C2 tire quality

[Leif A.]

Re: C2 tire quality

Would the whole tire be Vulcanized to produce this result? To vulcanize, the rubber is to chemically improve the properties and hardness,elasticity and strength of the rubber. Or is the process only to the sidewall? Are the Diamond Back tires a tire to stay away from?

Harry,

Diamond Back tires are some of the best available. As John stated, Diamond Back doesn't make tires, they buy them from the OEM and vulcanize the sidewalls to add the red line, gold line, etc. As I stated earler, I run these on my '67 (215-70R15) and abosolutely love the ride and drive. Mine are the Michelin Defender red lines. They, also, make these using BF Goodrich and Cooper tires. Take your choice. As I stated in an earlier post, go to their website and download their catalog and read how they "build" these units.

Leif

[Harry L.]

Re: C2 tire quality

Leif, why do you choose the size 215 70 15 instead of 205 75 15?

[Leif A.]

Re: C2 tire quality

Leif, why do you choose the size 215 70 15 instead of 205 75 15?

Virtually the same aspect ratio with a wider "footprint" on the road for better stability and handling.

[William F.]

Re: C2 tire quality

Duke et al
Do you really need better than S or T rating if you're not hot lapping, just driving freeway speeds, and doing an occasional pull to around 90-100?

[Leif A.]

Re: C2 tire quality

Duke et al
Do you really need better than S or T rating if you're not hot lapping, just driving freeway speeds, and doing an occasional pull to around 90-100?

Not in my estimation, you don't. Don't believe Big Brother would allow unsafe tires to be sold, knowingly.

[Joe C.]

Re: C2 tire quality

I feel the same way about the last set of Pirelli P4000 215/ZR70/15s I bought a few years back as they discontinued them. Great tires.

I bought a set of four about three years ago. Had to wait until a special production run was made. Was told that they do this about once/year, or when sufficient orders are placed to justify a production run.

Are you saying that things have changed, and the tires are no longer available by special order?

[Duke W.]

Re: C2 tire quality

Duke et al
Do you really need better than S or T rating if you're not hot lapping, just driving freeway speeds, and doing an occasional pull to around 90-100?

Ask yourself this: Do you really need seat belts if you're not hot lapping, just driving freeway speeds, and doing an occasional pull to about 90-100?

Cheap tires without the spriral wound nylon cap belts can suddenly disintegrate... the Ford Explorer fiasco from about a decade ago (which was due to a combination of poor poor design and quality control, insufficient pressure recommendation by Ford, and lax customer air pressure maintenance) and reports on the internet of other cars including vintage Corvettes. An ounce of prevention is worth a pound of cure, and I sure as hell don't rely on the government to keep me safe.

NHTSA has promulgated scores of car safety regulations over the last forty years, but they have been lax on tire safety regulations. IMO all tires should have spiral wrapped nylon cap belts. It doesn't cost that much more and would virtually eliminate sudden tire disintegration.

But NHTSA's response, instead of promulgating regulations to fix INADEQUATE TIRE DESIGN is to require tire pressure monitoring system on all cars, which in the long run will cost consumers a lot more than the few bucks to include spiral wrapped nylon cap belts on all tires and doesn't reallly solve the problem because the same poor design tires that can suddenly disintegrate, even with proper air pressure, continue to be manufactured and sold to the unknowing public.

... another example of government stupidity!

Duke

[Michael J.]

Re: C2 tire quality

I would also add that this tire disintegration can occur with a sudden loss of pressure (nail or other tire pressure failure) at highway speeds. Cheaper tires do not have the safety factors and redundancy (inner puncture sealers) of more expensive, speed rated tires, as Duke says. Just look at the amount of rubber all over the interstates from cheap truck and trailer tires, it happens and if you are in a vintage Corvette, it will be scary at best, and a bad accident at worst.

[Duke W.]

Re: C2 tire quality

Most tires won't rapidly lose air pressure from a small puncture like a nail, screw, or small shards of glass or metal. Nail and screw punctures are usually accompanied by a "ticking" sound that calls for investigation. If you find a puncture, don't remove the foreign object or the tire will lose pressure very rapidly. Drive the car to where it can be repaired, if possible, or change it on the spot. Large pieces of road debris can cause a sudden lose of pressure, but they are easier to see and can usually be avoided.

In the half million or so miles I've driven in 52 years I have never had to change a tire on the road. I've had my share of punctures, but the noise or a change in handling due to decreased pressure always gave me a warning, and I was able to safely drive to where I could get the tire repaired.

What kills tires is heat. High temperature can cause the internal bonds to lose strength and fail, which can result in a tread separtion that is uncontained without the spiral wound nylon cap belt, but this "safety belt" will usually contain an internal separation and maintain pressure. The internal failure will usually cause a big bulge in the tread area, which will always create a sudden significant vibration that calls for an immediate safe stop for investigation.

Low air pressure will increase tire temperatures, especially at freeway speeds in hot weather.

H and above speed rated tires will sustain higher temperature without failure, and this is indicated by the last letter in the UTQG data that is molded into the sidewall. Less than a H-rating usually results in a B or C. H and above with the spiral wrapped nylon cap belt are almost alway A, which is the highest rating.

It's certainly something to consider if you value your car and personal safety, but few people pay any attention to the UTQG rating and 99 percent of the public probably don't even know what it means and how to interpret the data.

The basic contruction architecture is also molded into the sidewall. Typical T and lower rated tires will read something like "plies: sidewall 2 polyester (or rayon), tread 2 polyester (or rayon) + 2 steel". On H and above rated tires the tread will usually read "2 polyester (or rayon) plus 2 steel plus 1 (or 2) nylon.

Another item I look at is what I call "load margin". All tires have the maximum load capacity at maximum cold inflation pressure molded into the sidewall. Vintage Corvettes use tire sizes that were common on large sedans. Typical load capacity for OE and replacement tire sizes is 1500+ pounds (at maximum cold inflation pressure) so the total load capacity is over 6000 pounds, but even the porky Corvettes from the mid to late seventies didn't have a gross weight of more than about 4000 pounds and earlier model years were less, so Corvette size tires have lots of load margin, which is a good thing.

Of course, we usually don't run maximum cold inflation pressure, so load capacity is less, but even at the miniumum cold inflation pressure I recommend of 32 psi, there is still plenty of margin.

Everyone should check out the speed rating, UTQG data, and maximum load and cold inflation pressure data on the tires of all the cars they own and determine whether the installed tires are adequate for your driving conditions.

Duke

[Michael J.]

Re: C2 tire quality

My experience may not be the norm, but I have had two SUV tires blow out the last 10 years with H rated tires due to nails (or at least that is what the tire store claimed they found), as the pressure decreased rapidly in hot highway driving, as these cheaper tires do not have that inner layer the more expensive speed rated tires have that cause the air to go out much more slowly or the cap belts. I have run Z or V rated tires ever since and never had a problem with blow-outs and disintegration, but still got some nails that were no problem to detect.

[Duke W.]

Re: C2 tire quality

Are you sayilng that H-rated tires installed on these vehicles did not have a nylon cap belt? I've never seen a H-rated tire that didn't have it. Are you sure they were H-rated tires?

I've been discussing replacment tires with a neighbor who owns Tahoe. It currently has Falken 275/55R20 117H tires installed, and they have a nylon cap belt. This is the OE size, but they were just S-rated

I found Kumhos in that size at the Tire Rack that are V-rated and less expensive than the Falkens, so that's what I am recommending to them. I'm surprised that a V-rated tire this size is only $128 each, which seems pretty inexpensive, and those suckers weight over 40 pounds each. I don't even want to know what the wheels weigh.

Carrie uses the Tahoe to haul her three little kids, age 8 months, 2, and 4, around, and I want them to have as much safety margin as possible.

Duke

[Michael J.]

Re: C2 tire quality

Oh, sorry I misspoke. Those were S rated tires, not H, they were Firestones OE tires on an Expedition. It was ten years ago, so maybe things have changed?

[Duke W.]

Re: C2 tire quality

That's what I figured and is further evidence for the argument I've presented recommending H or better rated tires with a nylon cap belt. If the OE tires were H-rated with a nylon cap belts they would not have blown out from a simple nail puncture.

Ten years ago was the era of the Ford Explorer/Firestone tire debacle, and there were a lot of management and quality issues/problems in Firestone plants. That's why they ended up selling-out to Bridgestone, and I'm sure today's Firestone brand tire quality is up to government and industry standards.

Duke

[John H.]

Re: C2 tire quality

Hi John, what tire and size do you run on your midyear? Thanks, Dutch

Dutch -

I run 205/75-15 Firestone Supreme Si radials with redlines applied by Diamond Back.


DBRedline2.JPGDBRedline.JPG

[Stuart F.]

Re: C2 tire quality

My understanding about rubbing the frame equated to steering adjustment, I.e. The fast ratio adjustment on mine never rubbed, but others I have known with standard ratio adjustment did, given the same larger tires. Anyone else notice that?

Stu Fox