tyre size - 120/70 and 150/70?

Aha, Sorry I read it wrong. I thought you'd written Powers.
The road 2Ct's do have an abrupt curve at the edge of the tread and You'll be doing well to get right to the edge. I understand what you mean now.

With the Powers the contact patch gets bigger as you lean over, with the Roads it gets progressively smaller. As the rear on the road 160 is pinched on the SV then this is going to make the transition even more abrupt and a 150 would work better.

Having the 120/70 on the front is helping tip the bike into the turns more than a 120/60 and the profile of the rear Pilot road is trying to stop the bike leaning so you have the same effect as a squared off rear tyre. They are fighting each other.

You could go back to Powers

C

A quick and slightly exagerated example of the profiles...

(not taking into account squash onto the road)

When pinched on the SV the Pilot Road takes up the shape shown in my pick although its quite obvious in the pics of the two tyres the difference in profiles.

I have a similar thing with my bridgestone 021s. The tyres feel great up until you get about 1cm off the edge then everything goes lighter and it feels like you are riding in the rain or something. I'm sure its just me being too scared to crank it over, but with the tyres the way they are I'm not sure it's a a good idea!

The 021s I have have a very flat profile, nothing like the triangle profile in Berlin's post..

[NedSVS]

The worn profile of the front is often the cause of this vague knife edge feeling as you aproach your limit of lean. The front profile often wears to reflect the lean angle you use most / are most comfortable with. this means when you lean a little bit further than this you are actually suddenly on a smaller contact patch - not good!
Ideally on the paddock stand, look down from above the front tyre and observe the profile, if it has covered some mileage you will probably see a noticeable change in profile where your well scrubbed section changes back to the original mould shape.
This change of profile is why I have in recent years not put a new rear on with a part worn front with the exception of the Avon Viper Sports I am running now. These avons have an exceptionally soft carcass, giving a large contact patch, which seems to stop this happening. Avon give it a posh name of something like "lifetime profile engineering".

[yorkie_chris]

Originally Posted by NedSVS

Avon Viper Sports I am running now. These avons have an exceptionally soft carcass,

Really?

[NedSVS]

Originally Posted by yorkie_chris

Really?

Yes, I have been doing my own tyre changes for about 5 years now. I've handled Bridgestone, Pirelli, Dunlop and Continental, but the Viper Sports have a noticeably softer carcass than all these.

[yorkie_chris]

From how they ride I found the viper sports harsh and stiff. Compare them to a racetec, SC pro, mich PR2, even the storm ST.

Something wrong there then! The avon's I've fitted in the past have been stiff as oot!
Admittedly not as stiff as the Conti's

[NedSVS]

Originally Posted by yorkie_chris

From how they ride I found the viper sports harsh and stiff. Compare them to a racetec, SC pro, mich PR2, even the storm ST.

Strange that isn't it? I ran the last of the SC (before the pro) and found them good on the road. Moved onto the SC pro and didn't like the because they need more warming up. Tried a pair of Road Attacks next and was neither impressed or unimpressed but I didn't like them enough to stick with them. Onto the Viper sports, which I liked. I didn't notice any harshness - pity I didn't run them staight after the SC pro's so I could get a direct comparison.

+1 on Vipers sports being harsh. Even lowering the pressures didn't help But there is a difference between air damping and carcass damping.

SCorsas, racetec, Power ones and the other super sports tyres are very soft (especially the new Interact racetec which you can tie in a knot! )

C