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No gap between lower head tube cup and fork crown??

alesupperalesupper Posts: 286
edited September 2019 in Workshop
Hi All

This is a strange one. I have swapped my medium Kinesis ATR frame for the exact same frame but in a small. I have taken my original components such as fork, headset, bearings, everything from my original frame. However, when I have tried to install the fork there is no gap at the bottom of the headtube and the crown of the fork, so when I tighten the top cap the fork will not turn because of the friction. See attached photos.

I have been to my LBS and also spoken to Kinesis and they can not explain this. As a last resort before swapping the frames back I wondered if anyone on this forum could offer an explanation to this very strange problem?

Cheers.

48687272373_558a70f3c0_b.jpg

48687612641_c08235de88_b.jpg

Posts

  • If I had to take an entirely uninformed guess, it would either be that the recess for the lower bearing is too deep, or there's a shim/spacer/something like that missing. If this was me I'd check that the bearing was even in there, you may trust yourself more.
  • Yes I think that the bearing recess is too deep. The bearing is definitely in there I can assure you. Cheers.
    Sparquin wrote:
    If I had to take an entirely uninformed guess, it would either be that the recess for the lower bearing is too deep, or there's a shim/spacer/something like that missing. If this was me I'd check that the bearing was even in there, you may trust yourself more.
  • imposter2.0imposter2.0 Posts: 11,969
    is the lower race angle the same for both frames?
  • Good question. I don't know the answer to that. How would I measure that?
    Imposter wrote:
    is the lower race angle the same for both frames?
  • imposter2.0imposter2.0 Posts: 11,969
    easiest way is to drop the fork out and offer up the lower bearing into the frame and see what kind of fit you're getting...
  • Yep I've already done that and the fit seems good. This is the most bizarre issue I have ever come across and it is battering my head.
    Imposter wrote:
    easiest way is to drop the fork out and offer up the lower bearing into the frame and see what kind of fit you're getting...
  • Call Kinesis office?
  • keef66keef66 Posts: 13,123
    Has the fork lost it's crown race in the swap?

    If not, can you compare both frames upside down and side by side? Drop the lower bearing into each and see if it sits deeper in the new one suggesting a machining difference
  • The fork has got integrated crown race. Can't compare the frames side-by-side as they are about 80 miles apart unfortunately. We have measured them both with a metal rule and they look pretty much the same but I guess they could be a few thou out and that could be the difference.
    keef66 wrote:
    Has the fork lost it's crown race in the swap?

    If not, can you compare both frames upside down and side by side? Drop the lower bearing into each and see if it sits deeper in the new one suggesting a machining difference
  • keef66keef66 Posts: 13,123
    What is the fork?

    The Kinesis ATR disc fork says it has a non integrated crown race, while the Tripster Disc says it has an integrated one...
  • maybe the new frame use a deeper/different bearing? this one which needs to be look at and measurement taken. Not an internet job
    http://www.thecycleclinic.co.uk -wheel building and other stuff.
  • keef66 wrote:
    What is the fork?

    The Kinesis ATR disc fork says it has a non integrated crown race, while the Tripster Disc says it has an integrated one...

    It is the Tripster Disc fork. See below:-

    48687829778_7a8416bd42_b.jpg

    48688167206_82b303b7f3_b.jpg
  • keef66keef66 Posts: 13,123
    That second photo shows there's plenty of clearance between the seated bearing and the fork crown, so it can only mean that the the recess in the new head tube is deeper than the original, or possibly that they've changed the angle of the bearing seat?
  • keef66 wrote:
    That second photo shows there's plenty of clearance between the seated bearing and the fork crown, so it can only mean that the the recess in the new head tube is deeper than the original, or possibly that they've changed the angle of the bearing seat?

    Agreed. I have ordered a replacement bearing that looks like it has a shallower chamfer than my original bearing. If that doesn't work then I guess my options are (1) swap the frame back and look for another small on ebay (2) get an engineer to mill 1 or 2mm of the bottom of the head tube, which is a bit scary!
  • keef66keef66 Posts: 13,123
    I think if they know what they are doing and they are aware it's Ti and not Alu, milling a couple of mm off the bottom of the head tube should be fairly straightforward.

    I also wonder if it's possible to find a bearing with the same angles and inner / outer diameters, but a bit taller?

    This looks like the lower Kinesis bearing but it's 8mm thick rather than 7. Can you measure yours?

    http://www.wychbearings.co.uk/ACB518K.html

    ETA Actually, I think the Kinesis / FSA original looks like it's 8mm too...

    Did the old bike have bearings supplied with the frame / fork? Could the lower bearing possibly be the wrong one?
  • Sorry for the slow response. Unfortunately I can't find a wider bearing in those dimensions but I have ordered a bearing that looks like it has a shallower chamfer which might make the difference fingers crossed.
    keef66 wrote:
    I think if they know what they are doing and they are aware it's Ti and not Alu, milling a couple of mm off the bottom of the head tube should be fairly straightforward.

    I also wonder if it's possible to find a bearing with the same angles and inner / outer diameters, but a bit taller?

    This looks like the lower Kinesis bearing but it's 8mm thick rather than 7. Can you measure yours?

    http://www.wychbearings.co.uk/ACB518K.html

    ETA Actually, I think the Kinesis / FSA original looks like it's 8mm too...

    Did the old bike have bearings supplied with the frame / fork? Could the lower bearing possibly be the wrong one?
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