Insignificant/ Significant things that BYP or just wind you up a little

[Noggin]

Ooooo - I've got some of that - will put that in the bathroom cabinet instead of the meds box!! Much easier to get at when the eyes are inhibited!! LOL

Its not a miracle cure, she still has triptan for when it gets bad but if she catches it early sometimes she can stop it before it gets bad enough for the triptan.

That's always my goal - to stop it turning into an actual headache! I'm always willing to try things to help, and haven't tried aspirin, but know I've got some. Having had a pretty sudden onset version I'm gonna be keeping easy to get to drugs to hand!! LOL

[mangocrazy]

And on a normal wheel the bolts are also the keys so transmit the turning force rather than relying on friction. Older cars with single hub nut had splines to transmit the force, Google tells me modern ones still have splines or pins and the nut like old cars is still just to hold the wheel in place.
So why do they need such massive torque when older cars were just hand tight and let physics do the rest? Maybe the wings on the old nuts were important and now they aren't allowed the self tightening won't work properly, or Porsche realised most of their customers are incapable of understanding a left hand thread.

I would guess that it's a function of reducing the cost while making it as idiot proof as possible. F1 cars use a single nut per wheel and I would guess a spline for positive location, although I couldn't be certain on that, so there's clearly nothing wrong with it from an engineering standpoint.

But letting LH threads loose on the great unwashed is a recipe for expensive repairs, I would suggest...

[Asian Boss]

And on a normal wheel the bolts are also the keys so transmit the turning force rather than relying on friction. Older cars with single hub nut had splines to transmit the force, Google tells me modern ones still have splines or pins and the nut like old cars is still just to hold the wheel in place.
So why do they need such massive torque when older cars were just hand tight and let physics do the rest? Maybe the wings on the old nuts were important and now they aren't allowed the self tightening won't work properly, or Porsche realised most of their customers are incapable of understanding a left hand thread.

I would guess that it's a function of reducing the cost while making it as idiot proof as possible. F1 cars use a single nut per wheel and I would guess a spline for positive location, although I couldn't be certain on that, so there's clearly nothing wrong with it from an engineering standpoint.

But letting LH threads loose on the great unwashed is a recipe for expensive repairs, I would suggest...

Doesn't virtually every bicycle have them?

[Mussels]

I thought the old one were run up hand tight and then flogged with a hammer until tight.

Only if your splines were knackered, normally they are only hammered off, I used to give them a gentle tap putting a wheel on just to make sure it was seated properly but that was it.

[Mr. Dazzle]

Er, no it doesn't. It does it because the two components are clamped together by bolts. You're thinking of how brakes work. And it's the hub that transmits torque to the wheel, whether it's under braking or acceleration, rather than the other way about..

Mate this is literally my day job. I design high performance vehcile parts for a living and I have a degree in Automotive Engineering I've even had a particular focus on drivetrain stuff for the last 10 years, including now. A yes that includes F1

The wheel transmits force to the hub via friction, that's the idea at least. The bolts generate an axial load via being stretched when you do them up, that axial force clamps the wheel to hub. Said clamping load allows the wheel to transmits torque via friction, in both directions. The lumps bumps and keys are their as a secondary feature or to provide alignment.

You misunderstand what I'm saying with the factor 5. Most cars have 4 or 5 stuf hubs, done up to 100Nm. Replacing that with a single nut means you need very roughly five times the torque for the same clamp force. "Roughly" cause the size of the thread comes into it to.

[Mussels]

And on a normal wheel the bolts are also the keys so transmit the turning force rather than relying on friction. Older cars with single hub nut had splines to transmit the force, Google tells me modern ones still have splines or pins and the nut like old cars is still just to hold the wheel in place.
So why do they need such massive torque when older cars were just hand tight and let physics do the rest? Maybe the wings on the old nuts were important and now they aren't allowed the self tightening won't work properly, or Porsche realised most of their customers are incapable of understanding a left hand thread.

I would guess that it's a function of reducing the cost while making it as idiot proof as possible. F1 cars use a single nut per wheel and I would guess a spline for positive location, although I couldn't be certain on that, so there's clearly nothing wrong with it from an engineering standpoint.

But letting LH threads loose on the great unwashed is a recipe for expensive repairs, I would suggest...

Doesn't virtually every bicycle have them?

Bicycles are a bit different as the spindle doesn't rotate so different forces are at work.

[Asian Boss]

I would guess that it's a function of reducing the cost while making it as idiot proof as possible. F1 cars use a single nut per wheel and I would guess a spline for positive location, although I couldn't be certain on that, so there's clearly nothing wrong with it from an engineering standpoint.

But letting LH threads loose on the great unwashed is a recipe for expensive repairs, I would suggest...

Doesn't virtually every bicycle have them?

Bicycles are a bit different as the spindle doesn't rotate so different forces are at work.

But virtually every bicycle has a left hand / reverse thread.

[Mr. Dazzle]

British Cycling's Olympic bikes don't, not on the wheels at least. They do on one side of the bottom bracket.

I know cause I helped design those too

[cheb]

I thought the old one were run up hand tight and then flogged with a hammer until tight.

Only if your splines were knackered, normally they are only hammered off, I used to give them a gentle tap putting a wheel on just to make sure it was seated properly but that was it.

Ah, thanks. Another misconception nailed.

[mangocrazy]

Er, no it doesn't. It does it because the two components are clamped together by bolts. You're thinking of how brakes work. And it's the hub that transmits torque to the wheel, whether it's under braking or acceleration, rather than the other way about..

The wheel transmits force to the hub via friction, that's the idea at least. The bolts generate an axial load via being stretched when you do them up, that axial force clamps the wheel to hub. Said clamping load allows the wheel to transmits torque via friction, in both directions. The lumps bumps and keys are their as a secondary feature or to provide alignment.

OK, it is down to friction at the molecular level, but that friction is provided by the clamping force. Without the bolts, and the clamping force they provide, you'd have no friction. And I still don't see how a wheel transmits force. The wheel is the recipient of force, not the source of that force.

You misunderstand what I'm saying with the factor 5. Most cars have 4 or 5 stuf hubs, done up to 100Nm. Replacing that with a single nut means you need very roughly five times the torque for the same clamp force. "Roughly" cause the size of the thread comes into it to.

OK, now I get you. But you have to admit your original statement was ambiguously worded.

[Mr. Dazzle]

I thought the old one were run up hand tight and then flogged with a hammer until tight.

Only if your splines were knackered, normally they are only hammered off, I used to give them a gentle tap putting a wheel on just to make sure it was seated properly but that was it.

Ah, thanks. Another misconception nailed.

If you're using a spline/key to drive the torque you don't need much clamp cause you're 'only' trying to stop the wheel coming off laterally.

One a more modern "smooth" wheel you need a lot more clamp because it works primarily through friction. A modern car clamps the wheel against the hub with the equivalent of more than 10 tonnes of force. Smooth wheels clamped up that way are what you want...splines wear out, cost more and allow the wheel the move about more.

[Mr. Dazzle]

And I still don't see how a wheel transmits force. The wheel is the recipient of force, not the source of that force.

Course it transmits force...what would make the car move otherwise?

[mangocrazy]

And I still don't see how a wheel transmits force. The wheel is the recipient of force, not the source of that force.

Course it transmits force...what would make the car move otherwise?

OK, my bad. Of course it transmits force. I was referring back to your earlier statement 'the wheel primarily transmits torque to the hub', regarding it as back to front.

[Mr. Dazzle]

That works both ways too....when you're on the gas the hub transmits to the wheel, if you let off and engine brake the wheel transmits to the hub.

That's why driveshafts have to work in both directions.

[mangocrazy]

That works both ways too....when you're on the gas the hub transmits to the wheel, if you let off and engine brake the wheel transmits to the hub.

That's why driveshafts have to work in both directions.

Don't believe so. The phrase is 'engine braking'. The engine is acting as a brake and is transmitting that drag to the hub and ultimately the wheel. Force in either direction is transmitted to the wheel, not the other way around.

[Mr. Dazzle]

Think about what you mean when you say "transmitting drag". The wheel is driving the engine innit? The wheel is driving the hub which is driving the engine.

Ultimately the road is driving the wheel is driving the.....

As I said, that's why driveshafts have to work both ways.

[mangocrazy]

When you back off the throttle the engine tries to return to its resting state (or tickover, at least); this is a 'drag' or deceleration force that the engine ultimately transmits to the wheels. So no, the wheel is not driving the engine; the engine is still driving the wheel(s) but in a decelerative mode, not an accelerative one. And the drive shafts are not going in reverse, they are merely decelerating. The only time the drive shafts are in reverse motion is when reverse gear is selected. That is why drive shafts have to work both ways.

[Mr. Dazzle]

Again dude...day job The shafts have to be able transmit torque both ways, they can -and do - transmit torque either way without changing spin direction.

Getting a bit off the thread topic here, but the primary source of engine braking is moving gasses through the engine. It takes a torque input into the engine to drive it around, you actively have to force it around. That's where the engine braking comes from, that's also why 2 strokes have very little cause its much easier to move air through them.

Think about what happens if you roll down a hill in gear. You can maintain a set speed on no throttle using the engine braking. The wheels are driving the engine around in that situation, not vice versa.

[mangocrazy]

Compare what it's like to back off the throttle completely in gear, and then do the same out of gear. When in gear you slow down quite rapidly, as the engine is acting as a brake. When in neutral (i.e. out of gear) the engine is removed from the equation and you freewheel for way further than if you were in gear. So it is the engine and whether it is in circuit or not that makes the difference, not some notional wheel 'reverse force'.

[Yambo]

What's this 'deceleration' thing?

There is only really acceleration.