Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 07-23-08, 08:25 PM   #1
ExPhys
Senior Member
Thread Starter
 
Join Date: Apr 2007
Bikes:
Posts: 58
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Top tube question

When considering reach (stem and handlebar length) do you use the horizontal top tube length (i.e., parallel to the ground) or the center-to-center top tube length?

For my current bike (which fits well), the horizontal tt is 545mm and the c-c is 542.5mm and I use a 90mm stem.

I am looking at another frame with a horizontal tt of 549 and c-c of 531. What size stem would elicit the same reach?

Thank you!
ExPhys is offline   Reply With Quote
Old 07-23-08, 08:38 PM   #2
JiveTurkey
Low car diet
 
JiveTurkey's Avatar
 
Join Date: Aug 2007
Location: Corvallis, OR, USA
Bikes: 2006 Windsor Dover w/105, 2007 GT Avalanche w/XT, 1995 Trek 820 setup for touring, 201? Yeah single-speed folder, 199? Huffy tandem.
Posts: 2,407
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Always use the effective/horizontal length if the top tube is not parallel to the ground (i.e., sloping)--it is still measured cnter of head tube to center of seat tube. If the top tube is parallel to the ground, then the center-to-center top tube length and horizontal length are the same.

The new frame is 4mm longer, so all things being equal you'd want a 4mm shorter stem (effective length of the stem, parallel to the ground). Things that do not make this "all things being equal" include but is not limited to: head and seat tube angles; saddle to handlebar drop; reach, drop and width of handlebars...you get the point. 4mm is not that big of a difference.
JiveTurkey is offline   Reply With Quote
Old 07-23-08, 08:41 PM   #3
ExPhys
Senior Member
Thread Starter
 
Join Date: Apr 2007
Bikes:
Posts: 58
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Thanks for your response, very helpful! I was thinking along the same lines, but needed another opinion.
ExPhys is offline   Reply With Quote
Old 07-23-08, 08:55 PM   #4
Al1943
Senior Member
 
Join Date: Feb 2005
Location: Oklahoma
Bikes: Trek 5500, Colnago C-50
Posts: 9,433
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by ExPhys View Post
For my current bike (which fits well), the horizontal tt is 545mm and the c-c is 542.5mm and I use a 90mm stem.
A 90mm stem is pretty short, sounds like you need a shorter top tube, not longer.

Al,
Al1943 is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

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



All times are GMT -6. The time now is 04:34 PM.