235 vs 245 tires: So when someone mentioned their tire size is 235/45R18, what does this actually mean? 235 actually denotes the width of the tires in mm. For example a 235/45R18 tire size, it means that the width of the tire is 235mm (~ 9.3 inch) wide. The picture below shows an illustration of the 235mm length tire width against a 245mm length tire.
So when a consumer asks, what is the difference between 235 vs 245 tires? This question is a bit completed as the sidewall height is a function of the tire width & aspect ratio. (235/45 R18 –> 45 denotes the aspect ratio) This indirectly determines the diameter of your tire. This is the reason why when you are inching up, you tend to go up higher in width and lower in aspect ratio to keep the diameter roughly the same. We have written extensively about inching up and you can find more info here.
To get an idea what tire sizes we are comparing, below are some examples of the popular tire sizes which carry the 235 & 245 width.
| 235 | 245 |
| 235/35R19 | 245/30R18 |
| 235/40R18 | 245/30R20 |
| 235/45R17 | 245/35R18 |
| 235/45R18 | 245/35R19 |
| 235/45R19 | 245/40R18 |
| 235/50R18 | 245/40R19 |
| 235/50R19 | 245/40R20 |
| 235/50R20 | 245/45R17 |
| 235/55R17 | 245/45R18 |
| 235/55R18 | 245/45R19 |
| 235/55R19 | 245/45R20 |
| 235/55R20 | 245/50R18 |
| 235/60R18 | 245/50R19 |
| 235/65R17 | 245/50R20 |
| 235/40R19 | 245/55R18 |
| 235/40R20 | 245/65R17 |
| 235/50R20 | 245/70R16 |
| 235/50R17 | 245/75R16 |
| 235/65R18 | 245/75R17 |
Table of Contents
Footprint 235 vs 245 tires
So regardless of your aspect ratio, the main key differences comparing 235 vs 245 tires comes in the footprint shape. An important point to note here is that your total footprint area stays the same regardless of what tire width you use as pressure is a function of weight. (Pressure = Force[weight]/ Area ) So please do not get swayed by articles telling you otherwise.
However with a bigger width tire (245) you have a slightly wider footprint width compared to 235.
So how does this wider footprint actually improve the tire performance? From past studies, it is common knowledge that a wider footprint tire (245) performs better in wet braking compared to smaller width (235) one. The concept is relatively simple as the faster you are able to dissipate water to create a semi dry patch, the better your wet braking performance. So with a 245 tire width with a wider footprint, you have less contact area on a semi dry surface compared to a 235 tire width with a narrower footprint.
The same principle also holds in ice & snow braking, as a wider width tire is able to dissipate the thin liquid layer on ice & snow to create a higher friction surface to ensure a more effective way to transmit forces to the ground.
Noise 235 vs 245 tires
Having a long footprint width might enhance your braking performances however it does come with a noise drawback. As the exterior noise generated is correlated to your tire width, the 245 width tire will be much more noisier than the 235 width tire. To minimize noise, you would like the air flow hitting the tire contact patch as narrow as possible to reduce the air pumping effect. Like everything in tires, trade offs are a common theme 🙂
Segmentation 235 vs 245 tires
Based on the tire size table list, 235 tires have a lower aspect ratio range of 35-65, with a big concentration of ultra ultra high performance segments. Popular sizes like the 235/40R18 for Honda Civic 1.5Tc Premium & also 235/45R18 carried by Toyota Camry 2.5V. These tires are either positioned in the UHP segment of the UUHP segmentation. Notable products in the 235 range include Continental ExtremeContact Force & Michelin Pilot Sport Cup 2.
There is however a small class of 60-65 aspect ratios in the 235 width designation which are classic SUV sizes for example the 235/60 R18 which Volvo XC 60 & Honda’s Cr-V carries. The tire segment for these tires are predominantly in the grand touring all season & crossover/SUV touring all season classification.
On the other hand 245 tires have even a much lower aspect ratio range of 35-50, with a big concentration of ultra ultra high performance segments. Popular sizes like the 245/40R18 for Audi A4 are either positioned in the UHP segment of the UUHP segmentation. Notable products in the 245 range include Continental ExtremeContact Force & Michelin Pilot Sport Cup 2. There is also a small selection of off-road tires in the hugely popular size of 245/70R16 which Isuzu D-Max & Mitsubishi Triton carries.
Summary
Overall in a comparison of 235 vs 245 tires, 245 tires come with a wider footprint which enables better wet/snow/ice braking performances compared to a 235 tire. However a 235 width tire having a narrow footprint has a better noise performance compared to a 245 width tire. I hope this clarifies the pros and cons of 235 vs 245 tires.