[Outahere]

I've never owned an AWD vehicle, but have always heard if you have a flat you can't use a smaller size spare. Is this true?….

Has Honda ever published a spec for how much tire circumference mismatch is allowed with VTM4? Subaru allows 1/4" max difference in tire circumference, the last time I checked.

 

[Outahere]

So I dug a little deeper into the Honda Press Kit to find out that the RL temporary spare tire is 165/90R17 size, which is 28.7" diameter. That's nearly an inch smaller than the 245/60R18 stock RL tires that measure 29.6" diameter. Apparently, Honda feels that's OK for emergency/temporary use and won't damage the iVTM-4 AWD system...

And of course there is the usual 50mph speed restriction.