Go Back  Bike Forums > Bike Forums > Framebuilders
Reload this Page >

Building a new fork; need input

Notices
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.

Building a new fork; need input

Old 09-05-17, 07:21 PM
  #1  
TitanBlue
Newbie
Thread Starter
 
Join Date: Sep 2017
Location: Sonoma County California
Posts: 2

Bikes: Uni's, road, mountain, vintage road, fixed gear....lots of 'em

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Building a new fork; need input

Hey all,
I have an early 90's Specialized Allez, lugged steel frame with the awful, in my opinion, aluminum direct drive fork. I love the ride of the frame, but the fork is stiff and uncomfortable with dull input feel. I want to build a lugged steel fork for this frame. Here's my question; if I build the new fork with the same spec's as the aluminum fork, will it perform the same? In other words, I'm thinking of using the alum fork as a copy to set my fork jig to build the steel fork.
What do y'all think?
Jay
TitanBlue is offline  
Old 09-05-17, 09:07 PM
  #2  
Andrew R Stewart 
Senior Member
 
Andrew R Stewart's Avatar
 
Join Date: Feb 2012
Location: Rochester, NY
Posts: 16,744

Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Mongoose Tomac ATB, GT Bravado ATB, JCP Folder, Srewart 650B ATB

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3628 Post(s)
Liked 2,576 Times in 1,615 Posts
No. The steel fork will feel different. How you describe that difference we might learn...


I will make a comment about this- " I have an early 90's Specialized Allez, lugged steel frame with the awful, in my opinion, aluminum direct drive fork. I love the ride of the frame, but the fork is stiff and uncomfortable with dull input feel."


Those forks were generally considered to be rather more flexible then steel ones. Main reason is they use nearly the same dimensions (steerer diameter) but with a material 1/3 as stiff as steel. I suspect what you're trying to describe is the lack stiffness.


Your frame is well designed and is, depending on the version, nice to really well done. The AL forks, on the other hand, took away from the crispness of handling IMO. Andy.
Andrew R Stewart is offline  
Old 09-06-17, 11:06 AM
  #3  
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 1,339 Times in 847 Posts
Id say comfort goal, go with an old 50s short radius J bend, at the small diameter, tip

being an adaptation to the rougher roads back then, would be better, than ...


the larger radius over the whole blade length ,Italian style, where the stiffer racing bike fork "looked better" more 'modern'

because the tip would flex more , and absorb, some roughness ...





....
fietsbob is offline  
Old 10-08-17, 09:37 PM
  #4  
calstar 
Senior Member
 
calstar's Avatar
 
Join Date: Mar 2012
Location: santa barbara CA
Posts: 1,098
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 91 Post(s)
Liked 27 Times in 18 Posts
Originally Posted by fietsbob View Post
Id say comfort goal, go with an old 50s short radius J bend, at the small diameter tip

being an adaptation to the rougher roads back then, would be better, than ...

the larger radius over the whole blade length ,Italian style, where the stiffer racing bike fork "looked better" more 'modern'

because the tip would flex more , and absorb, some roughness ...

....

I thought that regardless of the blade curve style(or lack of such as a straight blade) forks with the same rake will ride pretty much the same(given similar wall thickness and diameter). Comments??

thanks, Brian
__________________
Brian
calstar is offline  
Old 10-08-17, 10:12 PM
  #5  
ThermionicScott 
working on my sandal tan
 
ThermionicScott's Avatar
 
Join Date: Aug 2011
Location: CID
Posts: 22,080

Bikes: 1991 Bianchi Eros, 1964 Armstrong, 1988 Diamondback Ascent, 1988 Bianchi Premio, 1987 Bianchi Sport SX, 1980s Raleigh mixte (hers), All-City Space Horse (hers)

Mentioned: 95 Post(s)
Tagged: 0 Thread(s)
Quoted: 3643 Post(s)
Liked 2,092 Times in 1,327 Posts
Originally Posted by calstar View Post
I thought that regardless of the blade curve style(or lack of such as a straight blade) forks with the same rake will ride pretty much the same(given similar wall thickness and diameter). Comments??

thanks, Brian
It takes longer tubes to make a fork with the "French flick", so you get the benefit of that extra length bending when you go over bumps. Forks made in that style sometimes used blades that tapered down quite a lot to increase the effect (and save weight). Check out this 1950 Rene Herse:


(from Rene Herse project is about the Rene Herse velo de cyclotourisme, also Camille Daudon Alex Singer Narcisse Barra Maury Dujardin Goeland.)
__________________
Originally Posted by chandltp View Post
There's no such thing as too far.. just lack of time
Originally Posted by noglider
People in this forum are not typical.
RUSA #7498
ThermionicScott is offline  
Old 10-09-17, 09:24 AM
  #6  
Andrew R Stewart 
Senior Member
 
Andrew R Stewart's Avatar
 
Join Date: Feb 2012
Location: Rochester, NY
Posts: 16,744

Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Mongoose Tomac ATB, GT Bravado ATB, JCP Folder, Srewart 650B ATB

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3628 Post(s)
Liked 2,576 Times in 1,615 Posts
I suspect that the rake of the Direct Drive fork is about 1/3 that of the Herse's fork. That's a lot more dimension to have the tight radius actually start to curve towards horizontal. BTW I suspect that the Herse's head angle is slacker, further making the fork tips more horizontal. No way the Specialized would end up with such an extended forward fork tip and retain the handling nature it was designed with.


IMO if you mimic the dimensions of the Direct Drive fork the handling that's due to geometry will be the same. But not all handling is geometry controlled, there's a rider too. So I would expect no handed riding to be pretty much the same but with hands on the flex difference (between AL and steel) comes into play. The steel fork will likely feel stiffer when out of the saddle, using your upper body a lot and over bumps. It will add around a half pound of weight.


Back in that era one way to "up grade" your steel racing bike was to swap out the steel fork for an Al one. I knew quite a few riders who did this as well as sold a handful number of Al forks in my LBS. Most all liked the lesser weight, the smoother ride over bumps but noted that there was a certain snap that was lost in the handling/cornering aspect.


If I had this bike and really liked how it felt handling wise, I would consider doing the same. Making a steel fork with identical dimensions. Andy.

Last edited by Andrew R Stewart; 10-09-17 at 09:27 AM. Reason: better flow
Andrew R Stewart is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
armstrong101
Classic & Vintage
28
06-23-21 08:11 AM
sloar
Classic & Vintage
18
12-21-16 08:17 AM
xVoris
Singlespeed & Fixed Gear
7
01-12-15 05:42 PM
gmouchawar
Bicycle Mechanics
13
12-20-11 08:26 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


Thread Tools
Search this Thread

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

Copyright © 2022 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.