Author Topic: Tire Size Cross Reference Chart?  (Read 2556 times)

Offline Mike Wenrich #1666

  • Posts: 111
  • Name: M Wenrich
Tire Size Cross Reference Chart?
« on: January 30, 2017, 12:44:04 PM »
I've seen many comments re: current preferences for tires for my '41 Caddy but another car I have is in the sixties and the tire companies don't advertise a cross reference.  Since we have 60's cars on the forum, would someone know if there is a handy dandy chart to determine what to look for in a radial size for tires that were 800x 14, 850x14 and 760x15?  These sizes were used on Chryslers in 63-64.  I see "Classic" tires listing a 235x14, which might be in the ball park but no overall height listed.  I don't wish to trust a salesman with the answer.  Appreciate any help you might give.

Mike

Offline 35-709

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1935 Cadillac Sedan resto-mod "Big Red"
1973 Cadillac Caribou - Sold - but still in the family
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Offline D.Yaros

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Re: Tire Size Cross Reference Chart?
« Reply #2 on: January 31, 2017, 03:10:28 PM »
My 1962 Oldsmobile came from the factory with 800 x 14 tires.

It now sports P215 75 R 14 tires as a radial replacement.
Dave Yaros
CLC #25195
55 Coupe de Ville
92 Allante
62 Olds  

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Offline Mike Wenrich #1666

  • Posts: 111
  • Name: M Wenrich
Re: Tire Size Cross Reference Chart?
« Reply #3 on: February 02, 2017, 11:47:39 AM »
Thanks for the replies and reference chart.  Exactly what I was looking for.  Did not think this out far enough to realize the company might have posted something on line rather than pay to advertise the conversion. 

I presume the 215 radial is giving the correct speedometer reading?

Offline D.Yaros

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Re: Tire Size Cross Reference Chart?
« Reply #4 on: February 02, 2017, 05:16:18 PM »
I presume the 215 radial is giving the correct speedometer reading?

A good question.  I have never questioned or tested it?
Dave Yaros
CLC #25195
55 Coupe de Ville
92 Allante
62 Olds  

You will find me on the web @:
http://GDYNets.atwebpages.com  -Dave's Den
http://GrayLady.atwebpages.com -'55 CDV site
http://www.freewebs.com/jeandaveyaros  -Saved 62 (Oldsmobile) Web Site
The home of Car Collector Chronicles.  A  monthly GDYNets newsletter focusing on classic car collecting.
http://www.scribd.com/D_Yaros/

Offline Eric DeVirgilis CLC# 8621

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  • Name: Eric DeVirgilis
Re: Tire Size Cross Reference Chart?
« Reply #5 on: February 02, 2017, 05:30:52 PM »
The car will sit a good inch lower with 235 75 15 radials than with 8.20 x 15 (bias).
« Last Edit: February 03, 2017, 01:11:06 PM by Eric DeVirgilis CLC# 8621 »
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Offline Roger Zimmermann

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Re: Tire Size Cross Reference Chart?
« Reply #6 on: February 03, 2017, 02:55:46 AM »
The car will sit a good inch lower with 235 75 15 radials than with 2.30 x 15 (bias).
Eric, I suppose you wanted to write 8.20 x 15 (bias)...because 2.30 could be suitable for a light motorcycle!
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Offline Eric DeVirgilis CLC# 8621

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  • Name: Eric DeVirgilis
Re: Tire Size Cross Reference Chart?
« Reply #7 on: February 03, 2017, 01:13:02 PM »
That's why typing & talking don't mix.  ;D

Corrected - thanks!
A Cadillac Motorcar is a Possession for which there is no Acceptable Substitute

Offline Mike Wenrich #1666

  • Posts: 111
  • Name: M Wenrich
Re: Tire Size Cross Reference Chart?
« Reply #8 on: February 03, 2017, 07:29:34 PM »
Well this makes me wonder then if going to a radial means you should also upsize a bit.  For my 41, I now have L78-15 bias tires with a wide white and they look nice on the car.  If you go by the size charts, an L would be larger than the original 700-15 tires. 

I made a note to self awhile ago that folks on the forum were happy with Diamondback Yokohama 700-15 radials for a 41 but on looking at the Diamondback site I see Toyo mentioned.  And not in the 700 size.  Hmmmmm.  What to do?  What to do?  I have not called Diamondback to see if they also have the Yokohama.  I tried the Yokohama site yesterday and it would not download. 

Offline cadillacmike68

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Re: Tire Size Cross Reference Chart?
« Reply #9 on: February 10, 2017, 09:18:29 PM »
The series #s on these older cars was 80 or 83 or even higher. That's the height of the  tire as a ratio of the width expressed as a percentage, i.e., a series 80tire has its height as 80% of the width. so an 8.00 tire is 8" wide at the cross section and the height (of each end) is 6.4".

Those high series ratios mean even a thin tire will be quite tall. More modern 75 (and lower) series tires need to be wider to have the same height.
Regards,
"Cadillac" Mike

Offline G Pennington

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  • Name: Gary Pennington
Re: Tire Size Cross Reference Chart?
« Reply #10 on: February 11, 2017, 02:11:25 AM »
I purchased a set of Diamondback/Yokohama LT700R15 tires last May.  They work well on the '41 (original 5 1/2 inch wheels).  Ask for Rich at Diamondback.
Gary Pennington
   1953 6267X Convertible
   1941 6267D Convertible (2 door)

Offline Mike Wenrich #1666

  • Posts: 111
  • Name: M Wenrich
Re: Tire Size Cross Reference Chart?
« Reply #11 on: February 12, 2017, 02:23:51 PM »
If you are still looking at this thread, I thank you for the info and will call Rich.  Specifically to ask about the LT designation since that is usually is light truck tire nomenclature.  But I would also ask you what width whitewall you were able to get and if the overall size has kept your speedometer accurate.  Lastly...if you also placed radial tubes inside the tires on your original rims.  Rick can likely answer some of this but not the speedometer question.  Again, thanks for the feedback from all.

Offline G Pennington

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Re: Tire Size Cross Reference Chart?
« Reply #12 on: February 12, 2017, 06:52:04 PM »
I ordered a custom WW widrh of 3 1/4 inches because that's what the 1941 Authenticity manuel shows to be correct.
Did not use tubes.  No air leakage.  I run them at 35 psi.  Biggest difference from the old Coker bias-plys is truer tracking and lighter steering.  Quote from Rich's email;

" IN modern radials the tires are "ply rated", and do not actually have 6 or 8 ply like the old bias ply tires. The ply rating just means the bead area has been reinforced to carry a higher tire pressure.  A modern radial with  52 psi will drive much better than a 4 ply bias ply tire.  700R15 0nly made in a 8 ply.

If you have steel wheels in decent shape (bead area not pitted) then you do not need tubes.

If you are still concerned about the ride quality, buy a 235/75R15 in our DB II.  It is passenger car tire, a Toyo Extensa.  It has a modern tread but is 4/10 of an inch shorter and the tread width is 1.3" wider ( it will work with 5.5" wheels."
Gary Pennington
   1953 6267X Convertible
   1941 6267D Convertible (2 door)

 

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