I did some searching and a little confused so I want to ask everyone to get a better idea...

Well to make a long story short, I picked up a nail while out riding yesterday and rather than patching the tire, I am going to go ahead and replace both tires- the front needed it anyway and the rear- one with the nail would have in a few months. Well heres my dilema and questions....

My CBR comes stock with 120/60ZR17 and 160/60ZR17 tires. When I purchased the bike, it had/has 120/70ZR17 and 180/55ZR17 tires on it. THe bike feels good to me with this combo BUT from the reading I have been doing, this is not the best combo for the street because the rear tire actually looses contact patch. Is this correct? Or should I stick with what is on the bike now? What are your opinions and thoughts before I order my new tires.
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Boy I'm supprised you don't have a heap of replies, my personal choice, I replace with recommended sizes. But then & again I've been married for almost 30 years, so any shred of noncompliance wos lost years ago. I know that the CBR' rear rims are designed so that they can take a bigger profile at the rear for racing (or track day). (I read it in a bike magazine, so it must be true)
But seriously, it's down to you and wot you feel comfortable & confident with. The last thing you want to worry about when 9/10th's into a corner "Are my tyres ok?". Contact patches are well & good, but modern tyres have greatly overcome this problem by the rigidity and shape of the tyre.

 

the larger profile tire does lose contact patch, but it could increase turning a little bit, when you squeeze that big tire on the smaller rim it has more roll. i have a 180 in the rear, and i like it.