Kumho Solus 4S HA32+ Review

Leave a comment

The Kumho Solus 4S HA32+ is a decent grand touring all season option, with a blend of strengths and weaknesses, excelling in certain areas while needing improvement in others.

Lexus NX
Kumho Solus 4S HA32+ on Lexus NX.

Quick Takeaway

Overall, the Kumho Solus 4S HA32+ excels in various aspects including:

  • Excellent lateral grip in dry conditions, ensuring reliable handling during turns and maneuvers.
  • Superior steering feedback with a pronounced sense of control, particularly notable in mid-cornering and exiting turns.
  • Effective hydroplaning resistance, with a tread design that efficiently evacuates water and maintains good float speeds.

However, tire isn’t without its shortcomings, which are most evident in:

  • Linear traction in dry conditions, as it exhibits a longer braking distance compared to its competitors.
  • Wet braking performance, where it falls short due to less effective water absorption by the central sipes.
  • Noise comfort and tread longevity, with a noisier ride due to its tread pattern and faster wear due to higher rolling resistance and shallower tread depth.

Tread Structure

To capture the essence of the tire’s performance, we must first get into the specifics of its tread design.

Kumho HA32+ tread
Kumho Solus 4S HA32+

So, the Kumho Solus 4S HA32+ comes with a directional tread pattern.

It features multiple curved grooves that create a V-shaped pattern across the tire, contributing to effective water evacuation for resistance to hydroplaning.

These V-shaped grooves are interspersed with numerous siping, that enhance traction, particularly in wet and icy conditions.

These sipes are varied in length and orientation, with some running parallel to the grooves and others crisscrossing them, improving grip, particularly on slippery surfaces.

Moving towards tread edges, here, the shoulder lugs, separated by thick lateral and longitudinal slits, are the most voided up.

Here, you can see blocks, properly separated by lateral grooves. Moreover, they also vary slightly in terms of siping, where the sipes are very laterally oriented.

Sizes Info

The tire comes in 14 to 19 inches rims. And these sizes have following specs.

  • Speed ratings: T, H, V and W.
  • Load ratings: SL, and XL only.
  • Tread depth: 9/32″ on all.
  • Weight: 24 to 49 lbs.
  • UTQG: 400 A A.
  • Treadwear warranty: None.

Confused by the vast selection of all-season tires? Let’s make it simple.
Start your search here.

Overall Dry Performance

The key to understanding a tire’s dry performance lies in examining its adherence to the road, its agility in handling, and its responsiveness to driver inputs.

Let’s discuss these aspects further.

Dry Traction

Dry traction primarily hinges on two aspects: directional and lateral grip.

Directional, or linear grip, is determined by the tire’s central tread footprint and is evaluated based on stopping distance.

In contrast, lateral grip is reliant on how the tire’s shoulders interact with the road and is measured by lateral “g” forces.

Now, the Kumho Solus 4S HA32+ comes out with pretty mixed results here, where the tire provides superb lateral grip, but really lacks in linear traction.

To give you an idea, in my comparative testing analysis, the Solus 4S although showcased similar lateral grip compared to Nexen N Blue (review), it lacked to the same tire by over 10 feet in braking distance tests (on average).

And looking at the tire’s design, it makes sense why.

Though unlike the shoulders the tire’s central lugs offer greater rubber to road contact, it’s missing with in-groove notches that could bite the road linearly, as the tire brakes.

Steering Feedback

In steering performance, the Kumho tire excels with its stable handling and pronounced sense of control, especially evident during abrupt turns.

Although the tire has some shortcomings in directional grip, leading to a need for slower corner entry (requiring deceleration before turning), it performs exceptionally well during mid-cornering and upon exit.

I mean offers excellent balance between understeering and oversteering, along with a remarkable “on-center feel.”

This means that it maintains stability and precision when the steering wheel returns to a neutral position after cornering.

More specifically, after a turn, the wheels don’t veer off in any direction when you accelerate, illustrating the tire’s effective on-center steering feedback.

This superior performance of the tire is largely credited to its lightweight construction, where the tire features a lighter single ply casing and stiffer sides, thanks to spirally wound nylon caps.

This design reduces strain on the tread, and in conjunction with the reinforced foundations underneath all its lugs, the tire’s rubber composition effectively minimizes the unnecessary bending of the lugs (adding to direct steering responsiveness).

So, even though the Kumho Solus falls short in braking, its overall handling times are still impressive, where, it achieves handling times that are 1 second better compared to the BF Goodrich G Grip All Season 2.

Wet Performance

The evaluation of a tire’s wet performance focuses on its traction, handling capabilities, and resistance to hydroplaning.

Let’s break down each of these factors.

Wet Traction and Handling

Wet traction is fundamentally about how effectively a tire can disperse water, primarily achieved through grooves and sipes.

Now, most of the water is expelled through the tire’s grooves, while the remaining water particles are cleared by sipes or biters, which compress water particles against the road (under tread/lugs), pushing moisture in their slits.

In other words, these sipes and biters act like miniature reservoirs, capturing water particles and expelling them as the tire rolls over.

Now, here, the Kumho (just like its dry performance), comes out with mixed results. I mean, although the tire excels in wet handling, it really falls short in wet braking.

In my comparative testing analysis of top grand touring tires (see the list here), the Solus 4S HA32+ lagged behind the Crossclimate 2 in wet braking by over 7 feet, even though, it was relatively a second faster, on averaged handling lap times.

This discrepancy is due to the tire’s superior water clearance from its shoulder lugs, where the tire features a more voided up design.

Moreover, the angled sipes in these areas are more effective in (micro) water clearance, as well.

In contrast, its middle area, (which significantly influences braking qualities, its lugs are more crowded-up, and the sipes here are more laterally arranged.

And these sipes with their linear structures, tend to close up as the tire brakes, lowering their effectiveness in absorbing enough water particles, limiting wet braking performance.

Aquaplaning Resistance

Hydroplaning is defined by the effectiveness of the tire’s grooves, which take out the bulk of water, and here the Solus 4S HA32+ provides one of the best results in its category.

The tire’s directional tread pattern, which features prominent lateral voids and a rounded contact patch, is adept at displacing water efficiently.

Simply put it creases pressure points on its tread in a way, that water gushes out from the middle, towards shoulders, and out of the tread quickly.

Moreover, as its V shaped grooves are interconnected with each other, it further enhances the overall water evacuation process, allowing for decent float speeds, in both straight and curved aqua tests.

Snow Traction

In evaluating winter performance, I focus on a tire’s acceleration, braking, and handling on both icy and snowy surfaces. Based on these criteria, the Solus HA32+ falls squarely in the middle among tires with the 3-Peak Mountain Snowflake (3PMSF) certification.

While some may view this as a limitation, I see it as a notable achievement, especially since the Kumho HA32+ is positioned as a budget-friendly option yet delivers performance comparable to premium tires.

A key factor contributing to its performance is the tire’s abundance of biting edges, thanks to strategically designed interlocking sipes that are particularly effective at trapping snow within the tread.

This design promotes snow-on-snow contact, which is crucial for superior snow traction, as snowflakes tend to bond together more efficiently than rubber, enhancing friction, and with it, grip.

However, there’s potential for improvement in the tire’s rubber compound.

Although it’s thermally adaptive and adequately soft for cold temperatures, it lacks the ideal pliability for winter conditions. I mean, a softer rubber composition would allow for better conformity to the nuances of colder, winter terrains, further enhancing the tire’s performance in these challenging conditions.

For your Info: Compared to the best winter performer here, the Nokian SeasonProof (review), the Kumho’s tire only lacks by 6 feet in braking (which is still pretty impressive).

Noise Comfort

Tire noise fundamentally stems from the interaction of air with the tire’s structure.

Basically as the tire rolls, air gets compressed within its tread pattern, creating turbulence against the tread walls. This results in a primary noise source, which then goes on, creating in-groove resonance, and cavity sounds.

For Your Info: In-groove resonance is actually the echoing of sound-waves.

Now, with Kumho Solus 4S HA32+ emitting all these sounds, it becomes one of the loudest tires in its category.

Its design features more voided shoulder lugs, which allow greater air entry, resulting in pronounced in-groove resonance. This effect is further intensified by the tire’s heavily siped tread pattern, contributing to the overall noise in the form of growling.

Additionally, the tire emits loud cavity sounds, akin to the resonant noise produced in a hollow chamber. If I give you an example here, its reminds me of the sound a basketball makes, when it hits a surface.

However, the overall noise performance of the tire could have been worse if not for its advanced pitch sequencing technology.

This technology subtly alters the lug pattern with the aim of creating varied frequencies as air particles strike them. This prevents the noise waves from amplifying in unison, reducing the overall noise level.

Tread Wearing Rate

When considering tread longevity, two key factors are crucial: the tire’s internal and external construction, and its rolling resistance.

In these aspects, the Kumho Solus 4S HA32+ exhibits characteristics that lead to comparatively faster wear.

In my test evaluations, the tire generates significant rolling resistance. And with this increased friction the tire, not only compromises on fuel efficiency but also accelerates tread wear.

Moreover, it’s relatively shallower tread depth (comparing other tires in its category) is also not helping here.

Higher trad depth although causes increased rolling resistance, but in this tire’s case it essentially means, the tire reduces more quickly down to the legal tread depth limit in the U.S., which is 2/32″.

As a result, the tire typically offers a lifespan of only 25 to 30,000 miles, provided that the tires are rotated and aligned, every 4 to 5,000 miles.

And yes, the tire doesn’t offer any treadwear warranty, which makes sense here.

For Your Info: Yes, there’s a difference between rotation and Alignment. I simplified it here.

Closing Remarks

So what’s the verdict? Well there are a lot of variations in the tire’s performance, and it all comes down to your specific driving conditions and needs.

The Kumho excels in dry conditions, providing superb steering and handling, though it needs a bump up in its braking performance.

And the same is going on when it comes to wet roads, where the tire lacking behind in braking impacts its overall performance.

And on snowy terrains, although the tire delivers average performance for a budget-friendly option, there’s still a little room for improvement, particularly related to its rubber compound.

Other than this the tire is just okay in comfort and fuel/tread performance.

Leave a Comment