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

Mismatched Threaded Headset: Acceptable?

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.

Mismatched Threaded Headset: Acceptable?

Old 08-31-21, 06:03 PM
  #1  
ethet 
Catastrophe Merchant
Thread Starter
 
ethet's Avatar
 
Join Date: Jul 2015
Location: Tideland
Posts: 256

Bikes: Keirin and a Steamroller

Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 86 Post(s)
Liked 218 Times in 58 Posts
Mismatched Threaded Headset: Acceptable?

I have a track frame with a Dura-Ace HP-7410 headset installed with an undrilled track fork which has a 27.0mm crown race.

I have a Tange track fork drilled for a rim brake which I wish to install into the aforementioned frame, though it has a 26.4 crown race.

I have a Hatta Vesta headset which has the appropriate fittings for a 26.4mm crown race.

My idea is to leave the upper section of the HP-7410 installed, yet remove the lower race from the frame, install the lower Vesta interface into the frame, bang on the Vesta crown race to the drilled fork, and tighten it all up...

Is there a potential problem which I am neglecting to foresee?

Thanks so much for any help and advice—the gratitude is overflowing and the appreciation blooms like the flowers in spring

Edit: I should add that the reason I am trying to work this out is that it is my hope to use this frame with both its original fork and the drilled fork interchangeably... I love riding brakeless keirin frames on sunny days, but I have a special opportunity here to create a foul-weather track bike with brakes and would love to make it as easy as possible to switch between frontends as the season permits. (The HP-7410 has a sealed-bearing design and the Hatta Vesta uses a rubber o-ring to seal the bearing interface from water ingress.)

Last edited by ethet; 08-31-21 at 06:56 PM. Reason: Additional Context
ethet is offline  
Old 08-31-21, 06:15 PM
  #2  
thook
(rhymes with spook)
 
thook's Avatar
 
Join Date: Aug 2009
Location: Winslow, AR
Posts: 2,795

Bikes: '83 univega gran turismo x2, '85 schwinn super le tour,'89 miyata triple cross, '91 GT tequesta, '90 yokota grizzly peak, '94 GT backwoods, '95'ish scott tampico, '98 bonty privateer, '93 mongoose crossway 625, '98 parkpre ariel, 2k'ish giant fcr3

Mentioned: 26 Post(s)
Tagged: 0 Thread(s)
Quoted: 919 Post(s)
Liked 745 Times in 546 Posts
well, your tires could spontaneously explode upon turning. it's all i can think of....
thook is offline  
Old 08-31-21, 06:22 PM
  #3  
grizzly59
Senior Member
 
Join Date: Aug 2016
Posts: 712
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 283 Post(s)
Liked 262 Times in 164 Posts
Interesting, makes perfect sense to me. If the stack height works out, should be good.
grizzly59 is offline  
Likes For grizzly59:
Old 08-31-21, 06:23 PM
  #4  
ethet 
Catastrophe Merchant
Thread Starter
 
ethet's Avatar
 
Join Date: Jul 2015
Location: Tideland
Posts: 256

Bikes: Keirin and a Steamroller

Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 86 Post(s)
Liked 218 Times in 58 Posts
Originally Posted by thook
well, your tires could spontaneously explode upon turning. it's all i can think of....
Tires?

Sometimes these replies baffle me so much that I just wish I could delete my entire question and remove myself from the equation... I have obviously not made myself clear and have no idea how to make myself clearer.

(I often wish there was a giant brush that would just eliminate my entire history when trying to interact with these forums... It feels like such an embarrassment. It is a wonder why I even try.)
ethet is offline  
Old 08-31-21, 06:28 PM
  #5  
ethet 
Catastrophe Merchant
Thread Starter
 
ethet's Avatar
 
Join Date: Jul 2015
Location: Tideland
Posts: 256

Bikes: Keirin and a Steamroller

Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 86 Post(s)
Liked 218 Times in 58 Posts
Originally Posted by grizzly59
If the stack height works out, should be good.
Thanks for this... It makes sense to me, though perhaps there was a devil in the details which a knowledgable wrench would catch. The stack height will be fine, indeed I have already anticipated adding a few millimeters of spacers to accommodate the new fork per my measurements.
ethet is offline  
Old 08-31-21, 06:33 PM
  #6  
thook
(rhymes with spook)
 
thook's Avatar
 
Join Date: Aug 2009
Location: Winslow, AR
Posts: 2,795

Bikes: '83 univega gran turismo x2, '85 schwinn super le tour,'89 miyata triple cross, '91 GT tequesta, '90 yokota grizzly peak, '94 GT backwoods, '95'ish scott tampico, '98 bonty privateer, '93 mongoose crossway 625, '98 parkpre ariel, 2k'ish giant fcr3

Mentioned: 26 Post(s)
Tagged: 0 Thread(s)
Quoted: 919 Post(s)
Liked 745 Times in 546 Posts
Originally Posted by ethet
Tires?

Sometimes these replies baffle me so much that I just wish I could delete my entire question and remove myself from the equation... I have obviously not made myself clear and have no idea how to make myself clearer.

(I often wish there was a giant brush that would just eliminate my entire history when trying to interact with these forums... It feels like such an embarrassment. It is a wonder why I even try.)
i was just making a joke, man wasn't meant to be malicious or anything. i was sincerely hoping you'd get a chuckle. sorry
thook is offline  
Likes For thook:
Old 09-01-21, 12:48 AM
  #7  
delbiker1 
Mother Nature's Son
 
delbiker1's Avatar
 
Join Date: Mar 2016
Location: Sussex County, Delaware
Posts: 3,111

Bikes: 2014 Orbea Avant MD30, 2004 Airborne Zeppelin TI, 2003 Lemond Poprad, 2001 Lemond Tourmalet, 2014? Soma Smoothie

Mentioned: 14 Post(s)
Tagged: 0 Thread(s)
Quoted: 838 Post(s)
Liked 1,414 Times in 801 Posts
I am using mismatched top and bottom cups on a Fuji Ace. It has the proper specs and works like it was built to work that way. The only way you can even tell is with close inspection, the lower cup is older with more outer wear. The replacement I had on hand was with a 27mm crown race and I needed 26.4. So I used the bottom cup and crown race from the original.

Last edited by delbiker1; 09-01-21 at 12:54 AM.
delbiker1 is offline  
Old 09-01-21, 07:27 AM
  #8  
JohnDThompson 
Old fart
 
JohnDThompson's Avatar
 
Join Date: Nov 2004
Location: Appleton WI
Posts: 24,934

Bikes: Several, mostly not name brands.

Mentioned: 153 Post(s)
Tagged: 0 Thread(s)
Quoted: 3571 Post(s)
Liked 3,366 Times in 1,915 Posts
Originally Posted by ethet
I have a track frame with a Dura-Ace HP-7410 headset installed with an undrilled track fork which has a 27.0mm crown race.

I have a Tange track fork drilled for a rim brake which I wish to install into the aforementioned frame, though it has a 26.4 crown race.

[…]

I should add that the reason I am trying to work this out is that it is my hope to use this frame with both its original fork and the drilled fork interchangeably.
The least bothersome way to accomplish this is to use the same make/model crown race on both forks, and a matching lower pressed cup on the frame. Shimano, Hatta, and Tange all offer headsets with either JIS 27.0 crown races or ISO 26.4mm crown races; often these are available separately. A Dura Ace 7410 ISO crown race on your Tange fork would be an easy fix, as you wouldn't have to worry about stack height issues, crown race/cup compatibility, etc. Otherwise, a Tange or Hatta headset with both types of crown race is also a possibility, although you need to take care that the stack height is reasonably similar. You could just replace the lower stack (sometimes that can minimize stack height concerns) and leave the Dura Ace upper stack. I'd probably replace the whole thing, if stack height allows.
JohnDThompson is offline  
Old 09-01-21, 07:29 AM
  #9  
JohnDThompson 
Old fart
 
JohnDThompson's Avatar
 
Join Date: Nov 2004
Location: Appleton WI
Posts: 24,934

Bikes: Several, mostly not name brands.

Mentioned: 153 Post(s)
Tagged: 0 Thread(s)
Quoted: 3571 Post(s)
Liked 3,366 Times in 1,915 Posts
Originally Posted by grizzly59
Interesting, makes perfect sense to me. If the stack height works out, should be good.
Sometimes, mixing different make/model cup and cone doesn't work well, particularly with headsets that have seals, as the OP says he has. In the case of a mismatch, you'd need to replace the entire lower stack (crown race and lower pressed cup) with a matching set.
JohnDThompson is offline  
Old 09-01-21, 08:22 AM
  #10  
grizzly59
Senior Member
 
Join Date: Aug 2016
Posts: 712
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 283 Post(s)
Liked 262 Times in 164 Posts
The way I read it, Ethet is using all Dura-ace parts for the upper, and all Hatta Vesta parts for the lower.
grizzly59 is offline  
Likes For grizzly59:

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 © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.