Common handling myths.

Robbie wrote:

dculberson wrote:

Keith Tanner wrote: Another myth, mostly from Hollywood: the fastest way to stop is to lock up the wheels.

Oh! Like laying down your motorcycle to "avoid a crash." No, you just crashed to avoid stopping. If you have time and distance to lay it down, you have time to stop if you used your brakes right. It's entirely the cruiser crowd, half of whom think the front brake is dangerous to use.

I'd plus one a few more times if I could. You will also hear this from just about any proud motorcyclist who laid down their bike while trying to stop. "I laid it down because there wasn't anything else I could do..." Then you will have people like my parents, who listen to those proud motorcyclists tell their stories, then subsequently believe that the fastest way to stop a bike is to lay it down.

Devil's advocate here. I distinctly remember a wreck I had on my good old CM 400T at the tender age of 18, wherein as we both slid on asphalt, the bike seemed to accelerate away from me as my sticky flesh brought me to a quick (but not quick enough) stop. I figure the bike is pretty expendable in a crash, and flesh is stickier than rubber. Please note sarcasm/ smart aleckiness.

In reply to wheelsmithy:

Interesting, I recall a time skipping across the asphalt once as well but unfortunately my skin rubbed through before I came to a complete stop. 60-0mph in 150ft. Didn't bail though, the bike bailed on me.. hoe washed out from under me

1: Stock miatas are good handling cars.

In reply to Dietcoke:

Well...id call them nimble, predictable, fun, and capable of being driven fast.

compared to most other "stock" cars, I'd say they handle pretty well ... guess it's all comparative

Dietcoke wrote: 1: Stock miatas are good handling cars.

If you're talking about the 2006-12 cars yes. Otherwise, I suspect you've only driven ragged out ones. Or you're trolling.

Related myth: Cars must have no body roll to handle well.

Nathan JansenvanDoorn wrote: Related myth: Cars must have no body roll to handle well.

See BRZ vs Miata comparison on YouTube for reference.

Open differentials are one wheel drive.

MadScientistMatt wrote: Open differentials are one wheel drive.

Building off that, I still hear the myth from Jeep guys all the time that a locker gives a "50/50 power split". Nope. That locker gives whatever split it takes to maintain equal rotational speed. The open diff you started with was a 50/50 split unless there's a really big traction difference on the 2 sides.

The Forte is one of those travel limited vehicles. Rear travel on the Ksports is under 2 inches, so adding bar and spring helps keep it off the bumpstops.

In reply to rslifkin:

Oh jeez thank you! Someone else who "gets it"

But it's still 50:50 even if one side has no traction... zero is equal to zero after all!

I thought having a big enough traction difference (such as one tire in the air) led to all of the power falling to one side? Isn't that why you lose forward drive entirely, rather than still having half the power pushing you forward from one wheel while the other spins helplessly?

chiodos wrote: In reply to wheelsmithy: Interesting, I recall a time skipping across the asphalt once as well but unfortunately my skin rubbed through before I came to a complete stop. 60-0mph in 150ft. Didn't bail though, the bike bailed on me.. hoe washed out from under me

I put my '04 zx10 down in September.....my choices were the old growth trees(you're gunna die) or an empty roadway(you're a lot less likely to die). There was no between as I was off the roadway on a quickly disappearing ledge with a 8+ inch ridge of broken pavement to climb.

I walked away that day with a broken collarbone and a bruise on my thigh. Sometimes putting it down is indeed your best choice. Just ask Bobzilla, that hillside & trees were bad berkeleying news to go into.

rslifkin wrote: I thought having a big enough traction difference (such as one tire in the air) led to all of the power falling to one side? Isn't that why you lose forward drive entirely, rather than still having half the power pushing you forward from one wheel while the other spins helplessly?

50:50 means the torque is divided evenly. The torque is the resistance against turning the axleshafts.

If one side spins freely without any resistance, no torque is being applied. With an even torque split, the other side gets the same amount of torque, namely, zero.

The TORQUE is being distributed evenly.

This is why applying the rear brakes on a drum brake car can offset this a bit. Drum brakes have a degree of self-energizing with speed, so one wheel spins up hard, then you apply the parking brake, the brake preferentially applies to the fast spinning side. This torque load on that axleshaft allows the other side to recieve torque, and since that wheel ISN'T spinning fast, the brake doesn't absorb as much of it so some of it makes it down to the tire.

See also: HMMWVs with three Torsen diffs and how to get them unstuck with a wheel up. Apply brakes. Those have the added feature of having diffs that apply more torque to the slower moving output (can't backdrive a worm gear), but it's still an open diff so you need to resistance on the free-spinning end in order for torque to go to the other side.

If you want to be able to move with one wheel in the air, you need something that isn't stuck in a 50:50 torque split. Welded diffs allow up to and beyond 0:100 torque split. Lift one tire, 100% of the torque goes to the other tire. Try to make a tight enough low speed turn, you drag the outside tire forward, which is negative torque, and a the same amount is applied to the inside. -10:110 torque split? More?

Don't make tight turns with a spool unless you have very strong axles. Or poor traction.

rslifkin wrote:

MadScientistMatt wrote: Open differentials are one wheel drive.

Building off that, I still hear the myth from Jeep guys all the time that a locker gives a "50/50 power split". Nope. That locker gives whatever split it takes to maintain equal rotational speed. The open diff you started with was a 50/50 split unless there's a really big traction difference on the 2 sides.

Yep, that spool equalizes wheel speed regardless of torque and the open diff equalizes torque regardless of speed.

WOW Really Paul? wrote:

chiodos wrote: In reply to wheelsmithy: Interesting, I recall a time skipping across the asphalt once as well but unfortunately my skin rubbed through before I came to a complete stop. 60-0mph in 150ft. Didn't bail though, the bike bailed on me.. hoe washed out from under me

I put my '04 zx10 down in September.....my choices were the old growth trees(you're gunna die) or an empty roadway(you're a lot less likely to die). There was no between as I was off the roadway on a quickly disappearing ledge with a 8+ inch ridge of broken pavement to climb. I walked away that day with a broken collarbone and a bruise on my thigh. Sometimes putting it down is indeed your best choice. Just ask Bobzilla, that hillside & trees were bad berkeleying news to go into.

QFT. That was a nasty way down no matter which way you went. but the hillside with the cut off stubs would have likely impaled your sorry butt!

Miata is The Answer