I had to read that just out of curiosity. What I found most interesting was the reply from the engineer from Cane Creek
Clearing things up...hopefully
Greetings from Cane Creek.
I am posting this with the hope of clearing up some misunderstandings regarding headsets, head tube specifications, and industry standards regarding the two.
1) The industry standard for 1-1/8” threadless headsets is as follows:
Head Tube ID (mm): 33.90 – 33.95*
Headset Cup insertion OD (mm): 34.05* – 34.15
A range is specified (known as the tolerance) since it impossible to manufacture to exact dimensions. These dimensions and tolerances yield:
Headset Interference fit: 0.10*-0.25mm
* bold values are target values with tolerance ranges falling in the direction of increased interference.
This industry standard is published in Sutherlands Handbook for Bicycle Mechanics (available for reference at most bike shops) and also online for free from Cane Creek at:
http://www.canecreek.com/fileadmin/c...pecs_rev_C.pdfThis is the same standard provided to frame and fork manufactures, including Specialized.
2) In researching the issue with 2007 Stumpjumpers frames, I communicated directly with Specialized’s Product manager for Mountain Bikes (He is at the top of the food chain there when it comes to bike spec). He writes,“No, we do not do anything tricky with our HS’s…we do not have our own spec like the Internet Chat rooms would like to believe.” “Again, we do not have a non-std spec.”
So to be clear:
- Regardless of what “tech guys at Specialized” have said, Specialized did not intentionally specify Stumpjumper head tubes with 34.00mm bores (see above for proof).
- Nor has Specialized created a new “Metric Standard” head tube bore of 34.00mm. First, the industry standard is already metric (33.90mm-33.95mm). Second, to be a standard (by definition) it has to be accepted by the industry as such. Having a single frame model made by a single manufacture use a head tube bore that is 0.05mm different from an existing standard is an example of nonstandard.
3) Despite the 34.00mm head tube bore, it appears that headsets that came stock on 2007 Stumpjumper frames do meet the Cane Creek cup insertion OD of 34.05mm-34.15mm. These headsets are reported to work fine with these frames. It stands to reason that other headsets that meet the same cup insertion spec (34.05-34.15), which is all Cane Creek 1-1/8” headsets, will also work in these frames. This includes the new Cane Creek 110 headset.
4) King Components 1-1/8” aluminum headsets have a target Cup Insertion OD of: 34.0mm and recommends the following:
Head Tube ID: 33.9mm
Maximum Interference fit: 0.1mm
These values are available online for free at:
http://www.chrisking.com/specs/headsets_all.htmlKing’s target specification for Cup Insertion OD is outside of the industry standard. However, since no tolerances are provided on either the press fit or the Head Tube ID, it is not clear what constitutes a proper head tube bore for CK headsets. However, evidence suggests (by the tens of thousands of frames that are manufactured to Cane Creek standard that use King 1-1/8” headsets) that frames with head tubes manufactured to the Cane Creek standard (from the factory or by using widely available frame finishing tools) provides an appropriate interference fit.
Note that the “custom” CK headset (with 34.10mm cup insertion OD) meets the industry standard.
Addressing specific questions:
Q- If the Specialized frames use a slightly bigger headset, then that means that Cane Creek, and other companies that supply headsets for them, would have known about this and the info should have been out for awhile now, correct?
A- No. First, Specialized doesn’t use slightly bigger headsets. The headsets that came with the bikes meet the industry standard (see above). Second, Cane Creek and manufacturers that supply OEM customers (like Specialized) on behalf of Cane Creek supply headsets manufactured to the industry standards. If headsets that meet this standard are specified (like the one 1-1/8” headsets in question here) then frames are made to fit headsets, not the other way around.
Q- So if CK's are 33.9 what are other head set measurements? Are Cane CreeK, Race Face, FSA, Hopeand others larger the CK?
A-.Since CK does not specify tolerances it is not clear if CK cup insertion OD is always smaller than the standard. From the issues with 07 Stumpjumpers, it certainly appears that CK manufactures headsets with cup insertion OD that is, on the average, smaller than other headset manufacturers.
Q- Nice looking headsets (in reference to Cane Creek’s 110 Headset). The question is, do they make them in a special size?
A- The standard size for all Cane Creek headsets is the industry standard, same as the headset that came with your bike. The 110 headset, any Cane Creek headset, or any other headset besides the “standard” CK will fit fine. Note that the “custom” CK headset (with 34.10mm cup insertion OD) meets the industry standard.
Hope this helps.
you should measure any part you are installing on anything ---( and you need to do it not the local bike shop )
i am in aviation , automotive and build race motocross and supercross bikes and i have for over 40 years ,----
and i will get parts all the time that are not quite correct .
i am very picky on how parts fit ( especially press fit parts )
i can not believe a guy will just buy a part and slam it in ------this is asking for disaster .
i have had many head sets that were not quite correct , ------you can get a cup that is slightly small , and a head tube that is slightly large ---------now you have a problem .
its up to the guy building the bike or aircraft to make sure its all perfect.
there are way to many variables in the manufacturing process to think that its all going to fit correctly when you start assembling ------
you guys that build your oun bikes need to get used to checking and doubble checking everything yourselves to get it perfect .
it is what it is and its always been this way
