How long is the shim relative to the stem? If it's significantly shorter, you'll have the same problem of the stem trying to walk up the sleeve as you get with steerers which stop short of the top of the stem.
@gbj_tester started
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How long is the shim relative to the stem? If it's significantly shorter, you'll have the same problem of the stem trying to walk up the sleeve as you get with steerers which stop short of the top of the stem.