im glad u asked that question cos im in the same boat, i already have 235's but i wonder about the spare as i have a lwb also. i think u could fit a 225 or 235 in there if it flat eg no air. i got a spare 225 here i will c if it fits in the well and let u know tomorrow if u like.

01 sporty, king springs,235/75/15s,tjm nudge bar,narva blue spotties,triffa spotties,uhf,dual battery sys and a sub.