Tires

General topics, not covered elsewhere, of all things Packard.
quiettones55
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Tires

Post by quiettones55 » Wed Mar 14, 2018 4:38 am

What kind of tires are ideal for classic cars like Packard? Can you use modern street tires like Toyo Tires' for this type of vehicles?

Dave Czirr
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Re: Tires

Post by Dave Czirr » Wed Mar 14, 2018 5:09 am

The last Packard was produced long before radial-type tires were introduced in the U.S., thus all Packards had bias ply tires when new. If authenticity and/or appearance is important to you, then remain with bias ply; many of us, myself included, have done considerable longer distance touring on bias ply tires with complete satisfaction. But some folks favor modern radial tires which can give, though there are tradeoffs, somewhat improved handling on later postwar Packards. They really don't offer any advantages on the older cars with solid beam front axles.

The tires shown in your link are for the most part NOT the type of tires you'd want to install on a collector car.

Howard56
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Re: Tires

Post by Howard56 » Wed Mar 14, 2018 7:44 am

Depending on your car model one of the problems people have run into trying to fit modern radials is the width of the tire. Metric dimension radial tires are somewhat squat and with a rounder section profile compared to the bias ply and are quite noticeable in that respect. Many of the wheel wells on Packards are designed around narrow bias ply tires and in order to get a radial with close to the correct diameter so the speedo reading is not thrown too far off, the width on modern metric tires with a proper diameter becomes so wide it won't easily fit into the well without letting air out first.

If you are looking at radials you might want to check out the recent addition of radial tires which have a profile more closely matching the bias ply tires. Diamondback and Coker have made them available and Summit Racing and a few other places also carry some now. The tire designation being more like the old bias ply numbers is the way to tell them apart from the metric size radials.

A good example is the tire size on 55-6 seniors. The recommended metric radial tire comparable to the original bias 800 or 820-15 is the 235/75R15. That radial has a width of 9.1" and has a recommended rim width of 6-8". Some have reported the issue of needing to slightly deflate the tire to comfortably get it in and out of the wheel well. The newly available narrower bias comparable size radial 820R15 has a width of 8" and wants a rim width of 5-7". Diameters are within a few tenths of the original on those radial sizes.

Adam
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Re: Tires

Post by Adam » Fri Mar 16, 2018 5:10 am

Do take care to check the rolling radius of the tyres you are planning to fit to ensure that the gearing is not affected too far, and that the speedo is still reasonably accurate, as Howard has already suggested.

Web sites such as Longstone Tyres give great info and advice on all this, (and Dougal is very helpful too). Although they are probably a little far away for you!!
https://www.longstonetyres.co.uk/

Also, it is well worth keeping tyre pressures on the firm side and probably higher than your handbook states. I would use 36-40 psi in a 15 inch bias ply tyre. In fact on heavy cars like a Packard, I would use similar pressures in a radial too.

Hope this helps a little
Adam..
"Do not underestimate the English cousin.....they are not as stupid as they look!" - Signor Altabani in The Italian Job.

David Shepherd
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Re: Tires

Post by David Shepherd » Fri Apr 27, 2018 2:25 pm

Made the decision to put Coker Radials on my 37 super 8 ( 6 with the two sidemounts).
Ride is great and the steering is precise, downside is the sidemount covers do not fit without deflating the tyres :( .
Will buy Bias plies next time or replace the side mount tires.
Good luck.

Prudence
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Re: Tires

Post by Prudence » Sat Apr 28, 2018 7:04 am

Good morning David...It seems to me that I have been cautioned not to run a bias ply tire on one wheel and a radial tire on another wheel. If I am wrong, someone will take a minute to correct me. ;)

bakerallen
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Re: Tires

Post by bakerallen » Sat Apr 28, 2018 7:20 am

I believe you would be ok to mix tires if you keep the same kind of tire on each axel, although when I buy tires I am going with bias ply on all 4 wheels.

Adam
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Re: Tires

Post by Adam » Mon Apr 30, 2018 12:30 am

Please, never ever mix bias and radials on the same axle. The handling characteristics are quite different, the braking performance probably different too. Unless you want to visit a nearby hedgerow, do not do it!!

If you must mix bias and radial on the same vehicle, which is undesirable, only use bias ply on the front and radials on the back. This is the only safe condition. The reason is that bias ply have a larger slip-angle than radials, leading to relatively safe understeer when used as I describe. If fitted the other way round (bias on the back, radial on the front), you will create an oversteer situation which is inherently dangerous.

In the UK it is illegal to mix bias ply with radial on any axle and also only permissible to run bias ply on the front with radial on the back. Fines and penalty points await the unwary!!

A final point is that bias ply and radial tyres of the same size will have a different rolling radius, so if used together on the rear axle would lead to wear on the differential gears and bearings as it would have to compensate for the different wheel speeds.
"Do not underestimate the English cousin.....they are not as stupid as they look!" - Signor Altabani in The Italian Job.

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Tinman_70
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Re: Tires

Post by Tinman_70 » Mon Apr 30, 2018 5:10 am

I needed new tires for my '49 project. I bought American Classic Wide Whitewalls from Coker Tire. They have the bias look to preserve originality but are a radial design and are in the OEM size 760R15. This is what they look like.
760R15_2.jpg
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Leeedy
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Re: Tires

Post by Leeedy » Wed May 16, 2018 6:15 am

Prudence wrote:Good morning David...It seems to me that I have been cautioned not to run a bias ply tire on one wheel and a radial tire on another wheel. If I am wrong, someone will take a minute to correct me. ;)
Please, please, please. If you value your car and you value your life... never, never, never ever mix bias and radial tires on the same vehicle rolling on the ground. The result CAN be disastrous and it certainly will affect the vehicle's "handling"–especially for those who imagine they are improving same. If one insists upon having radials (and much of this insistence is pretty silly when it comes to vintage cars) these tires should never be rolling the pavement with bias-ply tires on ANY axle (unless for show as sidemounts as someone has mentioned). The rolling characteristics of these two types of tires are completely different. Radials do tend to roll easier (some would say faster) which is just one more reason why they should never be on the same axle–especially on the rear. Wanna wear out your rear differential? Run a radial on one side and bias on the other.

Anyway, Packards were never designed to have radials and while some swear that radials "handle better" the reality of mounting radials on a car that was never designed for them is that the benefits are mixed at best. Bias-ply tires made today are not the same as the "rim protector" grade bias ply tires of old. Furthermore, suspensions and steering on Packards were never designed to take advantage of radials. Don't believe this? Do yourself a quick favor. Go out and look at the front steering on your late-model modern car. Start your car and turn the steering wheel lock-to-lock and observe what happens to the camber of the front wheels. Then go do the same on your Packard. If you are watching closely, you will note that the modern car front wheels tend to lean over a bit into the direction of the turn. This is steering and suspension designed for radial tires. Packards don't do this. And making a radial with a squared edge on it to look like a bias does what in this formula?

The ultimate factors in potential hazards here are huge and certainly not worth the risk to you or your vehicle.
Last edited by Leeedy on Wed May 16, 2018 7:38 am, edited 1 time in total.

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