15 January, 2018

Stem Measurements

by Clint

Finding the right size stem is important to dial in the fit of your bike. This article is going to focus on defining dimensions of a stem, and not the fit.

Most of the important dimensions can be identified on a threadless stem, so let's start with those! Here's a neat infographic:


Length and angle are dimensions that affect fit, while steerer diameter, clamp diameter, and stack height are going to affect compatibility. Different combinations of length, angle, and position on the fork steerer can yield the same bar position, so do some trigonometry or trial and error to find the best fit for you!

Dimensions are mostly going to be the same for a quill stem. Height above minimum insertion is an important one specific to quill stems. That looks like this:

Our Cigne Stem is really what sparked this article. Due to its unusual look and function, dimensions are a little funky.  Here's a drawing that should clear things up:


Hopefully this answers a few questions about what to look for when deciding which stem will work for your needs.

9 comments:

Jim Mearkle said...

For angled threadless stems, is length measured parallel to the ground or parallel to the stem? If it's the latter, stem angle will affect the stack and reach quite a bit.

For example, a 100mm -17° stem will be close to level for most road bikes. It will add about 100mm to the total reach and little to stack. Flip it over, and it will be close to 35° from horizontal. It will add 83mm to the reach and 56mm to stack.

VeloOrange said...

@Jim

Length is measured center to center from steerer to handlebar so parallel to the stem! Hope that clears things up.

Ted Durant said...

I wish it was so straight forward!

Some complications -
1) The angle is not consistently measured by all manufacturers or sellers, and isn't consistent between threadless and quill. A standard "7" quill stem is 73deg, and plenty of quill stems are 90deg, which would translate to -17 and 0, respectively, for "typical" threadless stems.
2) Most quill stems are measured along the top from the center of the stem bolt to the center of the top of the handlebar. All Nitto stems are measured from the stem bolt to the true center of the handlebar, along the central axis of the extension.

You need to get comfy with basic trigonometry to compare stems and where they will put your handlebars. Luckily Excel has those functions built in!


Ian Tang said...

A neat little tool that does the trigonometry for you.

http://yojimg.net/bike/web_tools/stem.php

Brett Callahan said...

Speaking of stems, is there an ETA on when the Happy Stem will be back in stock?

VeloOrange said...

@ Brett Callahan
More of the Happy Stem are arriving this afternoon!

Scott

Brett Callahan said...

@ Scott, well that's fortuitous timing, thanks!

Anonymous said...

The pictures of the grey bike with Klunker bars on you site, what is that frame? I think its a campeur, I need to know what the stem dimensions are for that setup. I am thinking about a setup simalar to this on one of my bikes with a level 58cm toptube.Thank You

VeloOrange said...

That's an old 59cm Camargue prototype with a 110mm stem.

-Igor