Avon tire Profiles old vs new on WM2 rims

In case some have interest :

I have an almost new (tread depth) but very old Avon GP 4.10 H 19 tire fitted to a WM2 19 rim.

These were standard equipment on Norton Commando  front and rear roadster and combat models ?

I mounted a new Avon roadrunner 100/90-19  57 V  to an identical WM2 19 .

Measuring the circumference of both revealed the GP to be 82 3/4" and the roadrunner 82 1/4. both tires at 34lbs presure cold.

Avon states this tire is a replacement for the older size tires, you can believe it. 1/2 " isnt much difference . looking at both

mounted one would think the roadrunner is smaller. not.

Previously wrote:

I had Dunlop TT100's on my 1972 750 interstate when I bought it new & ive used them ever since.

Ive just fitted a pair of Avon Roadrider Tyres 19" 100/90 Front & Rear.

What a difference compaired to the TT100's. They are miles better for handling & seem grippier. It give me the confidence to hammer the bike around bends now. Also they stop the bike wobbling when I go over white lines & ruts in the road.

I wish I had fitted them years ago. 

Cheers Don

very much agree Don, I have avon super venom on my S bike and Atlas. From what I understand the Roadrider is the same tire, diffferent name. I am just "waking up" a Combat purchased at an estate auction, she only has 6000 miles, was apparently put away after a crash and never ran again. havent tried the engine yet, hoping it's ok. compression is high and even on both holes. anxious to try out the tires but these things take awhile. I keep my Nortons as close to stock as i can. 19 " wheels and tires are fine for my riding style.