The Marston Sunbeam Club & Register Forum

General Category => Technical Discussion Forum => Topic started by: Thomas on September 14, 2017, 01:26:24 PM

Title: Tyre pressures
Post by: Thomas on September 14, 2017, 01:26:24 PM
Hi all! What are the correct tyre pressures for a 1937 Model 9? Cheers, Thomas
Title: Re: Tyre pressures
Post by: phutton on September 14, 2017, 03:06:52 PM
The tyre pressures are not specified in the 1936 or 37 manuals, but in the 1938 instruction booklet, the recommended pressures for the M9, on 3.25x19 tyres, are 18psi front and 20psi rear.

P.
Title: Re: Tyre pressures
Post by: VicYouel on September 14, 2017, 04:17:48 PM
Some 20 or 30 years ago I went to presentation by an AVON tyre representative. His advice was that modern rubber used on traditional tyres required some 3 or 4 psi more than originally quoted by old manufacturers.

I also worry about tyres slipping around the rim and dragging the valve out with catastrphic results. With my weight (100 plus kilos) I tend to run a 325/19 at the front at 24/25 psi and  the rear slightly higher. it's more bumpy and may wear them in the centre and the grip is not so good in the wet but that's my approach.

I used to run my Vincent Rapide with a 300/20 front tyre at 26 psi but boy did it wear out quickly but at 80mph I felt safer with higher pressures which should be increased with weight and speed.