The fist issue I see with my 48 Dodge is the condition of the bias ply tires on it. No idea how old they are, but they appear to be dry rotted. On the test drive before buying it, they started to shake about 35 mph. Just wanted to know what size radial tires would be a good fit for my car? The current tire size of the bias tires are 7.10-15. The car has a 3.9 t0 1 rear ratio, so I want to stay with a radial that is at least the same height.
Check it with the Place you Buy The Tire's From they Should Have a Cross reference on it I when't with Radials on my Merc & It Rides like your on a Cloud. Just my 3.5 Cents Live Learn & Die a Fool
good luck finding radials with the same aspect ratio as the bias plies....they don't generally make them that way. The wheels are probably 5" wide, and a 205/75R15 is probably about as close as you'll get to the right size. It will not be as tall as the bias tire. It will cost a lot less, and get you rolling.
Finding a tire of comparable width is easy, but the diameter is more difficult. The reason being that bias tires of that era were usually in 80 to 83 percent aspect ratio, though they were not marked as such in those days. A current tire would be about 205/75-R-15. Alternatively, 215, 225 or 235 would all give you an increase in diameter but section width grows significantly. Where it my car, I wouldn’t worry too much about matching the exact diameter as with 3.90 gears, it’s going to be pretty busy rpm’s in any case. Unless you intend to use it regularly on open highways the small gain in rpm in urban/suburban driving is relatively insignificant. I would look towards a 225/75 R 15 as ‘close enough’. However, if frequent highway use is in your plans, your Dodge is pretty easy to swap in a later rear axle ***embly with a more suitable gear ratio. However, your stock wheels may be an issue of concern. My guess would be they are 5” wide rims, possibly a 1/2” less or more. What are you plans about hub caps or wheel covers? A newer more radial friendly wheel will not likely accept the (probably) stock hub caps as Mopars of that era used spring clips for cap retention and newer wheels do not. If you are going to use full wheel covers or custom wheels, that is a moot point. Online tire sellers, such as Tire Rack, have excellent websites that provide comprehensive tire specs to aid in selecting and comparing dimensions, wheel width requirements and revolutions per mile for a given size. Ray
The shop manual, (41-48 Dodge) that came with the car states that the wheels are 5" wide. Don't see anything about the bolt pattern though. Would these be a 5x4.5 wheels like newer Mopars? If so, I could possibly go with a later model 6" wheel.
Diamondback is making tubeless radial ply tires that look vintage and come in the old sizes. It is their Auburn Deluxe line. I put a big and little set on my Duce 3-window and they look great. Unlike others these tires are round and balanced with little weights. Highly recommended.
You need one of those little plastic circles which figure out many bolt patterns. Couple of dollars and you are all set.
A 225 or 235/75-15 will be the closest you can get to a 7.10-15 in duplicating diameter with a current tire. These will be considerably wider and really should be mounted on a 6" rim to look 'right'. Make sure you have room in the wheel well. Actual diameter/width for that size can vary quite a bit between manufacturers so it pays to do some research. If you use the typical 'conversion' chart you'll end up with tires that look like you stole them off a mini-car...
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