Sumitomo HTR A/S P03 Review

Leave a comment

The Sumitomo HTR A/S P03 is marketed as the Ultra High Performance All-Season tire, which is odd, as it only delivers speed ratings up to W. But does it affect it’s overall grip on dry, wet and winter conditions? Well let’s find out.

Subaru
Sumitomo HTR A/S P03

Key Takeaway

Overall, the Sumitomo HTR A/S P03 excels in:

  • Directional Grip: Enhanced by central ribs and in-groove notches, offering excellent straight-line traction.
  • Lateral Grip: Thanks to its compact shoulder design ensuring effective contact during cornering.
  • Hydroplaning Resistance: With its wide circumferential channels allowing effective water dispersion.
  • Winter Performance: Due to its advanced rubber composition and thermally adaptive compounds, even though, the tire doesn’t offer 3 peak mountain snowflake rating.
  • Durability and Tread Life: Thanks to its robust construction.

However, it needs improvements in:

  • Steering Response: Slightly vague in both wet and dry conditions.
  • Fuel Economy: Only average, impacted by the aggressive tread design and greater structural weight.
  • Noise Comfort: The tire could use ridges between the shoulder blocks (which lowers noise generation).

Available Sizes

The Sumitomo HTR A/S P03 comes in 15 to 20 inches rims, with total of 80 sizes having following specs.

  • Speed ratings: H, V and W.
  • Load ratings: XL and Standard on all.
  • Weight range: 18 to 36 lbs.
  • Tread depth: 10/32″ on all.
  • UTQG: Some have 540 AA, while other come with 640 AA.

Also Note: All sizes vary in mileage warranties, with some giving 65k miles, (for H and V rated sizes), while for W rated ones, you get 45k.

Tread Features

Although it’s subjective, the Sumitomo HTR A/S P03 is one of the best looking HP AS tires.

Sumitomo HTR A/S P03
Sumitomo P03 offers very tough passing, zigzag central most circumferential groove.

So this tire comes with asymmetric tread design, which is pretty obvious especially when you consider it’s outer ribs.

Here on one side, the shoulders form an “X-shaped” siping pattern, while on the other, each block comes with (single) wave-like siping slit.

The central two ribs are again very different, with the narrower one showcasing slanted notches and lateral voids.

Moreover, they also have a mix of linear and interlocking sipes, running parallel to those voids.

Now this siping pattern is also common with the other, fatter rib, as well.

But you can clearly see, that it also features a lot of longitudinal running in-groove notches, kind of like a vine with multiple edges, but without the leaves.

Dry Performance

In assessing dry performance, we evaluate the tire’s overall traction, which merges its straight-line grip with steering responsiveness. Let’s check out both of these factors here.

Overall Traction

The tire’s overall traction is a blend of directional and lateral grip.

Directional grip is crucial for straight-line traction and assessed by how well tire is able to stop (it’s measured by braking distances).

While the lateral traction is the ability to handle lateral forces during turns (and this gets measured by lateral g force evaluations).

Now, the Sumitomo HTR A/S P03 tire excels in directional grip, thanks largely to its two central ribs, packed with biting edges and in-groove notches.

And even though these wide grooves take away a lot of rubber, the underlain continuous-running secondary rubber layers still provide you with the needed stability and optimal rubber-to-road contact.

Moving towards lateral grip, here tire’s shoulders come in to play, as they make the most contact with the surface, while the tire corners.

And Sumitomo again takes the lead here, with its compact shoulder design, with minimal tread features.

As each lug only features linear sipes, they make a great contact patch, allowing for superior lateral grip.

To put things in to perspective, in my comparative analysis with this tire, I saw that the tire stopped only 5 feet short, and offered slightly lower later grip (on average), compared to Michelin Pilot All Season 4 (review), which is one of the best tires in it’s category.

Steering Feedback

Now sure, lateral grip defines a lot about overall handling scores, but here the final piece of the puzzle comes for analyzing tire’s steering characteristics.

Having said that, in tests, the Sumitomo HTR A/S P03 demonstrates accurate enough steering, responding predictably to driver inputs.

Though when pushed to its limits, the tire tends to exhibit slight understeering.

This room for improvement for this tire, where it comes with somewhat vague steering response, is attributed to its heavier internal construction, (relatively speaking, comparing others in its category).

And that extra weight leads to increased flexing of the tread and sidewalls during cornering (as they get pushed down more, against the road).

This flexibility impacts the tire’s on-center, and mid-cornering accuracy, particularly.

That’s why the Sumitomo falls behind by over 2 seconds in handling tests when compared to the leading tire in this category, even though its lateral traction isn’t on the lower side.

Wet Performance

The Sumitomo HTR A/S P03 although offers an above average score in overall wet performance, it still falls really short in certain aspects.

Taking about the good things here, the tire delivers satisfactory directional/longitudinal grip due to its combination of straight and lateral sipes.

And yes, its wet lateral traction is also great, attributed to its robust shoulders with full-depth sipes and in-groove notches, ensuring significant road-bite.

Though the tire lacks the needed steering precision here, especially when it’s judged against it’s direct rivals/competitors.

This is mainly because of the it’s extra weight, causing a lot of delay in steering feedback/communication, where it necessitates putting in extra effort, particularly when aligning the vehicle after cornering.

This delay in regaining control, directly impacts overall lap times (measured in seconds).

That’s why when compared to Michelin AS4 (a leader in wet traction), the Sumitomo HTR A/S P03 lacks by over 2 seconds in overall handling, lap performance tests (on average).

Hydroplaning Resistance

Hydroplaning could easily become a synonym for “floating of a tire”. And it happens when grooves aren’t able to properly evacuate the water out, in time.

Now, this the area, where the Sumitomo HTR A/S P03 excels, effectively channeling water to prevent loss of traction.

It achieves its above average float speeds with its 3 wide circumferential channels, interconnected to each other laterally, allowing water dispersion in all directions.

Moreover, the tire’s greater weight (relatively), and well-engineered contact patch is also helping here a lot.

Together, they make pressure differences on the tread in a way, that water is squeezed out from the middle towards shoulders, as it gushes out of the tread (via shoulder voids).

Winter Performance

The Sumitomo HTR A/S P03 stands out in winter performance among ultra-high performance all-season tires, even, (UHPAS) without the 3-Peak Mountain Snowflake certification.

So what makes this tire so good here? Well, consider its following features.

Advanced Rubber Composition: It rubber offers a good silica density, and some additives like multi-cell compounds, containing microscopic bubbles and tubes, which help in wicking away water from the ice surface, thereby increasing overall winter traction.

Thermally Adaptive Rubber: Its rubber also features compounds like Polybutadiene, which basically keep ow-temperature flexibility. As a result, the sipes (small slits in the tread) maintain their effectiveness in biting into snow and ice, without losing their grip (from freezing too much).

Narrower Section Width: Compared to other tires, the Sumitomo HTR has a narrower section width (on average). This design, combined with the tire’s relatively greater structural weight, allows it to exert more pressure on the snow. And this pressure embeds the snow into the tire’s sipes and grooves, creating effective snow-to-snow contact which is crucial for winter traction.

The significance of snow-to-snow contact lies in the nature of snowflakes themselves.

These snow particles having unique arms are pretty interlocking, and stick well with one another, instead of rubber, enhancing friction.

In essence, the Sumitomo P03 excels in overall winter performance, where it emerges as one of the top choices for budget-conscious buyers seeking reliable winter traction in UHPAS tires.

Noise Comfort

Noise in tires is primarily generated by the interaction of air with the tire’s tread walls.

Basically, air particles enter the rolling tire particularly from shoulder grooves, and the impact of them hitting against the tread is what creates primary noise.

Now in case of the Sumitomo HTR A/S P03, as the tire comes with larger shoulder voids, without ridges in between (unlike most of the tires in its category), it doesn’t restrict air entry, and that lowers its overall noise reduction performance.

Though the tire isn’t too bad, after all, as it keeps other originating (unwanted) sound waves low. So you get an average overall decibel readings (when compared to it’s direct rivals).

But I mean by other sound waves? Let me explain.

So initial sound waves are created by air, but they further echo within the tread, causing tread vibrato, and cavity sounds, and Sumitomo deals with that very well.

It offers some tread additives, which are highly effective in absorbing sound waves, so initial noise is prevented from being amplified.

Additionally, the tire’s asymmetric tread design incorporates advanced pitch sequencing technology which creates various tones as air particles strike the lugs from different angles, helping to cancel out each others’ frequencies.

Fuel Economy

When it comes to fuel economy, the Sumitomo HTR A/S P03 is just an average tire.

Speaking of its drawbacks, the tire comes with an aggressive tread design, filled with numerous “biters”, and these significantly increase the friction between the tire and the road, enhancing rolling resistance.

Moreover, it’s greater structural weight is also a culprit here. It pushes down on lugs more, causing them to flex, increasing overall energy expenditure.

(With lugs flexing/bending, fuel energy is predominately lost in to heat, and not utilized in to the rolling of the tire, as intended).

Though on a positive note, the tire still provides good enough results on some sizes, featuring below “V” speed ratings.

These sizes although do not offer high end grip (like other ultra high performance tires with “Y” speed ratings), it compensates with better fuel efficiency.

Tread Life and Durability

The Sumitomo HTR A/S P03 sets itself apart with a strong build and sophisticated design, which contribute to its durability and extended lifespan.

It comes with dual-ply polyester internal structure, with wide steel belts on top, and additional full-width nylon cap ply on the very top (spirally wound), ensuring top-tier toughness within its category.

Though this toughness comes with a cost, or I should say, extra weight, which puts extra pressure on the lugs during contact with the road, which can lead to accelerated wear.

Nevertheless, it’s important to note that the Sumitomo HTR A/S P03 generally offers better than average tread life. This is particularly true for sizes with H speed ratings, where the tire can exceed 65,000 miles on average.

Though sizes with higher speed ratings, only go up to 50k miles, since speed rating is inversely proportional to tread longevity.

To Sum Up

In conclusion, the Sumitomo HTR A/S P03 tire showcases a blend of strengths and weaknesses across various performance categories.

Its dry performance is marked by excellent directional grip, and superior lateral grip thanks to its numerous biters, and optimal contact patch. However, it falls slightly short in steering response due to its heavier build.

Moreover, same is the case when roads get wet, where the tire’s greater weight again cause lagging steering response.

And yes, its also the main culprit in lowering overall fuel economy too.

Though on the positive side, this extra weight is very beneficial for winter performance, where the tire excels.

And yes, as its the by-product of durability, there are no complaints, when it comes to tire’s toughness.

Other than that, the tire offers above average ride comfort, and tread longevity overall.

Leave a Comment