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Something is a little odd here...

Started by mr72, August 16, 2018, 10:52:28 AM

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qcbaker

Quote from: mr72 on August 30, 2018, 08:41:27 AM
I agree it's not nearly as simple as that, but it's also not as you suggest.

lateral G force can be calculated purely with speed and turn radius. It has nothing to do with the car really. It's easier to measure in-car with a meter.

That's what I thought too.

QuoteBut of course this whole "out-handle" statement I made before can't be fully equated to lateral G-force measurement. In a Miata, you can (and often would) perform a cornering maneuver that exceeds the lateral grip of the car. You can intentionally break the rear loose and get the car to oversteer and tighten a corner, making the turn faster than it would be if you stayed within the limits of adhesion. On a motorcycle this would result in a crash.

You're right, I hadn't really considered how oversteer would effect overall cornering speed.

Quote
But also "handling" is much more than simply how fast you can make a given corner. It's also about how controllable the vehicle is when going over the limit, how it transitions, how much braking you can apply especially while turning, how it can lay down power during a turn exit and etc. So a car with 4 tires on the ground and the ability to control camber in turns and vary roll stiffness front to rear really has a huge advantage, not to mention the fact that the driver is more physically capable of operating the car when it is over the limit. I mean, in a car you can recover from coming into a turn too hot or if it gets away at least part of the time.

It's an apples to oranges comparison anyway.

I mean, that's all true, but we're not comparing a motoGP bike to an f1 car. Of course, at their absolute limits, cars are faster. I was just talking specifically about a stock Miata vs a stock GSXR600.

mr72

Quote from: qcbaker on August 30, 2018, 09:16:11 AM
I was just talking specifically about a stock Miata vs a stock GSXR600.

Yes, which is also extremely apples to oranges. I was talking about MY Miata vs. a "most street motorcycles". If you want to consider a closer comparison between a GSXR600 and some car, the car needs to be one that is as close to a full-on race car as a GSXR600 is to a full-on race bike. So what, maybe a Lotus Elise? I think a Lotus Elise would annihilate a GSXR600 on the street or the auto-x course in terms of handling.

It's a uniqueness of the motorcycle market that near-track-ready bikes are readily available and reasonably common on normal roads. Only crazy people try to daily-drive the car equivalent.

qcbaker

Quote from: mr72 on August 31, 2018, 06:31:26 AM
Yes, which is also extremely apples to oranges. I was talking about MY Miata vs. a "most street motorcycles".

I fail to see how trying to compare cornering ability is apples to oranges... They're both vehicles that go around corners. You can measure how quickly each of them does it and compare the results. Lateral G was the measurement I figured would be the best way to compare the limits of both vehicles. Obviously its not perfect, in order to get an actual scientific result you'd have to run each vehicle on a track and make a bunch of measurements, but you can still compare them.

As for your Miata vs "most street motorcycles", I'll take your Miata every time. But against a supersport, I don't know :dunno_black: Your Miata, with all the work you did to it, probably corners much better than a stock one, so its totally possible it would keep up with a supersport, but I think it would be pretty close.

Quote
If you want to consider a closer comparison between a GSXR600 and some car, the car needs to be one that is as close to a full-on race car as a GSXR600 is to a full-on race bike. So what, maybe a Lotus Elise? I think a Lotus Elise would annihilate a GSXR600 on the street or the auto-x course in terms of handling.

It's a uniqueness of the motorcycle market that near-track-ready bikes are readily available and reasonably common on normal roads. Only crazy people try to daily-drive the car equivalent.

That's a good point. If you're comparing autocross style cornering, yes, I think an Elise (and probably any Miata for that matter) is going to massively outperform basically any motorcycle. On a road race course, though, I think the difference would be much less obvious.

mr72

I think we're talking about the same thing here :)

It's just semantics.

TL;DR

"Handling" != [only] max lateral Gs

If comparing "car vs. motorcycle", it's not fair to compare a supersport motorcycle to a garden variety car, any more than it is to compare a supercar to an adventure bike.

qcbaker

Quote from: mr72 on August 31, 2018, 07:47:29 AM
"Handling" != [only] max lateral Gs

I agree, but I don't have access to or the wherewithal to go gather all the data necessary to make a scientifically sound judgement lol. I still think max lateral G is a good approximation of a machine's cornering ability, even if it isn't the whole story.

Quote
If comparing "car vs. motorcycle", it's not fair to compare a supersport motorcycle to a garden variety car, any more than it is to compare a supercar to an adventure bike.

Whether or not its "fair" is sort of irrelevant, IMO. The two vehicles do the same task (go around a corner), so if your question is "which of these two vehicles accomplishes the task better", you can compare them. I'm not judging their worth, just their proficiency at a specific task. Obviously a supercar is going to corner better than an ADV bike, but that doesn't mean a comparison can't be made. The supercar is better at cornering. That doesn't mean the ADV bike isn't a "good" machine, it just means that its built to do different stuff. I feel like the focus of a Miata and a supersport motorcycle are similar enough, and even if they weren't, why not compare them?

I never liked the idea that because two things are really different, they shouldn't be compared. The whole point of comparing things is to highlight the differences between them. Even the phrase "apples to oranges" bothers me. You can absolutely compare apples and oranges lol.

mr72

It seems this debate (between you and me mostly) stems from my original statement "My Miata would out-corner most street motorcycles."

That's true enough, I think we both agree, but it somehow turned into "a stock Miata doesn't pull as many lateral Gs as a GSXR600" which is not at all what I was saying with my offhand, unscientific opinion.

With the fact that "most street motorcycles" includes a big number of adventure bikes, cruisers and touring rigs, I think that was a pretty sound opinion. The stock-Miata-vs-GSXR600 is a whole different argument, and I think a Miata is the wrong car to make a bike-vs-car comparison involving a sport bike. But it probably is interesting anyway because I bet a stock (ND) Miata would "out-corner" a stock (new) GSXR600, if we could agree on a way to measure. I mean, my Jeep Wrangler Unlimited lazily goes around the roundabout at my house at least 5-10mph faster than I can force my GS500 around the same roundabout without feeling the rear tire begin to slip, and the Wrangler has lots of margin before it begins to understeer like crazy.

But one other thing that helps here is that in my Jeep, any ordinary driver knows good and well that if you get into that roundabout too fast and it starts to slip, you panic and lift the throttle or tap the brake and it immediately will stop understeering and begin to oversteer or just grip normally, and of course if you truly find yourself over the limit in a 4-wheel vehicle with ABS I can just ram the brake to the floor and it will stop without putting me in the hospital or even at risk of scuffing a tire on a curb. On the other hand, on my GS, once you even BEGIN to feel the rear tire begin to slip you are already too far to do much of anything except try and lean in a touch more and for heaven's sake don't upset the chassis by braking or changing the throttle.

qcbaker

Quote from: mr72 on August 31, 2018, 09:59:13 AM
It seems this debate (between you and me mostly) stems from my original statement "My Miata would out-corner most street motorcycles."

That's true enough, I think we both agree, but it somehow turned into "a stock Miata doesn't pull as many lateral Gs as a GSXR600" which is not at all what I was saying with my offhand, unscientific opinion.

Admittedly, I turned it into that when I mentioned that GSXR600 can pull higher lateral G than a Miata. The reason I did that is because I would consider a GSXR600 a "street motorcycle", and like I said, I think max lateral G is a good indicator of a vehicle's cornering ability.

Quote
With the fact that "most street motorcycles" includes a big number of adventure bikes, cruisers and touring rigs, I think that was a pretty sound opinion.

I agree.

Quote
The stock-Miata-vs-GSXR600 is a whole different argument, and I think a Miata is the wrong car to make a bike-vs-car comparison involving a sport bike. But it probably is interesting anyway because I bet a stock (ND) Miata would "out-corner" a stock (new) GSXR600, if we could agree on a way to measure.

I agree with you that max lateral G is a flawed measurement. What measurement would you propose instead?

Quote
I mean, my Jeep Wrangler Unlimited lazily goes around the roundabout at my house at least 5-10mph faster than I can force my GS500 around the same roundabout without feeling the rear tire begin to slip, and the Wrangler has lots of margin before it begins to understeer like crazy.

I would be willing to bet that has much more to do with your body position and riding technique than it does the capabilities of either machine. I'm not trying to imply that you aren't a good rider, by the way. I just know you're not a sport-oriented rider and even if you were I wouldn't expect you to be hanging off and trying to drag knees around a roundabout lol.

Quote
But one other thing that helps here is that in my Jeep, any ordinary driver knows good and well that if you get into that roundabout too fast and it starts to slip, you panic and lift the throttle or tap the brake and it immediately will stop understeering and begin to oversteer or just grip normally, and of course if you truly find yourself over the limit in a 4-wheel vehicle with ABS I can just ram the brake to the floor and it will stop without putting me in the hospital or even at risk of scuffing a tire on a curb. On the other hand, on my GS, once you even BEGIN to feel the rear tire begin to slip you are already too far to do much of anything except try and lean in a touch more and for heaven's sake don't upset the chassis by braking or changing the throttle.

True enough, but we're not talking about which vehicle is easier to operate close at the limit of traction lol.

qcbaker

Even more off topic, but Jalopnik posted this video earler:



My dude is driving the HELL out of that Miata lol.

qcbaker

#28
And actually slightly back on topic, that race-prepped NC miata had a lap time of 7:37. From what I can see on Wikipedia, in 2008, a race-prepped (but still street legal) GSXR600 put down a 7:17, significantly faster. Shitty camera, but video of the lap here:


mr72

Yeah once you have big enough straights for acceleration to be a big factor, the bike will win almost every time. Hard to beat 0-60 in 2.x seconds, unless you just don't have enough runway to get up to that speed and back down again before the next turn.

qcbaker

So, to bring this thread slightly back on topic, on my ride in to work today I noticed that there is one of those wacky Bergman trike things in my neighborhood. I guess they must be more common than I thought...

mr72

Quote from: qcbaker on September 19, 2018, 10:03:01 AM
there is one of those wacky Bergman trike things in my neighborhood. I guess they must be more common than I thought...

more than one in the world is more common than I would have thought!

cbrfxr67

I drove a miata from MN to HOuston and the only that thing was good at was hurting my a## and back!

:laugh:
"Its something you take apart in 2-3 days and takes 10 years to go back together."
-buddha

mr72

Quote from: cbrfxr67 on September 20, 2018, 10:59:55 AM
I drove a miata from MN to HOuston and the only that thing was good at was hurting my a## and back!

You would have hated mine then.

approximately 3x stiffer springs vs. stock. No carpet. but mine did have the early NB seats, which are better than the later NB seats (the tall "surfboard" ones) , but some think the NC and ND seats were better.

These are sports cars. Touring is not their forte.

qcbaker

Not to keep coming back to this, but I saw that trike thing again and I couldn't help but tell you guys. This time, I was behind the guy riding it on my drive home from work. First, I yielded to him as he pulled out onto the street from the gas station he was at. As he pulled out, he turned to the left. As he completed the turn, the left trike wheel came off the ground entirely, and he had to lean hard to the left to avoid rolling over. And that wasn't the only turn where it happened. That thing looks like a literal death trap to ride.

mr72

Quote from: qcbaker on October 10, 2018, 05:31:46 AM
That thing looks like a literal death trap to ride.

Absolutely!

https://www.youtube.com/watch?v=QQh56geU0X8&start_radio=1&list=RDQQh56geU0X8

I can't imagine how these kinds of "trikes" can possibly pass any safety inspection in any state in the union.

qcbaker

That video is exactly what I thought was going to happen every time this dude went around a turn. I think the thing that bothers me the most about it, and the guy that rides it, is that there's a normal motorcycle parked right next to it in his driveway. So its not like he doesn't have access to a proper bike. I simply do not understand. I keep seeing this thing and every time I'm just like


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