31.7"

[Russel]

6 to 6.5 wide Doug
BF 235 85 16's with rims definetly dont way more than 38kg.

[Syncro G]

Good point that Glen. We tend to forget that big wheels carry extra weight and I imagine 235/85/16 wheels and tyres are, as you say about 45 - 50 Kgs each. What you have then is 4 flywheels that need to be braked and as we all know, the standard brakes are adequate, but poor by todays standards so the bigger wheels would add to braking distances / fade etc

No on the landy they are 35kg on a 5.5F rim (standard LR style rim, not the super thick really heavy "wolf" style) with an innertube (the 7.50's were under 30kg). A Syncro steel rim probubly isn't significantly different than the landy rim and of corse ditching the innertube saves about 2kg from where you want it least. A fag packet calculation I once did revealed the moment of inertia of an innertube fitted to a 235/85R16 tyre is double that of the same tube fitted to a 205R16! Unfortunately I haven't worked out the MOI of the rest of the rim/tyre setup so don't know what overall % effect it has thus its relivance, though mass=bad isn't a bad way of looking at it.

Recomended rim sizes for 235/85R16 seem to be 6...7in when I emailed Mitchalin and Goodyear. Strangely its 5...7in for 205R16.

Has anyone tried 7.50R16's? They are vertully as tall as 235/85's but not as wide [or heavy], rim range is 5.5...6.5in. They aren't speed rated as high as the modern sizes (about 140km/h from memory, worth thinking about if you want to do this speed) but so long as you make sure you get the radial versions (there are still some crossply 7.50's out there, as are non tubeless versions, both of which I'd avoid) they'll perform alright for MTs.