Hello.
I have just bought a 1975 JCB 3D mk II for restoration.
I would like to ask if someone can give me an advice for which front tyre it must have. The manual says 12.0 x 18, but it is mounted with 9.0 x 16 on the rims usually found on the 3C model. The rear tires is 18.4 x 26.
Today it seems that 12.5x 18 is a common size, with an outer diameter of 99 cm, and a less common but available size of 12.5/75 x 18 which is 94 cm in diameter. The 9.0 x 16 is 85 cm in diameter.
Would it be a problem to raise the front by at least 5 cm when mounting 12.5/75 x 18 ?
When I see pictures of the 3D mk II model, it seems like a low profile 18" tire used in the font, where a 12.5 x 18 really looks bigger.
As far as I can figure out, the 18" rim must have a negative ET of -50 mm or something like that.
Can anyone help clarify this for me?
Thanks in advance.
Martin
I have just bought a 1975 JCB 3D mk II for restoration.
I would like to ask if someone can give me an advice for which front tyre it must have. The manual says 12.0 x 18, but it is mounted with 9.0 x 16 on the rims usually found on the 3C model. The rear tires is 18.4 x 26.
Today it seems that 12.5x 18 is a common size, with an outer diameter of 99 cm, and a less common but available size of 12.5/75 x 18 which is 94 cm in diameter. The 9.0 x 16 is 85 cm in diameter.
Would it be a problem to raise the front by at least 5 cm when mounting 12.5/75 x 18 ?
When I see pictures of the 3D mk II model, it seems like a low profile 18" tire used in the font, where a 12.5 x 18 really looks bigger.
As far as I can figure out, the 18" rim must have a negative ET of -50 mm or something like that.
Can anyone help clarify this for me?
Thanks in advance.
Martin