6 posts)

Can someone translate stem rise?koala
Jan 20, 2002 6:26 AM
How much difference in actual bar height does an 80 degree stem make from a 73? If you flip the stem how many millimeters of spacers can you eliminate?
re: Can someone translate stem rise?Woof the dog
Jan 20, 2002 7:18 AM

maybe this will help.


Woof the ugly, disgusting, smelly, wet, dirty dog.
Apples and orangesElefantino
Jan 20, 2002 8:30 AM
Just to assure that things make sense, stems angles are not "measured" on a normal degree scale. A "90-degree" stem, for example (one whose stem is a 90 degrees from the quill or fork sleeve), is in cycling parlance referred to as a "0 degree" stem.

And the difference in bar height between stems depends on the length of the stem. The longer the stem, the more difference there is in bar height.

sort of...C-40
Jan 20, 2002 9:22 AM
There is only one type of "degree", it's the point of reference that is being confused. A 90 degree stem forms a 90 degree angle with the steering tube and produces a rise from the horizontal of about 17 degrees (90 minus the head tube angle). The rise in centimeters is the stem length times the sine of the rise (in this case sin17).

The stem angle tells most, but not all of the (bar height)story, since the steering tube clamp heights also vary between brands.

A 90 degree stem may be called a "zero" degree, but if so a line perpendicular to the steering tube is the reference.

The most common road stems are 73 (also called -17), 80, 84 and 90 degrees. Their respective rises would be 0, 7, 11, and 17 degrees, assuming a 73 degree head tube angle.

To add the the confusion, mountain stems may be identified only by their approximate rise from the horizontal. A 17 degree rise mountain stem stem would be a 90 degree road stem. Confusing isn't it?
get your protractor outishmael
Jan 20, 2002 8:58 AM
you can figure it out if you are really obsessed...i the way, ive found that other than salsa whom make alot of angles such as 70,80,90 etc, ritchey do 84, and there are 73s out there too as youve found..o and some 105s by itm
get your protractor out12x23
Jan 21, 2002 3:21 PM
Yeah, that's what I did. Based on a 73 degree headtube, I drew and measured several stem angles at 130cm length to determine the best for my Masterlight. This was in 1997, and I was really proud relating this over the phone to Tim at Branford Bikes (the guy I purchased the Mlight from). He listens patiently as I relate how I've really dialed this thing in and then says, "Mike, you really need to get out more." :-) Maybe so, but the stem I chose was perfect. Of course this was for a quill stem, and I didn't have to worry about clamp height as with nothread stems.