G78 bias is what I have on my 49 Kaiser Special (no overdrive). It is an older non-radial style measurement, after the original factory OEM system, but before radials. Kaisers had, depending on the year and model, had from a mid 6 to low 7 measurement on OEM tires, ie 6.40 or 6.70 through to 7.30 or so. My take on it is that 265/70 is way too wide (and short) for a Kaiser and you will run into other problems with other components of your steering and suspension.
Read this chart carefully as a starting point to understand what is involved:
http://clubs.hemmings.com/clubsites/chevylist/tech/tire_size_conversion.htmFor Kaisers and Frazers, there isn't an easy, cheap off the rack "modern" rim and tire combo. What you should be using in a radial is perhaps a 215/75/R15, or maybe as second best 205/75/R15. You want tall and narrow. You have King pins; don't start looking at 60 or 65 tires, and even 70s are not as good as 75s. Do NOT put wide tires on your car
Certain older Ford rims might work, but I can't remember the details. Light trucks? What does work, ISTR, is a Chrysler product rim from the 70-80s. These were the last of the slightly stubby boxy full size sedans with V8 or slant 6, front engine with REAR WHEEL DRIVE, that were used everywhere as taxis and police cars etc. Dodge Diplomat? Plymouth ? Chrysler LeBaron? They had the 4 sealed beam rectangular headlights I think. Adam-12 the police show used them. junkyards are your best bet. ISTR that the problem with some other rims that appear to fit is that the center hole is slightly too large, and therefore the rim isn't supported except by the lug nuts and bolts, which isn't a good idea. This is if you really want to drive on radials.
I keep my Kaiser on bias tires for several reasons.
-suspension (toe in, camber, etc) is set up for bias, and would have to be changed to something suitable for radials. Subtle, but quite different, for both handling and tire life. This is important!
-bias give a nice soft billowy ride, radials are 'firmer'
-the 226 flathead is no speed demon even after a full rebuild, and it is happiest at 50 or so. Even with overdrive, you would be well advised to not drive an earlier Kaiser/Frazer car continuously above 60 ever. EVER!
-radials on the original rims are not that good an idea. They will make your car handle better around curves, and you might be tempted to drive faster than you should on thinner (rusted a bit over the years? damaged and stressed at some time in the past?) 60 year old rims. Plus, they generally use a higher pressure than bias.
-glass belted bias tires can last years and years if you don't drive much, and protect them from sun and weather. Radials on the other hand, do NOT last, and should be discarded no matter how nice they look--if they have steel belts-- by 7 years after the date of construction. Do some research on this issue, and check your daily drivers!! Also, demand the date code before any radial is put on any car. Moisture over time will migrate through tires, and steel belted radials degrade internally via rusting/corrosion with no external signs.
That being said, I also have a flock of Studebakers, three 57s, and a 63 and 64. 3 sixes and 2 V8s. I run all the road licenced ones -three at present--on brand new Ford rims (there happens to be a perfect interchange on an older pre-93 rim, as long as you use the Ford lug nuts instead of the Studebaker lug nuts) with radials, with updated alignment camber and toe in. I have 8 new never used old rims still in reserve for future upgrades. These cars all came with bias tires, but I tend to drive my Studebakers, even the sixes, a bit faster and harder than my Kaiser, which is after all, still a 40s design. I still use as tall and narrow a radial as possible, which is generally a 205/75/R15 unless I can find a 215/75/R15.
YMMV, of course.
