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

Replacement for DA 7400 fork crown race?

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.

Replacement for DA 7400 fork crown race?

Old 07-10-15, 07:03 PM
  #1  
himespau 
Senior Member
Thread Starter
 
himespau's Avatar
 
Join Date: Jun 2008
Location: Louisville, KY
Posts: 10,900
Mentioned: 15 Post(s)
Tagged: 0 Thread(s)
Quoted: 1230 Post(s)
Replacement for DA 7400 fork crown race?

A while back I bought a Dura Ace 7400 headset off eBay for a build I'd planned. The seller said it worked great and it came with caged bearings, so I just assumed it was one of the later ones and only gave it a cursory examination when I got it. Finally dug it out of the parts bin a year + later for a completely different project and wouldn't you know it but it's one of those early ones with the annodized fork crown race and you can start to see a bit of wear in the annodizing. Not too bad, but starting to look like there's going to be some indexing eventually.

I know it's a long shot, but is there any source out there for a replacment fork crown race for these things? I think I only dropped $20 on it, so I'd be bummed, but not too terribly upset if it turns out I can't use it. Everything else on the bike (except the seatpost and saddle) is Italian, so I really ought to go with a campy headset, but my Veloce headset is 3 or so mm too tall (lock nut starts to thread on but not enough that it stays securely), and I had this on hand whereas I'd have to buy a new record headset.
himespau is offline  
Old 07-11-15, 12:18 PM
  #2  
himespau 
Senior Member
Thread Starter
 
himespau's Avatar
 
Join Date: Jun 2008
Location: Louisville, KY
Posts: 10,900
Mentioned: 15 Post(s)
Tagged: 0 Thread(s)
Quoted: 1230 Post(s)
Is my best bet scouring eBay looking for cosmetically bad headsets with good crown races? Is it possible to replace it with the fork crown race from say a 600 headset? Are there others that could replace it with? Should I just toss it?
himespau is offline  
Old 07-11-15, 01:04 PM
  #3  
JohnDThompson 
Old fart
 
JohnDThompson's Avatar
 
Join Date: Nov 2004
Location: Appleton WI
Posts: 20,137

Bikes: Several, mostly not name brands.

Mentioned: 99 Post(s)
Tagged: 0 Thread(s)
Quoted: 1581 Post(s)
By "anodizing" are you referring to the gold-colored titanium nitride coating on the races? That's to harden the surface, not decoration. I wouldn't worry about a little discoloration there -- unless you install the race in exactly the same orientation it had on its original installation, the balls aren't going to line up in the same places anyway. If you're really concerned, ditch the retainer and use loose balls. I suspect there's still a lot of miles left on that unit.

Regarding finding cosmetically bad headsets with good races: I wouldn't count on it. The crown race is always the first part to wear out on a headset. The only way to be sure of getting one in better condition than the one you already have is to buy new, old $tock.
JohnDThompson is offline  
Old 07-11-15, 03:39 PM
  #4  
dddd
Ride, Wrench, Swap, Race
 
dddd's Avatar
 
Join Date: Jan 2010
Location: Northern California
Posts: 6,370

Bikes: Cheltenham-Pederson racer, Boulder F/S Paris-Roubaix, Varsity racer, '52 Christophe, '62 Continental, '92 Merckx, '75 Limongi, '76 Presto, '72 Gitane SC, '71 Schwinn SS, etc.

Mentioned: 66 Post(s)
Tagged: 0 Thread(s)
Quoted: 470 Post(s)
John's right, just install it and be sure the adjustment is nowhere near being on the "tight" side, or the flex in the fork steerer will "pinch" the load path including the bearing races toward the front of the bicycle.
Forks/headsets installed with the quill stem removed become tighter when the steerer is finally tightened in place, so install a dummy stem, fully tightened, before adjusting the headset with the handlebars not yet installed.

Later on, years hopefully, you'll have the option to rebuild with a full complement of loose bearings, which will assure that any bearing defects won't settle into their old detenting ways.

I've put many a classic back on the road with a somewhat roached headset. Careful adjustment practices (and full-complement bearings only when needed) just about always means there will not have to be any effect on the steering's self-centering motions nor exhibit any audible looseness. Check final adjustment for looseness with the front wheel off the ground, and hit the top of the tire with your fist (like using a hammer) to check for any tell-tale knocking resonance that would indicate looseness. No need to have the bearing adjustment tighter than needed to prevent such knocking, in fact much better loose than tight.
BTW, those 7400 crown races were definitely not particularly resistant to "pitting", especially if the headset were adjusted even slightly too snug!

Last edited by dddd; 07-11-15 at 03:47 PM.
dddd is offline  
Old 07-11-15, 05:34 PM
  #5  
himespau 
Senior Member
Thread Starter
 
himespau's Avatar
 
Join Date: Jun 2008
Location: Louisville, KY
Posts: 10,900
Mentioned: 15 Post(s)
Tagged: 0 Thread(s)
Quoted: 1230 Post(s)
Great, thanks. I'll probably just give it a try then. Save myself $60 on the new headset.
himespau 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.