84 dgrees or 7?

Discuss light weight issues concerning road bikes & parts.
Post Reply
jeza
Posts: 63
Joined: Thu Mar 18, 2010 6:37 pm
Location: uk

by jeza

hi could someone tell me the difference between a stem of 84 degrees and on e of +/- 7 degrees ??? i know i'm being thick but....

by Weenie


mattr
Posts: 3546
Joined: Fri May 25, 2007 6:43 pm
Location: The Grim North.

by mattr

1 degree? (Or maybe 13!)
i.e. you are unlikely to notice.
You might find the 7 degree stem has graphics that work either way up

em3
Posts: 888
Joined: Tue Dec 23, 2008 2:57 pm
Location: NYC

by em3

+/- 8 aka 82 degrees

+/- 7 aka 83 degrees

For comparing stack and reach, use: http://yojimg.net/bike/web_tools/stem.php
______________

tinozee
Posts: 701
Joined: Wed Jun 01, 2011 7:53 am

by tinozee

It's actually a good question because it's one of few inconsistent ways people list that measurement. For starters, you have a 90 degree stem angle against the steerer tube as a starting point if the stem is dead straight. The 84 or -6, or -7 or -17, etc. is the angle of the stem. Some brands list the 84, others the -6 to indicate the angle, but those would be the same. The +/- indicates that you can flip the stem to have a positive or negative slope, plus is up, negative down.

User avatar
de zwarten
Posts: 839
Joined: Thu Dec 28, 2006 7:32 pm
Location: belgium

by de zwarten

jeza wrote:hi could someone tell me the difference between a stem of 84 degrees and on e of +/- 7 degrees ??? i know i'm being thick but....

good info here:
http://www.habcycles.com/fitting.html

smokva
Posts: 31
Joined: Tue Feb 17, 2009 9:13 pm

by smokva

jeza wrote:hi could someone tell me the difference between a stem of 84 degrees and on e of +/- 7 degrees ??? i know i'm being thick but....

Some manufacturers specify angle between fork tube and stem while some specify angle between imaginary line that is perpendicular to the fork tube and stem.
83 deg stem in first case would mean -7 deg stem in the second case. +|- means it can be installed so that the stem is both below or above imaginary perpendicular line.
Even if not noted every stem can be turned to positive or negative angle, worst that can happen is you will have letters upside-down.

So in short 84° is -6° and -7° is 83°. Thats only 1° of difference.

Team Murray
Posts: 30
Joined: Thu Apr 30, 2009 11:19 pm
Location: Los Altos, CA

by Team Murray

I believe this is how 17d and 6/7d became significant.

When bike only came with level top tubes, stem makers made quill stems with 17d pitch so the stem appeared parallel to the ground and the top tube. 17d is the orthogonal complement to the 73d head tube angle.

With the advent of compact geometry, the top tube sloped by roughly 7d degrees. Stem makers started making stems that complemented the sloping top tube. Stems had 6, 7, 8d pitch. However, racers wanted more drop or others wanted to overcome the taller headtubes. So, the 10d (e.g., Thomson) 17d threadless stem appeared. In my opinion, a sloping top tube frameset with a 17d stem looks odd.

wingguy
Posts: 3974
Joined: Thu Mar 08, 2012 11:43 pm

by wingguy

jeza wrote:hi could someone tell me the difference between a stem of 84 degrees and on e of +/- 7 degrees ??? i know i'm being thick but....


It's 1 degree. To be honest though, variances in stack height and measured vs actual length between different brands and models are often more significant!

allencanna
Posts: 29
Joined: Sat Feb 28, 2015 11:33 pm

by allencanna

they are nearly the same

ohhyeok90
Posts: 48
Joined: Sun Nov 08, 2015 2:24 am

by ohhyeok90

83 = -7

it's almost standards.

you can use this +7 for comfort ride as well.

cdkoo
Posts: 11
Joined: Sun Jul 17, 2016 4:18 am

by cdkoo

83 dgrees = 7

84 dgrees = 6

by Weenie


mimason
Posts: 654
Joined: Tue Feb 24, 2009 11:43 pm
Location: Florida

by mimason

smokva wrote:
jeza wrote:Even if not noted every stem can be turned to positive or negative angle, worst that can happen is you will have letters upside-down..

Not always the case but most of the time. Some stems are not designed to be flipped. For example, PRO stems are only -10 due to the puzzle clamp.

Post Reply