Go Back  Bike Forums > Bike Forums > General Cycling Discussion
Reload this Page >

Am I measuring my frame size correctly?

Notices
General Cycling Discussion Have a cycling related question or comment that doesn't fit in one of the other specialty forums? Drop on in and post in here! When possible, please select the forum above that most fits your post!

Am I measuring my frame size correctly?

Old 10-18-16, 08:11 PM
  #1  
Junior Member
Thread Starter
 
Join Date: Aug 2016
Posts: 17
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Am I measuring my frame size correctly?

For some reason my original post in the MTB forum went away. Mods can move this if need be.

I have a Trek 3700 mountain bike. I want to make sure I am measuring the frame right.
Based on what I'm seeing, it looks like either a 16" or 17" frame.

Is that correct? Is this how you measure all frames, including MTB frames with the slanted cross bar?

Here is a photo with tape measure for reference:

[IMG][/IMG]

Thanks so much!
comma is offline  
Old 10-19-16, 11:30 AM
  #2  
Senior Member
 
Carson Dyle's Avatar
 
Join Date: Feb 2013
Posts: 139
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 11 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
For what purpose?

The way to tell would be to find the Trek catalog for the model year of your bike (it should be online) and find their spec chart for the frame. From there, you should be able to compare measurements like that one and easily be able to tell which size Trek called it.
Carson Dyle is offline  
Old 10-19-16, 11:40 AM
  #3  
Banned
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Posts: 43,598

Bikes: 8

Mentioned: 197 Post(s)
Tagged: 0 Thread(s)
Quoted: 7607 Post(s)
Liked 1,354 Times in 861 Posts
Center of BB to top of seat tube is the length of the seat tube, itself..

Stand-over OTOH is mid point of top tube to the ground..
fietsbob is offline  
Old 10-19-16, 12:55 PM
  #4  
Junior Member
Thread Starter
 
Join Date: Aug 2016
Posts: 17
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by Carson Dyle
For what purpose?

The way to tell would be to find the Trek catalog for the model year of your bike (it should be online) and find their spec chart for the frame. From there, you should be able to compare measurements like that one and easily be able to tell which size Trek called it.
The purpose is that this bike fits me well and I want to know the frame size for when I get something new.

Finding an old Trek catalog can't be the only way to measure my frame size...can it?
comma is offline  
Old 10-19-16, 12:55 PM
  #5  
Junior Member
Thread Starter
 
Join Date: Aug 2016
Posts: 17
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by fietsbob
Center of BB to top of seat tube is the length of the seat tube, itself..

Stand-over OTOH is mid point of top tube to the ground..
So how do I know the frame size?
comma is offline  
Old 10-19-16, 01:12 PM
  #6  
 
Hardrock23's Avatar
 
Join Date: Oct 2015
Location: NoVA - DC Metro
Posts: 1,220

Bikes: 1987 Schwinn Prelude

Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 296 Post(s)
Likes: 0
Liked 8 Times in 5 Posts
https://www.google.com/search?q=how+...ih=887#imgrc=_

Look at those pictures...
You want to measure from the center of the bottom bracket (the middle of the crank arm, basically) to the top of the seat tube - for the seat tube measurement.

For the top tube measurement - Measure from the center of the seat tube to the center of the headtube.

For the stand over measurement - measure from the ground to the top of the toptube, near the middle section.

Your bike looks like maybe 15-15.5, but its hard to tell since its not lined up correctly.
Below are some pics from the search. You can also watch youtube videos (just search "how to measure a bike frame").
Attached Images
File Type: jpg
frame_size.jpg (51.4 KB, 56 views)

Last edited by Hardrock23; 10-19-16 at 01:19 PM.
Hardrock23 is offline  
Old 10-19-16, 01:13 PM
  #7  
Senior Member
 
Carson Dyle's Avatar
 
Join Date: Feb 2013
Posts: 139
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 11 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by comma
The purpose is that this bike fits me well and I want to know the frame size for when I get something new.

Finding an old Trek catalog can't be the only way to measure my frame size...can it?
Like the other poster said, it's typically measured from the center of the bottom bracket to the top of the seat tube. Looking at Trek's catalogs back to 2007 or so, they list 16" and 18" frames among the sizes for the 3700. You can be fairly certain that's a 16.

More importantly, from Trek's specs you could find other (more) important dimensions, such as effective top tube length and reach.
Carson Dyle is offline  
Old 10-19-16, 01:27 PM
  #8  
Senior Member
 
demoncyclist's Avatar
 
Join Date: Oct 2002
Location: Medway, MA
Posts: 2,727

Bikes: 2011 Lynskey Sportive, 1988 Cannondale SM400

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 20 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
yes, but... some modern sloping top tubed frames are measured to the top of a virtual horizontal top tube.
demoncyclist is offline  
Old 10-19-16, 03:15 PM
  #9  
Junior Member
Thread Starter
 
Join Date: Aug 2016
Posts: 17
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by Hardrock23
https://www.google.com/search?q=how+...ih=887#imgrc=_

Look at those pictures...
You want to measure from the center of the bottom bracket (the middle of the crank arm, basically) to the top of the seat tube - for the seat tube measurement.

For the top tube measurement - Measure from the center of the seat tube to the center of the headtube.

For the stand over measurement - measure from the ground to the top of the toptube, near the middle section.

Your bike looks like maybe 15-15.5, but its hard to tell since its not lined up correctly.
Below are some pics from the search. You can also watch youtube videos (just search "how to measure a bike frame").
Thanks!
My photo is the same measurement as the photo you posted on the right, or am I missing something?
comma is offline  
Old 10-19-16, 03:16 PM
  #10  
Junior Member
Thread Starter
 
Join Date: Aug 2016
Posts: 17
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by Carson Dyle
Like the other poster said, it's typically measured from the center of the bottom bracket to the top of the seat tube. Looking at Trek's catalogs back to 2007 or so, they list 16" and 18" frames among the sizes for the 3700. You can be fairly certain that's a 16.

More importantly, from Trek's specs you could find other (more) important dimensions, such as effective top tube length and reach.
Thanks!
How did you find that catalog?
comma is offline  
Old 10-19-16, 03:22 PM
  #11  
Senior Member
 
Join Date: Jun 2011
Location: Ontario
Posts: 1,128

Bikes: are all mine

Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 179 Post(s)
Liked 42 Times in 24 Posts
if you do not want to measure everything yourself - best bet is to find the catalogue.
Aside from seat tube length (which is pretty meaningless on MTB with modern sloping TT) - there are reach, stack, effective TT, standover height (and SO height can be affected by how tall are your tires). Moreover - if you get the exact same bike which was fitted for someone else it may have longer/shorter stem, stem angle could be different, your bars may have additional rise, they also may have setback and may have different setback angle.

Look at the pictures of frame geometries from different manufacturers (I recommend Surly, they have very detailed sizing info) and replicate the measurements on your bike.
here is an example to get you started, Karate Monkey 27.5+ | Bikes | Surly Bikes
mongol777 is offline  
Old 10-19-16, 03:28 PM
  #12  
 
Hardrock23's Avatar
 
Join Date: Oct 2015
Location: NoVA - DC Metro
Posts: 1,220

Bikes: 1987 Schwinn Prelude

Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 296 Post(s)
Likes: 0
Liked 8 Times in 5 Posts
Originally Posted by comma
Thanks!
My photo is the same measurement as the photo you posted on the right, or am I missing something?
Well it appears that the end of the tape measure is too low in the photo you posted. If you moved the end to the middle of the crank arm/bottom bracket, then it would measure about 16". But, i know its hard to take a photo while trying to hold everything in the correct space, so that could be it.
Hardrock23 is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
mryank9
Hybrid Bicycles
3
08-14-18 01:20 PM
comma
Mountain Biking
7
10-22-16 03:30 PM
dolfinack
General Cycling Discussion
6
04-04-11 04:25 AM
mangojasmine
Road Cycling
18
05-10-10 09:00 PM
MiniApple
Bicycle Mechanics
2
03-24-10 11:39 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.