Page 1 of 2 12 LastLast
Results 1 to 25 of 47
  1. #1
    RoadBikeReview Member
    Reputation:
    Join Date
    Jul 2010
    Posts
    122

    Crown race won't fit on carbon steerer

    I'm in the initial stages of a build and I can't seem to get the crown race onto the carbon steerer.

    The fork is all carbon, with a tapered steerer (1 1/8" to 1 1/4"). I've measured the diameter of the bottom of the steerer to be 33.6mm and the inside diameter of the crown race to be 32.9mm. This is a 0.7mm, which could be quite significant.

    So what should I do? So far I see my options being:

    1) Smash the crown race on anyways and see what happens. Maybe heat the crown race first?
    2) Face the inside of the crown race to get it closer to 33.6mm.
    3) Buy a new headset and hope that the new crown race is closer to 33.6mm.

    Any help here is much appreciated.

  2. #2
    RoadBikeReview Member
    Reputation: bikerjulio's Avatar
    Join Date
    Jan 2010
    Posts
    4,691
    Cane Creek have the standard 1 1/4" crown race at 33.06 +/- 0.03mm, putting both your measurements outside the limits.

    http://www.canecreek.com/manuals/Hea...ationGuide.pdf

    Not much help I know.

    Some carbon forks (see link) may not use a crown race at all. The carbon bears directly on the inner race of the lower bearing, just as the crown race would.
    Last edited by bikerjulio; 03-06-2012 at 11:57 AM.
    There's sometimes a buggy.
    How many drivers does a buggy have?

    One.

    So let's just say I'm drivin' this buggy...
    and if you fix your attitude you can ride along with me.

    http://www.youtube.com/watch?v=GekiIMh4ZkM

  3. #3
    FTR
    FTR is offline
    Burn baby, burn.
    Reputation: FTR's Avatar
    Join Date
    Sep 2006
    Posts
    2,417
    I am going to guess it is a pressfit crown race and if so it is designed to be basically hammered on.
    If it is the headset that came with a Chinese frame then it most definitely is pressfit.

  4. #4
    RoadBikeReview Member
    Reputation:
    Join Date
    Jun 2010
    Posts
    236
    What is the maker of the frame and fork and have you contacted them? I would guess they would exchange them...
    Regards,
    Dan

  5. #5
    RoadBikeReview Member
    Reputation:
    Join Date
    Mar 2007
    Posts
    609
    The correct crown race diameter for a 1 1/4" headset is 33.0mm. The fork you have is slightly over sized. What kind of fork is it? I would contact the manufacturer and see if they can offer an exchange.

    The next option would be to mill (or 'face') the fork down to 33.0. This is a little tricky because if you remove too much material, you're SOL.

    Whatever you do, DO NOT try to hammer the crown race onto the fork as is. That much of a dimensional difference (0.7mm) is too much for an interference fit. You will damage both parts in the process.

  6. #6
    RoadBikeReview Member
    Reputation:
    Join Date
    Jan 2009
    Posts
    1,846
    Quote Originally Posted by FTR View Post
    I am going to guess it is a pressfit crown race and if so it is designed to be basically hammered on.
    If it is the headset that came with a Chinese frame then it most definitely is pressfit.
    The amount of interference for a press fit crown race is typically .05mm, so if the OP is measuring accurately, there's no way the race could be pressed on.

    I suspect that he has a 33mm (nominal) race which should measure 32.95-33.00. If the fork as truly that much bigger there's something wrong with it, unless it came with it's own race.

    The OP might have the option of using a split "crown race" since on most sealed headsets the crown race isn't one at all, but only a centering cone for inner race of the lower bearing.
    fb
    www.chain-l.com

    Solving any problem requires understanding the underlying cause

  7. #7
    FTR
    FTR is offline
    Burn baby, burn.
    Reputation: FTR's Avatar
    Join Date
    Sep 2006
    Posts
    2,417
    Quote Originally Posted by TimV View Post
    The correct crown race diameter for a 1 1/4" headset is 33.0mm. The fork you have is slightly over sized. What kind of fork is it? I would contact the manufacturer and see if they can offer an exchange.

    The next option would be to mill (or 'face') the fork down to 33.0. This is a little tricky because if you remove too much material, you're SOL.

    Whatever you do, DO NOT try to hammer the crown race onto the fork as is. That much of a dimensional difference (0.7mm) is too much for an interference fit. You will damage both parts in the process.
    No way would I be "milling" a CF steerer.
    Also you are assuming he measured everything perfectly.
    You can easily get a variance if you dont.

  8. #8
    RoadBikeReview Member
    Reputation:
    Join Date
    Jun 2003
    Posts
    1,876
    My Colnago 1 1/8 all carbon fork had to be "faced" with a special tool before the Chris King race could be installed. No problems with the "facing".

  9. #9
    RoadBikeReview Member
    Reputation:
    Join Date
    Jun 2010
    Posts
    236
    Quote Originally Posted by Al1943 View Post
    My Colnago 1 1/8 all carbon fork had to be "faced" with a special tool before the Chris King race could be installed. No problems with the "facing".
    Was the carbon coated to protect it from moisture absorption?
    Regards,
    Dan

  10. #10
    RoadBikeReview Member
    Reputation:
    Join Date
    Jun 2003
    Posts
    1,876
    Quote Originally Posted by NEO Dan View Post
    Was the carbon coated to protect it from moisture absorption?
    I don't know, you'd have to ask Ernesto.

  11. #11
    RoadBikeReview Member
    Reputation:
    Join Date
    Mar 2007
    Posts
    609
    Quote Originally Posted by FTR View Post
    No way would I be "milling" a CF steerer.
    Also you are assuming he measured everything perfectly.
    You can easily get a variance if you dont.
    Just because you are afraid to do something, doesn't mean it can't be done. Assuming his measurements are close (and yes, I did assume that :roll eyes: ), we're only talking about 0.010" to 0.015" of material removal. That's not very much considering the material thickness in that part of the fork probably exceeds 0.250".

  12. #12
    FTR
    FTR is offline
    Burn baby, burn.
    Reputation: FTR's Avatar
    Join Date
    Sep 2006
    Posts
    2,417
    Quote Originally Posted by TimV View Post
    Just because you are afraid to do something, doesn't mean it can't be done. Assuming his measurements are close (and yes, I did assume that :roll eyes: ), we're only talking about 0.010" to 0.015" of material removal. That's not very much considering the material thickness in that part of the fork probably exceeds 0.250".
    Or you could just use the pressfit crown race how it was meant to be used.
    And I am not even going to assume that he knows the difference between .7mm and .07mm.

  13. #13
    RoadBikeReview Member
    Reputation:
    Join Date
    Jun 2010
    Posts
    236
    Quote Originally Posted by Al1943 View Post
    I don't know, you'd have to ask Ernesto.
    Yeah let me get right on that, I think I'll send an e-mail to Ernesto...

    But seriously, if you had a spot of bare carbon exposed on your bike due to a tire rub or something of that nature and it failed you'd be SOL in the warranty department. The interesting thing about the crown is that moisture/grease/grit/solvent can accumulate there and not easily be removed if at all while assembled. Washing your bike or getting caught out in the rain are not uncommon. Carbon needs to be sealed to prevent contamination of the layup, you could easily drop the fork and see if it's been sealed up.

    Incidentally I just bought and sent back an Easton fork that had been sanded on at the crown. Easton service e-mailed me a shipping tag within minutes of my calling to ask if they were OK with bare carbon at the crown.
    Regards,
    Dan

  14. #14
    RoadBikeReview Member
    Reputation: Kontact's Avatar
    Join Date
    Apr 2011
    Posts
    2,731
    Quote Originally Posted by NEO Dan View Post
    Yeah let me get right on that, I think I'll send an e-mail to Ernesto...

    But seriously, if you had a spot of bare carbon exposed on your bike due to a tire rub or something of that nature and it failed you'd be SOL in the warranty department. The interesting thing about the crown is that moisture/grease/grit/solvent can accumulate there and not easily be removed if at all while assembled. Washing your bike or getting caught out in the rain are not uncommon. Carbon needs to be sealed to prevent contamination of the layup, you could easily drop the fork and see if it's been sealed up.

    Incidentally I just bought and sent back an Easton fork that had been sanded on at the crown. Easton service e-mailed me a shipping tag within minutes of my calling to ask if they were OK with bare carbon at the crown.
    I have a bare carbon Calfee. We've sold multiple bare Parlees and Calfees. Carbon brake tracks are bare. They don't need paint or coatings, because carbon fiber composites consist of nothing more than solid graphite fibers in epoxy resin. There is nothing there that can absorb liquids.

    Your post wins the prize for craziest carbon fiber misinformation of the year. Congrats.
    Get a better saddle: www.kontactbike.com

  15. #15
    RoadBikeReview Member
    Reputation:
    Join Date
    Jun 2010
    Posts
    236

    typo

    Quote Originally Posted by Kontact View Post
    I have a bare carbon Calfee. We've sold multiple bare Parlees and Calfees. Carbon brake tracks are bare. They don't need paint or coatings, because carbon fiber composites consist of nothing more than solid graphite fibers in epoxy resin. There is nothing there that can absorb liquids.

    Your post wins the prize for craziest carbon fiber misinformation of the year. Congrats.
    OK then answer this question; if you get the frame wet for more than a moment and wipe it off does it look completely dry or like it was wet?
    Regards,
    Dan

  16. #16
    RoadBikeReview Member
    Reputation:
    Join Date
    Jun 2010
    Posts
    236
    Exposure to UV is also bad for some resins used in the manufacture of carbon fiber parts if you care to look around...
    Regards,
    Dan

  17. #17
    FTR
    FTR is offline
    Burn baby, burn.
    Reputation: FTR's Avatar
    Join Date
    Sep 2006
    Posts
    2,417
    Quote Originally Posted by NEO Dan View Post
    Exposure to UV is also bad for carbon if you care to look around...
    Yes it will assplode!!!
    And melt in the rain.

  18. #18
    RoadBikeReview Member
    Reputation:
    Join Date
    Jun 2010
    Posts
    236
    Sorry FTR,
    I understated the position, now corrected above... : )

    Steel is real, LOL

    Real heavy...


    I ride carbon - really
    Regards,
    Dan

  19. #19
    FTR
    FTR is offline
    Burn baby, burn.
    Reputation: FTR's Avatar
    Join Date
    Sep 2006
    Posts
    2,417
    Me too, and ti.
    One for probably a lot longer than the other before it needs replacing.

  20. #20
    RoadBikeReview Member
    Reputation: Kontact's Avatar
    Join Date
    Apr 2011
    Posts
    2,731
    Quote Originally Posted by NEO Dan View Post
    OK then answer this question; if you get the frame wet for more than a moment and wipe it off does it look completely dry or like it was wet?
    The surface is fiberous and water sits on the surface differently than something slick. But it isn't absorbing anything, it just has more surface area.

    Micarta is a composite made from fabrics and paper. The linen and canvas micartas used for knife handles will absorb some water into the fibers, but it doesn't hurt the epoxy structure.

    By contrast, nylon actually does break down chemically in the presence of water, but that's still not a problem that anyone worries about.


    UV can be a problem with everything - including paint. But UV doesn't damage the carbon fibers, and carbon composites are opaque, so how much damage could UV do to a composite as a whole?


    Now that I've answered your questions, how about sharing a source for this knowledge nugget for absorbent carbon fiber problems?
    Get a better saddle: www.kontactbike.com

  21. #21
    RoadBikeReview Member
    Reputation: gamara's Avatar
    Join Date
    May 2002
    Posts
    1,137
    Not to detract from the OP question but people have some very weird concepts about carbon. To some people its indestructible & to others its as fragile as glass. If people actually watch how a carbon frame is constructed, you would see that there is quite a bit of sanding involved. People with carbon tubular rims use solvents & glue on bare carbon all the time. So I don't think anything gets "absorbed".

    What people get confused about is when they think that something like a scratch in the carbon clear coat will lead to failure. Carbon failure is usually due to stress risers acting on an area over time. This could be anything from impacts to over tightening something.

    As for the OP, there was the recommendation of milling the area down. If the clear coat is too thick, there is nothing wrong with removing just enough of it to help ease installation.

  22. #22
    RoadBikeReview Member
    Reputation: Bill2's Avatar
    Join Date
    Oct 2007
    Posts
    9,403
    I had the same problem. Used very fine sand paper and spent an hour or two delicately removing the excess material from the circumference of the 7mm high shoulder at the base of the steerer. Pressed the crown fork race on and it's been working great for the past couple of years.

  23. #23
    RoadBikeReview Member
    Reputation:
    Join Date
    Jun 2010
    Posts
    236
    Quote Originally Posted by Kontact View Post
    Now that I've answered your questions, how about sharing a source for this knowledge nugget for absorbent carbon fiber problems?
    It's simple; carbon should not be exposed to contaminants if possible. Giving it a protective coating is normal and correct practice. I do have some practical experience with raw carbon fiber, you reminded me of my 940CF D2 this thing has shed many little pieces of it's surface over the years...
    Getting carbon fiber splinters in your fingers sucks
    Regards,
    Dan

  24. #24
    RoadBikeReview Member
    Reputation:
    Join Date
    Jul 2010
    Posts
    122
    Thanks for the replies and insight everyone.

    Here's the answers to a few questions:

    - Bike is a BMC Team Machine SLR01.
    - Crown race is press fit
    - There is no clear coat on the steerer, so if I were to sand it down, I would be sanding the bare carbon.

    Any objections to reaming the inside of the crown race? I can get a new one from FSA for $16 shipped if I accidently take out too much material.

  25. #25
    RoadBikeReview Member
    Reputation:
    Join Date
    Mar 2007
    Posts
    609
    Quote Originally Posted by Kneedragon View Post
    Any objections to reaming the inside of the crown race? I can get a new one from FSA for $16 shipped if I accidently take out too much material.
    How do you plan on doing this? Do you have a lathe? The reason I ask is that if you just plan on using a file or sandpaper, you going to be there for a while. Also, the result will be neither very pretty nor round.
    Last edited by TimV; 03-07-2012 at 10:23 AM.

Page 1 of 2 12 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Hot Deals

Contest

Tour De France

Latest RoadBike Articles


Latest Videos

RoadbikeReview on Facebook