Spare Tire size for BN7 Mk 1

["Brashear, Jack, N" <JNBrashear@garverengineers.com>]

Hi All, just needing a little help here.  What's the tire size needed
such that the spare will fit in the space allotted for it on a BN& Mk1??
We put a new 165-15 radial on a new 60 spoke wheel but it won't fit thru
the slot in to rear bulkhead.  Seems the tire cross-section is too great
to fit.  Shoving hard doesn't help either.  Does this sound like another
trip to the tire store??  Many thanks,

Jack