1930s Hercules tyres size question

[FrothNinja]

Just about to hit the hay but I will leave a question.
Having got the bottom bracket spinning beautifully on my recently acquired project 1930's Hercules Ladies bike, my thoughts turn to the tyres & tubes.
The ones on the rims are like solidified lava and no detail is readable on them.
I (hopefully) have added relevant pics and would appreciated availing myself of the Hive Wisdom and asking what tyres/tubes I should be seeking out in order to get the bike rolling?
Ta in advance.

 

[Sharky]

Can you remove the tyres and get to the inner tube?
Might have some guide on the inner tube.

 

[FrothNinja]

Can you remove the tyres and get to the inner tube?
Might have some guide on the inner tube.

That's a good idea, and could be a interesting challenge too.
Should have thought of that myself, doh.

 

[Cycleops]

I would think they’d be either 26” or 28”, probably the latter. You might find this place useful for the replacement :
https://www.jmhcycles.co.uk/Bike-pa...age-antique-raleigh-roadster-triumph-imperial

 

[Chris S]

The wheel diameter on my Raleigh is also about 61cm. It takes 26 x 1 3/8 tyres (ETRTO 590, 650A).
It's probably best to remove the tyre and measure the bead diameter of the rim. Hopefully it will be 590mm, there are plenty of 650A tyres about.
There's a small chance that it will be 597mm in which case you will have 26 x 1 1/4 tyres (ETRTO 597). You would be lucky to get a used one of these on ebay.

 

[T4tomo]

original question answer - measure the BSD if you can get the tyre off in one piece.

my question - are the wheels (rims spoke hubs) actually serviceable given the level of tyre decay? if might be new wheel time

 

[si_c]

Are those clincher type wheels or tubulars?

 

[FrothNinja]

original question answer - measure the BSD if you can get the tyre off in one piece.

my question - are the wheels (rims spoke hubs) actually serviceable given the level of tyre decay? if might be new wheel time

Going to try and get the tyres off this week so I'll know then. I have high hopes as the Woods valve came out easily enough.
The tyres may well have been in their for 80 years had basically dissolved so will probably have helped preserve the tyre by preventing oxidisation. Still on the original braided cables though they are stiff

 

[SkipdiverJohn]

My money would be on it being an ISO 590 rim taking 26" x 1 3/8" tyres. 28" wheels are generally associated with rod-braked heavy roadsters in larger mens size frames.

 

[FrothNinja]

The rim to rim diameter of the wheel is only 61cm / 24" and it is about 25mm / 1" across the rim. Hoping to get the tyres off this week - possibly tomorrow. Do I take the measurement across the rim internally or externally?
Ta

 

[SkipdiverJohn]

The rim sizing is essentially the internal diameter plus twice the thickness of the rim material, or the overall outer diameter minus twice the depth from the outer edge to the inside flat bottom of the rim. If you measure, say an ISO 622 road rim or an ISO 559 MTB rim, nowhere on the external surfaces of those rims will you get a measurement of either 622 mm or 559 mm. The overall diameters will be larger and the inner diameters where the spokes go through, will be less than the nominal ISO spec.
Essentially you have to judge where the inside edge of a fitted tyre will sit within the rim cross section.

 

[Ian H]

Are those clincher type wheels or tubulars?

It looks to me like a Westwood rim.

 

[FrothNinja]

The rim sizing is essentially the internal diameter plus twice the thickness of the rim material, or the overall outer diameter minus twice the depth from the outer edge to the inside flat bottom of the rim. If you measure, say an ISO 622 road rim or an ISO 559 MTB rim, nowhere on the external surfaces of those rims will you get a measurement of either 622 mm or 559 mm. The overall diameters will be larger and the inner diameters where the spokes go through, will be less than the nominal ISO spec.
Essentially you have to judge where the inside edge of a fitted tyre will sit within the rim cross section.

So much still to learn for me

 

[FrothNinja]

Westwood rim

Runs off to look up Westwood rim 🏃‍♂️

 

[T4tomo]

The rim to rim diameter of the wheel is only 61cm / 24" and it is about 25mm / 1" across the rim. Hoping to get the tyres off this week - possibly tomorrow. Do I take the measurement across the rim internally or externally?
Ta

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