Exactly What Wheels & Tires Fit C Bodies?

amazinblue82

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Maximum tire size

I recently went down this same path. Here is what I put on my 65 Sport Fury . 255 60/R15 on 8x15s 4.5 " BS in the rear. 215 65/R15s on 7x15s up front.

I went with this size to add to the rake I was looking for. You can also go with 70s as was recommended to me as the more exact fit to the rear tire height, but again, I was looking for a style. I felt the 275 was too much tire and I'm happy with my choice. The 255s fit great and look right in my opinion.
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amazinblue82

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TEACHING POST:

This explanation is here, in various forms, at least 40 different times to help novices take measurements. Always surprised how many folks get these measurements wrong .. and it makes all the difference sometimes between the set up working or not.

rim size and offset for newport

The goal is to not have the tire rub against the inner wheel tub or the leaf spring. I removed the wheel and using a straight edge measured the distance to the spring and to the wheel opening.

Using those measurements and 300rag's drawing you can figure out max rim width and offset. Remember the tire is wider than the rim in most situations. Go at least one inch less than the spring to wheel opening distance. You need to make a drawing and check the math to make sure it will work or you will have an expensive mess on your hands.

Start with your measurements. The mounting point on the drum is zero, mark the distances to the spring and wheel opening and subtract at least 3/4" on each side to be safe. The total distance is max rim width. The mounting flange to spring distance is back spacing, the other is front spacing. Offset is the distance from mounting flange to rim center. Negative moves the tire outward, positive inward.

Front wheels are more complicated since they turn. If you max out the rear wheel width you need to make the front narrower. At least 2-3 inches or they will rub the inner fender when turnmg
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amazinblue82

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rim size and offset for newport

Just put 17x7 front, 17x8 rear on my 66 Polara. ZERO offset. The standard size recommended by American Racing.

not sure of exact tire size, but the brand is Nitto (maybe 555R's?) . The recommended tire sizes for those diameter wheels tend to be 245/55, 255/45, or thereabouts. looks like a good fit, at zero offset, for a slabbie.without skirts

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amazinblue82

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TEACHING TOOL

Basic stuff here, but pretty good if somebody isn't sure about the things to plan for. Also geared for newer cars (e.g. no C's have front struts, some have front discs, rear skirts, etc),, radial metric tires, etc.

Sorta gives a clue on swap priorities: Backspacing, wheel/tire diameter, and wheel/tire width -- all using a a' baseline" of what OEM options existed for the particular C-body platform when it was in production.

Again, seems what we have said in all these posts is, VERSUS OEM BASELINE, an upsizing "envelope" (slabbies a little different from fusies, a little different again for formals) of something like:
  • plus 4 inches maximum on combo diameter,
  • plus 4 inches maximum 4 inches (2 inches suspension side, 2 inches fender/quarter side) on the combo width, and
  • about plus 1 inch (4.0 to 5.0 inches) on backspacing
lotsa wheel/tire combos can fit that envelop -- without irreversible modifications to the car.

Popular Mechanics - Guide To Upgrading Wheels and Tires

NOTE - graphic has an error in the aspect ratio - a "50" tire is 50% as tall as the tire is wide. Not 70%

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300rag

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TEACHING TOOL

Basic stuff here, but pretty good if somebody isn't sure about the things to plan for. Also geared for newer cars (e.g. no C's have front struts, some have front discs, rear skirts, etc),, radial metric tires, etc.

Sorta gives a clue on swap priorities: Backspacing, wheel/tire diameter, and wheel/tire width -- all using a a' baseline" of what OEM options existed for the particular C-body platform when it was in production.

Again, seems what we have said in all these posts is, VERSUS OEM BASELINE, an upsizing "envelope" (slabbies a little different from fusies, a little different again for formals) of something like:
  • plus 4 inches maximum on combo diameter,
  • plus 4 inches maximum 4 inches (2 inches suspension side, 2 inches fender/quarter side) on the combo width, and
  • about plus 1 inch (4.0 to 5.0 inches) on backspacing
lotsa wheel/tire combos can fit that envelop -- without irreversible modifications to the car.

Popular Mechanics - Guide To Upgrading Wheels and Tires

View attachment 400551 View attachment 400552 View attachment 400553
I will have to point out an error in this. Where were their editors/proof readers? A 50 series is not 70% as tall as wide...

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amazinblue82

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WILL THEY FIT 73 CHRYSLER NEW YORKER BROUGHAM

Beautiful car. I especially like when you can tell the American car isn't in Kansas anymore, Toto.

Here are 17" AR rims on my '73 Imperial. I tried to show pics that highlight the wheels/tires. In my opinion, you do need the whitewall, even if that means "spinning" a set of SUV white letters into a whitewall. At the time, you could get Michelin 225/60R17 WW's that were OEM on Lincoln Towncars. Wish I'd bought some extra sets because I don't think you can get them anymore. [/QUOTE]

maybe @carmine will see this and give backspacing he used.

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amazinblue82

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I listed it . Read it again... BS 4.5. that's as tight as I want it. Maybe a 275 would have fit, but I think it would have looked choked. That's just my opinion. I'm happy with my wheels.

yes, you did. sorry.

i was goin' cross-eyed looking through all the other posts and missed it. your fitment looks great.

real nice car. thanks for posting it.
 

amazinblue82

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Folks. that's it for me. Read over 400 threads. Sure I missed some photos and matching descriptions.

Using posts #5, #19, and #24, and links therein, I made the charts at the very bottom of this post. The equivalent diameter tire, using different diameter wheels.
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Say it another way, every tire listed in a single the chart is the same diameter ---25, 26, 27, 28, or 29 (these tall babies are moving into truck tire territory) inches tall. You will notice the wheel diameter in each chart is 15, 16, 17, or 18 inches (not yet "donk" territory if that's your thing). Next graphic illustrates the idea

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Presumably, to make it all work, a backspacing between 4.0 and 5.0 inches would work most often and therefore be a good place to start planning for.

Higher likelihood that, without permanent vehicle modifications (or removable stuff like spacers. airshocks, etc), and after you choose a wheel diameter and width (11-inch tread width un-inflated), calculate clearances and speedo effects, some combination of wheel & tire on these following charts will "fit" your C-body.

Notice, the word was "likelihood", and not "certainty". Respectfully, plesae take the extra time to plan for your car -- even if it is the same make/model of something you saw on this forum or in person.

Experience has painfully taught me to "measure twice, cut once" as that old saw would apply here too when you wanna move off the OEM "as-built" specs. Heck, if you arent the original owner of your C body, no telling what's been done to/changed on your C over the 43-55 years since it rolled outta the factory.

Obviously, there are really small, tall, skinny sizes listed that most people won't use in ordinary driving. Maybe not so obvious, as section widths get around 275+, aspect ratios get around 50+, that's getting to be BIG, TALL, and/or FAT tire -- moving into a size territory where chances of fitment without mods goes down.

Anyway, we haven't seen the last of the questions -- "what's the biggest .. , "what will fit ... Some of us will still roll our eyes at such questions. It's all cool. But if we keep adding real examples with descriptions to this thread and others, it may help us "grow the love" for our beloved C's.

Meantime, I will keep posting pics/info as I run across it, or do stuff to my own cars. Hope a few of you all do too.:)

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amazinblue82

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'68 300
The 67 New Yorker picture with the Magnum 500s has 15x8s with 255/70s on the rear and 15x7s with 225/70s on the front.

The wheels were from Wheel Vintiques and the backspacing is 4.5" on the 7s & 8s. The 8s would would fit with no issues on the front as well. Be aware that some of the early brake calipers may stick out past the bolt surface on the hubs and may not clear some wheels.
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bnz84

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17x9 rear with 275/55/17. 5" backspace (0 offset)). 17x8 front with 255/55/17 4" backspace (+12mm offset). I had a little rubbing on the drivers rear because the diff is not centered. I had to trim the valuable SS wheel trim and pinch welds about 1/2"
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amazinblue82

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17x9 rear with 275/55/17. 5" backspace (0 offset)). 17x8 front with 255/55/17 4" backspace (+12mm offset). I had a little rubbing on the drivers rear because the diff is not centered. I had to trim the valuable SS wheel trim and pinch welds about 1/2"
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excellent post. thanks for the comprehensive response. nice car too btw.

curious about this diff. centering question you point out?

I have not measured it, but eyeballin' C's in my fleet from every generation (even with other makes from '60's-'80's), and not accounting for reasons like where they wanna put exhaust pipes and such, in the rear on one side or another, there is more/less clearance between exactly the same size mounted wheel/tire combo and inner wheel opening lip.

1/4 to 1/2" or so difference driver vs pass. side -- which can make all the difference for interferences/clearances. I'd blame it on my advancing age but I been seeing this thing for 40 years.

My theory was that was designed-in somehow, vs. something that evolved over time with wear/usage of the vehicle. Since I never worked at Chrysler I couldnt confirm my theory with vehicle designers/builders at that company.

A little help? :)
 

amazinblue82

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hey rags .. if you were referring to my post #36, my observation is tires/wheels/hard parts ALL identical, level surface, the rear passenger side seems to show a little more "sticking out" of the tire/wheel on passenger side.

Stated another way, the driver side is "tucked in" a little bit more. Naked eye looks and its obvious.

my only thought is, looking at the car from the rear, the body sits a little left relative to the L/R centerline of car.

I believe the rear axle dimension is completely bi-sected by the centerline -- exactly same axle length either side

i don't have a C example i can show in photos, but I see this all the time on my J's, no matter the wheel/tire combo . And I have measured it.

Anyway, some J photos (rears are 17x9's, 5" Bsp, on 285/40-17 tires) that kinda show my observation.

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a 275/60-15 tire (28 inch tire is less than 11 inches wide itself) on a 10 inch wide rim doesn't tend to be recommended by wheel or tire manufacturers but i see people do it all the time. next closest size, 255/60-16 is a truck tire. -- never seen that size on a car.

IMG_20200903_194800.jpg


IF you werent talking about my post #36, sorry to butt in :)
 
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LocuMob

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the the rear passenger wheel seems to show a little more "sticking out" of the tire/wheel on passenger side.
This is exactly what I'm fighting on my Polara, the tire rubs on sharp right turns. Just a little, but still annoying.
 

amazinblue82

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This is exactly what I'm fighting on my Polara, the tire rubs on sharp right turns. Just a little, but still annoying.



for me, I had 15x8 3.5 bsp Center Line Auto drags on this car, same tire, 235/70and same thing happened. hard right, sidewall rub on inner quarter edge, passenger side. same thing tho on sharp lefts. i chalked it up to be more likely a little body roll changing the angles between sheet metal and tires.

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even now, with 4.0 in bsp, i can only get my fingers to my knuckles between sidewall and inner lip on pass. side. on driver side, I can get my palm in there, so about 1/4 in more clearance.

oh yeah, it aint just Mopars. 235/70, 15x7.5, 4.0 in bsp, rubbed on skirt on passenger side.
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