RE: 7.50x16 Tires and More ...

[Jim Grammer <jimg@domain.elided>]

>I enjoy the post regarding Travelall 7.50x16 tires.  How tall would
>this mounted tire and wheel be?  What size wheel to recommend?
>Will this size work on my Scout2?  How do these two bodystyles
>compare regarding wheel openings?  What ply ratings are recommended?
>I figure 4 ply will cover my loading needs, but read recently that a
>higher ply rating (6?) will allow better cornering.  Do higher ply
>tires imply less fuel economy?  I know little about tires and I note
>the 7.50x16 seems to be a favorite ... are there many widths
>available ie: 7.00, 7.25, 7.50, 7.75, 8.00, etc... or are there only
>a couple of sizes and this is the magic size?  Mark

Let's keep in mind we're talking about obsolete size designations and load 
ratings(and I threw that in...)that are still in mixed use for some things. 
Bias ply tires are disappearing from normal tire distribution, but are 
still available from 'collector' tire places so I doubt the old sizes will 
go away completely any time soon. With the old bias ply sizes, a general 
rule of thumb is the unloaded diameter at max pressure is roughly 2xstated 
width+rim diameter. For a 7.50x16, that's (2x7.5)+16, or 31". Makes for 
about a 29.5 or 30" tire effective at normal operating pressures and loads. 
This works for tires in sizes *.00 and *.50, if you see a *.60 size that's 
a 'low profile' bias ply size that equates to maybe a /75 series aspect 
ratio in a radial. OEM rims for 7.50's would have been 5.5 or 6.5" wide 
across the inside of the bead seat. The only available 16" bias ply 
sizes(truck tires) in this day and age are 6.00, 7.50, and 9.00. The 
9.00x16's on my S-120 are about 34" tall, 9" across the casing, with a 7.5" 
wide tread. I doubt you'll find anything in truck sizes that's not at least 
6PR. Last I looked, you could get highway tread, mud lugs, or military 
NDT's.

In radials, a 235/85-16 is a tiny bit bigger than a 7.50x16, with an 
unloaded diameter of about 31.5" and a casing width of about 9.5". Most 
radials aren't going to show a 'ply rating', so looking at the max pressure 
is a good way to tell unless you're a pro reading weight capacities.

For pre-'69 4x4 Travelalls with stock suspensions, I can confirm that a 
Gateway Buckshot Mudder in PR78-15(32x10.5) fits with no apparent clearance 
problems. They suck on the street, but they fit.

Jim