Going from V to H or T

[Jarlaxle]

That 95V is molded, not heat-stamped. Wild guess: the H tire uses the same mold, so the load/speed index, like the DOT number and date codes, are on replaceable blocks for easy swapping.

 

[Boss302fan]

Originally Posted By: Camprunner
I was wondering how much you compromise the handling of your car going from a V rated tire to a H or even T rated tire. Could it have an effect on the safety of the car handling wise?


H rated tires would be fine...

 

[Kira]

1) I once assumed a V or W rated tire would have been more carefully built so it can go faster and shake less. That may be true.
2) My Volvo is not turbo charged. The computerized listings used by tire stores frequently don't differentiate. Try getting a dim man-child to understand that. Kira

 

[Jarlaxle]

I honestly wonder what some of the tire shops would do if a car's stock size and speed rating is no longer available? Offhand: the 1994-6 9C1 Caprices ran a long-disco'd 235/70VR15...I recall early-90's P71 Vics ran a V-rated 225/70. For that matter...does anyone still make a 215/65VR15? (That was OE on a Buick Grand National.)

Just from vehicles Liz and I have OWNED, how would tire shops react to an OE size of...
HR70-15
145R12
8.75R16.5D
12-16.5
195/70R13

Then again...the size on my Dakota's door tag is a size I have NEVER seen on any Dakota!

 

[fdcg27]

As others have noted, if you do this with a little bit of sense, it should be no problem at all.
According to our industry expert member Capri Racer, the most important feature to look for would be a cap ply, which all H rated tires will have along with some tires of lower speed ratings as well.

 

[Hokiefyd]

Originally Posted By: raytseng

The tire specs for weight and wear and load and everything else is exactly the same for V and H. They don't advertise V has extra has any extra features over the H.

The 95V is "stamped" in at one of the final step, it's clearly not intrinsically molded the same way as the rest of main markings, and not even the same as the size marking.
Explain why they do this if not for the potential reason I laid out?


Remember that there are a lot of tire sizes where different vehicles may take the same tire size but differing speed ratings. An example I can easily come up with is 225/65R17. Honda's CR-V takes the 225/65R17 102T and Toyota's RAV4 takes the 225/65R17 102H (note difference in speed rating).

Different manufacturers take different approaches to this. Some will market the "same" tire with two different speed ratings, including the General AltiMAX RT43 and the Firestone Destination LE2. Both of these tires are available in this size in both speed ratings. Other tires offered in this size come only in the higher speed rating (such as the Bridgestone Dueler H/L 422 Ecopia). The higher speed rating applies to both applications, so it's relevant to both, right?

Yes, BUT. The BUT is that within the tire industry, speed ratings are one of the determinants in assigning the market niche the tire lives in. For example, S- and T-rated tires (for cars) are usually referred to as passenger all season tires, or sometimes standard touring tires. H-rated tires are usually referred to as high performance all season tires, or sometimes grand touring tires. V-rated and above are usually called ultra high performance tires. So when a tire manufacturer sets out to design a tire, it knows the speed rating it'll give to that tire based on what market niche they're trying to hit.

Here's a great example of that: the Michelin Primacy MXV4. Michelin designed this as a high performance all season tire, or a grand touring tire. Tire Rack calls it a grand touring tire. And most of the sizes are rated either H or V, depending on the applications that Michelin is trying to hit with that tire. But a few tires are actually only T-rated, like the P235/65R17. They still have an A temperature rating, but they're not H-rated. Why not? In these cases, the Primacy MXV4 is an OEM tire and made to the OEM's specifications, which apparently include a T speed rating in those cases. It doesn't mean that those tires failed the H- or V-rated speed testing. To the contrary, they might easily pass it. But the speed rating isn't a "pass/fail" test that's applied to the tire after it's manufactured. It's a specification that's agreed-upon at the design stage.

Here's another example going in the other direction: the Michelin Defender. It's a standard touring tire that's almost exclusively T-rated. But a few sizes are actually H-rated, like 205/55R16. Why? Again, Michelin is simply trying to hit a certain application with that size. There must be a popular application out there that takes that size and speed rating that Michelin's trying to hit with that particular tire.

Again, just because you have two "identical" tires that have two different speed ratings, and there appears to be no distinction between the two, doesn't mean that the speed rating is applied after manufacturing. It doesn't work that way; the two tires will have two different part numbers and will likely be manufactured in "lots" together...if they had co-mingled part numbers coming off the line, that'd be a logistical nightmare.

 

[Hokiefyd]

Originally Posted By: Jarlaxle
That 95V is molded, not heat-stamped. Wild guess: the H tire uses the same mold, so the load/speed index, like the DOT number and date codes, are on replaceable blocks for easy swapping.


Yes. If you have two different speed ratings both in the same size, and if they use the same tread mold, then they would use the same type of molding blocks that the DOT code uses. They'd run a batch of the H-rated tires, however many they'll make in that lot, and then they'd do a batch of V-rated tires. The key is that this is molded in at the time of rubber vulcanization. This is not something that's applied to the tire after it's manufactured based on balance or uniformity.