Can someone please confirm the stock tyre size for a 69 beetle.

The manual states 5.60-15 which equates to a 155/R15 however what is the side profile?

And did VW allow in its specs for a larger tyre size than this? Does anyone have any evidence of this?

155s haven't been around for decades.

Most people run 165/80s as they are that bit wider but the same rolling diameter as stock 155s.

Trouble is even they now are classed as a classic tyres which permits bullshit prices.

The last time I replaced tyres on stock rims I fitted Federal Formoza 185/65s (nice modern tyre and cheap) but thats on the later 4.5" rims, people do fit them on the earlier 4" rims but the walls balloon out abit.

I've got 4.5" stock rims and purchased 3 new tyres from Bob Jane last week.

Roadstone 165/80/R15 $99 each fitted and balanced. Seem okay.

At our work we fit thousands of 165/80/15 tyres every year. There are hundreds in stock. Austin Healey, MG, Triumph, Beetles, and the list goes on. They are easy to get. Kumho Power Star, Nangkang CX, Hankook Centrum or even Nexens.

I got Kumho's fitted to our Beetle at work, and the retail price would have been $110 each.

Guys Tim wants to go bigger than factory on his buggy
The engineer has stated he can only marginally increase the stock circumference per the ADR. I think he said 15mm!
As such we need to exactly establish "with evidence", what stock circumference was.

That is easy. 645mm.

so he can go to 660mm!

I think that he would be limited by width for the 4" rim more than the height.

The standard tyre was 5.60 not 155. A 5.60 would be taller than a 155.

Actually the acts don't refer to width. Theory refer to track. They don't let you change the track by more than x-mm. With track measured from the centre of the contact pad. Do by getting rims with the right offset you can keep the track nearly unchanged and therefore meet the ADR requirement.
It's all about forces on suspension,
I assume the rewuirement aims at keeping the same radius of gyration (proportional to rolling diameter and spring mass) and centre of the contact pad. They don't account for the sprung mass of the wheel!

Actually got it a bit wrong before:

ADR states:
4.2.4 Overall Nominal Diameter
The overall diameter of any tyre fitted to a passenger car or passenger car derivative must not be more than 15mm larger or 26mm smaller than that of any tyre designated by the vehicle manufacturer for that model.

Wheel Sizes and Axles
All rims fitted to a front axle or a rear axle must be of the same diameter, offset, width and mounting configuration (except for spare wheels used in an emergency situation).

4.2.8 Maximum Passenger Car Tyre and Rim Width
Tyres fitted to passenger cars or passenger car derivatives must not be more than 30% wider than vehicle manufacturer’s widest optional tyre.
The rim width must not exceed the recommendations for the tyre fitted.
For example, if the original widest optional tyre is 185mm, the maximum tyre width is 1.3 times 185mm = 240.5mm, i.e. a 235mm wide tyre. The maximum rim width for a 235mm tyre is 9 inches if the aspect ratio is 60 or below.

Some more ADR extracts
4.2.9 Passenger Car Wheel Track
The wheel track of passenger cars (or derivatives) must not be increased by more than 25mm beyond the maximum specified by the vehicle manufacturer for the particular model. This means that the rim offset must not be changed by more than 12.5mm.