Wide-Whitewall Radial Tire Choices

[Bob Riding]

I was fortunate to find four good 15" wheels with clips for the '52 Suburban, and now I'm trying to figure out what would look and work the best. It will have stock steering and suspension. I looked at Coker's website as a guide and put their five choices in a chart to better understand the differences. Coker's American Classic Bias-look tires have a wider whitewall than Coker Classics, but narrower tread width. They are also $50-$80 more per tire. Would a narrower tread width be easier for parking and low-speed maneuvers, but less stable on the highway than a wider tread width tire? 

[captden29]

fyi, the green rim has the oval hole for the stem, so you will need the special stems that it uses. ask your tire shop, but they are readily available. i have never used bias ply, but they are known to wander more than radials. i do not know about the radials that look like bias.personally i like a bigger tire, so the 215's would be my choice. less money too. i tried 235's on my 54 Windsor, but they rubbed on suspension, so i went to 225's. without power steering, all parking lot maneuvers will be hard no matter the tire. i went back to blackwall for the original look, but now i wish i got whitewalls.    dennis

[casper50]

I have run Coker radials www on my coupe for a year now.  I'm really happy with the way the car steers and tracks.  No problems yet.

[allbizz49]

My daily driver 59 F100 is on it's 3rd set of coker bias wide whites. Have never had any issues with the bias cokers. I drive it everywhere. Freeway, mountains, backroads, no issues. I've been getting roughly 30k miles out of a set. I make sure the pressure is always good and I also rotate them regularly. Never had a problem. 

[Dodgeb4ya]

I have used the large size valve stms in the oval hole rims with no leaks.

[Andydodge]

I had Coker Classic Radial Whitewalls on Wheel Vintique Chrome Smoothies on the 41 Plymouth, stock suspension and steering except 2' lowered with cut coils and blocks, they were 195/75xx15 and 235/75x15 and replaced a set of Republic 6.00x16 whitewalls which came with the car and were quite old and hard.................the Cokers improved the general ride and steering immensely and made the car a much more civilised driver, I ran them at 35psi and never had an issue and would happily use them again if need be............I sold the car after about 2000kms so can't comment on long term use.............and BTW the cost in 2009 was twice that you quote, $395 and $415 Australian per tyre plus shipping from the Oz importers then fitting at the local tyre shop, they owed me just under $1800 Aust once on the car...........lol.......yikes!..........lol...... andyd  

[Dan Hiebert]

The contact patch on the ground you are asking about will not make the car squirrely with narrower radial tires.  You'll actually get a hair better gas mileage (less contact = less friction) and better traction on wet surfaces.  Wider tires are better for traction on dry surfaces, and the slow speed maneuvering will suffer a tad.  But in the long run, you probably won't notice enough difference between the two to overcome whichever style you prefer the look of.

[Redmond49]

The main thing from my perspective is the diameter. That one inch difference between the modern size tires and the American Classics made a noticeable difference on my P15. I had 215s and tried out 6.70s. The speedo read true with the taller tires, the engine was slightly more relaxed at speed, and it seemed to accelerate better.  

[Bob Riding]

I discussed-the different options with my tire expert ( my cousin who owns and operate a tire business in Fresno since the 1960’s) and he wondered about clearance issues  if decide  to run disk brakes ( which I prefer)

any thoughts?

[casper50]

I run disc on all 4.  No clearance issues with the coker www radials that I bought.

[mrwrstory]

Can't beat radials even on an old car.

Have not had good luck with Cokers on several occasions.  A higher quality option in my opinion is Diamond Back.  Not cheap but better looking as well.

[Bob Riding]

16 hours ago, casper50 said:

I run disc on all 4.  No clearance issues with the coker www radials that I bought.

Who's disc brake did you go with? And are you running 15"s or 16"s?

[Bob Riding]

17 hours ago, Dan Hiebert said:

The contact patch on the ground you are asking about will not make the car squirrely with narrower radial tires.  You'll actually get a hair better gas mileage (less contact = less friction) and better traction on wet surfaces.  Wider tires are better for traction on dry surfaces, and the slow speed maneuvering will suffer a tad.  But in the long run, you probably won't notice enough difference between the two to overcome whichever style you prefer the look of.

 

[Bob Riding]

Great advice, thanks!

[casper50]

Original rims 16".  front disc is scarebird.

[rhelm1953]

FYI, when I converted my 1950 Plymouth with stock 15" rims to disc brake I had to replace the wheels.  The stock wheels did not clear the calipers, if you want to keep the stock wheels you may need to give up on the disc brakes.  I went with the ECI kit that uses GM calipers.

 

 

[BobT-47P15]

I'm using the B F Goodrich branded  ww radials sold by Coker (about $250 each) in 215R15....makes the car drive better

but harder to turn at very low speed.  I then bought one of the American Classic brand radials that look like bias ply for a

spare.....670 x 15....(about $250)…..so it will fit into the spare tire well.  My spare bias tire was many years old and it was

due for replacement.  So now all 5 tires are radials.  Mounted on 1955 Chrysler wire spoke wheels with original drum brakes.

 

  

 

Old bias ply Goodyear Double Eagle spare on left......new bias look radial on right.  Width of white wall just 

slightly larger on new tire.  Have never driven a car running a set of narrow radials.

 

 

 

Tread design of narrow radial.  

 

 

Sorry for the duplicate first pictures but I can't figure out how to delete one of them.

Edited November 8, 2018 by BobT-47P15

[dale]

Using coker 670-15 narrow redials on my 46 with 15 inch rims.  Scarebird discs on front with no clearance problems.  The spare fits its hole too.

[Bob Riding]

3 hours ago, dale said:

Using coker 670-15 narrow redials on my 46 with 15 inch rims.  Scarebird discs on front with no clearance problems.  The spare fits its hole too.

Sounds like the ECI front disc kit probably won't fit 15" wheels, but the Scarebird will. Great info!

[Bob Riding]

I was asked by a friend why Plymouth went from 6.00 X16" wheels to 670 X 15" in Nov/Dec of 1947, since the P15 models still had over a year to go. I couldn't answer, except to speculate that the postwar styling was getting long in the tooth and they wanted to lower the ride height to boost sales. Was there possibly a functional reason?

[MarkAubuchon]

I just switched my 47 from 16 to 15 stock wheels with coker wide white radial. I have it converted to disc no problem with tire rub.  Here is what I would recommend. A. take the wheels and checked to make they run true. B. Make sure the front end is in good shape, bushings, bearings. C. take it to a good front end shop get it back to factory specs D. Have the tires mounted and preferably the alignment done at a shop that has a working knowledge of high performance tires and suspension. Not that are Plymouths fill that void.  The shop I went this guy likes old cars, old American muscle and high performance new cars.  He has a high end Hunter Tire machine that fits the tire to the rim, rotating the tire on rim to find minimal vibrations, the computer also tells him which tire and wheel should go where.  Just took my 47 to Detroit, has never ridden so smooth.

[Bob Riding]

2 hours ago, MarkAubuchon said:

I just switched my 47 from 16 to 15 stock wheels with coker wide white radial. I have it converted to disc no problem with tire rub.  Here is what I would recommend. A. take the wheels and checked to make they run true. B. Make sure the front end is in good shape, bushings, bearings. C. take it to a good front end shop get it back to factory specs D. Have the tires mounted and preferably the alignment done at a shop that has a working knowledge of high performance tires and suspension. Not that are Plymouths fill that void.  The shop I went this guy likes old cars, old American muscle and high performance new cars.  He has a high end Hunter Tire machine that fits the tire to the rim, rotating the tire on rim to find minimal vibrations, the computer also tells him which tire and wheel should go where.  Just took my 47 to Detroit, has never ridden so smooth.

never heard of that process...I will investigate- what disc kit are you using?

[mrwrstory]

Also look for someone to "true" or "shave" the tires.  It's an old timey process done back in the day.

My guy says,....," don't do no good to balance 'em if they're not round!"  Pretty succinct I say. 

[Veemoney]

On ‎11‎/‎8‎/‎2018 at 1:42 PM, MarkAubuchon said:

C. take it to a good front end shop get it back to factory specs D. Have the tires mounted and preferably the alignment done at a shop that has a working knowledge of high performance tires and suspension

Just a note on alignment. Getting it back to factory specs may create more of a problem since those specs were made for Bias tires and were likely using settings with positive camber and negative castor in many cases. Radial tires are a different animal. I use the specs below for radials on my mopars. Castor makes a big difference in handling. If you have a good alignment guy he probably does this for you.

Driving style	Camber	Caster	Toe-in
Sunday Cruising	-0.25°	+1.5°	1/16" to 1/8"
Daily Driver / Street	-0.5°	+2.5°	1/16" to 1/8"

[Bob Riding]

20 hours ago, Veemoney said:

Just a note on alignment. Getting it back to factory specs may create more of a problem since those specs were made for Bias tires and were likely using settings with positive camber and negative castor in many cases. Radial tires are a different animal. I use the specs below for radials on my mopars. Castor makes a big difference in handling. If you have a good alignment guy he probably does this for you.

Driving style	Camber	Caster	Toe-in
Sunday Cruising	-0.25°	+1.5°	1/16" to 1/8"
Daily Driver / Street	-0.5°	+2.5°	1/16" to 1/8"

I had heard as much but never saw the exact specs...Thanks!