Maybe a stupid question about posi?

[Roc87]

I had a tire that was flat on the way to work yesterday, had some lady in a mustang honk at me and tell me that I had a low tire, I pulled into a gas station. It wasn't low it was flat! And by the looks of the sidewall, it had been flat for a few miles. Yeah I should have been able to tell by the way the car drove, but come on, it handles like the Titanic!

Anyways for my question, If I have a stock rim/tire 215-60-15 on the passenger rear, and my GNX rim with a 245-50-16 on the drivers side, will it affect the posi unit? Now I have to wait a few days for the TireRack to send my new BFG G-Force T/A, I'm not going to be doing 100mph for 3 hours straight. Only back and forth to work, maybe 5 miles, at 45mph. Or, should I take a front rim/tire and put it on the back until the new tire comes in?
Hope this question isn't as stupid as the one on Ls1.com about coasting!

 

[The Radius Kid]

Keep the speeds down and you should be fine.

 

[gofstbuick]

Why not play it safe and move a front tire to the rear. Not to say The Raduis Kid is wrong, but it may be better to err on the side of caution. I would hate to give you advice and then I see a post that your looking for a posi rebuild kit or new posi unit. Just my 0.02.

 

[BJM]

All you care about is tire rolling diameter. If they are the same then you are fine. Roll the car forward 10 tire revolutions after making marks on both rear tires. See if one turns a noticeable amount less or more. More than couple of % difference and you are working the posi constantly.