Could you post some pictures from behind? My bike is just a commuter, and i hate how the rear tiny is super skinny looking.

 

tire size is 160/60/17 it is very close to the chain guard but dose clear
http://p2p-evolution.com/cbr/dscn0375.JPG
http://p2p-evolution.com/cbr/backview.JPG

 

I have an 89 cbr600f. I needed a new rear tire. I have a michellin macadam 11/80-17 up front(stock size). I bought the Michellin Road Pilot(bias) in a 150/70-17 after checking with this forum. my reasoning-

the bike has a 3.5" wide rim on the rear, which can comfortably hold up to a 150 tire. while a 160 will fit clearance-wise, you change the dynamics of the handling because it is pinched, it won't corner the same. I was going to go with a 140/80 but after some calculations I found that the 150/70 is closer to the same overall diameter as the stock 130/80. matching the two second numbers isn't necessary, that's nonsense. the 2nd number is just the percentage of the width that equals the heighth. aspect ratio, right. so 80% of 130 is the heighth of a 130/80. keeping the rear wheel as close to the same height as the stock one will preserve stock geometery and keep your handling the same.

if you got a slightly larger than stock(total diameter) front tire then you would want to try to do the same for the back. how do you figure out the total diameter? and what if you want to do something crazy like use different width rims?

I have a great .xml chart that figures it out for you from a buddy over at the Honda SOHC-4 site where I spend most of my net time. it is on a list of resources as well as lots of stuff to help you do front end swaps and brake upgrades, etc. you just plug in the size of the tires,rims front and rear you want to use and it will tell you everything you need to know to compare the diff to stock. here's a link

http://sites.google.com/site/alansdocuments/

check out this one 1/2 way down the list: "Tire Size Comparison.xls" you will want to keep it for your documents.

my other bike is a 1971 cb750K1, I am putting aluminum rims on it and switching out the front end. this list has helped me a lot. everything you need for a front end swap.

 

installed conti road attacks on my bike a couple weeks ago. 150/70 and 110/70 woot! love em so far.

 

I have a 120 on the front with no problem.. And now that the guy with the 150 on the rear I'm doing that too now.

 

I have been running a 150 rear since I bought my back and it handles fine.

I know the different characteristics of a radial vs bias carcas.
My ? is this. as long as the profile of the tire is "forgiving" meaning not pointy in the center, why couldn't we run a 150 radial?

I am looking at a set of pilot power's but haven't found an answer on how radials run on these bikes.

 

Heres what im running and for a newbie i dont have ANY chicken lines lol. I am smart about it though.
120/70/17 Metzeler Steel Radial MEZ4 front
150/70/17 metzeler steel radial MEZ4 rear
Hope these are good but they do have serious crowning issuse

 

After looking the mez4 has a straight sidewall, whereas the pilot's and battleax's have a sidewall that comes in more.

Can you post a picture of your front and rear?

I don't get crazy on the ole cane but I do like playing in the twisties and the previous owner put on avon roadrider's which suck. They don't heat up at all and have a crappy profile. At my best lean they still have 1inch or bigger chicken strips.
Not to mention that because of the hard compound and not heating up they feel pretty squirrely when you get over on them.

 

Try to get a pick. Just ordered a set of road attacks in the same size get them tuesday

 

The Metz have a lot of miles I would assume too. The front has the most noticeable crown and the rear is bald with a short strip of wire. But on a roll to the right and feel it pick up cause of uneven wear.