Wide vs Narrow On- Road & Off-Road Tires

This is a 35 inch all terrain tire and this is pretty much the same tire except two inches narrower. The question is which one is better. Does the white tire actually have a larger contact patch and which tire fluxes better when we air down? So join us for a series of experiment to find out exactly how different they perform and spoiler alert. Some result really surprised me. At the end of this Blog. I will reveal which tire I end up getting a full set and mounted on my FJ alright. Let’s Get started. The tires I chose for our experiment were Mikey Thompson. Baja Boss. Altering the white tire is the common 300 and 5. 70 R- 17 and the narrow tire is 200 and 55 and 85 r-sete. Some people may point out that these two tires are not equal in diameter. Their 300 and 15 calculates to be 34.4 and the 200 and 55 is only 34.1. Yes, the math is correct, but if you read the book short, the 300 and 15 s actual diameter is 34.5 while the 200 and 55 is 34.6. I also measure both tire carefully using squares and I can confirm those numbers, so the diameter or the sidewall heights are pretty much identical. These tire also shared the same low range E which means the tire carcass has the same stiffness. This is especially important because we will compare how they behave when aired down. Therefore, the only difference between these two tires is the width, making this a true controlled variable experiment. The 300 and 15 and 200 and 55 mm refers to the overall section width CWA to sideway. But what we care more about is the tread width the stuff contacting the ground. For the white tire i measured 10.2 inches and for the narrow tire I got 8.5. To measure the contact patch. I applied block printing ink to the tread and painted it on paper. Starting with the white tire at 40 psi. Intuitively. I was expecting a short rectangle that looks something like this, but instead this is what I actually got. It was almost a perfect circle dropping down to 35 psi, which was the recommended pressure for my setup. The circle got bigger, but still we didn’t have the full trend in contact. I continued to reduce pressure and the contact patch got both longer and wider. Only when I aired down to five psi, we finally had the full trap width in contact, and here is what zero psi looks like. Many experienced wheelelerss will tell you airing down does not increase the contact patch width. It only grows longer like a tank track, and that was also what I believe all these years. But my data showed otherwise, at least for this particular tire. I then swapped in the PIA cutter and repeated the same measurements starting at 40 psi. The narrow tire also had a wrong contact patch, and just as expected, it was narrower, but at the same time longer. As we air down the K patch also grows longer and wider just like the other tire. If we plot the contact patch length versus tire pressure, we can see both tire behaved very similarly. Except the narrow tire was consistently longer for contact patch width, it was the other way around. Now I’m sure you are eager to know which one has the bigger area. Because the contact patches are not rectangular, we cannot simply do with times length, so I scanned all my blog printing in true scale, manually trace the border of each contact patch and then use my vector editing software to compute the exact area in square inches. And here is the area versus pressure curve for the white tire. And here is the curve for the narrow tire. They were almost on top of each other with no practical difference. Many people naturally assume a wider tire means more rubber on the road, but as we just saw the narrow and wide tires yield the same contact patch area, we are just trading between width and length. Now what about a completely different tire? Thus the brand and model affects contact patch, and this got really interesting when I measure my BF Goodri km three mu terrain, identical size and low range. As the wide Baja Boss. I found its contact patch has a totally different shape, it was more rectangular, wider, and shorter. But to my surprise, when I traced out the area, the kmthree was actually ten to 20 percent larger, especially at very low pressure. Keep this in mind as we will see something even more interesting near the end of this Blog. Here I want to shout out to a fellow Websiter Robert Pepper. If you’ve been everywhere else and not found what you’re looking for, try my channel robber is someone I highly respect. My contact patch experiment was inspired by the one he did for the same topic, except he measured tires that were a little more different from each other and we adopt different techniques to measure the area. But for the most part we came to similar conclusions. I will link his Blog in the description below. In robert’s Blog he brought up a very interesting theory because the narrow tire has a longer contact patch, then the tire can better sort of mold around things. Rocks and pebbles like this and I feel that’s an advantage as opposed to just sort of being very short and not having the length to sort of caterpillar track over the top of that. I really like his war choice caterpillar track and it makes intuitive sense to me, but I would still love to see it in action and quantify the difference. So that was what I did. I conducted two difference experiments for this. In the first experiment. I lowered the tire onto a piece of rock and measured how much the tire deformed at various psi. I made sure the rock was centered so the tire bulged out equally on each side. I measure the gap between the tire and the ground by stacking wood chimes with various thickness. The rock itself was 5. zero sixches tall, so how much the tire caved in was 5.06 minus the height of my filler gauges. I jacked up the tire every time I changed pressure because I found the deformation of the tire will affect pressure rating, especially at very low pressure with large deformation. Yeah it was a lot of work, but this gave me the most consistent and accurate measurement. Starting with white tire, the change was very minimal at higher pressure, dropping from 40 psi all the way down to 15. The tire deformation barely even changed only at ten psi and lower. We started to observe some meaningful tire flex, but at pressure this low the risk of FE beating is significantly higher. For 90 percent of us up here is where we operate and at these pressure we ain’t got no flex. Now let’s see how the narrow tire. Compare. Right off the bat at 40 psi we already observe more tire flees and it gets better. At 20 psi which is still fairly conservative for off-ro, we already have doubled the tire flax as the wide tire. To achieve this much tire flax, the wide tire has to drop down to around seven psi and that is definitely block territory. Interestingly, near zero psi, the white tire actually caught up. My theory is at extremely low pressure. The tired deformation across the width started to kick in. Basically it became more of a three D deformation. The 200 and 55 tire wasn’t much wider than this rock, so its three D effect wasn’t as pronounced but what? If the rock is wider, a rock ledge or staircase type of obstacle is very common. These obstacles can easily span across the entire tread. How would the wide versus narrow? Compare in that situation. I replaced the rock with a long 2.5 inch diameter two, which eliminates all deformation across the width. Now both tire has only two D deformation from Tobey. After seeing the result. I was so glad I pulled through the second experiment. But before I show you the result. I need to share something important. Did you know this Blog almost didn’t happen altogether. Earlier this year a major tire manufacturer reached out. They asked me to be their brand ambassador and review their new offer attire. I happily accepted, but as it turns out they werent very excited about how technical I got. I was not even allowed to measure the tire in my Blog. After some back and forth I respectfully returned my free tires and terminated a contract. I’m not disclosing who that company is, but just to be clear it was not Mikey Thompson. I used for this Blog and this was where Yoda Expedition came in. They are a new company specialized in Toyota modifications. When I proposed my Blog idea to them, they were way more excited than that tire manufacture. Since they carry all major brands. I am now free from brand affiliation. I can do whatever experiment I want and present my finding truthfully and that is why you are able to watch this Blog right now. So please thank you the Expedition by checking out their website and Website channel. Links are in the description below. Alright, let’s get back to our experiment now. The obstacle spans across the entire tread. Both tires deform less for the white tire. I measured identical tire flags from 40 psi all the way down to 15. The tire was visually deforming, but the bottom of the tire was just approaching a flat line. It didn’t mold around the tube. Even at 15 psi, the practical tireexx was still merely half an inch, only below ten psi. We started to see more increase, but like I said before, 90 percent of us will never get this low. And now it’s time for the pizza cutter. Pizza time right off the bat. The narrow tire has the same amount of flax at 40 psi as the white tire at ten psi as we aired down, the pizza cutter also started to deform much sooner. At 15 psi, we already reached one inch deformation, whereas the white tire has to drop down to five psi to achieve the same. And when we drop the pizza cutter to five psi, it completely molded around the tube and touch the ground. This was something the white tire never achieved, even a zero psi. At this point. I was fully convinced the pizza cutter was the performance choice, at least for what I like to do. But man. I still couldn’t get over the look. So it would be so nice if theres a tire that can both flax over rocks and look thick at the same time. But what if I told you there is such tire and I already have it? Remember the KM three having a very different contact patch. Guess what. It also behaved very differently over obstacles for the rock experiment. Despite the KM three being 300 and 15 wide, it flees even better than the 200 and 55 Baja Boss. My theory is. This is thanks to kmthree’s linear FLA zone design feature. Few tires out there actually advertise to have a similar feature, so BFG clearly knows how to rock roll. For the second experiment with the tube, the KN Three started out flexing the least at street pressure, but it quickly caught up as we aired down. Although it didn’t surpass the PIA cutter, the KM Three was still significantly better than the Baja Boss with the same size. So my K Three was truly the best of both worlds, and more importantly, they were already ontrob lock wheels, so I could actually utilize the Ultra Load pressure. But if my K Three is so good, why on Earth I am looking for alternatives well offro performance is only part of the equation. My FJ is not a dedicated rock crawler. Despite how much I care about off-royal performance, there are still a lot of other aspects for a well balanced setup. I will go over all those in a future Blog, so subscribe if you’re interested in that now, which Baja Boss at did I end up getting a full set for my FJ? My heart still goes to the white tire, but as a mechanical engineer. I followed what the data suggested. I chose the Pizza cutters. A 35 pizza cutter is a very rare size with short supply. I will leave the links to where you can get these in the Blog description. Besides the experiment we did each 200 and 55 Baja balls was seven pounds lighter than the 300 and 15 and all seven pounds came from the tread, which has the greatest impact to the moment of inertia. The narrow tire is also much easier to fit, especially on an IFS Toyota. If more of us consumers realize the benefits of pizza cutters, we will see more tire manufacturers start offering them again. I would like to thank Yoda X for making this Blog happen, so go check them out. Are you tired of being confused or overwhelmed when it comes to buying and installing parts on your Toyota. Our goal is to change that. With easy to follow installation Blogs and in-depth overview Blogs.