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Headset replacement query

andyrrandyrr Posts: 1,748
Wonder if anyone can help.
Bike is a 2013/14 Jamis Nova Sport Cross/road bike.
Headset really need replaced - both upper and lower.
I've found the Jamis spec but all this shows is FSA integrated 1 1/8 and 1 1/2
My measuring, using my callipers, indicates the following:
upper is 41.7 outrer, 28.7 inner, 7.8 height
lower is 51.8 outer, 39 inner, 7.8 height.
No markings remain on the old bearings that I can see for me to decipher.
I'll contact Jamis in case they will help me out but as I want to replace asap I'd like to identify this and get one ordered.


  • andyrrandyrr Posts: 1,748
    Since I can't seem to edit my original post ...
    Is it actually one of the few times when, despite having sufficient knowledge to perform the job, that the LBS would be appropriate to help out ?
  • andyrrandyrr Posts: 1,748
    Answering my own queries here ...
    Remeasured, searched the net and found what I am reasonably assured i the appropriate set of bearings:
    Tapered Headset | 1 1/8" - 1.5" | IS42/28.6 & IS52/40. Will cross finger they fit - present one are rough as.
  • i.bhamrai.bhamra Posts: 245
    If you are just buying bearings rather than complete headset, have you checked the contact angles are appropriate for the bearing seats in your head tube and the fork crown race (and possibly also important for the compression ring but not sure)? Internal and external angles are usually some combination of 36 and 45 degrees and if you have the wrong ones they won't seat properly.
  • andyrrandyrr Posts: 1,748
    Originals look like plain 45degree which matches the ones I've ordered. If new matches old then fine, if not then a trip to my LBS will be needed.
  • andyrrandyrr Posts: 1,748
    Well, a little surprisingly my email to Jamis via their contact page resulted in a response from Bryan Dubuc. He provided me with firstly a schematic for the headset - can't quite work out the bearings as it shows the bearings etc all broken down but it also shows the FSA Orbit C-40B as an appropriate item.

    but ... a bit more searching turned up this product on the Evans web page - it is out of stock (seems to be common for other dealers) and a question from a fellow Nova Sport owner who also reportedJamis recommending this headset. Evans response was
    "I can confirm that is not the correct headset for your bike and would recommend the following headset bearings, which will be compatible:
    - Pro Headset Upper- IS42/28.6mm (Product code: EV204267)
    - Pro Headset Lower- IS52/40mm (Product code: EV204276)
    - "
    - I am now puzzled but will await the arrival of the bearings I ordered to see how they do or don't work.
  • i.bhamrai.bhamra Posts: 245
    Looks like the lower bearing in the headset recommended by Jamis is 36x45 degrees.
  • andyrrandyrr Posts: 1,748
    i.bhamra said:

    Looks like the lower bearing in the headset recommended by Jamis is 36x45 degrees.

    You sure ? I looked up the specs for that (lower) headset and it appears to be 51.8/40/45 shows a picture with that stamped on it. Real pity I cannot see any markings on my existing one hence the doubt which will be clarified and ideally resolved with the arrival of the bearings I've ordered.
  • andyrrandyrr Posts: 1,748
    Oh well, replacements only 1/2 suitable - pretty certain the upper is fine but the lower has a different external angle - 36 I suppose, not the 45 as per what I spec'd and got supplied. Will get it sorted !
  • andyrrandyrr Posts: 1,748
    Hopefully correct one ordered now - seller (on ebay trail_vision) sell a big range of bearings and have identified the appropriate ones.
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