Run Flat vs Regular Tires: In the world of automotive technology, tires play an integral role, directly impacting a vehicle’s safety, comfort, and overall performance. As we navigate this expanse, two distinct categories often spark debates among car enthusiasts and industry experts alike: Run Flat Tires (RFTs) and Regular Tires. But what precisely separates these two tire types, and is one genuinely superior to the other? This article aims to explore this tire-tussle in detail.
Run Flat Tires, as the name suggests, are specifically designed to resist the effects of deflation when punctured. This remarkable feature enables drivers to continue their journey for a limited distance at a reduced speed, even after a tire puncture, allowing them to reach a safe place for tire repair or replacement. A marvel of engineering indeed, but it’s not without its critiques.
Detractors often point to RFTs’ purported lack of wet performance and subpar comfort level compared to their regular counterparts. But are these criticisms valid or mere automotive myths that have grown in the grapevine of car talk? Get ready, as we prepare to delve deep into this tire tangle, examining the truth behind these complaints, and putting to the test the real-world performance of Run Flat versus Regular Tires. Buckle up for an exciting, informative, and possibly surprising journey!
Table of Contents
Results : Run Flat vs Regular Tires
Results below were taken from Tyre Review’s “Are Modern Runflat Tires Finally Good? Normal, RFT and SEAL Tires Compared! test” which includes 3 different tire segments (Regular, Run Flat & Sealant). The graph below shows the comparison between Run Flat vs Regular Tires which is using Hankook’s Kingery 4S2 as the reference. The Regular Hankook Kingery 4S2 was set as a reference hence at the 100% mark.
The tire size of interest is 225/45 R18 which is a common tire size for BMW Z4. You can check out our latest tire size table for more information. The testing vehicle is a VW Golf.
Wet
A significant point of contention when comparing Regular Tires and Run Flat Tires is their respective performances in wet conditions. While some critics argue that Run Flat Tires lack efficiency in such environments, our comparison between the Regular Hankook Kinergy 4S2 and its Run Flat counterpart suggests a different narrative.
The wet braking performance of both tires was tested rigorously, and the results show an identical distance of 29.50 meters, highlighting the fact that both tire types offer similar stopping power when confronted with damp or rainy conditions. This characteristic is of utmost importance, as efficient braking performance can often mean the difference between a dangerous accident and a safe stop. Additionally, wet handling, measured by lap times on a wet course, provided equally compelling evidence. Both the Regular and Run Flat versions of the Hankook Kinergy 4S2 clocked in identical times of 76.50 seconds. This data further supports the conclusion that both tire types manage comparable control and maneuverability, even in less-than-ideal weather conditions.
These results may come as a surprise to some, especially given the prevailing narrative around Run Flat Tires. However, it’s important to note that both tires are crafted from the same compound, which is a crucial factor affecting their performance in various conditions. Therefore, the perceived differences in performance, particularly in wet conditions, seem to be more of a subjective impression than an objective fact. Below is a short summary from the test driver talking about the subjective differences between the 2 tires
The tire performance exhibited remarkable similarities, with less noticeable differences in dry conditions, as one might expect due to the reduced stress on the tires. Still, the parallels persisted. The run flat tire maintained a marginally crisper steering response, yet simultaneously offered somewhat less feedback during the onset of a slide. This could potentially be attributed to reduced vibrations transmitting through the tire’s sturdier sidewalls, although this remains purely conjectural. It’s indeed an interesting observation, and perhaps provides some insight into why BMW opts not to equip run flat tires on their M series vehicles.
Jonathan Benson (Tyre Reviews)
It’s important to remember that tire performance can vary based on numerous factors, including the vehicle, driving style, and environmental conditions. However, as far as the wet performances of these two Hankook Kinergy 4S2 models are concerned, the results indicate that the duel ends in a draw.
Run Flat :
- 0% in wet braking
- 0% in wet handling (lap time)
Dry
Dry conditions present another critical testbed for tire performance, where the Hankook Kinergy 4S2 Regular Tires and their Run Flat counterparts have been pitted against each other. In terms of measurable outcomes, the two tire types have again shown striking similarity.
Dry braking distances registered at 42.60 meters for the Regular Tires and 42.50 meters for the Run Flat variant. This minor variation falls within the accepted testing tolerance, hence making the two tires effectively equal in this aspect. The story is similar when considering dry handling, with lap times at 117.90 seconds for the Regular Tires and 118.20 seconds for the Run Flat Tires. Once again, these results fall within the testing margin, meaning both tires show analogous performances in dry conditions.
However, as drivers often report, the reality of the driving experience extends beyond raw data points. Subjectively, some have found that the Run Flat tires exhibit a slightly faster turn-in response, contributing to an overall perception of increased agility. It’s crucial to understand that while this might not reflect in the numerical comparison, subjective experiences like these form a significant part of the tire’s overall character and contribute to the tire selection process.
When it comes to ultimate performance parameters, both types of tires display a striking level of parity. However, the Run Flat tire does make a distinctive impression at road speeds that fall below their limits. I find myself leaning towards the Run Flat tire, as it offers a marginally swifter steering response and a more immediate steering reaction. This quality contributes to a heightened sense of directness that you can enjoy more as compared to a regular tire. However, it’s worth mentioning that there’s a trade-off: when pushed to their absolute limits, the feedback from the Run Flat tires does diminish somewhat, particularly in dry conditions. As it turns out, the dry test, which we initially thought would be a cakewalk for the Run Flat tire, presented its own unique challenges.
Jonathan Benson (Tyre Reviews)
So, while our head-to-head dry performance comparison showcases nearly identical performances on paper, the subjective driving experience introduces an additional dimension to this tire showdown.
Run Flat :
- +0.2% in dry braking
- -0.3% in dry handling (lap time)
Noise & Comfort
When assessing the comfort and noise performance of tires, subjective experiences often play a significant role. Let’s examine how the Regular Tires and the Run Flat variant of Hankook Kinergy 4S2 stack up in these respects. In terms of noise, the test findings surprisingly reveal that the Regular Tires and the Run Flats are on equal footing. Regardless of the surface traversed, both tire types produced similar sound levels, rendering any auditory differences virtually indistinguishable to most ears.
Comfort, however, presented a more nuanced picture. When tested across a variety of surfaces with distinct impacts ranging from 9 to 24 millimeters, some differences started to emerge. With the aid of a uniquely designed impact grading system, the test were able to discern subtle variations in the way each tire managed the shocks. On some types of impacts, both tire variants offered identical comfort levels. But in certain scenarios, the Regular Tires managed to edge out their Run Flat counterparts, providing a slightly smoother ride by rounding out certain impacts just a touch better. The differences were slim, but noticeable.
Interestingly, when confronting more significant obstacles—like potholes or rough roadworks—the Regular Tires continued to perform better, albeit by a slim margin of 5-10%. Nevertheless, under moderate impact, which corresponds to many of the harsher bumps encountered on the road, the Run Flat Tires seemed to offer a slight advantage.
While the Run Flat variant indeed exhibited a higher peak impact in the cabin, it was also shorter-lived. The Regular Tires, although initially less severe, elongated the impact, which was particularly noticeable through the vehicle’s rear axle. This resulted in a bit more shake in the back and more work for the rear suspension. In contrast, the Run Flat Tires’ impacts were sharper but quicker, resulting in a surprising edge in comfort in specific scenarios.
So, while the Regular Tires hold a slight advantage in dealing with the smallest and the most considerable impacts, the performance gap between the two tire types isn’t as pronounced as with older generation Run Flat Tires.
Run Flat :
- Regular Tires == Run Flat in subjective noise
- Regular Tires > Run Flat in subjective comfort
Price
A vital factor that often influences tire choice is the cost. In comparing the prices of the Regular Tires and Run Flat Tires, we find that one of the most commonly voiced criticisms about Run Flat Tires rings true—they are indeed pricier.
We have a clear example when comparing the Hankook Ventus S1 evo3 and its Run Flat counterpart. For the tire size 245/40R19, the Regular Tires are priced at $275, while the Run Flat variant is significantly more expensive, at $405. This price differential translates to Run Flat Tires being approximately 32% more costly than their Regular counterparts, a premium which could be attributed to the supply-demand imbalance, among other factors.
Tire size: 245/40R19
- Hankook Ventus S1 evo3 : $275
- Hankook Ventus S1 evo3 Run Flat : $405
Difference: +32% more expensive for Run Flat.
However, before concluding that the price increase is unjustified, it’s essential to consider the distinct advantages that Run Flat Tires bring to the table. A key benefit lies in their safety enhancements. The ability to continue driving at a reduced speed, even after a puncture, can be a real boon, particularly when traveling on highways or in areas where immediate assistance may not be readily available.
While the higher cost can indeed be a deterring factor, the added safety and convenience features that Run Flat Tires offer can certainly justify the price for many drivers. Ultimately, the choice between Run Flat and Regular Tires will depend on individual needs, preferences, and the perceived value of the unique benefits that Run Flat Tires provide.
Summary
In conclusion, our comprehensive comparison of the Regular Tires and Run Flat Tires reveals that the latest generation of Run Flats have made significant strides in matching their regular counterparts in numerous performance areas. Be it wet or dry conditions, noise level, or even subjective comfort, the gap between these two types of tires has been significantly reduced.
However, it’s worth noting that we didn’t touch upon one critical aspect – rolling resistance. Often, due to the additional sidewall rubber, Run Flat Tires tend to exhibit higher rolling resistance, which can lead to decreased fuel efficiency. This aspect might be a significant consideration for many drivers, particularly those who prioritize fuel economy.
Despite the higher cost and potential fuel efficiency trade-offs, the safety and convenience benefits of Run Flat Tires make them an attractive choice for many drivers. Ultimately, the selection between Regular and Run Flat Tires will hinge upon individual priorities, driving conditions, and personal preferences.
As the tire industry continues to evolve and innovate, we can look forward to even more refined and performance-focused options that cater to the diverse needs of drivers. In the meantime, it’s safe to say that the latest generation Run Flat Tires have successfully gone head-to-head with their regular counterparts, erasing many of the perceived drawbacks and offering drivers a compelling alternative in the tire market.