Flipping a 6* 100 mm stem
04-12-13, 10:47 AM
#1
Senior Member
Thread Starter
Flipping a 6* 100 mm stem
Will it give about 20mm difference in bar height? Can't seem to wrap my head around the maths.
04-12-13, 10:59 AM
#2
Senior Member
Join Date: Jun 2006
Location: Atlanta, GA
Posts: 1,586
Bikes: A couple
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 38 Post(s)
Likes: 0
Liked 1 Time
in
1 Post
https://www.brightspoke.com/t/bike-stem-calculator.html
This tool says that for a 73 degree head tube angle, flipping a -6 degree 100 mm stem up will result in a 20 mm taller stack and 6.1 mm shorter reach.
This tool says that for a 73 degree head tube angle, flipping a -6 degree 100 mm stem up will result in a 20 mm taller stack and 6.1 mm shorter reach.
04-12-13, 11:50 AM
#3
Banned.
Join Date: Mar 2013
Posts: 435
Bikes: 2 x 2012 GT Series 1, 2012 P2C
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 1 Time
in
1 Post
Originally Posted by deepakvrao
Will it give about 20mm difference in bar height? Can't seem to wrap my head around the maths.
04-12-13, 12:34 PM
#4
Senior Member
Join Date: Dec 2009
Location: Houston, TX
Posts: 28,682
Bikes: 1990 Romic Reynolds 531 custom build, Merlin Works CR Ti custom build, super light Workswell 066 custom build
Mentioned: 106 Post(s)
Tagged: 1 Thread(s)
Quoted: 6556 Post(s)
Likes: 0
Liked 58 Times
in
36 Posts
Originally Posted by CrankAndYank
Junior high math. What distance will twelve degrees subtend at 100 mm? Think about it...
04-12-13, 12:40 PM
#5
Senior Member
Join Date: Jul 2011
Posts: 157
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 1 Time
in
1 Post
Originally Posted by deepakvrao
Will it give about 20mm difference in bar height? Can't seem to wrap my head around the maths.
Stem Comparison
04-12-13, 01:08 PM
#6
Administrator
Join Date: Feb 2005
Location: Delaware shore
Posts: 13,514
Bikes: Cervelo C5, Guru Photon, Waterford, Specialized CX
Mentioned: 15 Post(s)
Tagged: 0 Thread(s)
Quoted: 1017 Post(s)
Liked 1,622 Times
in
1,120 Posts
Originally Posted by rpenmanparker
I don't think that simple approach accounts for the tilt of the head tube. The distance you calculate is not vertical. Close I am sure but not exactly the distance subtended by 12 degrees at 100 mm.
04-12-13, 01:12 PM
#7
Senior Member
Join Date: Oct 2011
Posts: 832
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 2 Times
in
2 Posts
Originally Posted by CrankAndYank
Junior high math. What distance will twelve degrees subtend at 100 mm? Think about it...
04-12-13, 02:04 PM
#9
Senior Member
Join Date: Dec 2009
Location: Houston, TX
Posts: 28,682
Bikes: 1990 Romic Reynolds 531 custom build, Merlin Works CR Ti custom build, super light Workswell 066 custom build
Mentioned: 106 Post(s)
Tagged: 1 Thread(s)
Quoted: 6556 Post(s)
Likes: 0
Liked 58 Times
in
36 Posts
Originally Posted by StanSeven
You are right. But it's close enough I think for most people to compute the new position.
04-12-13, 08:00 PM
#10
Senior Member
Join Date: Sep 2008
Location: Calgary
Posts: 135
Bikes: 2012 Merckx Emx-5 Campagnolo Super Record
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Often when I flip the stem, I move the spacer from the top to the bottom - a 5 mm spacer on a 90mm stem is almost ther same height.
04-12-13, 08:11 PM
#11
Senior Member
Join Date: Apr 2011
Location: San Diego
Posts: 2,181
Bikes: 2017 Specilized Roubaix, 2012 Scott CR1 Team, Felt Z85
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 26 Post(s)
Likes: 0
Liked 4 Times
in
2 Posts
Originally Posted by CrankAndYank
Junior high math. What distance will twelve degrees subtend at 100 mm? Think about it...
04-13-13, 06:47 PM
#13
Asleep at the bars
Join Date: May 2006
Location: San Francisco, CA and Treasure Island, FL
Posts: 1,735
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 230 Post(s)
Liked 203 Times
in
135 Posts
Originally Posted by rpenmanparker
Close I am sure but not exactly the distance subtended by 12 degrees at 100 mm.
04-13-13, 07:09 PM
#14
Senior Member
Join Date: Dec 2009
Location: Houston, TX
Posts: 28,682
Bikes: 1990 Romic Reynolds 531 custom build, Merlin Works CR Ti custom build, super light Workswell 066 custom build
Mentioned: 106 Post(s)
Tagged: 1 Thread(s)
Quoted: 6556 Post(s)
Likes: 0
Liked 58 Times
in
36 Posts
Originally Posted by sfrider
Just clarify: the subtend length is always exactly the same. Only it's parallel to the steerer. I know this is what you meant.
04-14-13, 01:21 AM
#15
Senior Member
For crying out loud, this isn't a root canal. Just flip the thing and see how you like it. It's a simple procedure that shouldn't require more than about 3 minutes to complete. Take the bike for a ride around the block or set it up on a trainer. If you don't like the new position, make a spacer adjustment or flip it back.
The collective time invested in this thread already exceeds that required to have conducted the experiment.
The collective time invested in this thread already exceeds that required to have conducted the experiment.
__________________
Birth Certificate, Passport, Marriage License Driver's License and Residency Permit all say I'm a Fred. I guess there's no denying it.
Birth Certificate, Passport, Marriage License Driver's License and Residency Permit all say I'm a Fred. I guess there's no denying it.
04-14-13, 01:37 AM
#16
Senior Member
Thread Starter
Originally Posted by bigfred
For crying out loud, this isn't a root canal. Just flip the thing and see how you like it. It's a simple procedure that shouldn't require more than about 3 minutes to complete. Take the bike for a ride around the block or set it up on a trainer. If you don't like the new position, make a spacer adjustment or flip it back.
The collective time invested in this thread already exceeds that required to have conducted the experiment.
The collective time invested in this thread already exceeds that required to have conducted the experiment.
Besides, if I get that it is 20mm difference, I don't 'need' to do a test to see if I like it or not. I can get a fair idea without actually flipping it.
04-14-13, 11:28 AM
#17
Senior Member
Join Date: Sep 2009
Location: Chico, CA
Posts: 669
Bikes: Colnago C59 Italia, 1981 Bianchi Pista
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Originally Posted by deepakvrao
Will it give about 20mm difference in bar height? Can't seem to wrap my head around the maths.
The angle of your stem, relative to a level plane (the ground), is 90*-(HTA)+/-(Stem angle). A 0* stem on a bike with head tube angle of 73* really has an angle of 17* up--most cyclists understand this part.
Your 6* stem, therefore, is really either an 11* stem or a 23* stem depending on how it's flipped. Since stem length is the hypotenuse of the triangle that determines the vertical height of the stem, the height difference is (100mm)*(sin23*)-(100mm)*(sin11*). The difference is almost exactly 20mm.
