1963 Imperial Tire Size


New Member
Nov 24, 2022
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Glassboro New Jersey
Good morning all,

This is my first post on this forum - very happy to be a part of this great knowledge base. I've been reading tons of useful info on here since I bought my green on green 1964 New Yorker Sedan last year. I am super excited to announce I will be picking up a gorgeous 1963 Imperial Crown LeBaron in a few weeks from now and I am already putting together a to-do list I want to get done to make it a solid "Sunday Driver". The car has 50,100 original miles, wears its original Black paint and has a very well preserved red leather interior. Body is straight and there is no rot - threw it up on the lift at sellers place to verify. Many service items covered by the previous owner and the vehicle drives like new. Only snag is that the tires on it are very old bias plys (8.20-15?) and I was thinking of putting some new radials on this thing. I was going to take the original wheels and keep them under a blanket in storage and throw on a set of nice U.S. Wheel 16x10 black steelies with chrome caps. I was thinking of doing a 265/70/r16 tire size on the car. This is a 30.6" dia tire vs the factory 29.6" dia tire. Width is 10.4 vs 8.4. Seems like an marginal size increase but I know this will ensure a ton of grip and improved handling vs the stock roller skates. I'm all for keeping the car as original as possible, but safety items such as a dual master and nice feet on the car take precedence for me. Since its an Imperial and the car has skirted rear wheel arches, would any of you guys that might have owned of these know if these 265/70/r16 tires are too wide? I was originally looking into a 16 x 8 wheel with a 235/75/r16 but that seems like a "baloony" tire size. Any insight or recommendations are warmly welcomed.


One of my top five favourite Imperials with favourite colour combos. You must post photos of your Imperial. I can't really say much on the wheel swap, I understand wanting to have better road feel. I would ask your tire wheel dealer if he can order in a tire and wheel for you to test on the car before committing to that size. My tire guy would for me. My first thought was just to say go with a new set of Nexxen AH% 235/75R15 tires narrow white walls and heavy rated. New shocks, brakes, and then front sway bar. The sway bar swap on my Imperial made a huge improvement in road stability. I am going to post about it soon, but the bar needs some tweeks from Firm Feel.
Is this your interior style in photo?
BEFORE you get too excited about "wheels", you need to download the factory service manual at www.mymopar.com (free download) and verify the wheel bolt circle as it is most probably not the same as normal Chryslers use, although it should be a 15x6 wheel. The OEM tire size might be i the manual, too.

Remember, too, that these cars were about ultimate luxury, which included an understated approach to their wheel covers. Repeat, "wheel covers", not "hub caps" or similar. Anything less is not a part of the Imperial orientation, then or now.

By the middle 1960s, the OEM tire size would have been 9.15x15 on the 15x6 wheel. Which converts to 232mm wide section width. Which would be a P235/75R-15 tire size. A few brands still have this size in "modern rubber" with whitewalls of an approximate width for back then. At a non-repro, normal price.

Seems like the OEM white sidewall style for those Imperials was a "double-stripe" whitewall rather than a solid white band. One little touch which meant "upscale" back then. Diamondback Classics can do the whitewalls on current-production tires, for a price.

As to roadability, download a copy of "It's a Wild, Wild, Wild World" and get to the car chase scenes. Which includes a '63 Imperial with the whitewall tires of the time on it. Watch the front end geometry of the front tires on the Chrysler products and you'll see what made them better than Fords and GMs. Pretty graphic in that respect too. Then watch some of the original "Hawaii 5-0" scenes where Jack Lord slides around Hawaii in his '69 Mercury Monterey sedan.

Some good HD shocks always helped, back then. But there is also a "Motor Trend" road test of a '65 Crown Coupe where they get a shot of it with all four wheels off of the ground on a public highway in the CA or Nevada desert, with the caption "She flies through the air with the greatest of ease, and doesn't bottom out when she lands". On those desert roads, they paved over the sand dunes and did not flatten them out as with other roads, so getting the speed high enough to "fly" was possible at normal speeds.

The Imperial sounds like a beautiful car. Congrats.

Happy Holidays,
Hello all,

Many thanks for the quick replies... some great information all around. I am downloading that manual as I type this. I had assumed the Imperial retained the standard 5x4.5 Mopar bolt pattern. I will have to confirm that. The New Yorker has a 4.25 inch backspacing with the 15x8 wheel size I run. The sway bar swap will be a must for me, I know my New Yorker has a front one and that car handles very well on 235/70/r15s. Boydsdodge may I ask what you did to get a sway bar on your car and where you were able to procure one? I cant imagine there would be a kit out there, this thing is just too obscure. Also, YES that is the exact interior specification this car has. When this thing shows up at my house next weekend I will be posting extensive pictures of it. Many little TLC things I will be doing immediately. Going to POR 15 the whole frame, the suspension links, the rear axle, probably soak the underside of the car with some Fluidfilm to keep things lubricated and safe from humidity. Seats will get a number of coats of Leatherique. No tears, just some stress lines. Will probably reach out to Coco Mats and have some custom floor mats made to protect the tear free original carpets. Replacing the in line auto trans filter and the internal paper filter too when I do the dual master conversion. I will check out those Nexxen tires. They will mount on the factory wheels no doubt.

CBody67 if you have any recs for HD shocks I would be interested in getting a set. The ones on the rear are new but the fronts look a little older. I have seen a 60s movie called It's a Mad Mad Mad Mad World its about 3 hours long of chaos. Some great car chase scenes in that. Not sure if you were referring to the same movie. I will look for the Imperial.

Thank you all, any more info or comments I'm all ears.
I deal with Firm Feel for my sway bars and suspension needs. They made a custom bar for my Imperial at regular bar price. I sent a stock sway bar to them to use as a template. The 235/75r15 tires will fit your original wheels. Late 60s and early 70s Imperials are 5x5 bolt pattern, early 60s I think are 5x5.5
Yes, that's the same movie. LOTS of little things to watch, like when Phil Silvers is driving the older Ford convertible to the river to seek to "Ford" it. He allegedly hits a rock and the oil pan is broken, except the oil is coming from a barely-visible tube from an auxiliary oil tank.

In another forum, the grandson of the stunt cocordinator for that movie came into the conversation. He said that there were no mods done to the car in the chase scenes, although I suspect that putting all of their tires up to about 40psi would not have been a "mod", as such.

The '57 Ford that Spencer Tracy drove over the cliff had a crude, Air Force Surplus remote control mechanism to steer it. Some of that hardware is visible in the scene where the car doesn't make a corner and flies over the edge of the cliff.

LOTS of little things that can be noticed, if you pay attention.

Take care,