tire size and modern alt. for singles?

[TrexDucatis]

I have found replica chinese tires for an original look..but I like the avons for a modern touch and road feel.
What is the max. that will fit an 18" rear rim on a 65' monza with side boxes.?
Originally had 2.75 - 18 ceat front tire and came with 3.25 -18 riken rear.
I believe the front is supposed to be a 80/90 ?
I have an inch of clearance all around the old rear tire. enough room to fit the 3.00 -19 scrambler tire from my 66'
I have "hardtailed" the rear swing arm to the frame and would like to fit the widest and tallest rear avon I can.
Being in Alaska getting the right ones the 1st time is very important.
Any narrowcase owners experiment with this? Your vast experience greatly appreciated .
Travis

[Daniil]

I have Pirrelli Street Demon on both front and back in sizes that you have listed above (original sizes). Great tires with aggressive enough/ modern thread. Hope this helps.

[Eldert]

hi Travis
with a hardtail you can a pretty big tire , if you had suspension the bolts that hold the seat and rear fender would rub the side of the tire when the suspension goes in even with a fairly small tire . reversing the bolt (nut on outside ) helps a little .if you can affort it get one of Phil Hichcock modern
alternator conversions (roadandrace Australia )

Regards Eldert

[TrexDucatis]

I will have the fender and boxes mounted shortly so I can measure the overall rear gap. Found the 3.50 wide rims at motociclismo and will probably run the stock front size 2.75-18...I believe this is a 90/90? the conversions so confuse me. I want a fat balloonish look to the rear tire and the front is just right. I'll prolly call up steve@ bevel heaven when i get it measured...and when my budget will measure up!lol Nickles and dimes add up to good times...eventually.
Thanks Travis