Dunlop run flats

Originally posted by Hanno Spoelstra
Dan, I think there is a problem. As far as I can tell, the inner tube for a runflat tyre is much smaller in diameter since the side walls are so much thicker (4"). So using the same inner tube in a normal tyre like the Michelin, means you will have to overinflate it to fit inside the tyre properly. Not the way to go, I think.

I'd agree with Hanno.
The RF tube is quite small and specific to the RF type tyre, not only are the tyre walls very thick but the bead spreader is a very thick part also making the tube volume quite small.

But not to worry as a standard 9.00 x 16 tube and regular thin-wall flap will be needed and generally these are off the shelf. (Well, in UK anyway). Of some concern, although this may be only applicable to car size radials, is the need for a specific radial type tube as we are told here never to fit tubes into radial tyres defined as tubeless. The reasoning being that radial side wall flexing is such that the tube is rapidly fretted, overheated by friction and then bursts at high speed. You need to check carefully perhaps the exact specification of the tyres proposed.

Of slightly more concern is the radial construction of your proposed replacements and the vastly increased traction. Ferret permanent 4WD may be a problem leading to hugely increased transmission loads as these radial tyres will not slip so readily as must be needed owing to differences in tyre rolling radius and in any event when cornering as the wheels all take different radius curves.

I cannot remember if the Ferret does have a tyre circumference matching spec, but it may well do and you will probably find that not only are the radials significantly smaller in radius than the RF HS2 T24 RF's, which are probably 110% - 120% aspect ratio, but four new radial types when mounted and measured around their circumference, show appreciably different dimensions between themselves.

This is fresh in my mind presently having spent the Easter weekend re-fitting the Stalwart with 6 new NATO pattern tyres, where I know matching is important and bought 8 therefore to replace the known on the spec limit NDCC's fitted; only to find when mounted even these new tyres presented two on the spec limit of 2" difference from the largest examples of the 8 I had.

So, I currently have 2 new but unusable tyres that are stored hopefully that in the fullness of time and with some wear in the others, they may become usable to match a part worn set later on.

R.