Tire Help

[Noah H]

Hello.

 One of my old bias ply tires finally gave out the other day. All 4 are pretty dry rotted and it is time to replace with new ones. 
 

I have done some reading on this site and know that everyone has their own opinion on tires. 
 

 

I drive this car daily and take it on long road trips. 
 

I am leaning more on radials. Wide whitewalls similar to the ones already on the car. 
 

I get all these options on tire sites for different sizes and it’s confusing for me. 
 

670R15?, 715R14  etc. the size on the tires now says. 7.10-15. I guess I need a lesson on tire sizes. 
 

Drum brakes. What tire would not rub, handle exceptionally. And be affordable for the younger car restorer. 
 

thank you

 

Noah 

[Young Ed]

Unfortunately you can't really get all 3. Wide white wall radials get you the handling and the look but they are not cheap. You're looking around$200 a tire. You can get a radial with a skinny white wall for probably 1/2 to 1/3 that price. 

[Sniper]

Well, I can say none of the sizes listed will ever handle exceptionally, lol. 

 

I have been running radials on my 51 since I got it, no issues there.  I'm running P215/75R15's on stock rims with no clearance issues and the speedometer reads correct.

 

Coker sells at least six different WWW radials in that size, though I can't comment on the handling or performance though.

 

Then there is adding a whitewall to your choice of tire.  https://dbtires.com/classic-car-tires/tire-making-process/

[Adam H P15 D30]

Remember these?

http://portawallshop.com/

Edited February 24, 2021 by Adam H P15 D30

[Noah H]

Thanks for the replies

 

 Are bias plys less expensive? 
 

 

[Hamilton]

Yes, bias ply tires are less expensive.  I bought a set of Cokers last fall, shipped to my home for just over $700 shipped to my door, including tax.  Understand though, I don't drive the long distances you mention.  If I did, I'd have spent the other few hundred dollars on radials.

_

[allbizz49]

G78 15 coker bias is what I run. I get about 30-35k miles out of them. Never any issues in over 15 years of running them on my daily. If you don't mind pinner whites (1"), Cooper makes a good affordable radial called trendsetter se. 

[knuckleharley]

1 hour ago, Adam H P15 D30 said:

Remember these?

http://portawallshop.com/

Not only liked,but bookmarked even though I prefer thinner whitewalls. I am starting to think the wider ones might look better on my 42 Dodge coupe.

[Adam H P15 D30]

1 hour ago, knuckleharley said:

Not only liked,but bookmarked even though I prefer thinner whitewalls. I am starting to think the wider ones might look better on my 42 Dodge coupe.

They are available on Amazon also....

[Marcel Backs]

I will be going with either Diamondback or Excelsior radials on my D14. I am presently running bias WWW tires on my 39 Chevvy and wished I would have went for radials.

[Sniper]

Bias plies do handle differently that radials.  When they break loose they do so in a different manner as well.

 

https://mechanicinsider.com/radial-vs-bias-ply/

[Doug&Deb]

Yokohama 21501 7.00R15. Forum member James Douglas recommended these. They are the correct height to keep your speedometer correct. They fit properly on the stock rims. 

[greg g]

The one thing about current market tires is that when you are on a long trip you can get a replacement from pep boys, Walmart, or other national chains without waiting for the ups guy to show up at your temporary location. The. 215, 225 75 15 size seems to fit the bill in everything except looking like a skinny vintage tire.

 

The key is the over all diameter and tire revolutions per mile.  I found the linked chart pretty easy to understand.  If your tires are 7 10 15 these are bigger than stock.  I believe the standard size was 6.25 or 6.50 15.  The believe the first number on the old bias plus were the widest point through the cross structure. 

 

The other thing about modern white Walls is where there is a narrow white was some carefully work with a wire brush or similar rotating abrasive is that the amount of white exposed can be adjusted.

 

https://www.turbinecar.com/tires.htm?fbclid=IwAR06HckEWsjdiOIdB5tynwMrox099QNGW7cjFT3ocZBX-3CVT3yWqoK5uWE

[wagoneer]

I offer only what others have said with some certitude, but I could not find original specs for Dodge, per se. I presume Dodge and Plymouth were similar. 

 

 

For Chryslers:

Found this good link from 2005 -- https://forums.aaca.org/topic/67008-48-chrysler-windsor/

 

Quoting Rick Hoover: 

"Your 1948 Windsor came through standard originally with 760X15 size tires. It also had a optional size of 820X15. The brand of tire would have been Goodyear. The white wall width of the 760X15 would have been 3 1/2 inches. The 820X15 tire would have been 4 to 4 1/4 inches depending on the molds used. Here lies the problem. As far as I know at this time, only the Goodyear brand 760X15 is available and it is only being made in a 2 3/4 white wall width, which is to small for your year of vehicle. The Goodyears Collector Series Tires are reproduced / manufactured by John Kelsey of Kelsey Tire in MO. I would recommend that you contact John and ask him what he has available, or coming up in future production runs, of the correct tire you need. You can get all the information at www.kelseytire.com Should the correct Goodyears not be available and you are ready for tires now, then I would recommend going with a Firestone brand 820X15 with a 4 1/4 inch white wall, as there are no 760X 15's being reproduced in Firestone. Those 820's you can buy through Coker Tire or Universal Vintage Tire."

 

 

For Plymouths:

https://www.allpar.com/threads/plymouth-1946-1948-an-incredible-sellers-market.227936/

 

"The standard tire size was 6.00x16in on all body styles. The diamond pattern tread used on rear tires prior to the war was discontinued, replaced by a rib tread used on all four tires. If a car was to be fitted with 6.50x16in tire, it was mandatory that 4-1/2in wide rims be used in place of the standard 4in rims.

The only noticeable change in the P15 Plymouths came late in November 1947. Beginning with Detroit-built Special Deluxe 11851594 and Deluxe 15251917, the factory began switching to 15 inch wheels and Goodyear Super Cushion 6,70x15in tires. Los Angeles- and Evansville-built cars didn't make the switch until December; Los Angeles with Special Deluxe 25036148 and Deluxe 26010991, and Evansville with Special Deluxe 20234249 and Deluxe 22063548.

Several tire manufacturers began offering a 6.70x16in tire about this same time, a tire Plymouth engineers found acceptable for all models except the station wagon. Government regulations dictated that spare tires and tubes could not be shipped with cars, including dealer drive-aways, a regulation that was lifted in December 1946. New car prices were adjusted accordingly when the spare again became standard equipment."

 

 

Desotos:

https://www.allpar.com/threads/illustrated-plymouth-desoto-buyers-guide-–-desoto-1940s.229636/

"Tire sizes were changed late in 1947, from 6.00 x 16 inches on regular chassis cars to 7.60 x 15 inches. Due to shortages, whitewall tires were not available until April '47, most of the early cars fitted with a plastic inner wheel liner that gave the effect of whitewalls. "

 

 

[wagoneer]

Speedometers, Speedometer gears, and Tire sizes - they are all highly related. My speedometer is accurate up until about 50 miles per hour, and after that it seems to be about 5mph faster than what my phone is saying. 

 

It'd be useful to understand the relationship between the gear, the meter, and the tire, and how the factory can change up everything so much without having a bunch of different gear parts. Maybe something in the calibration of the speedometer?

 

Theory on why mine is inaccurate after 50 but okay before? 

 

Does anybody have ideas on how the three relate? 

Edited February 26, 2021 by wagoneer

[Art Bailey]

I find the tire size thing confusing. The 1947 DeSoto owner's manual states that the standard tire size for short wheelbase vehicles is 6.50 x 15. One online source says 7.00 x 15, another says 7.60 x 15. Shop manual says 6.50 for early S-11, 7.60 for late. Is it logical to assume that the car will accept a range of tire sizes, and what's the last word on tire size? Right now, I've got 215/70R/15s on the stock rims. 

 

It's kind of a bummer to come to the conclusion that if you really want to do some driving, radials are the way to go...bias plys look so cool.

 

 

Edited February 26, 2021 by ratbailey

[Sniper]

They make bias looking radial tires

 

https://www.cokertire.com/tires/american-classic-bias-profile-radials.html

 

Speedometers are calibrated to read a certain speed for a given RPM at it's input.  I want to say 1000 revolutions equal 1 mile, but I may very well be misremembering here.

 

The factory can calculate how many inches a tire travels per rotation, it knows the gear ratio in the axle and comes up with a tooth count on the speedometer pinion gear in the transmission, this is the gear that drives the speedometer cable, so send the proper input to the speedometer.

 

If you change the tire height or the rear gear ration then you speedometer will read off, it will not be ok below 50 and be off by 5 mph above 50 unless there is something wrong with the speedometer itself, a speedometer shop can fix that. 

 

If you had a selection of speedometer pinion gears you could correct the tire or gear change difference.  Plenty of online calculators out there to sort that out, BUT you will also need to know the number of teeth on gear that drives the speedometer pinon and I don't know what that is for our rides.  The mentioned speedometer shop can usually make up a ratio adapter that will go inline between the speedometer pinion gear and the speedometer cable to correct for any gear or tire size changes, they will be able to tell you the info they need to do that. 

 

 

[Art Bailey]

15 minutes ago, Sniper said:

They make bias looking radial tires

$1500 for dimply things on the sides of my tires...that'll make you reconsider how cool you want to look ?.

 

Edited February 26, 2021 by ratbailey

[Sniper]

Or maybe redefine what cool looking is.  I never saw the appeal of the bias ply look, but then again my tastes are my own as well. 

[Doug&Deb]

My Coronet has 15x7 police wheels with 225/75r15 radials. The speedometer reads correct at all speeds. It’s important to match the diameter of the radials to the original bias tires. As much as I prefer the look of the bias tires I drive my car at least 3000 miles a year. If I need tires they’re easy to find and affordable.

[allbizz49]

10k plus a year with my daily f100 on coker bias whitewalls. Not sure why guys act like you can't drive every day on bias tires. I was commuting 110 miles round trip a few years back. Every day, no problems ever. Half highway half freeway. Are there better tires? Of course but there's better cars than these old heaps too. Why not just drive new stuff? My trucks steers, stops and rolls just fine. Still has manually adjusted brakes. I mean, these were the new cars at one time and people drove them every day.  Buy the tires you want and drive it for its intended use. I stay in the slow lane, 65-70 and cruise, enjoying my old stuff while laughing at priuses....

[Sniper]

1 hour ago, allbizz49 said:

Not sure why guys act like you can't drive every day on bias tires.

 

Nobody said that.

 

However bias plies have issues.  If you are looking for a load range tire then bias plies shine there, every where else they are a poor second.

 

How it looks is a personal thing so I can't comment on that.  But I have daily driven bias plies and radials, I prefer radials. 

[greg g]

My reference was for ease of replacement invade of a road damage issue if you need to rely on dilevery from a remote location to a remote location while on a road trip.  If you are 500 miles from home with the need to order a special market tire of either construction.  I suppose any thing round black and holding air would get you home in a pinch.

[keithb7]

I ordered and installed brand new bias black walls on my '38 Plymouth. I figure it was a lower-priced model car, for the average working Joe or Jolene. Who buys the cheaper car in 1938 and puts white walls on it? That's just my opinion. I went with Coker. Bought them from Summit Racing web site. Free freight. Coker was charging a premium for freight.

 

For my 1953 Chrysler, I bought brand new Coker Radial, wide-white walls. Expensive? Ya, sorta I guess. But the old car deserves it. The Chrysler was a premium product.  Good chance I figure that back in '53 folks might have been more inclined to buy white walls and fancy chrome spoked rims. 

 

The difference?  The radials float along and offer a cushioned, track-free ride. However my big old Chrysler does not have power steering. The bulge in a radial tire makes it harder to steer in low speed applications. Like pulling into a parking spot. Or parallel parking.  The bias are firm and do not flex. Low speed, strong arm steering wheel manipulation is easier. However the bias tires do want to follows ruts, cracks in the road. Sorta like they have ADD.  Ya gotta be ready with the steering wheel at all times. 

 

I read that putting radials (they bulge and flex) on original rims designed for bias tires, can cause pre-mature failures of the old rims. Cracking can develop from all the tire flexing.  Transferring additional stresses onto the rim.  Seems believable to me. I run tubes inside both types of tires.

I am fortunate to own 2 cars and 2 tire options. Spoiled.

 

Preference today? For me personally it makes no difference to me. Both tires have good and bad points. I just can't imagine putting wide white wall radial tires on my '38. For me it just doesn't work. You do whatever you like and I'm good with that.  Just leaving my experience and opinion for you. - K

 

 

          

Edited February 27, 2021 by keithb7

[knuckleharley]

On 2/24/2021 at 2:25 PM, Adam H P15 D30 said:

They are available on Amazon also....

Thanks,I didn't know that. I am trying to avoid buying anything at the moment,but it's good to know for "later" if "later" happens. Right now my focus is on paying off my bills and getting my estate in order.