Go Back  Bike Forums > Bike Forums > Bicycle Mechanics
Reload this Page >

Calculating trail from other measurements?

Notices
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.

Calculating trail from other measurements?

Old 07-16-12, 12:50 PM
  #1  
Jonathan Hanson 
Junior Member
Thread Starter
 
Join Date: Apr 2012
Posts: 74
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 22 Post(s)
Liked 8 Times in 6 Posts
Calculating trail from other measurements?

Everyone,

Can somebody tell me if there's a formula to calculate trail if you know the head angle, the fork offset, and the actual wheel/tire diameter? It seems there should be, but I haven't found a reference.


Thanks . . .
Jonathan Hanson is offline  
Old 07-16-12, 01:19 PM
  #2  
rogerstg
Fred-ish
 
rogerstg's Avatar
 
Join Date: Aug 2007
Location: Rhode Island
Posts: 1,800
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 1 Time in 1 Post
https://yojimg.net/bike/web_tools/trailcalc.php
rogerstg is offline  
Old 07-16-12, 01:33 PM
  #3  
cny-bikeman
Mechanic/Tourist
 
Join Date: Apr 2007
Location: Syracuse, NY
Posts: 7,522

Bikes: 2008 Novara Randonee - love it. Previous bikes:Motobecane Mirage, 1972 Moto Grand Jubilee (my fave), Jackson Rake 16, 1983 C'dale ST500.

Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 486 Post(s)
Liked 11 Times in 11 Posts
Originally Posted by Jonathan Hanson
Everyone,

Can somebody tell me if there's a formula to calculate trail if you know the head angle, the fork offset, and the actual wheel/tire diameter? It seems there should be, but I haven't found a reference.


Thanks . . .
You're kidding - did you not try Google? calculate bicycle trail
cny-bikeman is offline  
Old 07-16-12, 02:52 PM
  #4  
Jonathan Hanson 
Junior Member
Thread Starter
 
Join Date: Apr 2012
Posts: 74
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 22 Post(s)
Liked 8 Times in 6 Posts
Actually I can't believe I didn't Google it first either - thanks for the replies.
Jonathan Hanson is offline  
Old 07-16-12, 03:14 PM
  #5  
fietsbob
Banned
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Posts: 43,599

Bikes: 8

Mentioned: 197 Post(s)
Tagged: 0 Thread(s)
Quoted: 7607 Post(s)
Liked 1,346 Times in 853 Posts
Straight edge and a tape measure on the ground?
fietsbob is offline  
Old 07-16-12, 06:23 PM
  #6  
HillRider
Senior Member
 
Join Date: Aug 2005
Location: Pittsburgh, PA
Posts: 33,621

Bikes: '96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '20 Surly Midnight Special, All are 3x10. It is hilly around here!

Mentioned: 39 Post(s)
Tagged: 0 Thread(s)
Quoted: 2002 Post(s)
Likes: 0
Liked 1,049 Times in 714 Posts
Originally Posted by fietsbob
Straight edge and a tape measure on the ground?
It's difficult to accurately project the line through the center of the headtube to make a direct measurement. If you know the published HTA, fork rake and wheel radius, the calculation is easier than trying to measure it.
HillRider is offline  
Old 07-16-12, 07:39 PM
  #7  
RoadTire 
Senior Member
 
RoadTire's Avatar
 
Join Date: Mar 2012
Location: Minnesota
Posts: 1,968

Bikes: '09 Trek 2.1 * '75 Sekine * 2010 Raleigh Talus 8.0 * '90 Giant Mtb * Raleigh M20 * Fuji Nevada mtb

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by Jonathan Hanson
Actually I can't believe I didn't Google it first either - thanks for the replies.
Proof BikeForums is more respected than Google
__________________
FB4K - Every October we wrench on donated bikes. Every December, a few thousand kids get bikes for Christmas. For many, it is their first bike, ever. Every bike, new and used, was donated, built, cleaned and repaired. Check us out on FaceBook: FB4K.

Disclaimer: 99% of what I know about cycling I learned on BF. That would make, ummm, 1% experience. And a lot of posts.
RoadTire is offline  
Old 07-23-12, 07:18 AM
  #8  
Jonathan Hanson 
Junior Member
Thread Starter
 
Join Date: Apr 2012
Posts: 74
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 22 Post(s)
Liked 8 Times in 6 Posts
Proof BikeForums is more respected than Google.
Exactly!

Turns out my old Sekai is a mid-trail design.
Jonathan Hanson is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Ladel
General Cycling Discussion
11
04-01-18 05:29 PM
bashley
Fitting Your Bike
33
02-19-18 09:11 AM
bkentr
Alt Bike Culture
1
02-07-18 11:33 PM
TimothyH
Touring
2
02-06-18 03:08 PM
CHAS
Framebuilders
9
09-29-10 07:30 PM

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


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell or Share My Personal Information -

Copyright © 2023 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.