Go Back  Bike Forums > Bike Forums > Road Cycling
Reload this Page >

Flipping a 6* 100 mm stem

Notices
Road Cycling “It is by riding a bicycle that you learn the contours of a country best, since you have to sweat up the hills and coast down them. Thus you remember them as they actually are, while in a motor car only a high hill impresses you, and you have no such accurate remembrance of country you have driven through as you gain by riding a bicycle.” -- Ernest Hemingway

Flipping a 6* 100 mm stem

Old 04-12-13, 10:47 AM
  #1  
Senior Member
Thread Starter
 
deepakvrao's Avatar
 
Join Date: Nov 2008
Location: Bangalore India
Posts: 2,387
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 394 Post(s)
Liked 20 Times in 14 Posts
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.
deepakvrao is offline  
Old 04-12-13, 10:59 AM
  #2  
Senior Member
 
fa63's Avatar
 
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.
fa63 is offline  
Old 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.
Junior high math. What distance will twelve degrees subtend at 100 mm? Think about it...
CrankAndYank is offline  
Old 04-12-13, 12:34 PM
  #4  
Senior Member
 
rpenmanparker's Avatar
 
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: 109 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...
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.
rpenmanparker is offline  
Old 04-12-13, 12:40 PM
  #5  
Senior Member
 
mynameistaken's Avatar
 
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.
i like this calculator:

Stem Comparison
mynameistaken is offline  
Old 04-12-13, 01:08 PM
  #6  
Administrator
 
Join Date: Feb 2005
Location: Delaware shore
Posts: 13,565

Bikes: Cervelo C5, Guru Photon, Waterford, Specialized CX

Mentioned: 16 Post(s)
Tagged: 0 Thread(s)
Quoted: 1090 Post(s)
Liked 2,086 Times in 1,418 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.
You are right. But it's close enough I think for most people to compute the new position.
StanSeven is offline  
Old 04-12-13, 01:12 PM
  #7  
Senior Member
 
kv501's Avatar
 
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...
I can do long division by hand too, but I don't.
kv501 is offline  
Old 04-12-13, 01:14 PM
  #8  
RT
The Weird Beard
 
RT's Avatar
 
Join Date: May 2005
Location: COS
Posts: 8,554
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 3 Times in 3 Posts
I just played with a 90mm 6° stem and a 73.5° HT.

Computation not necessary - go by feel. Use the Force, Luke.
RT is offline  
Old 04-12-13, 02:04 PM
  #9  
Senior Member
 
rpenmanparker's Avatar
 
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: 109 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.
Right.
rpenmanparker is offline  
Old 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.
calgary_jim is offline  
Old 04-12-13, 08:11 PM
  #11  
Senior Member
 
Mike F's Avatar
 
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...
That was forty years ago... forget that crap. Thats what the interwbz are for
Mike F is offline  
Old 04-12-13, 11:09 PM
  #12  
Senior Member
 
Join Date: Feb 2013
Posts: 60
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
What if I have an adjustable 100mm stem?
Banershka is offline  
Old 04-13-13, 06:47 PM
  #13  
Asleep at the bars
 
sfrider's Avatar
 
Join Date: May 2006
Location: San Francisco, CA and Treasure Island, FL
Posts: 1,743
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 234 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.
Just clarify: the subtend length is always exactly the same. Only it's parallel to the steerer. I know this is what you meant.
sfrider is offline  
Old 04-13-13, 07:09 PM
  #14  
Senior Member
 
rpenmanparker's Avatar
 
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: 109 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.
Right. If I am not mistaken, the correct value is the subtended length X sin(head tube angle) which comes out to about 95% of the subtended length. Thanks for the clarification.
rpenmanparker is offline  
Old 04-14-13, 01:21 AM
  #15  
Senior Member
 
Join Date: Jan 2009
Location: NZ
Posts: 3,841

Bikes: More than 1, but, less than S-1

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Liked 1 Time in 1 Post
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.
__________________
Birth Certificate, Passport, Marriage License Driver's License and Residency Permit all say I'm a Fred. I guess there's no denying it.
bigfred is offline  
Old 04-14-13, 01:37 AM
  #16  
Senior Member
Thread Starter
 
deepakvrao's Avatar
 
Join Date: Nov 2008
Location: Bangalore India
Posts: 2,387
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 394 Post(s)
Liked 20 Times in 14 Posts
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.
Collective time required for replies, is collective and not mine

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.
deepakvrao is offline  
Old 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.
To simplify the math:
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.
Young Version is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
filipw1990
Road Cycling
20
08-18-19 08:30 AM
mooder
Road Cycling
15
06-13-16 01:35 PM
Saving Hawaii
Classic & Vintage
18
02-24-14 07:00 PM
shapiros
Singlespeed & Fixed Gear
1
06-13-13 09:03 AM
abstractform20
Road Cycling
4
02-09-12 10:56 AM

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.