Tires '38 Twelve

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Bluedevil
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Joined: Fri Oct 05, 2018 7:07 am

Tires '38 Twelve

Post by Bluedevil » Fri Mar 29, 2019 4:27 am

I am in the process of researching tires for my 12. The factory tire was a 8.25 x 16 bias tire, (unique to the 12 I am told). I have seen on some posts elsewhere that 7.50 x 16 radials are available and are a pretty close match. (1.25" shorter). I will probably drive this more than show it.

Anyone have any experience, recommendations, cautions etc, of one verses the other? Is one safer than the other?

Dave Czirr
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Re: Tires '38 Twelve

Post by Dave Czirr » Fri Mar 29, 2019 5:06 am

Perhaps more has been written about the radial versus bias ply question than any other aspect of old car restoration. Personally, I'm a bit of purist and would especially be one with a Twelve, that's a car that especially deserves authentic and correct restoration. I own a earlier prewar Packard and have driven it over 40,000 miles on bias ply tires and have absolutely no complaints. Yes, a quality radial tire will give better behavior when driving on irregular pavement and if one wants to correlate that to safety, then you would have to say it's safer. It will make steering, most especially at mow speeds, more difficult and put a bit more stress onto the front suspension components. Properly inflated and cared for, either is quite capable of trouble-free touring. As to size, 1.25" difference is a really large difference if it's on the diameter, if it's on the circumference then less of course. I would contact the makers of collector tires and use them as a reference for the closest size radial to the original bias tire, if you chose to go that way.

Adam
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Location: lincolnshire, uk

Re: Tires '38 Twelve

Post by Adam » Fri Mar 29, 2019 6:05 am

I must say I am with Dave on this one. I would tend towards a crossply (bias) tyre.

That said, if you wish to try a radial you must think about two considerations. Firstly, the tyre rolling radius (or circumference). This governs the number of tyre revs per mile and therefore the overall gear ratio. If you are looking at a radial, enquire about the rolling radius and compare it with any bias ply tyre you might have bought. It would be a shame to fit a low profile tyre that meant the gearing was lowered excessively. That would be a real pain on a car you plan to drive extensively.

The second thing is the load rating of the tyre. I suspect there would be plenty of margin here, but do check that the load rating of each tyre is more than sufficient for the weight of the car that it is to be carrying (gross weight not kerb weight). Overloading a tyre is very dangerous, it is also illegal here (in the UK) and would, I imagine, void your insurance.

After that, make sure that it looks authentic !

Good luck with the search.
"Do not underestimate the English cousin.....they are not as stupid as they look!" - Signor Altabani in The Italian Job.

Bluedevil
Posts: 120
Joined: Fri Oct 05, 2018 7:07 am

Re: Tires '38 Twelve

Post by Bluedevil » Fri Mar 29, 2019 6:53 am

Dave and Adam,

Those were the kind of inputs I was looking for. I planned to go with the 8.25", but the radial thing came up. I think I will keep with my original plan.

The load rating is another key. With a car this heavy, I inclined to think you really need the biggest tire you can get to feel safe. The load per tire exceeds the total weight of my Morgan. I also agree on the height issue, taller is visually better on this car, in my opinion.

Adam, when not trying to get my 12 to turn over I am helping my neighbor, British chap I might add, resurrect his fearsome 803cc Morris Minor. We have gotten it to turn over after 15 years. Spark and fuel are next. Now if I can just get the Packard to do the same.

Thanks

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