What's the latest on radial tires for a 63 (H speed rating)?

[Stuart F.]

I'm looking towards the next set of tires for my 63. Currently I have 205 x 75R - 15 Goodyears, but they are nearing 10 years old, and I no longer feel safe nearing redline in 3rd gear (3.36 final).

What's the latest on brand, size and availability?

Stu Fox

[Duke W.]

Re: What's the latest on radial tires for a 63 (H speed rating)?

What, as of yesterday? It changes constantly, so your best bet is to search the big tire retailers, manufacturers' Web sites, and Google for a 215/70R-15 in H and above speed ratings. To my knowledge there has never been a 205/75R-15 manufactured with nylon cap belts or a speed rating above T.

You could also try 205/65R-15 and 205/70R-15, but these tires are about 3-6 percent high on revs/mile compared to the OE 6.70-15's 760, which will shorten your effective gearing by that amount and add the same amount to the already somewhat high reading OE speedometer. In your case with a 3.36 axle using the driven gear for a 3.55 would get the speedo back to fairly accurate with 205/65s or 205/70s because the difference is five percent (21T versus 20T).

One thing for sure is that the days of finding something near OE revs/mile for OE wheels with a nylon cap belt and a H or above speed rating are definitely numbered.

Let us know what you find.

Duke

[Michael J.]

Re: What's the latest on radial tires for a 63 (H speed rating)?

Right Duke, and that is why I treasure the last few sets of Pirelli P4000s I bought as they were discontinued.

[Joe L.]

Re: What's the latest on radial tires for a 63 (H speed rating)?

I'm looking towards the next set of tires for my 63. Currently I have 205 x 75R - 15 Goodyears, but they are nearing 10 years old, and I no longer feel safe nearing redline in 3rd gear (3.36 final).

What's the latest on brand, size and availability?

Stu Fox

Stu-----


I don't think you're going to find ANY currently available H-rated tires in size 205-75-R15. You might find a few in the alternate sizes that Duke mentioned.

[Michael J.]

Re: What's the latest on radial tires for a 63 (H speed rating)?

Does anybody know what speed rating the Diamondback Michelin X radials are that are 205-75-15?

[Duke W.]

Re: What's the latest on radial tires for a 63 (H speed rating)?

Look up that specific Michelin model and size on the Michelin or Tire Rack Web site.

Duke

[Michael H.]

Re: What's the latest on radial tires for a 63 (H speed rating)?

Does anybody know what speed rating the Diamondback Michelin X radials are that are 205-75-15?

That would be my choice, no matter what the speed rating.

[Paul Y.]

Re: What's the latest on radial tires for a 63 (H speed rating)?

I'm looking towards the next set of tires for my 63. Currently I have 205 x 75R - 15 Goodyears, but they are nearing 10 years old, and I no longer feel safe nearing redline in 3rd gear (3.36 final).

What's the latest on brand, size and availability?

Stu Fox

Stu, Michelin has a 205 65 15 H rated tire that I just installed on the front of my 63 but I am running 225 75 15 Kumho on the rear. They seemed to work together fine on my last trip over the passes a couple of weeks ago. I really like the Michelins and am undecided about the Kumho although they are a high guaranteed mileage tire. I felt real limited in the selection I was able to find. I have the same rear end ratio as you and I don't want a smaller tire on the rear as I like highway driving the best. Paul

[Christopher R.]

Re: What's the latest on radial tires for a 63 (H speed rating)?

Can you put 205/65 or a 215/70 on a 5" wide rim?

[Duke W.]

Re: What's the latest on radial tires for a 63 (H speed rating)?

The data panels available for each make/model tire at manufacturers' and retail Web sites such as The Tire Rack usually include both the measuring wheel width and the acceptable wheel width range. Overall tire section width change when mounted on a different width wheel than the measuring wheel width can be approximated by adding/subtracting 40 percent of the change in wheel width for 60 and above series tires.

All data is usually very consistent for each size because the range is established for each size by the Tire and Rim Association, an industry trade group, and most manufacturers conform to Tire and Rim Assc. conventions.

The acceptable wheel width range for 215/70R-15 is usually 5.5 to 7.0", so C1 base steel 5.0" wheels are below the recommended range, but will probably not cause problems in normal driving. My recommendations if one wants to install 215/70s on a C1 or C2 with steel wheels is to buy a set of repro 6" Corvette Rally wheels, and I believe in most cases they will accept the OE wheel covers and fit all those models without fender interference, however, the tire shoulder may contact the frame on C2s at extreme lock.

In addition to the tire looking excessively "pinched" on narrow wheels, cornering performance may be compromised, however, the taller the sidewall the less sensitive the tire is to wheel width variation outside the recommended range. It's a lot more critical when you get down to 55 or lower series sidewall heights.

The 205/75R-15 size is okay on 5-6" wheels, but all these size tires have rock hard compounds, lack a safety enhancing nylon cap belt, and are only available in speed ratings up to T. I refer to them as "van tires".

One rule of thumb I use for 60 series and above radials is to measure the bead to bead distance of the new, unmounted tire. If the wheel width is +/- one inch of this dimension, there will likely not be any operational problems. This bead to bead dimension of the unmounted tire is usually very close to the measuring wheel width, and the measuring wheel width is usually at about the mid point of the acceptable wheel width range.

Duke

[Stuart F.]

Re: What's the latest on radial tires for a 63 (H speed rating)?

Thanks for all the comments and good advice fellows. My sons and I have a new lady friend that runs a new Firestone service store that just opened in our area. I was just in to have the tires rotated on my VW and we got to talking about my 63 (she knows her car stuff, Wow!). We scanned her book pretty thoroughly and got a couple ideas, but in general she said that if I can find a tire I like, she will beat the bushes to get them for me.

I'm making notes and will probably take her up on that. FWIW, she wouldn't change the oil on my VW as she said the drain plug was cock eyed and probably cross threaded. Told me to take the car back to the VW dealer as they were the last to change the oil. Told me not to let them use a self tapping plug or helicoil, rather make them change the pan! My kinda gal.

Stu Fox

[Michael J.]

Re: What's the latest on radial tires for a 63 (H speed rating)?

FWIW, she wouldn't change the oil on my VW as she said the drain plug was cock eyed and probably cross threaded. Told me to take the car back to the VW dealer as they were the last to change the oil. Told me not to let them use a self tapping plug or helicoil, rather make them change the pan! My kinda gal.

Stu Fox

That's great, but usually the cockeyed drain plug with the stripped threads happens at JiffyLube....

[Stuart F.]

Re: What's the latest on radial tires for a 63 (H speed rating)?

That's was exactly my first thought from the stories I have heard, but you never know where you'll find the "La Bamba" down here.

Stu Fox

[John S.]

Re: What's the latest on radial tires for a 63 (H speed rating)?

Stu,

I just installed some Pirelli Scorpion 205-75 R15 H rated tires on my 65 Fuel car. Look nice and ride super. Problem is my dealer said they are getting scarce also. The 67 has the P4000 super touring tires Duke recommended. Got thos a few years ago just before they discontinued them. I would compare the Scorpions to those although I think the P4000 tires are truely a W rated tire.

[Duke W.]

Re: What's the latest on radial tires for a 63 (H speed rating)?

...seems a lot of guys have trouble with tire sizes - both the correct numbers and proper format.

The H-rated Pirelli Scorpion STR is not available in size 205/75R-15. It IS available in a 215/70R-15 and the service description is 96H, so the proper full description is Pirelli Scorpion STR 215/70R-15 96H.

The Pirelli P4000 Super Touring 215/70ZR-15 97W has a speed rating of 168 MPH. Z-rated tires have unlimited speed rating unless modified by a speed rating in the service description such as "W" (168 MPH) or "Y" (186 MPH). If the service description of a Z-rated tire is enclosed in parentheses, such as (99Y), the the speed rating is "over 186 MPH". Look at the OE tires on modern Corvettes.

The number in the service description is the load index, which designates the tire's maximum load capacity. You have to look at the conversion table to convert the number to actual load, however, the maximum load at maximum COLD inflation pressure is placarded on the sidewall in both English and Metric units.

It looks like the above Scorpion STR is the only H or above rated tire currently available in a size that will fit C1 and C2 Corvettes with OE size wheels. Even the 205/75R-15 low speed rated "van tires" are being dropped by many manufacturers. The Tire Rack only lists 8 and most are offshore brands.