The Marston Sunbeam Club & Register Forum

General Category => Technical Discussion Forum => Topic started by: Alex on December 22, 2020, 05:17:10 PM

Title: Rear Tire M90
Post by: Alex on December 22, 2020, 05:17:10 PM
Hello all,

one question regarding the rear tire. In the part list on the website I saw that the front and rear tire spec for the M90 was 3.25x19. However, most of the bikes I have seen on pricture nowerdays seem to have 3.50x19 rear tires fitted? What are your thoughts on that? On mine there was a 3.50x19 tire fitted, but if 3.25x19 was the original spec I would prefer to use the original spec but not sure what it is now???
Title: Re: Rear Tire M90
Post by: Thomas on December 24, 2020, 07:54:58 AM
Hi Alex,

according to my files 26 x 3.25 and 26 x 3.50 were installed by the works. I wonder though about the difference between 26 x 'XXX' and 'XXX' x 19.

Cheers, Thomas
Title: Re: Rear Tire M90
Post by: phutton on December 24, 2020, 05:09:12 PM
What year is your M90?
p.
Title: Re: Rear Tire M90
Post by: phutton on December 28, 2020, 05:24:08 PM
The 1929 and 1930 catalogues both specify 26 x 3.25 tyres, equivalent to 3.25 x 19, for both front and rear wheels. For racing, a 27 x 2.75 front tyre is recommended, equivalent to 2.75 x 21.

The only Sunbeams up to 1935 that specified a 3.50 x 19 tyre were the 600cc Models 7A, 7B, 7C, 9A, 9B and 9C.

P.