'48 Chrysler radial tires/rims/ hubs

[Guest markrush]

I just took off my car's 20 + year-old tires and have a couple questions about which tires/rims came on my '48 Chrysler Windsor. The owner's manual says 7.60 x 15. I know the 15" rims came in two widths, a narrow and a wide. My car has wide rims, but the spare is a narrow rim. That surprised me. It was, as I recall, an old H78 x 15 bias tire.

Question 1) Was this narrow spare original (i.e. an early space saver tire, or maybe done later to get a wider tire into the spare tire well)?

Question 2) I have read old forum posts that refer to going up to an P225 75 R15 to replace the 7.60 x 15 original. Is this for the narrow or the wide rim? My wide rims had P235 75 R15. I never drove them but a few miles locally, so I can't say I put the through much of a test. Should I drop back to the 225's?

Question 3) In my trunk was a hubcap that does not fit my wheels. My hubcaps are 11' across and this hubcap has the same Chrysler script but it is only 10" across. What does that belong to?

Question 4) A local tire shop will powder coat my rims for $28 each which seems like a good deal. Would that interfere with the hubcaps or trim rings? I'm inclined to stay with paint as it is original. Any thoughts?

[61polara]

Mark,

You don't say if you have a 6 or 8 cylinder engine. My referece material shows the 15 x 5.5 rim was used on the 6's and 15 x 6 rim on the 8's. My guess is

that you have a 6 and the prior owner changed to the larger wheels, but they would not fit in the spare well in the trunk so they kept the original rim for the spare.

Attached is a good tire size conversion chart if you wish to stay with radials. The 75 series tires are the closest to the original size, but still not as tall. Your orginal tire would be about an 85 series in today's tire numbering system. Consider a set of original bias-ply tires. They will look better an give you true to period road feel. You car doesn't have power steering, the steering will be much lighter and be a much easier to drive car with bias-ply 7.60 x 15 tires.

I think your wheels should be body color. Can your tire shop match your paint?

Tire Size Conversion Chart

[61polara]

I just looked at your prior posts......beautiful car...........keep it original. Correct tires would look outstanding on the car.

[Guest markrush]

I do have a six cylinder 4 door sedan. So the 7.60 x 15 bias fits the narrow rim? Which bias fits on the wide rims? Shoud I consider looking for a set of narrow wheels? What radials fit the two different rims? My car is original (except a repainting in the original black some years ago) but in good condition. It is not a show car.

[61polara]

In these years Plymouth used a narrower 15" wheel. I would measure yours first to see what you actually have. The 8's used an 8.20 x 15 tire and the 6's the 7.60 x 15.

[Rusty_OToole]

All 5 wheels should be the same width. It appears your spare got lost somewhere along the way and replaced with a narrower Plymouth or Dodge rim. The 225s are a good tire for your car as long as you get the narrowest ones possible, this means the cheapest tires on the market. I use Walmart Marshal 791 tires on my DeSoto, they are the closest in width to original. More expensive name brand tires are more than 2 inches wider in the same nominal size.

Do not worry about using cheap tires, they are still better than what they had in 1948.

The powder coat is a good deal. As long as you can get the right color. If not you may want to paint them. Sandblasting and painting wheels is a tough, expensive job for a body shop or paint shop. Tire stores have a special bead blasting machine specifically for wheels, so they can do a good job much more reasonable.

[Guest markrush]

All this is helpful, but I'm as confused as ever. I looked up the wheels in my parts book. It says my C-38 Windsor 4-door had a "15 x 450" wheel (part 1120 888). Now I assume that means I should have a 4 1/2 inch wide wheel. The book says the "7 Sed., Limo., Town and Country" had "15 x 500" wheels (part 864 275), which I would think would mean they were 5 inches wide. None of that matches what I measure (see below).

Then I looked at the owners manual I downloaded from the imperialclub.com site. It has C-38 on the cover and refers to a six cylinder engine but under tires on p.38 refers to a size of 6.50" x 15" inflated to 28 lbs. I have another owners manual without cover I was led to believe was to a C-38 (it does refer to a six cylinder engine). Under tires on p.38 it lists two sizes, 7.60" x 15" and 8.20"x 15" inflated to 24 lbs.

Then to really confuse me, my reprint of the shop manual has a chart on p.310 that lists, under tires for a C-38, a 6.00 x 18 (misprint ? it is listed between 15" and 16" tires) and a 6.50 x 15 all at 28 lbs.

The guy at the tire shop told me rim width is measured from outside bead to outside bead.( Was it in 1948?) My 4 wide rims are 5 1/2 " bead-to-bead and about 6 1/2 " outside- rim-to-outside rim. My single narrow rim that had the spare on it is 4 1/2 " outside-bead-to-outside-bead and 5 5/8 inches outside-rim-to outside-rim.

Can anyone tell me what rims I have?

[Rusty_OToole]

Canadian Service Data Book says your car came with 6.50 15 tires. This would be about right for a 4 1/2" wide rim. So maybe your spare is the original size and some previous owner put the wider wheels on the car probably with oversize tires. Width is measured inside the rim where the beads seat.

Heavier cars like the straight eight New Yorker and Imperial, station wagons, and limousine had bigger tires and wider wheels.

It is possible that Chrysler offered 18" wheels as an option. Some owners of limousines and station wagons used for bus service, or who lived in rural areas in the west where roads were rocky and rugged, preferred the oversize truck tires as they gave higher ground clearance, longer wear, and could carry heavy loads without danger of a blowout. Or as you say it may be a misprint.

I went to Coker Tire's website and entered 1947 Chrysler Windsor C38, and got back a choice of 670-15 or 205 75 R15 tires. So those would be the closest available to your original tires.

Using oversize tires will make your car go faster for a given RPM. This is desirable as the original gear ratio was rather low for today's highways. You might consider 215R75 or even 225R75 tires. Get the narrowest ones you can find and they will be ok on your rims.

Edited July 25, 2012 by Rusty_OToole (see edit history)

[Guest markrush]

Thank you, so I guess the narrow rim is the stock. Now I have one more question. The tires you mention (6.50 x 15, 7.60 x 15 or the 75 series radials)- which rims would those fit? Would they only fit the narrow rims? Should I start looking for some more narrow rims? If I were to stick with the wide rims, what tire size would I be looking for?

[christianad1156]

I know this is a very old thread but after re-reading this, I went to check some of the info quoted and I found something interesting that I didn't realize previously.

 

There were two editions of the "Owner's Manual."  There are minor differences between the two that are mostly related to changes in dipstick marks, location of certain instruments (starter switch, high-beam indicators vs. turn signal indicators, etc), oil pressure ratings @30mph, Chrysler products highlighted in the care section and some of the words regarding when/how to check your oil and air cleaner oil.

 

The other difference is the information regarding tires.  The second edition seems to update information that matches the 1949 version of the Parts Book that updated the wheels and tires for late 1947 and1948 models to the wider wheel sizes. 

 

See below for examples of differences.  Note that one set shows that there was a second edition of the Owner's Manual.