IP2 and Classic tyre sizes

[BlackIP2]

New tyres are needed for my IP2 but I am confused over sizes, as there seem to be quite a few different combinations posted in various road tests, the workshop manual, etc.
They are all V18: 100/80; 100/90; and 110/80 for the front tyre. And for the rear: 110/90; 120/80; and 120/90. I have seen all of these quoted as the sizes fitted to both the IP2 and Classic.
Can anyone offer advice or guidance on this please if it is OK to fit any of these, are there specific combinations that must be fitted together, or is it purely down to personal choice/availability?
I want to fit Avon Roadriders and they have all the sizes except the front 100/80, so I was thinking of 110/80 on the front and a 120/80 on the rear.
Incidentally, the Commander appears to be far more consistent in that everywhere shows the tyres as 100/90 front and 110/90 rear.
Cheers
Mark

[johnbirchjar]

Hi Mark,over the past 68,000+ miles I have allways stuck to the original sizes for my Classic of 100x90x18 for the front and 110x90x18 for the rear,rgd,J.B.

[David Rodgers]

Hi Mark
Recently had a new rear tyre fitted, i use 100/90-18 front and 120/90-18 rear on the ex IP2 Classic rep. These work well, two ways of deciding on tyre aspect ratio. These are:- 1 With the lower 80 profile you will have slightly lower gearing, bike will be lower making it harder to get on the main stand but easier to get your feet down and it will sit more upright on the side stand. 2. With the deeper 90 profile you have slightly higher gearing, bike is easier to get on the main stand and more lean on the side stand which is good on sloping parking areas. As always you pay your money and take your choice! I do a European tour every year and have the 90 profile just for the gearing advantage!
Cheers
David

[David Rodgers]

One other benefit of the 90 profile is more clearance when cornering, still touches the sidestand down with the 90's though.