Go Back  Bike Forums > Bike Forums > Classic & Vintage
Reload this Page >

Fork conversion from threadless to threaded?

Classic & Vintage This forum is to discuss the many aspects of classic and vintage bicycles, including musclebikes, lightweights, middleweights, hi-wheelers, bone-shakers, safety bikes and much more.

Fork conversion from threadless to threaded?

Old 03-16-18, 07:20 AM
  #76  
copperfind
Senior Member
 
Join Date: May 2015
Posts: 250

Bikes: 1986 Centurion Facet 105 Equipped, Diamondback Zetec 2.1

Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 108 Post(s)
Liked 0 Times in 0 Posts
Not sure how safe but it appears this is intended to convert 1 1/8 t 1" Headtube https://www.ebay.com/itm/1-1-8-to-1-...sAAOSwF1dUR0Zf
copperfind is offline  
Old 03-16-18, 12:03 PM
  #77  
gugie 
Crapmaster Emeritus
 
gugie's Avatar
 
Join Date: Jul 2014
Location: Portland, OR
Posts: 7,284

Bikes: JP Weigle'd Raleigh Competition reconstruct, 73 Raleigh Competition 650b'ed, 96 Bike Friday NWT, 83 Lotus Classique, 78 Centurion ProTour, 73 Raleigh Grand Sports

Mentioned: 763 Post(s)
Tagged: 0 Thread(s)
Quoted: 2183 Post(s)
Likes: 0
Liked 22 Times in 20 Posts
Originally Posted by copperfind View Post
Not sure how safe but it appears this is intended to convert 1 1/8 t 1" Headtube https://www.ebay.com/itm/1-1-8-to-1-...sAAOSwF1dUR0Zf
I would think they're safe, since everything's "clamped" together. How well they work is another question. If you chase and face the head tube properly, and these things press in, then you'd be pressing in the cups on something already pressed in. Off-concentricity from tolerance stack-up might make for a less than ideal headset adjustment, but then, a lot of production bikes were built with poorly faced and chased head tubes, and they're rideable.
__________________
If someone tells you that you have enough bicycles and you don't need any more, stop talking to them. You don't need that kind of negativity in your life.
gugie is offline  
Old 03-16-18, 12:35 PM
  #78  
jonwvara 
Senior Member
Thread Starter
 
jonwvara's Avatar
 
Join Date: Apr 2006
Location: Washington County, Vermont, USA
Posts: 2,898

Bikes: 1966 Dawes Double Blue, 1976 Raleigh Gran Sport, 1975 Raleigh Sprite 27, 1980 Univega Viva Sport, 1971 Gitane Tour de France, 1984 Lotus Classique, 1976 Motobecane Grand Record

Mentioned: 40 Post(s)
Tagged: 0 Thread(s)
Quoted: 287 Post(s)
Likes: 0
Liked 1 Time in 1 Post
Okay, I think I have a solution: Bilenky Cycle Works in Philadelphia can braze on a new threaded steerer in place of the original threadless one for $125, which strikes me as very reasonable. The new steerer will have rolled threads. More about that in a moment. I assume that the powder coat on the fork crown and surrounding area will be toast after the work is done. It wouldn't be hard to have the whole fork refinished--there's a powder coat outfit near me that seems to do excellent work on bike frames--but knowing me I won't bother. I specialize in cosmetically imperfect bikes.

The Yellow Jersey shop in Madison would be willing to thread my threadless steerer for $60 per centimeter. Figuring a headset with a 40mm stack height, that's in the neighborhood of $250. Steerer replacement wins big in terms of cost, compared to cutting threads.

Also, based on my correspondence with Steve at Bilenky and Andrew at Yellow Jersey, I gleaned the following information, although it's still not as definitive as I would like it to be.

Andrew seems to say that cut threads are indeed smaller than rolled threads, and don't engage as well with the headset threading:

"I have filled in cut thread and recut where the material was intended for rolling or AH [not sure what AH is JV] and the cut thread engagement was poor. On our fine-thread bicycle formats, a few thousandths matters.

If it were a one inch I'd be more positive about it. It's a better design and we have better piloted tooling.
For 1-1/8x26 the format is ridiculously fine thread for the diameter and tooling isn't quite as positive for new thread centering.

The threadless column material is on the small side for a perfect cut thread. A good caliper and two forks will show that."

I guess all that makes sense. Rolled threads on spokes--which is the rolled thread that I think most of us are familar with--are obviously larger in diameter than the spoke itself. But the fine threads on a threaded steerer are so small in proportion to its 1" or 1 1/8" diameter that it's probably not easy to measure (hence Andrew's comment about a few thousandths mattering.) It would mostly be reflected in a somewhat sloppier fit of the headset parts.

In practice that might not matter much. If threading the threadless steerer was a lot cheaper, I might be tempted to take that route. But since a new steerer with rolled threads (per Steve at Bilenky) is half the price and gives a better end result, that seems like the obvious way to go.
__________________
www.redclovercomponents.com

"Progress might have been all right once, but it has gone on too long."
--Ogden Nash

Last edited by jonwvara; 03-16-18 at 01:27 PM.
jonwvara is offline  
Old 03-16-18, 01:14 PM
  #79  
himespau 
Senior Member
 
himespau's Avatar
 
Join Date: Jun 2008
Location: Louisville, KY
Posts: 10,930
Mentioned: 15 Post(s)
Tagged: 0 Thread(s)
Quoted: 1313 Post(s)
Liked 13 Times in 10 Posts
I don't get why 1 1/8" standard decided to go with 26 tpi rather than the 24 tpi used for 1" and french. Are you going to have a 1 1/8 steerer brazed on and deal with the limited headset/stem options or go with a 1" steerer and use headtube shims to get a wider variety of headset/stem options?

I agree that the new steerer seems to be the way to go. Even with powdercoating the fork, it would probably come out cheaper.
himespau is offline  
Old 03-16-18, 01:24 PM
  #80  
Salamandrine 
Senior Member
 
Join Date: Oct 2015
Location: Los Angeles
Posts: 4,853

Bikes: 78 Masi Criterium, 68 PX10, 2016 Mercian King of Mercia, Rivendell Clem Smith Jr

Mentioned: 105 Post(s)
Tagged: 0 Thread(s)
Quoted: 1693 Post(s)
Likes: 0
Liked 15 Times in 13 Posts
Cool. For $125 the new steerer is the way to go. Problem solved! I'd probably rattlecan the fork myself. Surly's are supposed to be utilitarian anyway, I think.

I checked and 1 1/8" threaded headsets are still pretty easy to come by. Ritchey sells one for ~ $15, or splurge on a Chris King for 10x that. There's a Tange in between.
Salamandrine is offline  
Old 03-16-18, 01:32 PM
  #81  
jyl
Senior Member
 
jyl's Avatar
 
Join Date: Aug 2006
Location: Portland OR
Posts: 7,516

Bikes: 61 Bianchi Specialissima 71 Peugeot G50 7? P'geot PX10 74 Raleigh GranSport 75 P'geot UO8 78? Raleigh Team Pro 82 P'geot PSV 86 P'geot PX 91 Bridgestone MB0 92 B'stone XO1 97 Rans VRex 92 Cannondale R1000 94 B'stone MB5 97 Vitus 997

Mentioned: 124 Post(s)
Tagged: 0 Thread(s)
Quoted: 336 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
I love happy endings! Pics will of course be demanded.
jyl is offline  
Old 03-17-18, 03:16 PM
  #82  
SquidPuppet
Calamari Marionette Ph.D
 
SquidPuppet's Avatar
 
Join Date: Dec 2013
Location: Coeur d' Alene
Posts: 7,965

Bikes: 3 Chinese Gas Pipe Nerdcycles and 2 Chicago Electroforged Boat Anchors

Mentioned: 73 Post(s)
Tagged: 0 Thread(s)
Quoted: 2345 Post(s)
Liked 0 Times in 0 Posts
Originally Posted by jonwvara View Post
$60 per centimeter.
Holy smokes!
SquidPuppet is offline  
Old 03-17-18, 03:31 PM
  #83  
Ghrumpy
Senior Member
 
Join Date: Jul 2009
Posts: 802
Mentioned: 14 Post(s)
Tagged: 0 Thread(s)
Quoted: 379 Post(s)
Likes: 0
Liked 2 Times in 2 Posts
Originally Posted by himespau View Post
I don't get why 1 1/8" standard decided to go with 26 tpi rather than the 24 tpi used for 1" and french.
French thread steerer pitch is 1mm or 25.4 tpi.

Who knows why, but the BSC spec for 1⅛ was 26tpi and has been since 1949. It was used on tandem steerer tubes long before mountain bikes picked up the size. The reason I would guess is that a finer thread removes less material from the tube, so the threaded section stays stronger. That's probably more important on a tandem headset that has to carry twice the rider load on only a slightly larger diameter tube.
Ghrumpy is offline  

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

Copyright 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.