Packard Forum Index » V-8 (1955-56)

Hi, I can get 4 new whitewall tires for my ?55 clipper but someone told me they were too big.Can I only use 225/75/15 ?

235's will work but you have to put them on car before inflating them to clear rear fender. I am running 225's on 56 Executive with no problem with clearance and am happy with them, just a bit shorter in height than bias.

Here's a useful chart. Your original tire size was 7.60 x 15 as I recall.

http://www.tirerack.com/tires/tiretech/45_conversionchart.html

235 75 R15 on my 56 Executive. To install on rear jack up car at the frame allowing axle to drop down. Remove fender skirt. Tite fit but the 235's will go in just fine. There is very minor inner fender well (near trunk side) rubbing marks that has apparently occured under extreme off-camber operation. Never heard them rub but there is evidence on the inner rear fender well where they have.

Fronts have just barely enuf clearence but enuf. REAL close at lock turn.

HOWEVER note that i run economy grade 235 75 R15's and they are most likely 1/2" narrower than premium priced tires. So if u are hell bent for the high dollar premium grade tyres then there very well could be significant clearence problems.

Hello:

I've mentioned on another post about tire sizing that Diamondback now has a 15" RADIAL tire in BIAS ply sizing. Check out the bottom of page 17 in their catalogue:
http://www.dbtires.com/2011_catalog/2011catalog_Lo.pdf

They refer to it as a special size for "Pre 1948 Luxury Cars." Notice that the sizing is in INCHES (7.00) and not metric, as with all their other radials.

I am mounting them later this week on my '41 120 business coupe. They have the proper look of a bias ply tire -- narrow and no noticeable radial bulge.

Compare:
A 225/75R/15 tire has a width of 8.8" and a height of 28.3"
A 235/75R/15 tire has a width of 9.0" and a height of 29.0"
This 700R/15 tire has a width of 7.7" and a height of 29.4".

Why wouldn't you go for a tire that has the proper, period look AND fits inside a wheel well better? Just asking.

Not sure that the 700R15 special would be the answer, here, since the question involves a 1955 Clipper, which was only available with 7.60-15 tires from the factory, IIRC.

A 225/75R15 calculates to a height of 28.29 inches.

A 235/75R15 calculates to a height of 28.88 inches.

The math is relatively basic, but the devil is in the profile (aspect ratio) for inch type tires. That might have been common knowledge back in the day, with no other choices, but not so today. Turns out that 1964 and earlier tires had a 90 profile, but for 1965-72 they were 80 series.

A 7.60-15 tire calculates to a height of 28.68 inches.

An 8.00-15 tire calculates to a height of 29.4 inches.

Certainly, there are other factor that have an effect on the dimensions, as mounted, but you'll drive yourself nuts trying to cover all of them. Best to stick to the essentials.

Either one of these metric replacments will throw off the speedo reading (which can be corrected), but given the greater section width of the 75-series metric radial, I'd personally go with the smaller 225/75R15 radial for a 55-56 Clipper (or Exec).

Hello Brian:

OK, so the OEM tire for a 1941 120 is 700x15.

The 700R/15 is made to fit the following sizes: 700, 800 and 820. Did you see the link I provided to page 17? I have added it here:http://www.dbtires.com/2011_catalog/hi/17.htm

Notice that the width of the 700R/15 tire is 7.7" - that sounds awfully close to the 7.60 used on the '55s and '56s to me.

The 700R15 also taller than the metric radials and probably closer to the OEM bias-ply height. This might alleviate the speedo correction issue.

You can always give Diamondback a call to discuss if they are right for your particular car -- the call is free.

Quote:
"Why wouldn't you go for a tire that has the proper, period look AND fits inside a wheel well better? Just asking."

Take a look at this thread:

https://packardinfo.com/xoops/html/modules/newbb/viewtopic.php?post_id=51656#forumpost51656


My personal preference is to go with what i know. I know that a PRODCUTION (not REproduction) tire will work. Radial or bias ply is not the issue for me. Each individual owner has different vintage automobile operation expectations from every other owner. I have no experience wit h the REprodcution radial vintage look alike tires therefore i do not know if they will or will not hold up well for 25K miles of mostly driving at 70+ mph on I'state hwy or cutting out thru the woods on a logging road or climbing a steep 1/2 mile rutted one lane road.

I do not know the price difference between the vintage look alike radials and the modern tire store regular production radials. Price always seems to be left out of arguments/debates/analysis among many topics.

Has anyone ran a set of ANY type or kind of REproduction tire for 25K miles under condtions i have listed above???? I'd like to know the results.

In the meanwhile, i have to go with what i know. It's a tire.

Quote:
"I'd personally go with the smaller 225/75R15 radial for a 55-56 Clipper (or Exec)."

Is that to say the 235/75R15 is better suited to the 55-56 Sr's?? I really don;t know. There is more room in the fender wells of the Sr's vs Jr's???

The following quote by BH from a few posts above is the last word on tire sizes:

"Certainly, there are other factor that have an effect on the dimensions, as mounted, but you'll drive yourself nuts trying to cover all of them. Best to stick to the essentials."

Even if 50 years ago, 10 years ago or today we were to compare two tires of the same labeled size but different manufacturers we would find at least a 1/4" variation in ACTUAL SCALED measure. THere has never been a REAL standard among tyre sizing except wheel diameter dimension.