FWIW, the spare tire and rim I bought for my MH weighs 100 lbs. I'm thinking the biggest problem would be trying to figure out where to put it under the MH. I just put mine on my hitch which can be a pain when I want to tow. I rigged up a lift on my RV port to make it easier to handle when taking on and off. When on the road I'll be calling road service.
2015 Greyhawk 29MV
Honda CRV toad with Blue Ox baseplate
Ready Brute Elite towbar with braking system
TST 507 Flowthru TPMS