Rywokast Posted April 17, 2019 Share Posted April 17, 2019 10 hours ago, Smoother said: Better get used to going airborne over every little obstacle then, too. thats what makes it exciting Quote Link to comment Share on other sites More sharing options...
maimedlord Posted July 11, 2019 Share Posted July 11, 2019 I hope it is okay that i'm resurrecting this thread... I've noticed that at lower psi I can maintain high speed over bumps. I originally used my 18xl at the recommended psi but hadn't noticed the pressure drop down to 26 over the past couple months. At 26 psi I can maintain near 30mph speed over bumps that would send me flying at a recommended (or even lower) psi. Today, after reading this thread, I moved the psi up to 45 before going on a 15 mile ride. I still had a good time but my legs are noticeably wobblier as I had to use my legs as suspension over the many bumps on the trail I ride. I still had a good time but the lower psi allows for almost fearless riding. I want to go back to a lower psi but I'm concerned that I may damage the rim... I only weight 150lbs. Do any of you weight similar to myself and also use lower psi in your tire? I'm curious if you've actually damaged your rim or if that's only in rare/serious circumstances. Quote Link to comment Share on other sites More sharing options...
Rywokast Posted July 11, 2019 Share Posted July 11, 2019 19 minutes ago, maimedlord said: I hope it is okay that i'm resurrecting this thread... I've noticed that at lower psi I can maintain high speed over bumps. I originally used my 18xl at the recommended psi but hadn't noticed the pressure drop down to 26 over the past couple months. At 26 psi I can maintain near 30mph speed over bumps that would send me flying at a recommended (or even lower) psi. Today, after reading this thread, I moved the psi up to 45 before going on a 15 mile ride. I still had a good time but my legs are noticeably wobblier as I had to use my legs as suspension over the many bumps on the trail I ride. I still had a good time but the lower psi allows for almost fearless riding. I want to go back to a lower psi but I'm concerned that I may damage the rim... I only weight 150lbs. Do any of you weight similar to myself and also use lower psi in your tire? I'm curious if you've actually damaged your rim or if that's only in rare/serious circumstances. 35 is the lowest id recommend.. some people may do lower.. doubt youd notice a difference between 30 and 35, and its not like the tire is going to GAIN air from riding it lol.. to me that seems ludicrously low but its all personal taste you could definitely get away with it no problem being 150 lbs.. haha consider it leg training day and continue on i can do a 50 mile ride with twice that pressure and my legs arent sore a bit, used to it.. dont wanna get too comfortable now do you O.o im only kidding, its totally fine but i wouldnt do 26 thats supremely low... dont worry toooooo much about the numbers just go for a ride at the current pressure, let out a little air, ride for a few mins, let out a little more air etc until its at a level thats comfortable to you but try not to go too crazy low just ride it for a couple days youll adjust very quickly.. benefits of more pressure are its better for the tube, gives you finer maneuverability, dont have to top up so often, and youll get better battery life.. the cons are it will take you a few hours/days idk how often you ride to get used to it.. 120 lbs 60-65 PSI i dont bounce excessively or have sore legs you just have to get used to it 1 Quote Link to comment Share on other sites More sharing options...
Ben Kim Posted July 12, 2019 Share Posted July 12, 2019 my 18S has the same tire as the XL, I use 35 psi. 40+ got a little too twitchy for my tastes, and although I love the cushy feeling of going below 30 psi, 35psi appears a nice sweet spot for me. 2 Quote Link to comment Share on other sites More sharing options...
Meserias Posted July 12, 2019 Share Posted July 12, 2019 (edited) why you don't you guys not buy on of these GIYO 300psi ? shock pump problem solved. Edited July 16, 2019 by Meserias Quote Link to comment Share on other sites More sharing options...
svenomous Posted July 16, 2019 Share Posted July 16, 2019 On 7/11/2019 at 3:37 PM, maimedlord said: At 26 psi I can maintain near 30mph speed over bumps that would send me flying at a recommended (or even lower) psi. Riding at very low tire pressure: cushy, yes, and better suspension characteristics, but this is because the tire and tube is flexing/deforming more than designed to. The lateral/torsional load in turns causes even greater distortion, especially with centripetal force at speed. The tire is routinely exposed to momentarily multiple times the static load when it has to absorb a vector change. One day you might fly over just enough of a bump/curb/twig/pebble at just enough speed, and the tube will get compressed just enough to fail catastrophically: pinch flat. A pinch flat can be small enough to happen over several seconds, or it can be a large gash that flattens the tire in less than a second (depending on the shape and size of the pinch). In case of rapid pressure loss at higher than walking speed that's probably a faceplant on an EUC. I'm about 210lbs fully geared up, so not a light-weight, and on a KS18XL 40-42psi feels about right to me. Have tried 35 and didn't like the handling (turns were mushy). I think less than 35 at my weight would be asking for trouble. At the other end of the spectrum I think that 60psi, even if the rim, tube, and tire can take it, would feel rock hard to me, and would take away what little "suspension" the tire does provide. I've read on this forum that the tires, even the ones that recommend fairly low pressures, can handle quite high pressures safely, and maybe that's true, but I've experienced the sudden "bang" of a blowout when an inner tube suddenly poked out through the sidewall of a bicycle tire, for no apparent reason (in that case it was a manufacturing defect in a new tire, during the 2nd time it was ever ridden), so assuming that a tire that says "don't go above 45psi" can take 60psi seems like taking a risk regarding manufacturing tolerances. Also, don't forget traction, tread, contact patch, etc. A super-inflated tire will have an out-of-spec profile and tread contact with the ground. You're a "test pilot" if you go too far beyond recommended specs. All that said, you can have pressure right at recommended levels, and do everything right, and still have a material defect in the tube/tire, or a nail in the road that you didn't see, and bam! So wear that protective gear! Too bad an EUC takes about 20 million screws (and several high-voltage connectors) to take apart to get at the tire, or else I would carry a spare tube on my rides as I do when I cycle. Instead my plan B for a flat tire on my EUC is...phone a friend, or Uber. 1 1 Quote Link to comment Share on other sites More sharing options...
erk1024 Posted July 16, 2019 Share Posted July 16, 2019 (edited) 10 hours ago, svenomous said: but this is because the tire and tube is flexing/deforming more than designed to. I'm not sure if this is something that would happen with an EUC tire, but in other instances, a tire that deforms too much from underinflation generates too much heat which causes the tire to fail. At 265 lbs, my minimum tire pressure is 50psi. At 45 I get that spongy feel, and you can't twist the wheel at all because the contact patch is too big. I'm assuming those are signs that 45psi is too low at my weight. Edited July 16, 2019 by erk1024 1 Quote Link to comment Share on other sites More sharing options...
MacPara Posted July 16, 2019 Share Posted July 16, 2019 On 7/11/2019 at 3:37 PM, maimedlord said: I hope it is okay that i'm resurrecting this thread... I've noticed that at lower psi I can maintain high speed over bumps. I originally used my 18xl at the recommended psi but hadn't noticed the pressure drop down to 26 over the past couple months. At 26 psi I can maintain near 30mph speed over bumps that would send me flying at a recommended (or even lower) psi. Today, after reading this thread, I moved the psi up to 45 before going on a 15 mile ride. I still had a good time but my legs are noticeably wobblier as I had to use my legs as suspension over the many bumps on the trail I ride. I still had a good time but the lower psi allows for almost fearless riding. I want to go back to a lower psi but I'm concerned that I may damage the rim... I only weight 150lbs. Do any of you weight similar to myself and also use lower psi in your tire? I'm curious if you've actually damaged your rim or if that's only in rare/serious circumstances. Your body weight is of course a factor if you want to compare what other riders are using for tire pressure. I like my 18XL to be at 37 psi at 180 lbs rider weight. If the road will be very smooth i'm ok with 40 psi but it does get exhausting at that pressure when there are a ton of tiny heat cracks around (the ones that push upwards around the cracked area from asphalt getting too hot). 1 Quote Link to comment Share on other sites More sharing options...
Tadas Posted August 19, 2019 Share Posted August 19, 2019 Rider+wheel weight: 130 kg (286 lb). KS18XL tire pressure: 3.1 bar (45 psi). Apparently much too low!! 1 1 Quote Link to comment Share on other sites More sharing options...
Unventor Posted August 19, 2019 Share Posted August 19, 2019 Well I am a little late to reply here. I use my KS18L at 2.6-2.4bar or 40-35psi. I prefer it on 2.4bar but when I pump it up I top it so I don't have to pump it so often. My weight is 81kg + gear and backpack 8kg. Then again I tend not to ride up or down high or sharp curbs if I can avoid it. Due to bad knee I prefer the more cushion effect from the tyre with the knowledge that some curbs/stones must be avoided. Quote Link to comment Share on other sites More sharing options...
erk1024 Posted August 19, 2019 Share Posted August 19, 2019 (edited) 1 hour ago, Tadas said: Rider+wheel weight: 130 kg (286 lb). I'm 265 pounds (not including the wheel) and I have to run 50 psi minimum. Otherwise the tire feels squishy it deforms too much. Nice photos by the way! (Woops, I just realized I said the same damn thing in this thread a few posts (and a few months) ago) Edited August 19, 2019 by erk1024 1 Quote Link to comment Share on other sites More sharing options...
Tadas Posted August 19, 2019 Share Posted August 19, 2019 Those low pressure pictures really scared me. Experimented more with 3.6 bar, seems much better now: Now I think I will try to never go lower than 3.5 bar (50 PSI) for my total weight 130 kg (286 lb). Quote Link to comment Share on other sites More sharing options...
mrelwood Posted August 20, 2019 Share Posted August 20, 2019 10 hours ago, Tadas said: Those low pressure pictures really scared me. Something about the photos bug me. I don’t think 3.0 bars should be that far off on the 18XL for you. And even the 3.6 bar photos show that the ridge digs in very deep into the tire. Have you confirmed your tire pressures with another gauge? For example, Mike Sachristan just found out that his brand name pump shows readings roughly 1 bar too low. Do you ride straight on to the curb with stiff legs? Several reasons not to do that. One is apparent from the photos, the second being that in order for the wheel (and your weight) to stay upright it has to increase the power by a huge amount in a very short perioid of time. This is a huge sudden stress that may once turn out to be too much for the fuses, or other parts of the wheel. For an obstacle like that I hop a bit to reduce the weight I push down on the wheel with, and ride with loose ankles and deeply bent knees. How fast were you going for the photos? A sudden sharp obstacle like that has to be taken in slowly. 1 Quote Link to comment Share on other sites More sharing options...
Tadas Posted August 20, 2019 Share Posted August 20, 2019 It was mostly a test for myself how the tire would react in case of unexpected bump. I thought those bumps were small actually, the roads here are really bad. I glad I did it, else I would have never known. Mostly stiff legs, not fast, around 15 km/h. I measured the pressure with an external gauge, looks reliable, but I will compare it to others when I can and post if my numbers were off. Quote Link to comment Share on other sites More sharing options...
Rywokast Posted August 20, 2019 Share Posted August 20, 2019 15 hours ago, Tadas said: Rider+wheel weight: 130 kg (286 lb). KS18XL tire pressure: 3.1 bar (45 psi). Apparently much too low!! dear god.... pump it up to 60 that is way too low i bet you can feel it smack the rim when you go up a curb like that, thats not even a sharp curb its at a 45 degree angle!! 1 Quote Link to comment Share on other sites More sharing options...
Tadas Posted August 20, 2019 Share Posted August 20, 2019 Actually it didn't feel bad, I wouldn't have known it was this bad had I not filmed it! Quote Link to comment Share on other sites More sharing options...
Rywokast Posted August 20, 2019 Share Posted August 20, 2019 5 minutes ago, Tadas said: Actually it didn't feel bad, I wouldn't have known it was this bad had I not filmed it! interesting.. maybe due to the size of the euc/rim it doesnt translate to something you really feel like you would on a 14 or 16 inch wheel.. i like my psi 55+ and im less than half your weight.. seen too many dented rims lol.. and you get used to it, i absolutely hate anything below 45 now feels so bad and sloshy.. i like rock hard feedback and bounce, with better agility it makes for a much more interesting ride in my opinion 1 Quote Link to comment Share on other sites More sharing options...
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