Steve Sr. wrote:
Is this small diameter difference likely to cause a problem in real
life? I am trying to put a high angle (130 degree) stem on my road
bike to improve the fit and the high angle stems seem to only
available for Mountain bars.

Thanks,

Steve

Depending on the stem it may either case a bent bolt or bolts that don't
engage enough treads. Both bad ideas. A broken stem/habr connection when
out of the saddle climbing can really hurt. Stems are cheap, get the
proper one. Dental bills are not cheap.