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

Quill Fork Steer Tube Thread Length Definition

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.

Quill Fork Steer Tube Thread Length Definition

Reply

Old 06-13-18, 11:00 AM
  #1  
mtb_addict
Senior Member
Thread Starter
 
mtb_addict's Avatar
 
Join Date: Jun 2011
Posts: 3,036
Mentioned: 15 Post(s)
Tagged: 0 Thread(s)
Quoted: 2203 Post(s)
Quill Fork Steer Tube Thread Length Definition

Hi
I'm trying to learn the industrial lingo, so I can buy the correct replacement fork on my Walmart Huffy mtb.
The keyed washer on the headset destroyed the thread on the steerer tube, when I torque down on the lock nut...so I'm looking to upgrade to a pair of snazzy chrome fork.

"Steer Tube Length" and "Thread Length"...is this what they mean?





  • 26" MTB Fork, Hi-Ten, Uni-Crown, Oval, Chrome
  • Non-Canti
  • Steer tube length 198 mm (7-3/4")
  • Thread length 95mm (3-3/4")
  • OD 25.4mm, ID 22.2mm
Type: MTB; Size: 26"; Steerer Type: Threaded; Steerer Size: 1" (7/8 ID); Steerer Length: 198mm; Brake Mount: Caliper; Material: Hi-Tensile; Color: Chrome; Rake: 45mm; Axle-to-Crown: 393mm; Race Diameter: 27mm; Axle: 3/8"; Thread Length: 95mm

Last edited by mtb_addict; 06-13-18 at 11:08 AM.
mtb_addict is offline  
Reply With Quote
Old 06-13-18, 11:40 AM
  #2  
HillRider 
Senior Member
 
Join Date: Aug 2005
Location: Pittsburgh, PA
Posts: 31,105

Bikes: '''96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '12 Surly Pacer, All are 3x8,9 or 10. It is hilly around here!

Mentioned: 29 Post(s)
Tagged: 0 Thread(s)
Quoted: 1003 Post(s)
Yes, the "steerer tube length" is the distance from the crown race seat to the top of the steerer tube. The thread length is what you show, the length of the threaded section. To determine what you need you will have to measure the length of the frame's head tube and look up the stack height of the headset. The steerer length must be a minimum of headtube length + stack height -2 mm. If it's longer than that by a bit, you can place spacers under the top lock nut. Too short obviously won't work. Too long by a lot, even if you cut it down, may prevent the threaded section from extending far enough to allow the top race to thread on far enough to adjust the headset properly.

BTW, the fork you show uses a 1" JIS (27.0 mm) crown race. Be sure the headset you buy is that size.
HillRider is offline  
Reply With Quote
Old 06-13-18, 12:02 PM
  #3  
mtb_addict
Senior Member
Thread Starter
 
mtb_addict's Avatar
 
Join Date: Jun 2011
Posts: 3,036
Mentioned: 15 Post(s)
Tagged: 0 Thread(s)
Quoted: 2203 Post(s)
Is it difficult to make a straight cut, when chopping off the steerer tube?

I'm worried my hacksaw skill level is rather low .
mtb_addict is offline  
Reply With Quote
Old 06-13-18, 12:09 PM
  #4  
HillRider 
Senior Member
 
Join Date: Aug 2005
Location: Pittsburgh, PA
Posts: 31,105

Bikes: '''96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '12 Surly Pacer, All are 3x8,9 or 10. It is hilly around here!

Mentioned: 29 Post(s)
Tagged: 0 Thread(s)
Quoted: 1003 Post(s)
Originally Posted by mtb_addict View Post
Is it difficult to make a straight cut, when chopping off the steerer tube?

I'm worried about hacksaw skill is rather low level.
There are commercial cutting guides that make it very easy but for a one-time use, tighten a radiator clamp around the steerer with the upper edge right on the cut line and use that edge as a cutting guide. Use a fine tooth hacksaw blade (32 tpi is good) and let the weight of the saw do the work. Don't lean on it and work your way around the steerer as you cut. Use a file to smooth out the cut edge when you are done. Another tip is to thread the locknut completely down the threads before cutting. After the cut is finished, unthreading the nut will clean up the thread lead.
HillRider is offline  
Reply With Quote
Old 06-13-18, 01:04 PM
  #5  
fietsbob 
coprolite
 
fietsbob's Avatar
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Posts: 36,813

Bikes: 8

Mentioned: 139 Post(s)
Tagged: 0 Thread(s)
Quoted: 5396 Post(s)
Originally Posted by mtb_addict View Post
Is it difficult to make a straight cut, when chopping off the steerer tube?

I'm worried my hacksaw skill level is rather low .

Because of threadless steerers, A saw guide is now part of a decent bike shop's tool inventory ..




...
fietsbob is offline  
Reply With Quote
Old 06-13-18, 02:40 PM
  #6  
JohnDThompson 
Old fart
 
JohnDThompson's Avatar
 
Join Date: Nov 2004
Location: Appleton WI
Posts: 19,632

Bikes: Several, mostly not name brands.

Mentioned: 82 Post(s)
Tagged: 0 Thread(s)
Quoted: 1390 Post(s)
Originally Posted by mtb_addict View Post
Is it difficult to make a straight cut, when chopping off the steerer tube?
A couple threaded headset cups separated by a saw blade's width make a good guide for a straight cut. A half-round file will de-burr the inside and outside of the cut when you're done.
JohnDThompson is offline  
Reply With Quote

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