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pokie posted:Can anyone tell why the gently caress I lost traction here? Looks like you broke the golden rule and added lean angle and gas at the same time. You entered the corner at 43mph, were at the midpoint where the slide happened at 45mph. It's _possible_ that it's due to the change in tire size as you leaned it over but I don't think it'd be that significant at that pace.
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Nov 27, 2018 22:50
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MomJeans420 posted:I impulse bought these last night after reading more about them, then realized this morning I barely signal anyway, oops. At least I do signal for when I really wanted them, waiting to turn left where you don't have a dedicated lane. Those are crazy bright. I've seen them. Also, use your turn signals religiously WTF
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Nov 27, 2018 22:52
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I use them around town, but not on the freeway going around people. The PO put flush mount ones that are pretty much invisible anyway, which is why I wanted those incredibly bright ones.
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Nov 28, 2018 00:18
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MomJeans420 posted:I use them around town, but not on the freeway going around people. this is unsafe and also reinforces the idea that motorcyclists are careless assholes it may well be that no one pays any attention, but you should still signal your intentions every time
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Nov 28, 2018 00:21
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why signal when you can just accelerate out of danger  Mustangs, Camero's and Chargers are always dangerous to pass for me, especially the GT, SS or R/T. They like to accelerate when im trying to pass. No im not racing you retards, no the sound of your poo poo exhaust isnt impressing me. They all seem to take being passed as a challenge to their masculinity when the car itself does that plenty. Challengers are the exception and all seem pretty laid back Fauxtool fucked around with this message at 01:22 on Nov 28, 2018 |
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Nov 28, 2018 01:18
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Z3n posted:Looks like you broke the golden rule and added lean angle and gas at the same time. You entered the corner at 43mph, were at the midpoint where the slide happened at 45mph. It's _possible_ that it's due to the change in tire size as you leaned it over but I don't think it'd be that significant at that pace. Interesting. I don't believe I have heard of this rule. Why is this an issue?
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Nov 28, 2018 01:58
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Your tires can only take so much force parallel to the road surface before they break loose and slide. Forces applied in multiple directions can add up and exceed that limit. There are multiple ways of applying these forces to tires. As you lean into a turn, your bike's weight is supported partially by a centripetal force (acceleration, whatever). That force is transmitted into the ground as a sideways force on the tire. As you lean further, trigonometry says that the sideways component will begin to increase exponentially, until the point that you exceed the traction limit, the tire can't hold its place any longer, and it slides. Here is a nice chart from an aeronautical publication regarding lateral g-forces versus bank angle in aircraft (the physics are the same):  What that's saying is that at a 60 degree bank, the tire has to resist a force equal to double the bike's + your weight, pushing it sideways. Maybe a thousand pounds of force trying to slide it along the road. Only the stickiest motoGP tires (I think I've heard of 63-64 degrees) on a perfect surface can do that. Similarly, as you open the throttle, your engine torque pushes the tire's contact patch backwards, creating a forwards force. If that force exceeds the tire's traction limit, it breaks loose and you do a burnout. That one is easier to grasp. Aside from minor anisotropic features like treads, though, the tire doesn't really care which way the force is going. A thousand pounds sideways or a thousand pounds forwards, it's all the same. Say you are leaned over in a turn at 45 degrees at a constant speed, and your tire is experiencing 80% of the force required to break it loose. You're safe, but leaning over further would be risky. All of that force is at 90 degrees to the tire. Now, while still leaned over, you hit the gas, and the engine tries to push the tire backwards. Say that you opened the throttle enough to use 80% of the tire's grip limit in a straight line (i.e. 80% of the way to a burnout). Basic trig says that the two forces combined result in a net force at 45 degrees to the bike's direction of travel, at 113% of the grip limit -- so down you go. Essentially, you can just think of your tires as having a limit of traction, and anything you do that pushes them around (leaning, braking, accelerating) brings you closer to that limit. If the road is wet or sandy or covered in leaves, the limit is lower because the road friction is reduced. If the tires are hot, the limit may be higher because the rubber is softer. If you're going downhill, the limit (on the rear tire) is lower because there is less weight on the back. s'cool Sagebrush fucked around with this message at 02:39 on Nov 28, 2018 |
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Nov 28, 2018 02:33
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Yeah, that's what I thought. I am a bit surprised given that I wasn't going very fast or leaning much, but I suppose I just got used to riding more spiritedly and failed to notice. And of course there is the wet road.
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Nov 28, 2018 02:52
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Slowing down into the turn? You have to add lean angle while taking away brakes; the same principles as above apply to front tyres under braking. Braking harder while leaning even more violates the rule, eventually your tyre runs out of grip and you crash. Coming out of the turn? You have to add throttle while taking away lean angle. Those are really the only two 'correct' modes a cornering bike has, anything is else Doing It Wrong and will eventually lead to a crash.* You probably get away with violating the throttle rule all the time, as do I and probably everyone else ITT, because the forces are so low at traffic/sane speeds that you can do all kinds of stupid poo poo and stay safely away from 100% available grip. Which is a very, very good thing as IRL roads are filled with off-camber down-hill stop signs, car drivers who brake out of fear of gravity, all kinds of poo poo that makes it impossible to religiously stick to the rule. You need that spare grip capacity so in an emergency or awkward situation you have some margin to abuse the tyres and stay upright. Also so you don't nearly die every single ride, when that bend you've never ridden before abruptly tightens or there's a train of ducks across the road or whatever. *: unless you really know wtf you're doing in which case stop reading this and go for a ride
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Nov 28, 2018 06:31
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OK, so what I am hearing then is that when coming into a turn it's better to lean in first, then accelerate so as not to apply too much force to tires at once.
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Nov 28, 2018 08:17
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pokie posted:OK, so what I am hearing then is that when coming into a turn it's better to lean in first, then accelerate so as not to apply too much force to tires at once. Slow, Look, Press, Roll.
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Nov 28, 2018 14:44
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did your time on your wr250 teach you nothing? BRAKE TURN GAS gently caress i wanted to go to cornerspin again this year
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Nov 28, 2018 15:13
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pokie posted:Interesting. I don't believe I have heard of this rule. Why is this an issue? https://www.youtube.com/watch?v=qXP-itbNi8E&t=360s - starts six or seven minutes in.
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Nov 28, 2018 15:17
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Razzled posted:did your time on your wr250 teach you nothing? On WR you just go gas everywhere :v
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Nov 28, 2018 19:18
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builds character posted:https://www.youtube.com/watch?v=qXP-itbNi8E&t=360s - starts six or seven minutes in. That's really informative. I wish he went more into detail as to why his traction circle is not symmetrical. Why wouldn't accelerating increase your contact patch (like braking would) and thus allow for greater lateral force (more leaning)? Also, yeah, I was definitely not taught to get into a corner the way he describes.
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Nov 28, 2018 19:49
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pokie posted:That's really informative. I wish he went more into detail as to why his traction circle is not symmetrical. Why wouldn't accelerating increase your contact patch (like braking would) and thus allow for greater lateral force (more leaning)? Just off the top of my head, acceleration lifts the front (or at least lightens it, even if you don't wheelie), so it makes sense the contact patch would be reduced in the front if the tyre isn't getting smushed into the road. I don't actually know, that's just my guess.  I'm happy to have been introduced the the term "camber thrust" as well, his explanation makes sense of a lot of stuff I didn't quite get.
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Nov 28, 2018 20:29
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pokie posted:Why wouldn't accelerating increase your contact patch (like braking would) and thus allow for greater lateral force (more leaning)? It does - on the rear tire. Accelerating causes the rear to squat, biasing weight towards the back of the bike and decreasing contact at the front tire. The effect may not be as pronounced. Watch the full video, he gets into it around 28 minutes. Jazzzzz fucked around with this message at 21:02 on Nov 28, 2018 |
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Nov 28, 2018 20:59
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Jazzzzz posted:It does - on the rear tire. Accelerating causes the rear to squat, biasing weight towards the back of the bike and decreasing contact at the front tire. The effect may not be as pronounced. Watch the full video, he gets into it around 28 minutes. I did watch the full vid. I guess it's not pronounced enough to offset the force from acceleration in the case of me losing traction in the vid I posted.
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Nov 28, 2018 21:05
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It's easy if you don't get too bogged down in details and just think about what happens when you do X and what that means for your situation. Giving it throttle makes the bike taller in the front and rear, which also makes it have a shorter wheelbase. Making the bike taller is trading away grip in favour of ground clearance. Making the bike shorter is trading away stability in favour of a tighter turning circle. Braking (with both brakes) makes the bike lower front and rear, which makes it have a longer wheelbase. More grip, more stability at the cost of ground clearance and turning circle. So tall, stubby bike = agile and unstable. Low, long bike = stable but slow. This is why correct lines are absolutely crucial. You brake with front and rear brakes, the bike is nice and long and low giving you maximum stability and lots of weight on the front tyre which forces it into the ground and makes the contact patch nice and big. Getting on the gas shifts weight rearward (makes the rear tyre contact patch bigger) so your rear tyre grip is maximised. Your front tyre contact patch and grip correspondingly get smaller but, crucially, this doesn't matter as long as you never shut off the throttle once you've started rolling on, because most of the weight is on the rear. You can only tighten your line while you're on the brakes or on closed throttle and the bike is decelerating. If you try to tighten your line while on the gas, you're adding lean angle and speed whilst not taking away throttle and you crash. If you try to lift or brake mid-corner to tighten the line, you're simultaneously unsettling the bike, flopping a whole lot of weight onto the front unexpectedly (contact patch isn't large and weighted so you have much less grip than under braking) and making the bike less tall (so more likely to run out of ground clearance) at the same time, and you crash. So the only way out of the trap is to stand the bike up so you reduce your lean angle and that gives you more grip budget to brake; unfortunately this also makes your line wider and exacerbates the problem you were trying to solve (not hitting oncoming traffic/going off the road). The way to avoid getting in this trap in the first place is to use correct lines - turn as late and wide as you possibly can, don't get on the gas until you can see the corner opening up. Basically the danger zone is in the transitions between upright and turning, and between turning and upright as that's when the contact patches are changing size and you're adding/taking away brake or adding/taking away throttle. Riding at a constant speed, constant lean angle, constant throttle like if you were just going around and around a roundabout with no changes of speed is completely safe.
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Nov 28, 2018 21:13
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Cool, thanks for all the teachings, folks. I tried it in practice today by getting my rear to lose traction in the rain on purpose. Yup extra throttle while leaning can do that. Good to know. Out of curiosity - how practical is the trail braking stuff from the video that builds character linked outside of racing? In the twisties I just don't see myself gunning for a turn so hard that I need to apply brakes through the turn for the apex.
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Nov 29, 2018 04:20
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pokie posted:Cool, thanks for all the teachings, folks. The answer is this, from Slavvy's post: Slavvy posted:You can only tighten your line while you're on the brakes or on closed throttle and the bike is decelerating. So if you go into a corner where you can't see the exit, the only way to have the ability to avoid an obstacle by tightening your turn is to already be on the brakes. Assuming you're close to the limits of traction. Therefore, trail braking is super useful when you can't see your corner exit, especially because conditions can also change in the middle of a corner, bringing you closer to the limits of traction. (gravel patch, manhole cover, road paint, etc.) pun pundit fucked around with this message at 12:46 on Nov 29, 2018 |
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Nov 29, 2018 12:43
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Worth noting that decelerating on closed throttle is basically the same as braking, except you have no control - you're decelerating at whatever rate your engine + gearing happen to result in. Using the brakes puts you in charge of the situation. Everyone gets taught to gradually apply the brakes, but learning to gradually release them is an extremely valuable skill as well. Likewise shutting the throttle gradually rather than just snapping it shut.
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Nov 29, 2018 18:26
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I don't follow FZ-07s really but I know a number of people on here have them and said the suspension could really use an upgrade. My friend has one and wants to start doing some beginner track days, but was wondering if he needed to upgrade anything first. I have to assume that the stock suspension is fine for your first couple of track days, right?
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Nov 29, 2018 19:40
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MomJeans420 posted:I don't follow FZ-07s really but I know a number of people on here have them and said the suspension could really use an upgrade. My friend has one and wants to start doing some beginner track days, but was wondering if he needed to upgrade anything first. I have to assume that the stock suspension is fine for your first couple of track days, right? If you dont know enough about it to know if you need it, you dont. Having an inferior but functional suspension isnt going to make him automatically crash on the first corner.
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Nov 29, 2018 19:46
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Yeah, first you need to know what your problem is, then you figure out what you need to do to fix the problem. 'Upgrade' doesn't really mean anything in suspension terms, there isn't a graph somewhere to gauge how lovely/good it is in an absolute sense. Making suspension changes is entirely dependant on rider skill and weight, and then riding style and tyres when you've reached a certain level. If you haven't got the skill to identify what part of the corner you want to improve, it's best to just ride what you've got until you learn what the gently caress, otherwise you just get lost making changes you can't judge. Same reason suspension adjusters on factory bikes may or may not be a net negative, I go back and forth on this. It's great being able to dial a bike in just-so when you know exactly what you want but for every person with that mindset there's ten cunts who set it all to HARD cause they're a HARD RIDER yo.
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Nov 29, 2018 21:29
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Thanks, I figured as much but he was reading random forum posts and reddit and made it sound like it was instant death. All this reminds me I need to finally get off my rear end and dial in my suspension, I bought a sag gauge when someone posted in here, but haven't gotten around to using it. Thankfully I've had nothing to do at work so I've been watching Dave Moss videos all day, I'll be a pro in no time.
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Nov 29, 2018 23:56
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trying to turn an fz-07 into a track bike seems dumb as hell when you can pick up a f4i with scraped up plastics for way way cheaper and have an enormously more capable track bike. I would get a track only bike if i was at all serious rather than trying to turn my every day commuting bike into one
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Nov 30, 2018 00:58
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MomJeans420 posted:Thanks, I figured as much but he was reading random forum posts and reddit and made it sound like it was instant death. plenty of pictures all over the interwebz of non-exploded bone stock FZ07s at track days, your pal will be fine
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Nov 30, 2018 01:16
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I thought it was the fz-09 that had the suspension shortcuts from the factory anyways
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Nov 30, 2018 02:05
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Slavvy posted:Everyone gets taught to gradually apply the brakes, but learning to gradually release them is an extremely valuable skill as well. Likewise shutting the throttle gradually rather than just snapping it shut. In other news I have a PSA about electrical tools. Was reminded of this the other day while doing some checking on a Garelli Broncco which has a moped electrical system and moped electrical systems are the most obnoxious electrical systems. If you want a multimeter (you want a multimeter) that's good and you don't want to spend stupid money then you want this: https://www.harborfreight.com/5-in-1-digital-multimeter-98674.html It's expensive by HF standards but it's genuinely good quality and I've used them heavily in a shop for 8ish years now and only had one break. It'll do almost anything you'd ever want to do with a multimeter on a bike and it'll take a beating.
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Nov 30, 2018 02:14
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Revvik posted:I thought it was the fz-09 that had the suspension shortcuts from the factory anyways Also the fz07, the '18 model has improved suspension.
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Nov 30, 2018 09:34
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High Protein posted:Also the fz07, the '18 model has improved suspension. Is there a Yamaha where they *don't* inexplicably cheap out on the suspension?
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Nov 30, 2018 09:53
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goddamnedtwisto posted:Is there a Yamaha where they *don't* inexplicably cheap out on the suspension? FJR1300ES?
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Nov 30, 2018 11:06
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Skreemer posted:FJR1300ES? TBH it's probably too specific a question, has there ever been any motorbike ever made by any manufacturer that didn't inexplicably cheap out on one component?
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Nov 30, 2018 14:42
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cheap bike with awesome suspension is a much harder sell than cheap bike with poo poo suspension and bigger engine than the other cheap bikes.
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Nov 30, 2018 17:33
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It's not just a bigger engine; it's a better engine.
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Nov 30, 2018 18:34
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Yup. Most people can't ride for poo poo but everyone can see one number is bigger.
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Nov 30, 2018 18:36
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goddamnedtwisto posted:TBH it's probably too specific a question, has there ever been any motorbike ever made by any manufacturer that didn't inexplicably cheap out on one component? I'd like to see you try making 10,000 go-machines, Mr. smarty-smart.  Easy: Lawless third world market. Seasons are separated into "dry" and "flood" but populace doesn't differentiate between them. Bikes are not measured in cc's but in livestock transport capacity Difficult: Seasoned yet obligated home market, that also has bone fide seasons. Petrol and tax laws might favor you. Fuel is also called "petrol". Diesel is a road hazard and a brand of jeans Insane: Snotty first-world export market that doesn't need your 1,300 cc toy any more than it needs a designer cappuccino machine. Riders take form of inverse vampires, avoiding anything but 70-degree sunshine like the plague
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Dec 1, 2018 00:13
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Anyone rented bikes on Oahu? Seems like a ton of scooter places but I'd rather do a motorcycle if possible. Found one place with a F800 but can't get a hold of them. Everyone else has harleys and cruisers. I'll be 2up if that matters.
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Dec 1, 2018 00:56
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I rented a Yamaha Majesty from these guys, they have tons of Harleys but also a nice selection of BMWs, Yamahas, and Hondas. What I found funny about Hawaii is the locals all ride scooters, and the tourists rent Harleys. I'm stopped a light and the ultimate bro truck full of locals pulls up and rolls down their window. I'm thinking they're going to mock me for being on a scooter, instead they're all super into the Majesty (400cc ridiculous scooter) and wanted to know all about it, top speed, etc. Super friendly! It had a 90mph top speed, but with no gear and also "it's a scooter" I had no desire to try and achieve that. *edit* they have a BMW R 1200 R, wtf kind of naming scheme is that *extra edit* If you like katsu, check out Tonkatsu Ginza Bairin. They do a loco moco with tonkatsu - it's a bed of rice, a fried pork cutlet on top, covered with a fried egg and gravy. MomJeans420 fucked around with this message at 01:37 on Dec 1, 2018 |
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Dec 1, 2018 01:30
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