3 Scientific Experiments to Settle This | Wide vs Narrow 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 a few weeks ago I ran a poll on the YouTube Community post to my surprise 60 of you actually favored the narrow tire at the same time I ran the exact same poll on Instagram and that result reached almost a 70 30 split but the other way around more people preferred the wide tire well if we are doing it for the gram the White Tire would definitely got more likes because that pizza cutter just looked like it skipped lactate but for those who are watching this video we care more about practical performance does the white tire actually have a larger contact patch and which Tire Flex is better when we are down so join me 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 video I will review 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 all terrain the white tire is the common 31570r17 and the narrow tire is 255 85 R17 some people may point out that these two tires are not equal in diameter their 315 calculates to be 34.4 and the 255 is only 34.1 yes the math is correct but if you read the bookshore the 315's actual diameter is 34.5 while the 255 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 tires also share 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 315 and 255 millimeters refers to the overall section width sidewall to sidewall 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 apply block printing ink to the thread 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 track width in contact I continued to reduce pressure and the contact patch got both longer and wider only when I air down to 5 PSI we finally had the full track width in contact and here is what 0psi looks like many experienced wheelers will tell you airing down does not increase the contact patch with 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 swap in the pizza 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 contact 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 behave 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 block 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 does the brand and model affects contact patch and this got really interesting when I measure my BF Goodrich km3 muttering 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 km3 was actually 10 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 video here I want to shout out to a fellow YouTuber 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 video in the description below in Robert's video 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 to limp to sort of Caterpillar track over the top of that I really like his word 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 different 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 shims with various thickness The Rock itself was 5.06 inches 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 reading 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 the 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 10 psi and lower we started to observe some meaningful Tire flex but I pressure this low the risk of speeding is significantly higher for 90 percent of us up here is where we operate and at this 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 flex and it gets better at 20 psi which is still fairly conservative for off-road we already have doubled the tire Flex as the White Tire to achieve this much Tire Flex the white tire has to drop down to around 7 PSI and that is definitely B log territory interestingly near 0 psi the White Tire actually caught up my theory is at extremely low pressure the tire deformation across the width started to kick in basically it became more of a 3D deformation the 255 Tire wasn't much wider than this rock so its 3d 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 thread how would the wide versus narrow compare in that situation I replaced the rock with a long two and a half inch diameter tube which eliminates all deformation across the width now both tire has only 2D deformation from tobac after seeing the results 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 video 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 off-road tire I happily accepted but as it turns out they weren't very excited about how technical I got I was not even allowed to measure the tire in my video after some back and forth I respectfully returned my free tires and terminated a contract I'm not disclosing who their company is but just to be clear it was not Mikey Thompson I used for this video and this was where Yoda Expedition came in they are a new company specialized in Toyota modifications when I propose my video idea to them they were way more excited than that tire manufacturer 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 video right now so please thank you to Expedition by checking out their website and YouTube channel links are in the description below alright let's get back to our experiment now the obstacle spans across the entire thread both tires deform less for the Wide 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 mode around the tube even at 15 psi the Practical Tire Flex was still merely half an inch only below 10 psi we started to see more increase but like I said before 90 percent of us would 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 flex at 40 PSI as the Y tire at 10 psi as we air down the Pisa cutter also started to deform much sooner at 15 psi we already reached 1 inch deformation whereas the white tire has to drop down to 5 PSI to achieve the same and when we dropped the piece of cutter to 5 PSI it completely mowed around the tube and touched the ground this was something the White Tire never achieved even at 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'll be so nice if there's a tire that can both Flex 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 km3 having a very different contact patch guess what it also behaved very differently over obstacles for the rock experiment despite the km3 being 315 wide it Flex even better than the 255 Baja boss my theory is this is thanks to km3's linear Flex Zone design feature feel tires out there actually advertise to have a similar feature so BFG clearly knows how to rock crawl for the second experiment with the tube the kn3 started out flexing the least at Street pressure but it quickly caught up as we air down although it didn't surpass the pizza cutter the km3 was still significantly better than the Baja boss with the same size so my kn3 was truly The Best of Both Worlds and more importantly they were already on true B lock wheels so I could actually utilize the ultra low pressure but if my kn3 is so good why on Earth I am looking for alternatives well off-road performance is only part of the equation my FJ is not a dedicated rock crawler despite how much I care about off-road performance there are still a lot of other aspects for a well-balanced setup I will go over all those in a future video so subscribe if you are 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 inch piece of cutter is a very rare size with short supply I will leave the links to where you can get these in the video description besides the experiment we did each 255 Baja boss was seven pounds lighter than the 315 and all seven pounds came from the thread 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 video 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 videos and in-depth overview videos we give you the confidence to buy and install the right part on your Toyota so head over to yodaexpedition.com we'd be glad to help

Channel: Tinkerer's Adventure

Views: 1,426,594

Keywords: baja boss at, mickey thompson, baja boss, 315/70R17, 255/85R17, pizza cutter tires, wide vs narrow tires, narrow vs wide tires, wide vs skinny tires, skinny vs wide tires, off-road tires, all terrain tires

Id: 6wAJAOxh8LE

Length: 16min 43sec (1003 seconds)

Published: Thu Jul 27 2023