Petitioning Coker for Proper 890-15 Tires for our Coaches

Nicholas Studer

PCS Elected Director 2022-2025
Folks,

As you likely know - many of our coaches were equipped originally with the 890-15 bias ply tire under the sizing system used 1965-1977. Tire technology changed over time, and this size became the N78-15 under the 78-series. Some of these tires were even labeled for "Ambulance Service." With the radial tires becoming more common, the P235/75R15 is often listed as the "equivalent." However, it's actually 2" shorter at 29" vs 31", and the wider width accentuates the effect of "lowering" the car. In addition, very few are rated at the "XL" weight requirement of 2500 lbs per tire that the tires the car was intended for had. Even fewer of these have white-wall, making Hankook Optimo H724's all but our only option these days. L78-15 tires are available and appropriate for many/most limousines, but these smaller tires (basically same size as P235/75R15) have a lower weight limit that is suboptimal for high-top ambulances in particular. This has been discussed several times in the past, at the CLC at http://forums.cadillaclasalleclub.org/index.php?topic=107748.0 and here http://www.professionalcarsociety.org/forums/showthread.php?t=6340 being one thread.

Coker still makes an 890-15 tire in 3" and 5" whitewall widths using the original Firestone mold, which works for the early 1960s but not for later on. They also have the XL weight limit of 2500 lbs per tire. https://www.cokertire.com/890-15-firestone-5-whitewall-tire.html I'd personally love to get the "correct" tall set of tires for when my 1970 C/B-Oldsmobile is done, but think the wide whitewalls will look silly. They don't make a blackwall variant either, and I hesitate to consider expensive tires just to mount "reversed."

I reached out to Coker, and they are willing to consider making a narrow white wall that would work for our coaches, if they see enough interest. This wouldn't be hard for them to produce at all, since they would just need to adjust the white rubber application. If you personally support the idea, please consider reaching out to them and ask for them to be made. They're apparently tallying up requests. Contact info below:

Andrew Randall
Web Sales
1317 Chestnut Street
Chattanooga, TN 37402
Direct: 800-251-6336
Fax: 423-756-5607
andrewr@coker.com
 
to be correct it needs to be this design the double pinstripe. they offer this in there there lines for the Cadillac. but it is the one used by all the manufactures original. they do offer it on a l78x15 I have them on the 72 blue Sevile. they are taller then the 235s but not heavy enough for a full size pro car with a floppy 2 ply side wall. this it there L78 15. the other is the original spare in the 72 890x15 Unroyal Laredo. they would most likly sell more os they produced it in there American Classic line. for some reason people are reluctant to buy bis ply tires. though I have had them for some time on all mine
 

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The tire with the double stripe wouldn't be correct for my 1969 Miller Meteor ambulance. The real question is, can they get the correct tire carcass to make a 2500 rated tire? It would be nice if they had the molds for more than just the Firestone tires. U.S. Royal would be correct for some of our cars, and then Uniroyal would be for the later production cars. Once you go down this rabbit hole, you have to be prepared to put you money on the line. I doubt that they will produce anything, without a strong deposit.
 
the 69 had black wall tires on it when new i still have that one you said keep they were the corp change from US Royal to Uniroyal the exact same tire that was the spare in my 72 high-top. I don't see them have two different white walls. all the ones I got off that 69 superior in New York were the duel stripe . but they were as I recall all after market. don't think there were any Uniroyal in them. they one spare studied snow out of the 67 was a N-78 duel WW it's right one the size as the later modal 890x15.

every time i have contacted Cooker or there other outlet Universal I have asked about the 890 on a at least 1 inch but my guess the 1&1/4 would be correct fr 65-70s stuff the 3 inch is good for 63-50s

the L78 is just under sized it throws the speedometer off by about 2 mph but they are not load rated heavy enough.

the set of the new 890s I got for the 58 project were labeled correct and has a stiff enough sidewall to be the 8 pl rating they were stated as. i did not mount them my self. but i did the set I got from New York. they were a challenge to put one by hand with Chinese equipment. here is the picture of the 69 spare and it compared to the 58 spare.890x15 unaroyal 69 same style as the 72.JPG890x15 cookre.jpgIMG_2308.JPGIMG_4064.jpgIMG_4068.jpg
 
Tires

Folks,

As you likely know - many of our coaches were equipped originally with the 890-15 bias ply tire under the sizing system used 1965-1977. Tire technology changed over time, and this size became the N78-15 under the 78-series. Some of these tires were even labeled for "Ambulance Service." With the radial tires becoming more common, the P235/75R15 is often listed as the "equivalent." However, it's actually 2" shorter at 29" vs 31", and the wider width accentuates the effect of "lowering" the car. In addition, very few are rated at the "XL" weight requirement of 2500 lbs per tire that the tires the car was intended for had. Even fewer of these have white-wall, making Hankook Optimo H724's all but our only option these days. L78-15 tires are available and appropriate for many/most limousines, but these smaller tires (basically same size as P235/75R15) have a lower weight limit that is suboptimal for high-top ambulances in particular. This has been discussed several times in the past, at the CLC at http://forums.cadillaclasalleclub.org/index.php?topic=107748.0 and here http://www.professionalcarsociety.org/forums/showthread.php?t=6340 being one thread.

Coker still makes an 890-15 tire in 3" and 5" whitewall widths using the original Firestone mold, which works for the early 1960s but not for later on. They also have the XL weight limit of 2500 lbs per tire. https://www.cokertire.com/890-15-firestone-5-whitewall-tire.html I'd personally love to get the "correct" tall set of tires for when my 1970 C/B-Oldsmobile is done, but think the wide whitewalls will look silly. They don't make a blackwall variant either, and I hesitate to consider expensive tires just to mount "reversed."

I reached out to Coker, and they are willing to consider making a narrow white wall that would work for our coaches, if they see enough interest. This wouldn't be hard for them to produce at all, since they would just need to adjust the white rubber application. If you personally support the idea, please consider reaching out to them and ask for them to be made. They're apparently tallying up requests. Contact info below:

Andrew Randall
Web Sales
1317 Chestnut Street
Chattanooga, TN 37402
Direct: 800-251-6336
Fax: 423-756-5607
andrewr@coker.com

Has anyone investigated Diamondback tires for radial whitewall tires for your coach, I have Diamondbacks on my 1955 Meteor Combo.
Performance is great and looks classic.
 
They would be the 235x15 size. The ones that have a heavy enough load rating are all raised white letters. Which they could convert to 3 in ww easily enough but not to the 1 inch for late 60 threw 70.
 
Has anyone investigated Diamondback tires for radial whitewall tires for your coach, I have Diamondbacks on my 1955 Meteor Combo.
Performance is great and looks classic.

They would be the 235x15 size. The ones that have a heavy enough load rating are all raised white letters. Which they could convert to 3 in ww easily enough but not to the 1 inch for late 60 threw 70.

Ed is correct. Diamondback Tire (https://dbtires.com/) can make any whitewall desired. Not in question. These are 235/75R15 tires and thus are just as short as any of the other tires at 29" compared to the original 890-15's. I don't believe Diamondback can remove excess whitewall to make the 3" whitewall narrowed to the proper size, but perhaps someone here can comment if that's worth asking about. It'd be unfortunate to have to send the already costly reproduction tires to yet another vendor for more work at personal expense though, rather than just make some that way to be begin with...

One more thing to consider. 265/75/R15 was suggested by Diamondback Tire as an option we could consider when I discussed this very topic some time ago. These are 30.6", and thus very close to 890-15's height of 31". Weight limit is around 2450, solving that issue as well. The issue is they are 10.4" wide, when the 890-15 is 8.8" wide and the 235/75R15 sits at 9.3". I suspect this would be a problem in particular with fender skirts, but others are likely more knowledgable on the topic.
 
they do come in the right white wall. but I have seen them 12 inches wide and 8 inches wide depending on the manufacture. they were used mainly on the jeeps. but if you can run the 235s I would think you can run them. but at 80 bucks each you want to talk about sending them back if the won't go in before you buy. they other option is 700 x 15 they are 30 in tall narrow enough and if you get 8 ply heavy enough but they only come in black wall. the idea of buying tires and sending them in to have the WW cut in and they getting them shipped back is what stalls me on Diamondback.
 
Guys,, I'm just gonna throw this out and let you work with it or not.
My knowledge of building tires ends with retreading.

As I read boards across the automotive spectrum I note everybody has tire problems. The Military collectors on Steel Soldier have resorted to buying from Europe and the far east. The M-37 guys are pretty close to mounting Amish tires, and you don't want to know the grumblings from arm collectors.

The small volume needed by collectors isn't going to get any tire builder salivating. Molds, even retread molds cost a fortune, and it just might be difficult to find tire builders who can assemble a tire given the industry has gone off shore.

Honestly if I were in need of tires, I'd reach out to others with the same need and then talk to a tire manufacturer if you can find one. 4 tires ain't worth building, but 200 are.
 
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