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    Are fat or narrow tires fast?

    Are fat or narrow tires fast?
    click here buy now!https://cyrusherbikes.nl/

    For nearly a century, riders have "known" that narrower tires will roll faster. For example, in the last century, the riders in the Grip Roubaix, even though they used shock forks, still chose narrower 20C tires for the race. Today, we have theoretical support: dikke band are faster because they have a shorter contact area, because they have less deformation when rolling. But this is just as problematic, in real-world use, the actual dikke band, will have a lower tire pressure limit, which in turn affects the performance of the dikke band at speed. So it seems paradoxical that if you want to ride faster, you still need relatively narrow tires.

    On this issue, Cycling Quarterly did a test 12 years ago. Since they are a long-distance riding-driven magazine, their thought was whether narrower tires would really suit the rider? If dikke band would reduce the rider's speed by a few percentage points, would the comfort that comes with dikke band reduce rider fatigue? Will these extra comforts help us improve efficiency on multi-day rides and ultimately ride faster on average than with narrower tires? With these questions in mind, we first need to know just how much speed dikke band will cost us.
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    Real road test
    For the test they chose three tire widths under the same model: 20mm, 23mm and 25mm. first of all the test results largely support the above conclusion that dikke band will be faster. This holds true not only for the same power test, but also for the downhill test: the narrower tires are slower than the fat ones.
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    As the testing continued, however, they found that once the tires were fat than 25mm, the performance of the tires would no longer change with width. Also in the test they found that starting from 26mm to 54mm, these tires performed very close to each other on smooth tarmac in real road tests and did not lose anything because the tires were fat. However, on rough roads, dikke band will definitely be faster.
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    As their research continued, they discovered that people had historically realized that dikke band were faster. When pneumatic tires were first invented, Scorchers bicycles used them because they could get over bumps better, and in the 1920s, Velocio, editor of the French magazine Le Cycliste, discovered that if the casing was soft enough, it could roll as fast as a narrow tire. But in the decades that followed, it was all but forgotten as racers opted for narrower tires to compete.
    Why was this theory reintroduced after almost a century?

    Because there were two main reasons why racers at the time thought narrow tires would be faster.

    First: laboratory testing. Under controlled test conditions, those narrower tires eliminated the loss of elasticity. The shape change of the tire is small, just like the suspension loss of a soft-tailed bicycle when pedaling. When narrower tires run at higher tire pressures, they have less elasticity, which means they absorb less energy. That is, we often say that there will be less
    venting.
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    However, when tested in real world conditions, narrower tires will bring more intense vibrations and thus cause more energy loss, which in turn offsets the gains from the reduced elasticity mentioned above. The loss from these vibrations will eventually be absorbed by the rider. Imagine a bag of beans being dropped on the ground and not bouncing back because the energy is all converted into friction between the beans and the beans and the beans and the bag. The human body works on the same principle, and studies have shown that the more discomfort the vibration brings to the body, the more energy the body absorbs away.

    Second: Psychological comfort (illusion). Typically, the faster we ride, the higher the frequency of vibration on our bikes, because the tires will pass over uneven roads at a faster rate. And, narrower tires will make this vibration frequency higher. So, this can give us the illusion that a narrower tire will be faster, even though it's not actually faster. Filling your tires with higher pressure allows you to experience this feeling quickly and gives your brain the false impression that you're going fast, but if you look at your yardstick, you'll see that the line doesn't actually increase your speed. Instead, dikke band have less vibration and therefore will feel slow to most riders.
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    So, for nearly a century, it has been assumed that a narrower tire would be faster, and under experimental test conditions, it is indeed faster. There's no reason for people to wonder if it's really faster. In real road tests, when the shock is absorbed by the rider and the bike, it slows the bike down.
    What all this means is that if you run dikke band and lower tire pressure, you increase the elasticity of the tires, but reduce the bumps. The two effects cancel each other out and the speed will remain the same. Just like the road test results for the 26mm to 56mm tires in the test above.
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    This explains why a softer tire casing is superior in performance: because the tire will deform more easily and absorb less energy. And softer tires absorb road vibration better, reducing the amount of vibration transmitted to the bike and rider. So, combining these two aspects, a softer tire casing will allow you to air faster and be more comfortable.
    Aerodynamic Performance
    So, how do dikke band perform in terms of aerodynamic performance? Many riders believe dikke band will be slower because they have a larger windward area. Comparative tests in wind tunnel tests found that the difference between 25mm and 32mm tires was too small to reliably test the difference in real world conditions. The German magazine TOUR built a sophisticated test setup using simulated riders and found that when facing the wind head-on, 28mm and 32mm tires had the same wind resistance coefficient between them. While in the side wind, the dikke band will be slightly worse. Even so, the dikke band had only a 5W power loss in the change test, and the reduced vibration may make up for that loss.
    This explains why a softer tire casing is superior in performance: because the tire will deform more easily and absorb less energy. And softer tires absorb road vibration better, reducing the amount of vibration transmitted to the bike and rider. So, combining these two aspects, a softer tire casing will allow you to air faster and be more comfortable.
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    In Cycling Quarterly's long-distance test, there was no speed difference between fat and narrower tires when riding at 19.3 mph (29.5 km/h) on smooth pavement. If you can go much faster, then the dikke band may be slightly slower, but the difference will be so small that these speed differences will be lost in the various environmental and human factors throughout your ride. Conversely, if you ride slower, the advantage of dikke band will be greater.
    What about spinning up?


    The truth is that dikke band do weigh a little more than narrower tires. But the difference is smaller than many riders think. First of all, the weight of the gas filled tires is basically negligible, but dikke band do use more rubber and materials. So does this make the tires slower in acceleration? The answer is NO, and the reason is simple: the bike will not have a lot of acceleration. Even a professional cyclist's power-to-weight ratio is far lower than the slowest economy car, so even such a car's throttle can't generate enough acceleration to keep you in your seat, let alone the rider. The bike doesn't accelerate fast enough, and the small change in wheel weight isn't enough to make an impact. That's why the sprinters (riders who weigh more themselves) among professional riders can win with bigger wheelsets.
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    The UCI rules limit wheel size to a minimum of 55cm in diameter, but riders are using 700C wheelsets that are almost 10cm larger than the minimum limit. if the weight and impact of the wheels is what most cyclists think it is, then the rider with the smallest wheel size should win all the races. However, although many have used smaller wheels, they have ultimately opted for the 700C wheelset. This is probably because the larger wheels offer better overall performance due to their optimized rotational inertia.

    Conclusion:
    What this means for us is that we have the freedom to choose the width of our tires without worrying about performance. Of course, this does not mean that a fat all-terrain tire will behave like a racing narrow tire. The performance of the casing determines 95% of the speed of a road bike tire, while the other 5% is determined by the thickness of the crown. So in order to get a good performance, you need a tire with a softer casing.
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    The width of the tire affects the feel of the bike, but not its speed. If you like buzz, and a strong feeling of feedback from the ground, then choose narrower tires. If you want a tire that turns and grips well, and can pass quickly even on rough surfaces, then choose a fat tire.

    click here buy now!https://cyrusherbikes.nl/
    Last edited by Vornor; 01-07-2022, 12:10 AM.

    #2
    This was a very good read...Thanks! We need more posts like this.

    Comment


    • calfee20
      calfee20 commented
      Editing a comment
      Schwalbe has some of the same information on their website. What I would like is some information on the differences between Fat tire bikes "4.0 inch tires or greater vs 50mm or 2 inch tires". Has anyone seen any tests like that?

    • Vornor
      Vornor commented
      Editing a comment
      Thank you,I will post more similar articles in the future.

    #3
    Wide tires may roll well, but they are heavier. It takes more energy to accelerate and decelerate them.
    "I need another SimuLatte"

    Comment


    • Vornor
      Vornor commented
      Editing a comment
      Yes, the current electric bicycle can solve this problem perfectly.

    • AZguy
      AZguy commented
      Editing a comment
      Unless you are constantly doing a ton of accelerating and decelerating (not the norm on a bicycle) I'd suggest the energy delta due to tire weight to accelerate and decelerate the tires is negligible and the principal contributor to the energy delta is going to be rolling resistance and even if we are accelerating and decelerating a lot the energy delta due to accelerating and decelerating will be more dictated by the overall weight of the bike for which the tires are almost a negligible contributor even if fat...

      The schwalbe technical papers say that that on hard smooth surface that pressure is the greatest factor in rolling resistance and after that narrow will win against wide (but pressure is far more important here) but that once you are off hard smooth surface wide will offer less rolling resistance and lower pressures can be better too up to a point

      From riding both I can say intuitively (which admittedly is a far cry from fact) that on rough off-road fat is lower resistance for the most part but the real benefit to fat for off-road is to run far lower pressures than skinny tires will allow for better traction and "float" on soft terrain... A low pressure fat on soft terrain (think sand or deep pea gravel) offer far lower rolling resistance albeit much higher than smooth surfaces of course and since we are typically running much lower pressure in our fatties they will suffer more from that then the width on smooth surface... I've got friends that will air their fatties up to max when they are riding principally on hard sruface - to me it's not worth the effort

      Especially since as pointed out - who really cares if you have a big box of 'trons on the bike? These differences don't really make a whole lot of real-world differences IMO

      YMMV

    #4
    Originally posted by Wheelbender6 View Post
    Wide tires may roll well, but they are heavier. It takes more energy to accelerate and decelerate them.
    A couple of years ago I was all in on trying motorcycle tires. I put a K-81 3.60 X 19 Dunlop on my Electra Fat Cruiser. It was an old Norton take off from the 70's so it didn't cost anything. I used it for quite a while but got tired of the harsh ride so I rebuilt the rear wheel with a 26 X 80mm rim. I installed a 26 X 4.0 Origin 8. This was the only change and I went from 30 watts / mile to 20.

    I experimented with various tires and found Maxxis Mammoth's are the most efficient. If I am cruising around 15 mph I can get less than 15 watts/mile. Needless to say the MC tire idea hit the scrap heap. The change in efficiency was due to weight.

    Comment


      #5
      https://www.bicyclerollingresistance.com/ Some of my personal observations did not match well with this site.

      Comment


      • Vornor
        Vornor commented
        Editing a comment
        This is a professional assessment.
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