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


Go Back   > >

Framebuilders Thinking about a custom frame? Lugged vs Fillet Brazed. Different Frame materials? Newvex or Pacenti Lugs? why get a custom Road, Mountain, or Track Frame? Got a question about framebuilding? Lets discuss framebuilding at it's finest.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 05-20-17, 01:34 AM   #1
jonnya123
Newbie
Thread Starter
 
Join Date: May 2017
Bikes:
Posts: 1
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Fork rake unknown.

Hello,

I have a 53cm Diamant frame. The forks broke and I disposed of the fork before I noted the rake of the fork. I have now services and reassembled the bike but want to know the correct rake of fork I need to have befroe I buy a new fork. How do I find this out?

I have contacted Diamant directly but have had no response.

Cheers, Jon.
jonnya123 is offline   Reply With Quote
Old 05-20-17, 08:13 AM   #2
velonomad
Older I get, Better I was
 
velonomad's Avatar
 
Join Date: Nov 2003
Location: Greenfield Lake, Wilmington NC
Bikes: '14 BD Lurch Fatbike, '10 custom road,'03 custom tourer, '94 Yokota Tandem, '88 custom MTB
Posts: 1,733
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 20 Post(s)
IIRC, Diamant is owned by Trek, try contacting them.
velonomad is offline   Reply With Quote
Old 05-21-17, 11:46 AM   #3
fietsbob 
coprolite
 
fietsbob's Avatar
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Bikes: 8
Posts: 25,842
Mentioned: 42 Post(s)
Tagged: 0 Thread(s)
Quoted: 2241 Post(s)
Generic to type of bike , look at similar bikes of that type ... Same sort of wheel size and head tube angle ,
and measure those bike's forks
fietsbob is online now   Reply With Quote
Old 05-22-17, 06:32 PM   #4
unterhausen
Randomhead
 
Join Date: Aug 2008
Location: Happy Valley, Pennsylvania
Bikes:
Posts: 15,323
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
axle to crown (a-c) is the most important measurement. But isn't saying you have a Diamont sort of like saying you have a Ford and asking what tires you need?
unterhausen is offline   Reply With Quote
Old 06-09-17, 08:51 PM   #5
Andrew R Stewart 
Andrew R Stewart
 
Andrew R Stewart's Avatar
 
Join Date: Feb 2012
Location: Rochester, NY
Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Raleigh Pro, Trek Cycle Cross, Mongoose tomac ATB, GT Bravado ATB, JCP Folder
Posts: 8,385
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 661 Post(s)
An informed person might view this moment to have that chance to dial in the steering feel that they wish for. To do this well it will take some efforts. A fork of around the correct axle to crown (axle to brake hole plus brake hole to crown seat) length to nearly attain the top tube's slant, or horizontalness. Then minor corrections for final A-C dimension and trail (or rake).

I suspect that the top tube was designed to be fairly level. This then establishes the head tube angle, not that knowing it really is important for this. Dropping a plumb line from the axle to the ground and measuring forward to the front tire contact point gets you the trail. By measuring the mule fork, rake and a-c, one can then figure out what trail changes one gets with rake changes. Additionally the a-c dimension can be played with if needed. But this dimension's changes result in fairly minor steering angle changes. As long as the wheels intended are what the rear triangle ad brake reach likes and one matches these in the front handling geo can be played with to some degree.

But if this is all jibberish or "greek" to you then just get a fork that fits the head tube and ride the darn bike. Andy (who writes from 3000 miles from his desk).
Andrew R Stewart is offline   Reply With Quote
Old 06-17-17, 02:32 PM   #6
Ryder1
Junior Member
 
Join Date: Jul 2007
Location: Phoenix
Bikes: '10 Roubaix, '11 Kona Unit, '16 Pivot 429T
Posts: 24
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 11 Post(s)
Quote:
Originally Posted by Andrew R Stewart View Post
Dropping a plumb line from the axle to the ground and measuring forward to the front tire contact point gets you the trail.
I just measured all 37 bikes in my shop. Each time the measurement came out to 0.
Ryder1 is offline   Reply With Quote
Old 06-19-17, 03:28 PM   #7
Dancingbear
Member
 
Join Date: Apr 2009
Bikes:
Posts: 28
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
See the drawing here for how trail is measured. A picture is worth......https://en.wikipedia.org/wiki/Bicycl...cycle_geometry
Dancingbear is offline   Reply With Quote
Old 06-19-17, 03:36 PM   #8
CliffordK
Senior Member
 
CliffordK's Avatar
 
Join Date: Nov 2014
Location: Eugene, Oregon, USA
Bikes:
Posts: 13,508
Mentioned: 40 Post(s)
Tagged: 0 Thread(s)
Quoted: 2865 Post(s)
Quote:
Originally Posted by Ryder1 View Post
I just measured all 37 bikes in my shop. Each time the measurement came out to 0.
You're supposed to measure it on a hill

Quote:
Originally Posted by Andrew R Stewart View Post
But if this is all jibberish or "greek" to you then just get a fork that fits the head tube and ride the darn bike. Andy (who writes from 3000 miles from his desk).
Yeah,

Quite a few different fork rakes, I'm not sure if there really is a single magic number.

Find a fork you like, and try it out. Give it a few miles to get used to it.
CliffordK is offline   Reply With Quote
Old 06-20-17, 07:25 AM   #9
unterhausen
Randomhead
 
Join Date: Aug 2008
Location: Happy Valley, Pennsylvania
Bikes:
Posts: 15,323
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
rake generally doesn't matter if you get the a/c right. That's pretty tricky unless you are making a fork
__________________
Randonneuring -- it's touring for people that aren't smart enough to stop for the night.
It's a wonderful sport when you can make up for a lack of ability with a lack of sleep
unterhausen 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 07:04 AM.


 
  • Ask a Question
    get answers from real people!
Click to start entering your question.
I HAVE A QUESTION