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how are mtb stem angles measured?

14K views 15 replies 5 participants last post by  bing! 
#1 ·
For this stem:

Race Face Evolve Am Stem at JensonUSA.com

it says 82/98 degree. The midpoint of those angles is 90 degrees. For a road stem, 72 -73 degrees is considered level. So for a road bike a 6 degree rise stem would be 78-79 degrees. If an mtb stem's reference point is 90 degrees = 0, then a 90 degree stem already angles upward, correct? So a 6 degree stem really angles up? And a 10 degree stem points almost straight up?
 
#2 · (Edited)
No. Six and 10 degree stems are still angled up just slightly. Considered low rise stems.

Some companies give the stem extension angle relative to the steerer, some as a rise angle: 90 degree angle = 0 degree rise.

The Race Face is a +/-8 degree rise.

Traditionally, road stems have a -17 degree rise.

Final functional rise when installed depends on the frame's head tube angle, even on a road bike.
 
#6 ·
No. Six and 10 degree stems are still angled up just slightly.
Thanks for the info...but I can't agree with your characterization. A 90 degree stem already angles up--and by more than what I would call 'slightly', because the head tube angles are slacker on mtbs. So 6 more degrees angles up a lot in my opinion, and a 10 degree stem is a smoke stack!

My observation is that 90 degree stems are normally perpendicular to the steer tube,
Yes, thanks.
 
#7 ·
Thanks for the info...but I can't agree with your characterization. A 90 degree stem already angles up--and by more than what I would call 'slightly', because the head tube angles are slacker on mtbs. So 6 more degrees angles up a lot in my opinion, and a 10 degree stem is a smoke stack!

Yes, thanks.
Like it or not, 5-10 degree stems are low rise in the mtb world. 40 degree is a high rise stem. You can flip one of the later if you really are bothered by your stem angling upward.
 
#13 ·
Thanks for all the responses. I put the steerer of my Fox Talas 36 1 1/8" through the head tube of my XL Santa Cruz Blur LT2, then I added the headset pieces, and on top of that I added 30mm of spacers, which the Fox manual says is the maximum. Then I set the center-of-bottom-bracket to top-of-saddle height to the same height as my road bike, and I eyeballed where my 6 degree, 90mm stem and 25 mm riser bars would put the grips, and I think I'm still 3-6cm below my saddle height. I spent two hours looking at all the stems at JensonUSA and Universal, and the only stem I could find with more than 6-8 degree rise was a Ritchey stem with 30 degrees of rise.

Where are all the 15-45 degree rise stems?
 
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