We are currently running 110/70-17 on the NC30.
Is it possible to run 120/70-17 without problems?

You may find that it hits the rads under braking and so it is worth hecking your clearances beore you commit to it.

I have a 120/70 on a wheel and want to run it but I am concerned about the space and contact. Also I cannot get my mudguard over it!

Hi
Just pop the fork tops and drop the bike down slowly as not to have oil all over the place and check your clearance
you will need about 10mm to allow for flex in the bump stops and fork flex and tyre deformation.
A friend run on at cadwell and it rubbed the paint off the head where it protrudes below the top rad
but was said to give good feel with no handling issues.

Thanks
Antwar

Antwar wrote: A friend run on at cadwell and it rubbed the paint off the head where it protrudes below the top rad
but was said to give good feel with no handling issues.

On a road bike you'll rub the radiator guard v-piece through long before it hits the head. For a street bike it's best to stick with the recommended size.

Not such an issue with race bodywork.

We've just fitted her bike with a Pirelli Diablo SuperCorsa 120/70-17.
She has a trackday tomorrow and I'll post the result here.
Id that doesn't work, we'll order the new Bridgestone BT016 in 120/60-17, as she wants a littel bit more stability in the bike when cornering. It flicks over just a little bit to easy now she says, when running 110/70.

Wht are you running a 110 now?

Is it a 3inch rim or a std 3.5?

I have a 120/70 on a rim but it would not fit under my mudguard...let alone drill my V piece...so I have never used one even though it is in the garage and in better shape than my current tyre!

We run her bike on used racetyres from the Aprilia RS250 cup (Sportproduction).
Thet must run on 110/70 and 150 or 160/60 Dunlop 209GP's.
Since we both do alot of trackdays and schools, this had been the far most economic solution.....as well as the Dunlops are great tires that lasts very long.
However, the Sport Production class has fewer and fewer races and is now a rookie-class. So buying tires has become very difficult. All the rookies tend to use them to the fullest and then just throw them as scrap.

She does have racefairings on the bike which are prepared for the street with lights and inicators.
But it did not scrape the front fender on her bike with the 120/70.... (stock fender and stock 3,5")
She's on the track today and tonight we'll see if it worked out

Back from the track.

There are no scrapes on the fender, V-piece or radiator.
She'll probably go with the 120/60.

Hope this info can help some others with the same questions