Widest tire you can run on front of a '55?

[Lamar Wadsworth]

Current front tires on my '55 are G78x15 on the stock rims (that's how old the tires are--bias ply). What's the widest tire I can run on the stock rim without it rubbing the upper ball joint? There's not a lot of clearance there. Will a 70 series tire (205 or 215) work? It's going to be a driver, not a show car, so I'm not concerned with original look on the tires.

[55blacktie]

55 what?

[dmsfrr]

Do you know the width and backspace on the wheels you have?

Are they 15 x 5 with a 3 & 1/2 inch backspace, or something else? Maybe 5 & 1/2 inches wide?

A 205/70 x 15 seems a little too wide for a 5 inch wheel, but it may not rub the ball joint depending on the wheel offset. A 195/70 would be a better fit on a 5 inch wheel but will likely look noticeably smaller and reduce the ride height slightly as well.
If used on the rear of the car they will throw the speedometer off, it will read higher than the car is actually moving.
A more common tire size used on stock 15 x 5 wheels is 205/75. It's a good combination of added tread width, overall tire height, and compatibility with the stock rim width.

Do be aware that radial tires stress the rims differently than non-radials and full wheel covers have been know to come off while cornering.

I couldn't find the tire / wheel recommended width chart I remember using before but these should be good substitutes...

https://www.tyresizecalculator.com/c...rim-size-chart

https://www.tiresandco.ca/tire-equivalence-advice.html

https://m.roadkillcustoms.com/tire-w...y-wheel-width/

.

[KULTULZ]

Maybe this will help - https://www.ctci.org/fender-skirt-tire-rub/

[Lamar Wadsworth]

Thanks! The 205.75 is probably close to the width of the G78x15 that is on it.

[dmsfrr]

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Originally Posted by Lamar Wadsworth

Thanks! The 205.75 is probably close to the width of the G78x15 that is on it.

And the overall diameter may be close to the size of the original 50's tires that came on the car.
https://dbtires.com/conversion-chart/

The wheels on the car may be 5 & 1/2 inches wide?
.

[jayvee34]

Based on the cross reference listed above. G78-15 = 215-75R15 radial.

[dmsfrr]

Originally Posted by jayvee34

Based on the cross reference listed above. G78-15 = 215-75R15 radial.

... on a (recommended) 6 to 8 inch wide wheel.

And could still be a problem with ball joint clearance if was a good fit on a stock wheel.
This first example is a 205/75 and the other is a 195/75, and the plain steel wheels are 'close but not quite' original to the two cars.

[KULTULZ]

Here's another TECH ARTICLE to add to the confusion -

https://www.classictbird.com/pdf/Thu...ghtening-5.pdf

RU just trying to add radials that will fit within the confines of the BIRD or are you trying to modify for increased handling and/or performance. Is it a driver or saver?

[dmsfrr]

Originally Posted by KULTULZ

....
RU just trying to add radials that will fit within the confines of the BIRD or are you trying to modify for increased handling and/or performance. Is it a driver or saver?

He didn't say what body style / model the '55 is when he started this thread. Just a '55 with stock wheels and G78 tires.
It would be helpful to know...

[KULTULZ]

... hmmph ...

I a$$-u-med BIRD.

If it is a FORD, he has lots of more leeway.

[paul2748]

Not sure why you want to go with a 70 series tire. Wider tire will mean it will be harder to steer. I have 75? series on my 54 and it rides nice. Just match up the diameter if that bothers you. I think I am using 195X 14 tires on the front, bigger ones on the back.. 195 X 15 would be another choice. Getting harder to find 14 and 15 inch tires now a days

[Lamar Wadsworth]

It's a '55 Fairlane Town Sedan. Parents bought it new. Using the wheels that came on it from the factory.

[55blacktie]

My OEM 15 x 5 wheels are sitting on 215/70r tires, but 215 is a bit wide for 5-inch wheels. 205/75R15 tires are commonplace on 15 x 5 wheels. 70-series tires look right, but I would not go with a lower profile unless you increase the wheel diameter. I can't see any interference issues with the 215/70r tires on my 55 Tbird, and I have 1 1/2-inch drop spindles and Aerostar springs. Although the Aerostar springs are shorter than the OEM springs, they are progressive, and I could neither see/measure a significant difference in ride height on the front. However, the Tbird has less weight over the front suspension than full-size Fords. The Aerostar springs will do more to drop the front ride height on Full-size. The 1 1/2-inch drop spindles, on the other hand, do bring things down on the Tbird.

[Daves55Sedan]

I am running P205-75R15's on the front and P215-75R15's on the rear of my '55 Sedan (in the avatar).
The 205's have a little smaller circumference than the original 670x15's, but the 215's have a close enough circumference with the 670's that you don't need to change the speedo driven gear.
The 215's are a tiny bit wider than the 205's and hard to get on the rear unless using a bottle-jack under the axle with a bumper jack, which must be manipulated to get a 215 on or off. I just hope I never need to change a rear on the highway, although I carry both jacks in the trunk.
In the early seventies, the G78-15's are what I had on this same car.

[Anteek29]

Currently cruising with P215-75R15 on all four stock rims on my '55 Vic.