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Yokohama (Diamondback) RY215 {700R-15} Safety Issue


James_Douglas

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Hi all,

As a rule, I do not use product supplier names on forums.  But in this case I am as it is a safety issue.


A few years back I had an issue with my diamondback tires. The splice where they vulcanized the white rubber to started to show a crack line.  Diamondback was not too helpful, the whole time accusing me not checking the tire pressure or hitting it hard on a curb while parking.  It was like they were reading a script!  How the left rear would be hit...how many times does one parallel park on one way streets on the left side, even here in San Francisco.

 

In any event, although I have spent almost $5K in tires with them in the last 7 years, I let it drop as it is just cosmetic and you really cannot see it unless you are right up close.

 

About 6 months ago the car developed a "thump, thump,thump".  It had all the earmarks of a bearing or universal joint going bad.  Perhaps even a spider gear in the rear end.  It has gotten worse as time goes on.  Several professional mechanics in their 60's to 80's who all are long time classic car men could not fine it.  I tried for months without any luck.  We just could not hear exactly where is was coming from.

 

Today we had the car on the rack at a gas station - shop (full service gas, old time shop, vintage 1930's gas station) that does my oil and full under car lubrication. While we had it up in the air we went over the car real good.  We could not fine a thing.  When one of the guys spun the drivers side front tire.  In the daylight you could see a severe high/low spot. One the passenger side, we spun that tire and it had one about half as bad.  That has to be it.

 

These tires are seven years old and have about 25K miles on them, perhaps a little more.

 

Now it is possible that the problem is due to under inflating the tires. When I purchased them, I called Yokohama and asked about the 60 PSI pressure. Yokohama told me that I could go down to 40 PSI as my car come in at a little under 5000 pounds.  A few years back the outer edges of the tires had that look like they had some under-inflation wear so I increased the pressure to 50 PSI.

These tires are rated at over 2000 pounds each or 8000 pounds total.  I also run them on the freeway and at times have gone a steady 70 MPH and on occasions up to 75.  The tires in the Yokohama catalog show the maximum speed as 65 MPH. (Which I did not find out until well after I purchased them.)

So, the question is: Did I push the tires on pressure (too low) and Yokohama gave me bad advice that I could run 40 PSI?  Is the freeway running up to sustained 70 MPH the problem?  Is the once in a while 75 MPH the problem?  Or, is there a problem with these tires in their construction?

The rear tires show no problem.

I know that a LOT of people have recommended these tires for the 1930's and 1940's cars.  I did when I got them years ago. 

Heck, I like them very much as they are the same diameter, about 29 inches, and the same contact patch, at 4.5 inches, as the original bias ply tires. The contact patch at 4.5 makes steering way better.  Plus the big white walls look great.

Now I have to decide what tires to get.  As this is the car I drive all the time, no new cars for me, I need tires that not only look correct, but function.

Since I suspect that one or both of these tires could come apart in the future if I keep running them, the flat spot - Bulge is good size and producing a wheel trump that is very noticeable, I wanted to write up what is going on for others to be aware of.

 

Best, James

 

 

 

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I find it very odd that Yokohama, an all around better than average tire of some acclaim would state the very max speed of a DOT rated tire would be limited to 65, less than the interstate speed, that is almost unsafe to begin with on todays highway traveling that slow.  It is a DOT rated tire and not a tire not designed for use on US highways and bought in bulk just for the with wall process. 

  UNLESS they themselves will limit the tires overall rating AFTER THE FACT of second party vulcanizing a WWW on the tire.  for the record...what is the speed rating marked on the sidewall of your tire?  My 2015 is stock with Yokohama tires...they have a 118 speed rating...I am hoping for better than average tire service from a factory equipped tires by this brand name.

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9 minutes ago, Plymouthy Adams said:

I find it very odd that Yokohama, an all around better than average tire of some acclaim would state the very max speed of a DOT rated tire would be limited to 65, less than the interstate speed, that is almost unsafe to begin with on todays highway traveling that slow.  It is a DOT rated tire and not a tire not designed for use on US highways and bought in bulk just for the with wall process. 

  UNLESS they themselves will limit the tires overall rating AFTER THE FACT of second party vulcanizing a WWW on the tire.  for the record...what is the speed rating marked on the sidewall of your tire?  My 2015 is stock with Yokohama tires...they have a 118 speed rating...I am hoping for better than average tire service from a factory equipped tires by this brand name.

See https://www.yokohamatruck.com/public/img/tires/31/bulletin_en.pdf

Jamesyokohama_speed.JPG.317d9b5e4df753b8c0d44d4d859d207c.JPG

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you did not say if DOT rated...on the very specs you pasted there is no wear, heat or speed index....Yoko has had to recall a lot of tires just for not having the DOT or the ABC ratings stamped on the tire.  I too would be a bit upset especially seeing the cost of these without a vulcanized WWW

added note.......I am wondering if by the very fact that these are listed as COMMERCIAL series tires that the limiting facts are in place...

Edited by Plymouthy Adams
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Yup was looking at these tires, but no thanx, rated at 65 mph, so using it near 100% or better speed rating.

You used the tires for 7 years, well again, they are "radials" so near the end of their life.

Not  a bad looking tire, nice and tall, section width not too wide, nice for narrow rims.

These tires are built for delivery trucks, and were never meant for passenger vintage cars necessarily.

Rim widths are 5-6.5, so if you are using them on 4 1/2 inch wide rims, you already are pushing the envelope on what's recommended, add the fact you inflated them to the lowest the manufacturer recommends and then create abnormal wear issues.

They are relatively cheap in price, but again you have ran them on your big heavy boat for 7 years, time for new shoes, no doubt...

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I have 6 inch rims.  These tires had driven nice and been fine except for the new flat spot issue. I was planning on changing them out next year at eight year point.

These are DOT approved tires. see https://www.summitracing.com/parts/yok-21501

I know at least a dozen people who use these tires.  I have them on the '49 and I know someone who has them on a 1946 Chrysler T&C and a 1937 Cad.  A lot of the Packard guys use them as well.

In my case they get more "real world" use on the 1947 then most old cars. All of the dozen or so people I know who are using them don't put much mileage on them.

I drive the car several times a week in the middle of San Francisco as well as 160 mile round trips to my place out of town at 65-70 MPH a couple of times a month. I have warned my friends to up the pressure to at least 55 PSI even if the ride is a little stuff and see what happens.  In my case, I have to decide if I want to order another set from Diamondback or try Coker's new radial that looks like an old bias tire...

 

James.

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10 hours ago, 55 Fargo Spitfire said:

Yup was looking at these tires, but no thanx, rated at 65 mph, so using it near 100% or better speed rating.

You used the tires for 7 years, well again, they are "radials" so near the end of their life.

Not  a bad looking tire, nice and tall, section width not too wide, nice for narrow rims.

These tires are built for delivery trucks, and were never meant for passenger vintage cars necessarily.

Rim widths are 5-6.5, so if you are using them on 4 1/2 inch wide rims, you already are pushing the envelope on what's recommended, add the fact you inflated them to the lowest the manufacturer recommends and then create abnormal wear issues.

They are relatively cheap in price, but again you have ran them on your big heavy boat for 7 years, time for new shoes, no doubt...

I agree with most of this post except for the part about these tires being designed for A delivery truck.  47 DeSoto suburban weighs 4195lbs. True it ain't a sports car but I wouldn't think you would find a delivery truck that didn't weigh at least that and probably more. If they were designed for a delivery truck I would think it would have to be a light truck plus not be hauling much weight.

  I've always paid a lot of attention to the ratings on my motorcycle tires, never given car tires ratings much thought unless it was a ton truck. This thread may have changed my outlook.

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44 minutes ago, Flatie46 said:

I agree with most of this post except for the part about these tires being designed for A delivery truck.  47 DeSoto suburban weighs 4195lbs. True it ain't a sports car but I wouldn't think you would find a delivery truck that didn't weigh at least that and probably more. If they were designed for a delivery truck I would think it would have to be a light truck plus not be hauling much weight.

  I've always paid a lot of attention to the ratings on my motorcycle tires, never given car tires ratings much thought unless it was a ton truck. This thread may have changed my outlook.

Well are you running these tires?

They were designed for delivery trucks in mind, and not classic vintage vehicles necessarily.

In my post, if they are under inflated, driven over the max speed rating on a regular basis, possibly abnormal wear may develop, especially belt separation etc.

I really like the look f these tires too, so believe me, I really wanted to buy them, and maybe I still might at some point a nice looking tire...

 

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51 minutes ago, James_Douglas said:

I have 6 inch rims.  These tires had driven nice and been fine except for the new flat spot issue. I was planning on changing them out next year at eight year point.

These are DOT approved tires. see https://www.summitracing.com/parts/yok-21501

I know at least a dozen people who use these tires.  I have them on the '49 and I know someone who has them on a 1946 Chrysler T&C and a 1937 Cad.  A lot of the Packard guys use them as well.

In my case they get more "real world" use on the 1947 then most old cars. All of the dozen or so people I know who are using them don't put much mileage on them.

I drive the car several times a week in the middle of San Francisco as well as 160 mile round trips to my place out of town at 65-70 MPH a couple of times a month. I have warned my friends to up the pressure to at least 55 PSI even if the ride is a little stuff and see what happens.  In my case, I have to decide if I want to order another set from Diamondback or try Coker's new radial that looks like an old bias tire...

 

James.

Well "BINGO", you drove a lot more, higher speeds, less inflation a lot more heat develops.

I do like the look of these tires, and they are not a bad price, about $140 us each here...

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3 minutes ago, 55 Fargo Spitfire said:

Well are you running these tires?

They were designed for delivery trucks in mind, and not classic vintage vehicles necessarily.

In my post, if they are under inflated, driven over the max speed rating on a regular basis, possibly abnormal wear may develop, especially belt separation etc.

I really like the look f these tires too, so believe me, I really wanted to buy them, and maybe I still might at some point a nice looking tire...

Nope I'm not running them, if max speed is only 65 mph, I wouldn't be interested in them.

 

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I've used the RY-215's on various old trucks over the years...primarily late 40's through early 50's International Harvesters...and never had a problem.  I ran them on rural highways routinely.  A couple of caveats though are that those trucks were heavier 3/4 to 1 ton models and were limited by their gear ratios to a top speed of about 55-60 mph. Also, the tires were stock Yokohama and had not been modified by Diamondback to add whitewalls.  

When replacing the worn (and much too wide) radials installed on my '50 Plymouth P-20 by a previous owner, I considered using the RY-215, but ultimately decided against it. While the contact area is right, they have an awfully stiff sidewalI that is better suited to the heavier trucks they were designed for.   I bit the bullet and gave the Coker Bias look radials a try, even though I haven't had the best luck with Coker in the past.   After running them for several months now, I have to say I'm really happy with them.  They balanced up beautifully, and the car handles much better than it did with the traditional wider (215 series) radials it used to have. I have the 7.10R15, which have the correct diameter and contact patch, and mounted them on 15 x 5 rims...my stock rims that I had re-shelled from 4 1/2 to 5 inch width. I run them at 32 PSI.  Like you James, I drive my car regularly in city traffic and on the highways (in Los Angeles) and need more than just "looks" in a tire.  

Edited by st63
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On ‎5‎/‎6‎/‎2017 at 10:43 AM, st63 said:

I've used the RY-215's on various old trucks over the years...primarily late 40's through early 50's International Harvesters...and never had a problem.  I ran them on rural highways routinely.  A couple of caveats though are that those trucks were heavier 3/4 to 1 ton models and were limited by their gear ratios to a top speed of about 55-60 mph. Also, the tires were stock Yokohama and had not been modified by Diamondback to add whitewalls.  

When replacing the worn (and much too wide) radials installed on my '50 Plymouth P-20 by a previous owner, I considered using the RY-215, but ultimately decided against it. While the contact area is right, they have an awfully stiff sidewalI that is better suited to the heavier trucks they were designed for.   I bit the bullet and gave the Coker Bias look radials a try, even though I haven't had the best luck with Coker in the past.   After running them for several months now, I have to say I'm really happy with them.  They balanced up beautifully, and the car handles much better than it did with the traditional wider (215 series) radials it used to have. I have the 7.10R15, which have the correct diameter and contact patch, and mounted them on 15 x 5 rims...my stock rims that I had re-shelled from 4 1/2 to 5 inch width. I run them at 32 PSI.  Like you James, I drive my car regularly in city traffic and on the highways (in Los Angeles) and need more than just "looks" in a tire.  

I am glad to see you like the Coker tire.  I have a friend with a '58 Cad Eldorado Biarritz Convertible that had bad luck with Coker tires.  Are your tires that you purchased the "Coker American Classic Bias Look Radial" line?

The American Classic Bias Look Radial is the only whitewall tire (760R15) I could find that is close in the size and load to the RY-215. 

I will order them later today.

Best, James

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1 hour ago, James_Douglas said:

I am glad to see you like the Coker tire.  I have a friend with a '58 Cad Eldorado Biarritz Convertible that had bad luck with Coker tires.  Are your tires that you purchased the "Coker American Classic Bias Look Radial" line?

The American Classic Bias Look Radial is the only whitewall tire (760R15) I could find that is close in the size and load to the RY-215. 

I will order them later today.

Best, James

Yes, the ones I purchased are the American Classic Bias Look Radial...in my case, the 7.10R15.  I was hesitant to try Coker tires again...I've had bad luck with them in the past in terms of being out of round straight from the factory, but I decided to give these a chance.  So far, so good.  My tire shop had no problem getting them mounted and balanced properly, and they ride very nicely.   I still like the Yokohama tires on my truck, but these seem better suited to my sedan.  By they way, I ordered mine through Summit Racing, and got free shipping.  They're expensive enough without the added shipping costs.      

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1 hour ago, st63 said:

Yes, the ones I purchased are the American Classic Bias Look Radial...in my case, the 7.10R15.  I was hesitant to try Coker tires again...I've had bad luck with them in the past in terms of being out of round straight from the factory, but I decided to give these a chance.  So far, so good.  My tire shop had no problem getting them mounted and balanced properly, and they ride very nicely.   I still like the Yokohama tires on my truck, but these seem better suited to my sedan.  By they way, I ordered mine through Summit Racing, and got free shipping.  They're expensive enough without the added shipping costs.      

I had heard years ago they had machines that would shave an out of round tire back to round. Never seen one, wonder if these machines are still around? Seems like if you did this and balanced it it would run really true.

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2 hours ago, Flatie46 said:

I had heard years ago they had machines that would shave an out of round tire back to round. Never seen one, wonder if these machines are still around? Seems like if you did this and balanced it it would run really true.

I have seen this done a long time ago . The machine took off a lot of rubber and the customer was watching and didn't look very happy . 

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15 minutes ago, Jerry Roberts said:

I have seen this done a long time ago . The machine took off a lot of rubber and the customer was watching and didn't look very happy . 

Ha! I bet, sounds like the tires wernt much to begin with. 

 

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21 hours ago, Flatie46 said:

I had heard years ago they had machines that would shave an out of round tire back to round. Never seen one, wonder if these machines are still around? Seems like if you did this and balanced it it would run really true.

Used to have this done to my bias truck tires at a small (but old school) tire shop when decent quality heavy duty bias truck tires became harder and harder to find.  The machinery was pretty ancient though, so I guess some of the old truck tires always needed it!    

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cutting a tire tread to run true was but a stop gap to the ultimate demise and replacement of the tire.  The carcass is what is cast out of round and the truing as they called the process was short lived as the thumping of the carcass would ultimately cause the out of round condition to reappear in fairly short order.  Great side business for a used car salesman where moving the car off the lot was the prime concern.  Once out of round, aways out of round...today our tires are made very well, out of round is not so much an issue with new tires (discounting any tire company using the old molds..they still doing it out of round  wink wink nod nod) our issues today are separating belts....don't recommend any x rotations either....many other myths in the business...

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